Android Apps – Phone Calls and SMS · Android telephony features you can use from within your app by launching the Phone app with an implicit intent. You can add code to your app

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TableofContentsIntroduction

Lesson1.PhoneCalls

Concepts

1:PhoneCalls

Practicals

1.1:MakingPhoneCalls-Part1


Lesson2.SMSMessages

Concepts

2:SMSMessages

Practicals

2.1:SendingandReceivingSMSMessages-Part1

2.2:SendingandReceivingSMSMessages-Part2

TableofContents

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AndroidApps–PhoneCallsandSMSTheAndroidApps–PhoneCallsandSMScourseincludestwolessonscreatedbytheGoogleDeveloperTrainingteam.Thelessonsaredesignedtobeusedininstructor-ledtraining,butthematerialsarealsoavailableonlineforself-study.

Prerequisites

CompletionoftheentireAndroidDeveloperFundamentalscourse,orequivalentknowledgeJavaprogrammingexperienceKnowledgeofAndroidprogrammingfundamentals

Coursematerials

ThecoursematerialsincludetheconceptuallessonsandpracticalexercisesinthisGitBook.Slidedecksarealsoavailableforoptionalusebyinstructors.

Whatdothelessonscover?

InAndroidPhoneCalls,studentslearnhowtousethetelephonyfeaturesinAndroid.Inthepractical,theycreateanappthatlaunchesthePhoneappwithaphonenumbertomakeacall,andanotherappthatchecksforneededpermissionsandservices,andthenletstheusermakeaphonecallfromwithintheapp.

InAndroidSMSMessages,studentslearnhowtousetheSMSfeaturesinAndroid.Inthepractical,theycreateanappthatlaunchesanSMSmessagingappwithamessage,andanotherappthatchecksforneededpermissions,sendsanSMSmessage,andreceivesSMSmessages.

DevelopedbytheGoogleDeveloperTrainingTeam

Lastupdated:March2017

Introduction

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https://developers.google.com/training/courses/android-fundamentalshttps://drive.google.com/drive/folders/0B5Kg0X0yIQ1PTWJlNG9nSFdFYk0

ThisworkislicensedunderaCreativeCommonsAttribution-NonCommercial4.0InternationalLicense

Introduction

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1:PhoneCallsContents:

ThedifferencebetweendialingandcallingSendinganintentwithaphonenumbertodialMakingacallfromwithinyourappUsingemulatorstotestphonecallsRelatedpracticalLearnmore

Androidmobiledeviceswithtelephone/cellularservicearesuppliedwithaPhoneappformakingcalls,whichincludesadialerfordialingaphonenumber.ThischapterdescribestheAndroidtelephonyfeaturesyoucanusefromwithinyourappbylaunchingthePhoneappwithanimplicitintent.Youcanaddcodetoyourappto:

Dial:LaunchthePhoneapp'sdialerwithaphonenumbertodialacall.Thisisthepreferredtechniqueforappsthatdon'tneedtomonitorthephone'sstate.Call:Requesttheuser'spermissionifnecessary,andmakeaphonecallfromwithintheapp,withtheabilitytomonitorthephone'sstate.Thistechniquekeepstheuserwithinyourapp,withouthavingtonavigatebacktotheapp.ItalsoenablesphonecallsifthePhoneapphasbeendisabledinSettings.

Android'sPhoneappautomaticallyreceivesincomingphonecalls.YoucanusethePhoneStateListenerclasstomonitorthephone'sringingstateandshowtheincomingphonenumber.

Tip:YoucanalsouseabroadcastreceiverinyourapptodetectanincomingcallorSMSmessage.BroadcastreceiversaredescribedinBroadcastReceiversintheAndroidDeveloperFundamentalsCourse.

ThedifferencebetweendialingandcallingYouuseanimplicitintenttolaunchthePhoneappfromyourapp.Youcandothisintwoways:

UseanimplicitIntentandACTION_DIALtolaunchthePhoneappanddisplaythephonenumberinthedialer.

Thisisthesimplestway,withnoneedtorequestpermissionfromtheuser(thePhoneappasksforuserpermissionifneeded).

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https://google-developer-training.gitbooks.io/android-developer-fundamentals-course-concepts/content/Unit%203/73_c_broadcast_receivers.htmlhttps://developer.android.com/reference/android/content/Intent.htmlhttps://developer.android.com/reference/android/content/Intent.html#ACTION_DIAL

Theusercanchangethephonenumberbeforedialingthecall.TheusernavigatesbacktoyourappusingtheBackbuttonafterthecalliscompleted.

UseanimplicitIntentandACTION_CALLtomakethephonecalldirectlyfromwithinyourapp.

Thisactionkeepstheuserwithinyourapp,withouthavingtonavigatebackfromthePhoneapp.Yourcodemustasktheuserforpermissionbeforemakingthecalliftheuserhasn'talreadygrantedpermission.Justasyourappneedstheuser'spermissiontoaccessthecontactsorusethebuilt-incamera,itneedstheuser'spermissiontodirectlyusethephone.Yourappcanmonitorthestateofthephonecall.

FormattingaphonenumberTouseanintenttolaunchthePhoneappwithaphonenumbertodial,yourappneedstoprepareaUniformResourceIdentifier(URI)forthephonenumber.TheURIisastringprefixedby"tel:",forexample,tel:14155551212foraU.S.number(usethecompletenumberasyouwouldenteritonaphonekeypad).Youcanhard-codeaphonenumberinsideyourapp,orprovideanEditTextfieldwheretheusercanenteraphonenumber.

ThePhoneNumberUtilsclassprovidesutilitymethodsfornormalizingandformattingphonenumberstrings.Forexample,toremoveextraneouscharacterssuchasdashesandparentheses,usethenormalizeNumber()method,whichremovescharactersotherthandigitsfromaphonenumberstring.Forexample,thestatementbelownormalizesaphonenumberenteredintoanEditTextviewnamededitText:

StringnormalizedPhoneNumber=PhoneNumberUtils.normalizeNumber(editText.getText().toString());

Note:ThenormalizeNumber()method,addedtoAndroidAPIlevel21(correspondingtoLollipop),isnotavailableinolderversionsoftheAPI.UsetheformatNumber()methodtoformataphonenumberstringforaspecificcountryifthegivennumberdoesn'tincludeacountrycode.YoucanuseLocale.getDefault().getCountry()togetthecurrentcountrysetting,orusetheISO3166-1two-lettercountrycodetospecifyacountrytouse:

StringformattedNumber=PhoneNumberUtils.formatNumber(normalizedPhoneNumber,Locale.getDefault().getCountry());

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https://developer.android.com/reference/android/content/Intent.htmlhttps://developer.android.com/reference/android/content/Intent.html#ACTION_CALLhttps://developer.android.com/reference/android/telephony/PhoneNumberUtils.htmlhttps://developer.android.com/reference/android/telephony/PhoneNumberUtils.html#normalizeNumber(java.lang.String)https://developer.android.com/reference/android/telephony/PhoneNumberUtils.html#normalizeNumber(java.lang.String)https://developer.android.com/reference/android/telephony/PhoneNumberUtils.html#formatNumber(java.lang.String,%20java.lang.String)

UsinganintentwiththephonenumbertodialTouseanintenttolaunchthePhoneapp,useabuttontolettheuserstartthecall.Whentheusertapsthebutton,itsclickhandlerinitiatesthecall.Forexample,asimplelayoutcouldprovideanImageButtonlikethephoneiconinthefigurebelow.

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ThePhoneappopenswiththenumbertobedialed.Theusercanchangethenumberandinitiatethecall.ThePhoneappthenmakesthecall.

InthedialNumber()method,useanimplicitintentwiththeintentactionACTION_DIALtopassthephonenumbertothePhoneappasaURI.

publicvoiddialNumber(){TextViewtextView=(TextView)findViewById(R.id.number_to_call);//Useformatwith"tel:"andphonenumbertocreatephoneNumber.StringphoneNumber=String.format("tel:%s",textView.getText().toString());//Createtheintent.IntentdialIntent=newIntent(Intent.ACTION_DIAL);//Setthedatafortheintentasthephonenumber.dialIntent.setData(Uri.parse(phoneNumber));//Ifpackageresolvestoanapp,sendintent.if(dialIntent.resolveActivity(getPackageManager())!=null){startActivity(dialIntent);}else{Log.e(TAG,"Can'tresolveappforACTION_DIALIntent.");}}

Intheaboveexample,thecodedoesthefollowing:

GetsthetextofthephonenumberfromtextViewwithgetText()andusesitwithString.formattoincludethetel:prefix(forexampletel:14155551212):

...StringphoneNumber=String.format("tel:%s",textView.getText().toString());...

CreatesanimplicitintentwiththeintentactionACTION_DIAL,andsetsthephonenumberasthedatafortheintentusingsetData():

…Intentintent=newIntent(Intent.ACTION_DIAL);//Setthedatafortheintentasthephonenumber.intent.setData(Uri.parse(phoneNumber));...

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https://developer.android.com/reference/android/content/Intent.html#setData(android.net.Uri)

Checksiftheimplicitintentresolvestoanappthatisinstalledonthedevice.

1. Ifitdoes,thecodesendstheintentwithstartActivity(),andthesystemlaunchesthePhoneapp,asshowninthefigurebelow.

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2. Ifitdoesnot,anerrorislogged.

Iftherearenoappsonthedevicethatcanreceivetheimplicitintent,yourappwillcrashwhenitcallsstartActivity().Tofirstverifythatanappexiststoreceivetheintent,callresolveActivity()onyourIntentobjectwithgetPackageManager()togetaPackageManagerinstanceforfindingpackageinformation.TheresolveActivity()methoddeterminesthebestactiontoperformforagivenintent.Iftheresultisnon-null,thereisatleastoneappthatcanhandletheintentandit'ssafetocallstartActivity().

…if(intent.resolveActivity(getPackageManager())!=null){startActivity(intent);}else{Log.e(TAG,"Can'tresolveappforACTION_DIALIntent.");}...

Thisexampleusesahard-codedphonenumber,whichisausefultechniqueforprovidingasupporthotlinenumber,ortheselectedphonenumberforacontact.Inthenextexample,userscanentertheirownnumberstomakecalls.

MakingacallfromwithinyourappTomakeaphonecalldirectlyfromyourapp,dothefollowing:

1. Addpermissionsthatenablemakingacallandreadingthephoneactivity.2. Checktoseeiftelephonyisenabled;ifnot,disablethephonefeature.3. Checktoseeiftheusercontinuestograntpermission,orrequestpermissionifneeded.4. ExtendPhoneStateListener,andregisterthelistenerusingtheTelephonyManager

class.5. UseanimplicitintentwithACTION_CALLtomakethephonecall.

Addingpermissionstothemanifest

Accesstotelephonyinformationispermission-protected.Inordertomakeacall,yourappneedstheCALL_PHONEpermission.Inaddition,inordertomonitorthephonestate,yourappneedstheREAD_PHONE_STATEpermission.Bothmustbedeclaredintheapps'sAndroidManifest.xmlfile.

Addthefollowingtoyourapp'sAndroidManifest.xmlfileafterthefirstline(withthepackagedefinition)andbeforethesection:

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https://developer.android.com/reference/android/content/pm/PackageManager.html#resolveActivity(android.content.Intent,%20int)https://developer.android.com/reference/android/content/Context.html#getPackageManager()https://developer.android.com/reference/android/telephony/PhoneStateListener.htmlhttps://developer.android.com/reference/android/telephony/TelephonyManager.html

...if(isTelephonyEnabled()){Log.d(TAG,getString(R.string.telephony_enabled));//Todo:RegisterthePhoneStateListener....//Todo:Checkforpermissionhere....}else{Toast.makeText(this,R.string.telephony_not_enabled,Toast.LENGTH_LONG).show();Log.d(TAG,getString(R.string.telephony_not_enabled));//Disablethecallbutton.disableCallButton();}...

Checkingandrequestinguserpermission

BeginninginAndroid6.0(APIlevel23),usersgrantpermissionstoappswhiletheappisrunning,notwhentheyinstalltheapp.Thisapproachstreamlinestheappinstallprocess,sincetheuserdoesnotneedtograntpermissionswhentheyinstallorupdatetheapp.Italsogivestheusermorecontrolovertheapp'sfunctionality.However,yourappmustcheckforpermissioneverytimeitdoessomethingthatrequirespermission(suchasmakingaphonecall).IftheuserhasusedtheSettingsapptoturnoffPhonepermissionsfortheapp,yourappcandisplayadialogtorequestpermission.

Tip:Foracompletedescriptionoftherequestpermissionprocess,seeRequestingPermissionsatRunTime.

Followthesestepstocheckforandrequestuserpermissiontomakephonecalls:

1. Atthetopoftheactivitythatmakesaphonecall,andbelowtheactivity'sclassdefinition,defineaconstantvariabletoholdtherequestcode,andsetitto1:

privatestaticfinalintMY_PERMISSIONS_REQUEST_CALL_PHONE=1;

Whytheinteger1?Eachpermissionrequestneedsthreeparameters:thecontext,astringarrayofpermissions,andanintegerrequestCode.TherequestCodeisanintegerattachedtotherequest,anditcanbeanyintegerthatsuitsyourusecase.Whenaresultreturnsintheactivity,itcontainsthiscodeandusesittodifferentiatemultiplepermissionresultsfromeachother.

2. Intheactivitythatmakesaphonecall,createaprivatemethodcheckForPhonePermission()thatreturnsvoid.

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https://developer.android.com/training/permissions/requesting.html

privatevoidcheckForPhonePermission(){if(ActivityCompat.checkSelfPermission(this,Manifest.permission.CALL_PHONE)!=PackageManager.PERMISSION_GRANTED){//Permissionnotyetgranted.UserequestPermissions().Log.d(TAG,getString(R.string.permission_not_granted));ActivityCompat.requestPermissions(this,newString[]{Manifest.permission.CALL_PHONE},MY_PERMISSIONS_REQUEST_CALL_PHONE);}else{//Permissionalreadygranted.}

3. Intheactivity'sonCreate()method,callthemethodtoperformthetelephonycheck:

...if(isTelephonyEnabled()){//Checkforphonepermission.checkForPhonePermission();//Todo:RegisterthePhoneStateListener.}else{...

NotethefollowingaboutthecheckForPhonePermission()method:

ThecodeusescheckSelfPermission()todeterminewhetheryourapphasbeengrantedaparticularpermissionbytheuser.Ifpermissionhasnotbeengranted,thecodeusestherequestPermissions()methodtodisplayastandarddialogfortheusertograntpermission.TherequestPermissions()methodneedsthreeparameters:thecontext,astringarrayofpermissions,andthepredefinedintegerrequestCode.WhenyourappcallsrequestPermissions(),thesystemshowsastandardpermissiondialogtotheuser,asshowninthefigurebelow.Yourappcan'tconfigureoralterthedialog.

Tip:Ifyouwanttoprovideanyinformationorexplanationtotheuser,youmustdothatbeforeyoucallrequestPermissions(),asdescribedinExplainwhytheappneedspermissions.

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https://developer.android.com/reference/android/support/v4/content/ContextCompat.html#checkSelfPermission(android.content.Context,%20java.lang.String)https://developer.android.com/reference/android/support/v4/app/ActivityCompat.html#requestPermissions(android.app.Activity,%20java.lang.String[],%20int)https://developer.android.com/reference/android/support/v4/app/ActivityCompat.html#requestPermissions(android.app.Activity,%20java.lang.String[],%20int)https://developer.android.com/training/permissions/requesting.html#explain

Whentheuserrespondstotherequestpermissiondialog,thesysteminvokesyourapp'sonRequestPermissionsResult()method,passingittheuserresponse.Overridethatmethodtofindoutwhetherthepermissionwasgranted:

@OverridepublicvoidonRequestPermissionsResult(intrequestCode,Stringpermissions[],int[]grantResults){switch(requestCode){caseMY_PERMISSIONS_REQUEST_CALL_PHONE:{if(permissions[0].equalsIgnoreCase(Manifest.permission.CALL_PHONE)&&grantResults[0]==PackageManager.PERMISSION_GRANTED){//Permissionwasgranted.}else{//Permissiondenied.Stoptheapp.Log.d(TAG,getString(R.string.failure_permission));Toast.makeText(this,getString(R.string.failure_permission),Toast.LENGTH_SHORT).show();//DisablethecallbuttondisableCallButton();}}}}

TheabovecodesnippetshowsaswitchstatementbasedonthevalueofrequestCode,withonecasetocheckifthepermissionistheoneyoudefinedasMY_PERMISSIONS_REQUEST_CALL_PHONE.

Tip:Ithelpstouseaswitchstatementsothatyoucanaddmorerequeststotheapp.

Theuser'sresponsetotherequestdialogisreturnedinthepermissionsarray(index0ifonlyonepermissionisrequestedinthedialog).Comparethistothecorrespondinggrantresult,whichiseitherPERMISSION_GRANTEDorPERMISSION_DENIED.

Iftheuserdeniesapermissionrequest,yourappshouldtakeappropriateaction.Forexample,yourappmightdisablethefunctionalitythatdependsonthispermission(suchasthecallbutton)andshowadialogexplainingwhyitcouldnotperformit.

ExtendingandregisteringPhoneStateListener

PhoneStateListenermonitorschangesinspecifictelephonystatessuchasringing,off-hook,andidle.TousePhoneStateListener:

ImplementalistenerclassthatextendsPhoneStateListener,andoverrideits

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https://developer.android.com/reference/android/support/v4/app/ActivityCompat.OnRequestPermissionsResultCallback.html#onRequestPermissionsResult(int,%20java.lang.String[],%20int[])https://developer.android.com/reference/android/telephony/PhoneStateListener.html

onCallStateChanged()method.IntheonCallStateChanged()method,provideactionsbasedonthephonestate.RegisterthelistenerusingtheTelephonyManagerclass,whichprovidesaccesstoinformationaboutthetelephonyservicesonthedevice.

Implementingalistener

CreateaprivateclassinyouractivitythatextendsPhoneStateListener:

privateclassMyPhoneCallListenerextendsPhoneStateListener{...}

Withinthisclass,implementtheonCallStateChanged()methodofPhoneStateListenertotakeactionsbasedonthephonestate.ThecodebelowusesaswitchstatementwithconstantsoftheTelephonyManagerclasstodeterminewhichofthreestatesthephoneisin:CALL_STATE_RINGING,CALL_STATE_OFFHOOK,andCALL_STATE_IDLE:

@OverridepublicvoidonCallStateChanged(intstate,StringincomingNumber){switch(state){caseTelephonyManager.CALL_STATE_RINGING://Incomingcallisringing.break;caseTelephonyManager.CALL_STATE_OFFHOOK://Phonecallisactive--offthehook.break;caseTelephonyManager.CALL_STATE_IDLE://Phoneisidlebeforeandafterphonecall....break;default://Mustbeanerror.Raiseanexceptionorjustlogit.break;}}

Provideactionsforphonestates

Addtheactionsyouwanttotakebasedonthephonestates.Forexample,yourcodecanlogamessagefortestingpurposes,anddisplayatoasttotheuser.TheCALL_STATE_RINGINGstateincludestheincomingphonenumber,whichyourcodecanshowinatoast.

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https://developer.android.com/reference/android/telephony/PhoneStateListener.html#onCallStateChanged(int,%20java.lang.String)https://developer.android.com/reference/android/telephony/TelephonyManager.htmlhttps://developer.android.com/reference/android/telephony/PhoneStateListener.htmlhttps://developer.android.com/reference/android/telephony/PhoneStateListener.html#onCallStateChanged(int,%20java.lang.String)https://developer.android.com/reference/android/telephony/TelephonyManager.html

ThephoneisintheCALL_STATE_IDLEstateuntilacallisstarted.ThephonestatechangestoCALL_STATE_OFFHOOKinordertomaketheconnectionandstaysinthestateforthedurationofthecall.ThephonestatereturnstotheCALL_STATE_IDLEstateafterthecallfinishesorifthecallisdeniedornotcompleted.

YourappresumeswhenthestatechangesbacktotheCALL_STATE_IDLEstate.

Tip:AnapprunningonAndroidversionspriortoKitKat(version19)doesn'tresumewhenthephonestatereturnstoCALL_STATE_IDLEfromCALL_STATE_OFFHOOKattheendofacall.ThecodebelowsetstheflagreturningFromOffHooktotruewhenthestateisCALL_STATE_OFFHOOK,sothatwhenthestateisbacktoCALL_STATE_IDLE,youcanusetheflagtocatchtheend-of-callandrestarttheapp'sactivity.

privateclassMyPhoneCallListenerextendsPhoneStateListener{privatebooleanreturningFromOffHook=false;

@OverridepublicvoidonCallStateChanged(intstate,StringincomingNumber){//Defineastringforthemessagetouseinatoast.Stringmessage=getString(R.string.phone_status);switch(state){caseTelephonyManager.CALL_STATE_RINGING://Incomingcallisringingmessage=message+getString(R.string.ringing)+incomingNumber;Toast.makeText(MainActivity.this,message,Toast.LENGTH_SHORT).show();Log.i(TAG,message);break;caseTelephonyManager.CALL_STATE_OFFHOOK://Phonecallisactive--offthehookmessage=message+getString(R.string.offhook);Toast.makeText(MainActivity.this,message,Toast.LENGTH_SHORT).show();Log.i(TAG,message);returningFromOffHook=true;break;caseTelephonyManager.CALL_STATE_IDLE://Phoneisidlebeforeandafterphonecall.//Ifrunningonversionolderthan19(KitKat),//restartactivitywhenphonecallends.message=message+getString(R.string.idle);Toast.makeText(MainActivity.this,message,Toast.LENGTH_SHORT).show();Log.i(TAG,message);if(returningFromOffHook){//Noneedtodoanythingif>=versionKif(Build.VERSION.SDK_INT<Build.VERSION_CODES.KITKAT){Log.i(TAG,getString(R.string.restarting_app));//Restarttheapp.

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Intentintent=getPackageManager().getLaunchIntentForPackage(.getPackageName());i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);startActivity(i);}}break;default:message=message+"Phoneoff";Toast.makeText(MainActivity.this,message,Toast.LENGTH_SHORT).show();Log.i(TAG,message);break;}}}

Registeringyourlistener

RegisterthelistenerobjectusingtheTelephonyManagerclass:

UsegetSystemService()withContext.TELEPHONY_SERVICE.UsetelephonyManager.listen()withthePhoneStateListenersettotheLISTEN_CALL_STATE.

Agoodplacetodothisisintheactivity'sonCreate()methodrightaftercheckingforphonepermission,whichisafterensuringthattelephonyisenabled.Followthesesteps:

1. Atthetopoftheactivity,defineavariableforthePhoneStateListener:

privateMyPhoneCallListenermListener;

2. IntheonCreate()method,addthefollowingcodeaftercheckingfortelephonyandpermission:

...if(isTelephonyEnabled()){...checkForPhonePermission();//RegisterthePhoneStateListenertomonitorphoneactivity.mListener=newMyPhoneCallListener();telephonyManager.listen(mListener,PhoneStateListener.LISTEN_CALL_STATE);}else{...

3. Youmustalsounregisterthelistenerintheactivity'sonDestroy()method.Thismethodisusuallyimplementedtofreeresourceslikethreadsthatareassociatedwithan

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https://developer.android.com/reference/android/telephony/TelephonyManager.htmlhttps://developer.android.com/reference/android/content/Context.html#getSystemService(java.lang.String)https://developer.android.com/reference/android/telephony/PhoneStateListener.htmlhttps://developer.android.com/reference/android/telephony/PhoneStateListener.htmlhttps://developer.android.com/reference/android/app/Activity.html#onDestroy()

activity,sothatadestroyedactivitydoesnotleavesuchthingsaroundwhiletherestofitsapplicationisstillrunning.OverridetheonDestroy()methodbyaddingthefollowingcode:

@OverrideprotectedvoidonDestroy(){super.onDestroy();if(isTelephonyEnabled()){telephonyManager.listen(mListener,PhoneStateListener.LISTEN_NONE);}}

Usinganimplicitintenttomakethecall

TolaunchthePhoneappandstartthecall:

UseabuttoninthelayoutwithanonClickmethodsuchascallNumber().InthecallNumber()method,createanimplicitintentwiththeintentactionACTION_CALL.SetthephonenumberasthedatafortheintentwithsetData().

ThefollowingisansamplecallNumber()method:

publicvoidcallNumber(Viewview){EditTexteditText=(EditText)findViewById(R.id.editText_main);//Useformatwith"tel:"andphonenumbertocreatephoneNumber.StringphoneNumber=String.format("tel:%s",editText.getText().toString());//Createtheintent.IntentcallIntent=newIntent(Intent.ACTION_CALL);//Setthedatafortheintentasthephonenumber.callIntent.setData(Uri.parse(phoneNumber));//Ifpackageresolvestoanapp,checkforphonepermission,//andsendintent.if(callIntent.resolveActivity(getPackageManager())!=null){checkForPhonePermission();startActivity(callIntent);}else{Log.e(TAG,"Can'tresolveappforACTION_CALLIntent.");}}

Asinthepreviousexampleforpassinganumberfordialing,youuseastringforthephonenumberwiththetel:prefix.

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Iftheimplicitintentresolvestoaninstalledapp,usethecheckForPhonePermission()methodyoucreatedpreviouslytochecktoseeiftheappstillhaspermissiontomakethecall.Youmustcheckforthatpermissioneverytimeyouperformanoperationthatrequiresit,becausetheuserisalwaysfreetorevokethepermission.Eveniftheappusedthephoneaminuteago,itcan'tassumeitstillhasthatpermissionaminutelater.

UsingemulatorstotestphonecallfunctionalityIfyoudon'thavecellularserviceonyourdevice,ortelephonyisnotenabled,youcantesttheappusingtwoemulatorinstances—oneemulatorinstancecallstheotherone.

1. LaunchanemulatordirectlyfromtheAVDManagerbychoosingTools>Android>AVDManager.

2. Double-clickapredefineddevice.Notethenumberthatappearsintheemulator'swindowtitleonthefarright,asshowninthefigurebelowas#1(5556).Thisistheportnumberoftheemulatorinstance.

3. OpentheAndroidStudioprojectforthephone-callingapp.4. Runthephone-callingapp,butchooseanotheremulatorfromthelist—nottheonethat

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isalreadyrunning.5. Inthephone-callingapp,insteadofarealphonenumber,entertheportnumber(asin

5556),andclickthecallbutton.Theemulatorshowsthephonecallstartingup,asshowninthefigurebelow.

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Theotheremulatorinstanceshouldnowbereceivingthecall,asshowninthefigurebelow:

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6. ClickAnswerorDismissontheemulatorreceivingthecall,.AfteryouclickAnswer,alsoclicktheredHang-upbuttontoendthecall.

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RelatedpracticalMakingPhoneCalls-Part1MakingPhoneCalls-Part2

LearnmoreAndroidDeveloperReference:

CommonIntentsTelephonyManagerPhoneStateListenerRequestingPermissionsatRunTimecheckSelfPermissionRunAppsontheAndroidEmulatorIntentsandIntentFiltersIntent

StackOverflow:HowtoformataphonenumberusingPhoneNumberUtils?Howtomakephonecallusingintentinandroid?RingingmyselfusingandroidemulatorFakeIncomingCallAndroidSimulatingincomingcallorsmsinAndroidStudio

OtherUser(beginner)tutorial:HowtoMakePhoneCallswithAndroidDeveloperVideo:HowtoMakeaPhoneCall

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https://developer.android.com/guide/components/intents-common.htmlhttps://developer.android.com/reference/android/telephony/TelephonyManager.htmlhttps://developer.android.com/reference/android/telephony/PhoneStateListener.htmlhttps://developer.android.com/training/permissions/requesting.htmlhttps://developer.android.com/reference/android/support/v4/content/ContextCompat.html#checkSelfPermission(android.content.Context,%20java.lang.String)https://developer.android.com/studio/run/emulator.htmlhttp://developer.android.com/guide/components/intents-filters.htmlhttp://developer.android.com/reference/android/content/Intent.htmlhttp://stackoverflow.com/questions/6106859/how-to-format-a-phone-number-using-phonenumberutilshttp://stackoverflow.com/questions/4275678/how-to-make-phone-call-using-intent-in-androidhttp://stackoverflow.com/questions/2577785/ringing-myself-using-android-emulatorhttp://stackoverflow.com/questions/4964703/fake-incoming-call-androidhttp://stackoverflow.com/questions/27638462/simulating-incoming-call-or-sms-in-android-studiohttp://www.beginandroid.com/phonecall.shtmlhttps://youtu.be/3PHDcQOGFtg

1.1:Part1-MakingPhoneCallsContents:

WhatyoushouldalreadyKNOWWhatyouwillLEARNWhatyouwillDOAppoverviewTask1:SendanintentwiththephonenumbertodialTask2:Makeaphonecallfromwithinanapp

Androidmobiledeviceswithtelephone/cellularservicearepre-installedwithaPhoneappformakingcalls,whichincludesadialerfordialinganyphonenumber.YouuseanimplicitIntenttolaunchthePhoneappfromyourapp.Youhavetwochoices:

UseACTION_DIALtolaunchthePhoneappindependentlyfromyourappwiththephonenumberdisplayedinthedialer.TheuserthenmakesthecallinthePhoneapp.Thisisthepreferredactionforappsthatdon'thavetomonitorthephone'sstate.UseACTION_CALLtolaunchthePhoneappinthecontextofyourapp,makingthecalldirectlyfromyourapp,andmonitoringthephonestate.Thisactionkeepstheuserwithinyourapp,withouthavingtonavigatebacktotheapp.Yourappmustrequestpermissionfromtheuserbeforemakingthecalliftheuserhasn'talreadygrantedpermission.

WhatyoushouldalreadyKNOWFromthepreviouschapters,youshouldbeableto:

CreateandruninteractiveappsinAndroidStudio.WorkwithXMLlayouts.Createanimplicitintenttoperformanactionusinganotherapp.

WhatyouwillLEARNInthispractical,youwilllearnto:

PassaphonenumbertothePhoneapp'sdialer.Performaphonecallwithinyourapp.Testtoseeiftelephonyservicesareenabled.


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https://developer.android.com/reference/android/content/Intent.htmlhttps://developer.android.com/reference/android/content/Intent.html#ACTION_DIALhttps://developer.android.com/reference/android/content/Intent.html#ACTION_CALL

Checkforcallingpermission,andrequestpermissionifrequired.

WhatyouwillDOInthispractical,youwill:

CreateanappthatusesanimplicitintenttolaunchthePhoneapp.Createanotherappthatmakesphonecallsfromwithintheapp.Testtoseeiftelephonyservicesareenabledbeforeenablingtheapp.Checkforcallingpermission,whichcanchangeatanytime.Requestpermissionfromtheuser,ifnecessary,tomakethecall.

AppoverviewYouwillcreatetwoapps:

PhoneCallDial:AbasicappthatusesanimplicitintenttolaunchthePhoneappwithahard-codedphonenumberfordialing.ThePhoneappmakesthecall.Youcouldusethistechniquetoprovideaone-buttondialertocustomsupport.Inthislessonyouwillbuildalayout,showninthefigurebelow.ItincludesaTextViewwithahard-codedphonenumber,andanImageButtonwithanicontolaunchthePhoneappwiththatphonenumberinitsdialer.


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https://github.com/google-developer-training/android-fundamentals-phone-sms/tree/master/PhoneCallDial


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PhoneCallingSample:Anappthatsecurespermission,usesanimplicitintenttomakeaphonecallfromtheapp,andusestheTelephonyManagerclasstomonitorthephone'sstate.Youwouldusethistechniqueifyouwanttokeeptheuserwithinyourapp,withouthavingtonavigatebacktotheapp.Inthislesson,youmodifytheabovelayouttouseanEditTextsothatuserscanenterthephonenumber.Thelayoutlookslikethefigurebelow:


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https://github.com/google-developer-training/android-fundamentals-phone-sms/tree/master/PhoneCallingSamplehttps://developer.android.com/reference/android/telephony/TelephonyManager.html


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Task1.SendanintentwiththephonenumbertodialInthistaskyouwillcreateanappthatusesanimplicitintenttolaunchthePhoneapptodialagivenphonenumber.Tosendthatintent,yourappneedstoprepareaUniformResourceIdentifier(URI)thatisprefixedby"tel:"(forexampletel:14155551212).

1.1Createtheappandlayout

1. CreateaprojectusingtheEmptyActivitytemplateandcallitPhoneCallDial.

2. Addaniconforthecallbuttonbyfollowingthesesteps:

i. Selectthedrawable/folderintheProject:AndroidviewandchooseFile>New>VectorAsset.

ii. ClicktheAndroidiconnextto"Icon:"tochooseanicon.Tofindahandseticon,chooseCommunicationintheleftcolumn.

iii. Selecttheicon,clickOK,clickNext,andthenclickFinish.

3. Opentheactivity_main.xmllayoutfile.

i. ChangetherootviewtoRelativeLayout.ii. Inthe"HelloWorld"TextViewelement,removethelayout_constraintattributes,if

theyarepresent.iii. ChangetheTextViewtoshowadummycontactname,asiftheapphadretrieved

thenamefromacontactsdatabaseandassignedittoaTextView:

4. Extractthestringsanddimensionsintoresources:

24sp:contact_text_sizeforthetextsize.JaneDoe:contact_nameforthetext.

5. AddanotherTextViewforthephonenumber:


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Youwillusetheandroid:idnumber_to_calltoretrievethephonenumber.

6. Afteraddingahard-codedphonenumberstring,extractitintotheresourcephone_number.

7. AddanImageButtonforinitiatingthecall:

Usethevectorassetyouaddedpreviously(forexampleic_call_black_24dpforaphonehandseticon)fortheandroid:srcattribute.Youwillusetheandroid:id@phone_icontorefertothebuttonfordialingthephone.

ThedialNumbermethodreferredtointheandroid:onClickattributeremainshighlighteduntilyoucreatethismethodintheMainActivity,whichyoudointhenextstep.

8. Afteraddingahard-codedcontentdescription,extractitintothestringresourcemake_a_call.

9. ClickdialNumberintheandroid:onClickattribute,clicktheredlightbulbthatappears,andthenselectCreatedialNumber(View)in'MainActivity'.AndroidStudioautomaticallycreatesthedialNumber()methodinMainActivityaspublic,returningvoid,withaViewparameter.ThismethodiscalledwhentheusertapstheImageButton.

publicvoiddialNumber(Viewview){}


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Thelayoutshouldlooksomethinglikethefigurebelow.


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ThefollowingisthecompletecodefortheXMLlayoutinactivity_main.xml,includingcomments:

1.2EdittheonClickmethodinMainActivity

1. InMainActivity,defineaconstantforthelogtag.

publicstaticfinalStringTAG=MainActivity.class.getSimpleName();

2. InsidethedialNumber()methodcreatedintheprevioussection,createareferencetothenumber_to_callTextView:

publicvoiddialNumber(Viewview){TextViewtextView=(TextView)findViewById(R.id.number_to_call);...


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3. TocreatethephonenumberURIstringphoneNumber,getthephonenumberfromtextViewanduseitwithString.formattoincludethetel:prefix:

...//Useformatwith"tel:"andphonenumbertocreatemPhoneNum.StringphoneNumber=String.format("tel:%s",textView.getText().toString());...

4. Defineanimplicitintent(dialIntent)withtheintentactionACTION_DIAL,andsetthephoneNumberasdatafortheintent:

...//Createtheintent.IntentdialIntent=newIntent(Intent.ACTION_DIAL);//Setthedatafortheintentasthephonenumber.dialIntent.setData(Uri.parse(phoneNumber));...

5. Toverifythatanappexiststoreceivetheintent,callresolveActivity()onyourIntentobjectwithgetPackageManager()togetaPackageManagerinstanceforfindingpackageinformation.TheresolveActivity()methoddeterminesthebestactiontoperformforagivenintent.Iftheresultisnon-null,thereisatleastoneappthatcanhandletheintentandit'ssafetocallstartActivity().

...//Ifpackageresolvestoanapp,sendintent.if(dialIntent.resolveActivity(getPackageManager())!=null){startActivity(dialIntent);}else{Log.e(TAG,"Can'tresolveappforACTION_DIALIntent.");}...

Thefullmethodshouldnowlooklikethefollowing:


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https://developer.android.com/reference/android/content/pm/PackageManager.html#resolveActivity(android.content.Intent,%20int)https://developer.android.com/reference/android/content/Context.html#getPackageManager()

publicvoiddialNumber(){TextViewtextView=(TextView)findViewById(R.id.number_to_call);//Useformatwith"tel:"andphonenumbertocreatephoneNumber.StringphoneNumber=String.format("tel:%s",textView.getText().toString());//Createtheintent.IntentdialIntent=newIntent(Intent.ACTION_DIAL);//Setthedatafortheintentasthephonenumber.dialIntent.setData(Uri.parse(phoneNumber));//Ifpackageresolvestoanapp,sendintent.if(dialIntent.resolveActivity(getPackageManager())!=null){startActivity(dialIntent);}else{Log.e(TAG,"Can'tresolveappforACTION_DIALIntent.");}}

1.3Runtheapp

Youcanruntheapponeitheranemulatororadevice:

1. Clickortapthephoneicon.Thedialershouldappearwiththephonenumberreadytouse,asshowninthefigurebelow:


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2. Thephone_numberstringholdsafixednumber(1-415-555-1212).YoucanchangethenumberinthePhoneapp'sdialerbeforecalling.

3. UsetheBackbuttontoreturntotheapp.YoumayneedtotaporclickittwoorthreetimestonavigatebackwardsfromthePhoneapp'sdialerandFavoriteslist.

Solutioncode

AndroidStudioproject:PhoneCallDial

Task2.MakeaphonecallfromwithinanappInthistaskyouwillcopythePhoneCallDialappfromtheprevioustask,refactorandrenameittoPhoneCallingSample,andmodifyitslayoutandcodetocreateanappthatenablesausertoenteraphonenumberandperformthephonecallfromwithinyourapp.

Inthefirststepyouwilladdthecodetomakethecall,buttheappwillworkonlyiftelephonyisenabled,andiftheapp'spermissionforPhoneissetmanuallyinSettingsonthedeviceoremulator.

Insubsequentstepsyouwilldoawaywithsettingthispermissionmanuallybyrequestingphonepermissionfromtheuserifitisnotalreadygranted.Youwillalsoaddatelephonychecktodisplayamessageiftelephonyisnotenabledandcodetomonitorthephonestate.

2.1Createtheappandaddpermission

1. CopythePhoneCallDialprojectfolder,renamethefoldertoPhoneCallingSample,andrefactortheapptopopulatethenewnamethroughouttheappproject.(SeetheAppendixforinstructionsoncopyingaproject.)

2. AddthefollowingpermissiontotheAndroidManifest.xmlfileafterthefirstline(withthepackagedefinition)andbeforethesection:

Yourappcan'tmakeaphonecallwithouttheCALL_PHONEpermissionlineinAndroidManifest.xml.ThispermissionlineenablesasettingfortheappintheSettingsappthatgivestheuserthechoiceofallowingordisallowinguseofthephone.(Inthenexttaskyouwilladdawayfortheusertograntthatpermissionfromwithintheapp.)

2.2Createtheapplayout


42

https://github.com/google-developer-training/android-fundamentals-phone-sms/tree/master/PhoneCallDialhttps://google-developer-training.gitbooks.io/android-developer-fundamentals-course-practicals/content/appendix_utilities.html

1. Openactivity_main.xmltoeditthelayout.2. Removethecontact_nameTextView,andreplacethenumber_to_callTextViewwith

thefollowingEditTextview:

3. Afteraddingahard-codedstringfortheandroid:hintattribute,extractitintothestringresourceenter_phone,andnotethefollowing:

Youwillusetheandroid:idfortheEditTextviewinyourcodetoretrievethephonenumber.TheEditTextviewusestheandroid:inputTypeattributesetto"phone"foraphone-stylenumerickeypad.

4. ChangetheImageButtonasfollows:

i. Changetheandroid:layout_below,android:layout_toRightOf,andandroid:layout_toEndOfattributestorefertoeditText_main.

ii. Addtheandroid:visibilityattributesettovisible.YouwillcontrolthevisibilityofthisImageButtonfromyourcode.

iii. Changetheandroid:onClickmethodtocallNumber.ThiswillremainhighlighteduntilyouaddthatmethodtoMainActivity.

5. AddthefollowingButtonattheendofthelayout,beforetheendingtag:


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6. Afteraddingahard-codedstring"Retry"fortheandroid:contentDescriptionattribute,extractitintothestringresourceretry,andthenreplacethehard-codedstringintheandroid:textattributeto"@string/retry".

7. Notethefollowing:Youwillrefertothetheandroid:idbutton_retryinyourcode.Makesureyouincludetheandroid:visibilityattributesetto"invisible".Itshouldappearonlyiftheappdetectsthattelephonyisnotenabled,oriftheuserpreviouslydeniedphonepermissionwhentheapprequestedit.

Yourapp'slayoutshouldlooklikethefollowingfigure(thebutton_retryButtonisinvisible):


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2.3ChangetheonClickmethodinMainActivity

1. InMainActivity,refactorandrenamethedialNumber()methodtocallitcallNumber().2. Changethefirststatement,whichreferredtoaTextView,touseanEditTextview:

publicvoidcallNumber(Viewview){EditTexteditText=(EditText)findViewById(R.id.editText_main);...}

3. ChangethenextstatementtogetthephonenumberfromtheEditTextview(editText)tocreatethephonenumberURIstringphoneNumber:

//Useformatwith"tel:"andphonenumbertocreatephoneNumber.StringphoneNumber=String.format("tel:%s",editText.getText().toString());

4. Beforetheintent,addcodetoshowalogmessageandatoastmessagewiththephonenumber:

//Logtheconcatenatedphonenumberfordialing.Log.d(TAG,"PhoneStatus:DIALING:"+phoneNumber);Toast.makeText(this,"PhoneStatus:DIALING:"+phoneNumber,Toast.LENGTH_LONG).show();

5. Extract"PhoneStatus:DIALING:"toastringresource(dial_number).ReplacetheseconduseofthestringintheToast.makeText()statementtogetString(R.string.dial_number).

6. RefactorandrenamethedialIntentimplicitintenttocallIntent,andreplaceACTION_DIALwithACTION_CALL.Asaresult,thestatementsshouldnowlooklikethis:

...//Createtheintent.IntentcallIntent=newIntent(Intent.ACTION_CALL);//Setthedatafortheintentasthephonenumber.callIntent.setData(Uri.parse(phoneNumber));//Ifpackageresolvestoanapp,sendintent.if(callIntent.resolveActivity(getPackageManager())!=null){startActivity(callIntent);}else{Log.e(TAG,"Can'tresolveappforACTION_CALLIntent.");}...

Thefullmethodshouldnowlooklikethefollowing:


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publicvoidcallNumber(){EditTexteditText=(EditText)findViewById(R.id.editText_main);//Useformatwith"tel:"andphonenumbertocreatephoneNumber.StringphoneNumber=String.format("tel:%s",editText.getText().toString());//Logtheconcatenatedphonenumberfordialing.Log.d(TAG,getString(R.string.dial_number)+phoneNumber);Toast.makeText(this,getString(R.string.dial_number)+phoneNumber,Toast.LENGTH_LONG).show();//Createtheintent.IntentcallIntent=newIntent(Intent.ACTION_CALL);//Setthedatafortheintentasthephonenumber.callIntent.setData(Uri.parse(phoneNumber));//Ifpackageresolvestoanapp,sendintent.if(callIntent.resolveActivity(getPackageManager())!=null){startActivity(callIntent);}else{Log.e(TAG,"Can'tresolveappforACTION_CALLIntent.");}}

2.4Runtheapp

Whenyouruntheapp,theappmaycrashwiththefollowingscreendependingonwhetherthedeviceoremulatorhasbeenpreviouslysettoallowtheapptomakephonecalls:


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InsomeversionsofAndroid,thispermissionisturnedonbydefault.Inothers,thispermissionisturnedoffbydefault.

Tosettheapp'spermissiononadeviceoremulatorinstance,performthefunctionthatauserwouldperform:chooseSettings>Apps>PhoneCallingSample>Permissionsonthedeviceoremulator,andturnonthePhonepermissionfortheapp.SincetheusercanturnonoroffPhonepermissionatanytime,youhavetoaddacheckinyourappforthispermission,andrequestitfromtheuserifrequired.Youwilldothisinthenexttask.

Ifyoudon'thavecellularserviceonyourdevice,oriftelephonyisnotenabled,youcantesttheappusingtwoemulatorinstances—oneemulatorinstancecallstheotherone.Followthesesteps:

1. TolaunchanemulatordirectlyfromtheAVDManager,chooseTools>Android>AVDManager.

2. Double-clickapredefineddevice.Notethenumberthatappearsintheemulator'swindowtitleonthefarright,asshowninthefigurebelowas#1(5556).Thisistheport

numberoftheemulatorinstance.

3. OpentheAndroidStudioprojectfortheapp,ifitisn'talreadyopen.


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4. Runtheapp,butchooseanotheremulator—nottheonethatisalreadyrunning.AndroidStudiolaunchestheotheremulator.

5. Intheapp,entertheportnumberoftheotheremulatorratherthanarealphonenumber.

6. Clickthecallbuttonintheapp.Theemulatorshowsthephonecallstartingup,asshowninthefigurebelow.


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Theotheremulatorinstanceshouldnowbereceivingthecall,asshowninthefigurebelow:


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7. ClickAnswerorDismissontheemulatorreceivingthecall.IfyouclickAnswer,alsoclicktheredHang-upbuttontoendthecall.


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EndofPart1-ContinuewithPart2


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1.2:Part2-MakingPhoneCallsContents:

Task3:CheckfortelephonyserviceandrequestpermissionTask4:MonitorthephonestateCodingchallengeSummaryRelatedconceptLearnmore

Task3.CheckfortelephonyserviceandrequestpermissionIftelephonyfeaturesarenotenabledforadevice,yourappshoulddetectthatanddisablethephonefeatures.

Inaddition,yourappmustalwaysgetpermissiontouseanythingthatisnotpartoftheappitself.IntheprevioustaskyouaddedthefollowingpermissiontotheAndroidManifest.xmlfile:

ThisstatementenablesapermissionsettingforthisappinSettings.TheusercanallowordisallowthispermissionatanytimeinSettings.Youcanaddcodetorequestpermissioniftheuserhasturnedoffphonepermission.

3.1Checkiftelephonyservicesareenabled

1. OpentheAndroidStudioprojectforthePhoneCallingSampleapp,ifitisn'talreadyopen.

2. AtthetopofMainActivitybelowtheclassdefinition,defineavariablefortheTelephonyManagerclassobject:

privateTelephonyManagermTelephonyManager;

3. AddthefollowingstatementtoonCreate()methodinMainActivitytousethestringconstantTELEPHONY_SERVICEwithgetSystemService()andassignitto


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https://developer.android.com/reference/android/telephony/TelephonyManager.html

mTelephonyManager.Thisgivesyouaccesstosomeofthetelephonyfeaturesofthedevice.

@OverrideprotectedvoidonCreate(BundlesavedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);//Createatelephonymanager.mTelephonyManager=(TelephonyManager)getSystemService(TELEPHONY_SERVICE);

4. CreateamethodinMainActivitytocheckiftelephonyisenabled:

privatebooleanisTelephonyEnabled(){if(mTelephonyManager!=null){if(mTelephonyManager.getSimState()==TelephonyManager.SIM_STATE_READY){returntrue;}}returnfalse;}

5. CalltheabovemethodintheonCreate()method,rightafterassigningmTelephonyManager,inanifstatementtotakeactioniftelephonyisenabled.Theactionshouldbetologamessage(toshowthattelephonyisenabled),andincludeacommentaboutcheckingpermission,whichyouwilladdinthenextstep.Iftelephonyisnotenabled,displayatoastmessage,logamessage,anddisablethecallbutton:

@OverrideprotectedvoidonCreate(BundlesavedInstanceState){...mTelephonyManager=(TelephonyManager)getSystemService(TELEPHONY_SERVICE);if(isTelephonyEnabled()){Log.d(TAG,"Telephonyisenabled");//ToDo:Checkforphonepermission.//ToDo:RegisterthePhoneStateListener.}else{Toast.makeText(this,"TELEPHONYNOTENABLED!",Toast.LENGTH_LONG).show();Log.d(TAG,"TELEPHONYNOTENABLED!");//DisablethecallbuttondisableCallButton();}}


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6. Extractthehard-codedstringsintheabovecodetostringresources:

"Telephonyisenabled":telephony_enabled"TELEPHONYNOTENABLED!":telephony_not_enabled

7. CreatethedisableCallButton()methodinMainActivity,andcodeto:

Displayatoasttonotifytheuserthatthephonefeatureisdisabled.Findandthensetthecallbuttontobeinvisiblesothattheusercan'tmakeacall.Iftelephonyisenabled(butthephonepermissionhadnotbeengranted),settheRetrybuttontobevisible,sothattheusercanstarttheactivityagainandallowpermission.

privatevoiddisableCallButton(){Toast.makeText(this,"Phonecallingdisabled",Toast.LENGTH_LONG).show();ImageButtoncallButton=(ImageButton)findViewById(R.id.phone_icon);callButton.setVisibility(View.INVISIBLE);if(isTelephonyEnabled()){ButtonretryButton=(Button)findViewById(R.id.button_retry);retryButton.setVisibility(View.VISIBLE);}}

8. Extractastringresource(phone_disabled)forthehard-codedstring"Phonecallingdisabled"inthetoaststatement.

9. CreateanenableCallButton()methodinMainActivitythatfindsandthensetsthecallbuttontobevisible:

privatevoidenableCallButton(){ImageButtoncallButton=(ImageButton)findViewById(R.id.phone_icon);callButton.setVisibility(View.VISIBLE);}

10. CreatetheretryApp()methodinMainActivitythatwillbecalledwhentheuserclicksthevisibleRetrybutton.Addcodeto:

CallenableCallButton()toenablethecallbutton.Createanintenttostart(inthiscase,restart)theactivity.

publicvoidretryApp(Viewview){enableCallButton();Intentintent=getPackageManager().getLaunchIntentForPackage(getPackageName());startActivity(intent);}

11. Addtheandroid:onClickattributetotheRetrybuttontocallretryApp:


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3.2Requestpermissionforphonecalling

1. AtthetopofMainActivitybelowtheclassdefinition,defineaglobalconstantforthecall-phonepermissionrequestcode,andsetitto1:

privatestaticfinalintMY_PERMISSIONS_REQUEST_CALL_PHONE=1;

Whytheinteger1?Eachpermissionrequestneedsthreeparameters:thecontext,astringarrayofpermissions,andanintegerrequestCode.TherequestCodeisacodeattachedtotherequest,andcanbeanyintegerthatsuitsyourusecase.Whenaresultreturnsbacktotheactivity,itcontainsthiscodeandusesittodifferentiatemultiplepermissionresultsfromeachother.

2. InMainActivity,createaprivatemethodcalledcheckForPhonePermissiontocheckforCALL_PHONEpermission,whichreturnsvoid.Youputthiscodeinaseparatemethodbecauseyouwilluseitmorethanonce:

privatevoidcheckForPhonePermission(){if(ActivityCompat.checkSelfPermission(this,Manifest.permission.CALL_PHONE)!=PackageManager.PERMISSION_GRANTED){Log.d(TAG,"PERMISSIONNOTGRANTED!");ActivityCompat.requestPermissions(this,newString[]{Manifest.permission.CALL_PHONE},MY_PERMISSIONS_REQUEST_CALL_PHONE);}else{//Permissionalreadygranted.Enablethecallbutton.enableCallButton();}}

3. UsecheckSelfPermission()todeterminewhetheryourapphasbeengrantedaparticularpermissionbytheuser.Ifpermissionhasnotbeengrantedbytheuser,usetherequestPermissions()methodtodisplayastandarddialogfortheusertograntpermission.

4. WhenyourappcallsrequestPermissions(),thesystemshowsastandarddialogtotheuser,asshowninthefigurebelow.


60

https://developer.android.com/reference/android/support/v4/content/ContextCompat.html#checkSelfPermission(android.content.Context,%20java.lang.String)https://developer.android.com/reference/android/support/v4/app/ActivityCompat.html#requestPermissions(android.app.Activity,%20java.lang.String[],%20int)https://developer.android.com/reference/android/support/v4/app/ActivityCompat.html#requestPermissions(android.app.Activity,%20java.lang.String[],%20int)


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5. Extractthehard-codedstring"PERMISSIONNOTGRANTED!"intheabovecodetothestringresourcepermission_not_granted.

6. IntheonCreate()methodaftercheckingtoseeiftelephonyisenabled,addacalltocheckForPhonePermission():

@OverrideprotectedvoidonCreate(BundlesavedInstanceState){...if(isTelephonyEnabled()){//Checkforphonepermission.checkForPhonePermission();//ToDo:RegisterthePhoneStateListener....

7. Whentheuserrespondstotherequestpermissiondialog,thesysteminvokesyourapp'sonRequestPermissionsResult()method,passingittheuserresponse.Overridethatmethodtofindoutwhetherthepermissionwasgranted:

@OverridepublicvoidonRequestPermissionsResult(intrequestCode,Stringpermissions[],int[]grantResults){//Checkifpermissionisgrantedornotfortherequest....}

8. ForyourimplementationofonRequestPermissionsResult(),useaswitchstatementwitheachcasebasedonthevalueofrequestCode.UseonecasetocheckifthepermissionistheoneyoudefinedasMY_PERMISSIONS_REQUEST_CALL_PHONE:


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https://developer.android.com/reference/android/support/v4/app/ActivityCompat.OnRequestPermissionsResultCallback.html#onRequestPermissionsResult(int,%20java.lang.String[],%20int[])

...//Checkifpermissionisgrantedornotfortherequest.switch(requestCode){caseMY_PERMISSIONS_REQUEST_CALL_PHONE:{if(permissions[0].equalsIgnoreCase(Manifest.permission.CALL_PHONE)&&grantResults[0]==PackageManager.PERMISSION_GRANTED){//Permissionwasgranted.}else{//Permissiondenied.Log.d(TAG,"Failuretoobtainpermission!");Toast.makeText(this,"Failuretoobtainpermission!",Toast.LENGTH_LONG).show();//DisablethecallbuttondisableCallButton();}}}

9. Extractthehard-codedstring"Failuretoobtainpermission!"intheabovecodetothestringresourcefailure_permission,andnotethefollowing:

Theuser'sresponsetotherequestdialogisreturnedinthepermissionsarray(index0ifonlyonepermissionisrequestedinthedialog).Thecodesnippetabovecomparesthistothecorrespondinggrantresult,whichiseitherPERMISSION_GRANTEDorPERMISSION_DENIED.Iftheuserdeniesapermissionrequest,yourappshouldtakeappropriateaction.Forexample,yourappmightdisablethefunctionalitythatdependsonthispermissionandshowadialogexplainingwhyitcouldnotperformit.Fornow,logadebugmessage,displayatoasttoshowthatpermissionwasnotgranted,anddisablethecallbuttonwithdisableCallButton().

3.3Runtheappandtestpermission

1. Runtheapponce.Afterrunningtheapp,turnoffthePhonepermissionfortheapponyourdeviceoremulatorsothatyoucantestthepermission-requestfunction:

i. ChooseSettings>Apps>PhoneCallingSample>Permissionsonthedeviceoremulator.

ii. TurnoffthePhonepermissionfortheapp.

2. Runtheappagain.Youshouldseetherequestdialoginthefigureintheprevioussection.


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i. TapDenytodenypermission.Theappshoulddisplayatoastmessageshowingthefailuretogainpermission,andtheRetrybutton.Thephoneiconshoulddisappear.

ii. TapRetry,andwhentherequestdialogappears,tapAllow.Thephoneiconshouldreappear.Testtheapp'sabilitytomakeaphonecall.

3. SincetheusermightturnoffPhonepermissionwhiletheappisstillrunning,addthesamepermissioncheckmethodtothecallNumber()method—aftertheintentresolvestoapackage,asshownbelow—tocheckforpermissionrightbeforemakingacall:

//Ifpackageresolvestoanapp,checkforphonepermission,//andsendintent.if(callIntent.resolveActivity(getPackageManager())!=null){checkForPhonePermission();startActivity(callIntent);}else{Log.e(TAG,"Can'tresolveappforACTION_CALLIntent");}

4. Runtheapp.IftheuserchangesthePhonepermissionfortheappwhiletheappisrunning,therequestdialogappearsagainfortheusertoAlloworDenythepermission.

i. ClickAllowtotesttheapp'sabilitytomakeaphonecall.Theappshouldmakethecallwithoutaproblem.

ii. JumptotheSettingsapptoturnoffPhonepermissionfortheapp(theappshouldstillberunning):

i. ChooseSettings>Apps>PhoneCallingSample>Permissionsonthedeviceoremulator.

ii. TurnoffthePhonepermissionfortheapp.

iii. Gobacktotheappandtrytomakeacall.Therequestdialogshouldappearagain.Thistime,ClickDenytodenypermissiontomakeaphonecall.Theappshoulddisplayatoastmessageshowingthefailuretogainpermission,andtheRetrybutton.Thephoneiconshoulddisappear.

Task4.MonitorthephonestateYoucanmonitorthephonestatewithPhoneStateListener,whichmonitorschangesinspecifictelephonystates.Youcanthenshowtheuserthestateinatoastmessage,sothattheusercanseeifthephoneisidleoroffthehook.


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https://developer.android.com/reference/android/telephony/PhoneStateListener.html

Whenthephonecallfinishesandthephoneswitchestotheidlestate,yourapp'sactivityresumesiftheappisrunningonKitKat(version19)ornewerversions.However,iftheappisrunningonaversionofAndroidolderthanKitKat(version19),thePhoneappremainsactive.Youcancheckthephonestateandrestarttheactivityifthestateisidle.

TousePhoneStateListener,youneedtoregisteralistenerobjectusingtheTelephonyManagerclass,whichprovidesaccesstoinformationaboutthetelephonyservicesonthedevice.CreateanewclassthatextendsPhoneStateListenertoperformactionsdependingonthephonestate.YoucanthenregisterthelistenerobjectintheonCreate()methodoftheactivity,usingtheTelephonyManagerclass.

4.1Setthepermissionandloggingtag

1. OpentheAndroidStudioprojectforthePhoneCallingSampleapp,ifitisn'talreadyopen.

2. AddthefollowingREAD_PHONE_STATEpermissiontotheAndroidManifest.xmlfileafteraftertheCALL_PHONEpermission,andbeforethesection:

Monitoringthestateofaphonecallispermission-protected.ThispermissionisinadditiontotheCALL_PHONEpermission.

4.2CreateaclassthatextendsPhoneStateListener

1. Tocreatealistenerobjectandlistentothephonestate,createaprivateinnerclasscalledMyPhoneCallListenerinMainActivitythatextendsPhoneStateListener.

privateclassMyPhoneCallListenerextendsPhoneStateListener{...}

2. Withinthisclass,implementtheonCallStateChanged()methodofPhoneStateListenertotakeactionsbasedonthephonestate.ThecodebelowusesaswitchstatementwithconstantsoftheTelephonyManagerclasstodeterminewhichofthreestatesthephoneisin:CALL_STATE_RINGING,CALL_STATE_OFFHOOK,andCALL_STATE_IDLE:


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https://developer.android.com/reference/android/telephony/TelephonyManager.htmlhttps://developer.android.com/reference/android/telephony/PhoneStateListener.html#onCallStateChanged(int,%20java.lang.String)https://developer.android.com/reference/android/telephony/TelephonyManager.html

@OverridepublicvoidonCallStateChanged(intstate,StringincomingNumber){switch(state){caseTelephonyManager.CALL_STATE_RINGING://Incomingcallisringing(notusedforoutgoingcall).break;caseTelephonyManager.CALL_STATE_OFFHOOK://Phonecallisactive--offthehook.break;caseTelephonyManager.CALL_STATE_IDLE://Phoneisidlebeforeandafterphonecall.break;default://Mustbeanerror.Raiseanexceptionorjustlogit.break;}}

3. Justabovetheswitch(state)line,createaStringcalledmessagetouseinatoastasaprefixforthephonestate:

...//Defineastringforthemessagetouseinatoast.Stringmessage="PhoneStatus:";switch(state){...

4. Extractthestring"PhoneStatus:"tothestringresourcephone_status.5. FortheCALL_STATE_RINGINGstate,assembleamessageforlogginganddisplayinga

toastwiththeincomingphonenumber:

...switch(state){caseTelephonyManager.CALL_STATE_RINGING://Incomingcallisringing(notusedforoutgoingcall).message=message+"RINGING,number:"+incomingNumber;Toast.makeText(MainActivity.this,message,Toast.LENGTH_SHORT).show();Log.i(TAG,message);break;...

6. Extract"RINGING,number:"tothestringresourceringing.7. AddabooleanreturningFromOffHook,settofalse,atthetopofthe

MyPhoneCallListenerdeclaration,inordertouseitwiththetheCALL_STATE_OFFHOOKstate:


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privateclassMyPhoneCallListenerextendsPhoneStateListener{privatebooleanreturningFromOffHook=false;...}

Tip:AnapprunningonAndroidversionspriortoKitKat(version19)doesn'tresumewhenthephonestatereturnstoCALL_STATE_IDLEfromCALL_STATE_OFFHOOKattheendofacall.ThebooleanreturningFromOffHookisusedasaflag,andsettotruewhenthestateisCALL_STATE_OFFHOOK,sothatwhenthestateisbacktoCALL_STATE_IDLE,theflagdesignatesanend-of-callinordertorestarttheapp'sactivity.

8. FortheCALL_STATE_OFFHOOKstate,assembleamessageforlogginganddisplayingatoast,andsetthereturningFromOffHookbooleantotrue.

...switch(state){caseTelephonyManager.CALL_STATE_OFFHOOK://Phonecallisactive--offthehook.message=message+"OFFHOOK";Toast.makeText(MainActivity.this,message,Toast.LENGTH_SHORT).show();Log.i(TAG,message);returningFromOffHook=true;break;...

9. Extract"OFFHOOK"tothestringresourceoffhook.10. FortheCALL_STATE_IDLEstate,loganddisplayatoast,andcheckif

returningFromOffHookistrue;ifso,restarttheactivityiftheversionofAndroidisearlierthanKitKat.


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...switch(state){caseTelephonyManager.CALL_STATE_IDLE://Phoneisidlebeforeandafterphonecall.//Ifrunningonversionolderthan19(KitKat),//restartactivitywhenphonecallends.message=message+"IDLE";Toast.makeText(MainActivity.this,message,Toast.LENGTH_SHORT).show();Log.i(TAG,message);if(returningFromOffHook){//Noneedtodoanythingif>=versionKitKat.if(Build.VERSION.SDK_INT<Build.VERSION_CODES.KITKAT){Log.i(TAG,"Restartingapp");//Restarttheapp.Intentintent=getPackageManager().getLaunchIntentForPackage(.getPackageName());intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);startActivity(intent);}}break;...

IftheappisrunningonKitKat(version19)ornewerversions,thereisnoneedtorestarttheactivityafterthephonecallends.ButiftheappisrunningonaversionofAndroidolderthanKitKat(version19),thecodemustrestartthecurrentactivitysothattheusercanreturntotheappafterthecallends.

Tip:ThecodealsosetsFLAG_ACTIVITY_CLEAR_TOPsothatinsteadoflaunchinganewinstanceofthecurrentactivity,anyotheractivitiesontopofthecurrentactivityareclosedandanintentisdeliveredtothe(nowontop)currentactivity.Thisflaghelpsyoumanageastackofactivitiesinanapp.

11. Extract"IDLE"tothestringresourceidle,andextract"Restartingapp"tothestringresourcerestarting_app.

ThecodebelowshowstheentireonCallStateChanged()method:

...@OverridepublicvoidonCallStateChanged(intstate,StringincomingNumber){//Defineastringforthemessagetouseinatoast.Stringmessage=getString(R.string.phone_status);switch(state){caseTelephonyManager.CALL_STATE_RINGING://Incomingcallisringing(notusedforoutgoingcall).


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https://developer.android.com/reference/android/content/Intent.html#FLAG_ACTIVITY_CLEAR_TOP

message=message+getString(R.string.ringing)+incomingNumber;Toast.makeText(MainActivity.this,message,Toast.LENGTH_SHORT).show();Log.i(TAG,message);break;caseTelephonyManager.CALL_STATE_OFFHOOK://Phonecallisactive--offthehook.message=message+getString(R.string.offhook);Toast.makeText(MainActivity.this,message,Toast.LENGTH_SHORT).show();Log.i(TAG,message);returningFromOffHook=true;break;caseTelephonyManager.CALL_STATE_IDLE://Phoneisidlebeforeandafterphonecall.//Ifrunningonversionolderthan19(KitKat),//restartactivitywhenphonecallends.message=message+getString(R.string.idle);Toast.makeText(MainActivity.this,message,Toast.LENGTH_SHORT).show();Log.i(TAG,message);if(returningFromOffHook){//Noneedtodoanythingif>=versionKitKat.if(Build.VERSION.SDK_INT<Build.VERSION_CODES.KITKAT){Log.i(TAG,getString(R.string.restarting_app));//Restarttheapp.Intentintent=getPackageManager().getLaunchIntentForPackage(.getPackageName());intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);startActivity(intent);}}break;default:message=message+"Phoneoff";Toast.makeText(MainActivity.this,message,Toast.LENGTH_SHORT).show();Log.i(TAG,message);break;}}...

4.3RegisterthePhoneStateListener

1. AtthetopofMainActivitybelowtheclassdefinition,defineavariableforthePhoneStateListener:


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https://developer.android.com/reference/android/telephony/PhoneStateListener.html

privateMyPhoneCallListenermListener;

2. IntheonCreate()method,addthefollowingcodeaftercheckingfortelephonyandpermission:

...if(isTelephonyEnabled()){...checkForPhonePermission();//RegisterthePhoneStateListenertomonitorphoneactivity.mListener=newMyPhoneCallListener();telephonyManager.listen(mListener,PhoneStateListener.LISTEN_CALL_STATE);}else{...

3. Youmustalsounregisterthelistenerintheactivity'sonDestroy()method.OverridetheonDestroy()methodbyaddingthefollowingcode:

@OverrideprotectedvoidonDestroy(){super.onDestroy();if(isTelephonyEnabled()){telephonyManager.listen(mListener,PhoneStateListener.LISTEN_NONE);}}

4.4Runtheapp

1. Runtheapp.IftheuserchangesthePhonepermissionfortheappwhiletheappisrunning,therequestdialogappearsagainfortheusertoAlloworDenythepermission.ClickAllowtotesttheapp'sabilitytomakeaphonecall.

2. Afterenteringaphonenumberandclickingthecallbutton,theemulatorordeviceshowsthephonecallstartingup,asshowninthefigurebelow.Atoastmessageappearsshowingthephonenumber(leftsideoffigure),andthetoastmessagechangestoshowanewstatusof"OFFHOOK"(rightsideoffigure)afterthecallhasstarted.


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https://developer.android.com/reference/android/app/Activity.html#onDestroy()

3. Theotheremulatorinstanceordeviceshouldnowbereceivingthecall,asshowninthefigurebelow.ClickAnswerorDismissonthedeviceoremulatorreceivingthecall.


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4. IfyouclickAnswer,besuretoalsoclicktheredHang-upbuttontofinishthecall,asshowninthefigurebelow.


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Afteryouhangup,theappshouldreappearwithatoastmessageshowingthatthephoneisnowintheidlestate,asshowninthefigurebelow.


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Solutioncode

AndroidStudioproject:PhoneCallingSample

CodingchallengeNote:Allcodingchallengesareoptionalandarenotprerequisitesforlaterlessons.Challenge:

1. UsethenormalizeNumber()methodinthePhoneNumberUtilsclasstoremovecharactersotherthandigitsfromthephonenumberaftertheuserhasenteredit.ThismethodwasaddedtoAPIlevel21.Ifyouneedyourapptorunonolderversions,includeacheckfortheversionthatusesthenormalizeNumber()methodonlyiftheversionisolderthanLollipop.Yourappalreadyusesalogstatementtoshowthephonenumberasdialed,soiftheuserenters"1-415-555-1212"thelogmessageshouldshowthatthenumberwasnormalized:

D/MainActivity:PhoneStatus:DIALING:tel:14155551212

2. AddaninvisibleTextViewtothePhoneCallingSampleapp.ThisTextViewshouldappearbelowtheinvisibleRetrybutton,butonlywhenthephoneisringing(indicatinganincomingcall),anditshouldshowthephonenumberofthecaller.

Ifyouhavebothemulatorsopenasdescribedpreviously,installtheapponbothemulators.Youcanthentestanincomingcallbyusingtheappononeemulatortocalltheotheremulator.

Tip:Youcanalsoemulatereceivingacallbyclickingthe…(More)iconatthebottomoftheemulator'stoolbarontherightside.ClickPhoneintheleftcolumntoseetheextendedphonecontrols,andclickCallDevicetocalltheemulator.

AndroidStudioproject:PhoneCallingSampleChallenge

SummaryTosendanintenttothePhoneappwithaphonenumber,yourappneedstoprepareaURIforthephonenumberasastringprefixedby"tel:"(forexampletel:14155551212).Todialaphonenumber,createanimplicitintentwithACTION_DIAL,andsetthephonenumberURIasthedatafortheintentwithsetData():


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https://github.com/google-developer-training/android-fundamentals-phone-sms/tree/master/PhoneCallingSamplehttps://developer.android.com/reference/android/telephony/PhoneNumberUtils.html#normalizeNumber(java.lang.String)https://developer.android.com/reference/android/telephony/PhoneNumberUtils.htmlhttps://developer.android.com/reference/android/telephony/PhoneNumberUtils.html#normalizeNumber(java.lang.String)https://github.com/google-developer-training/android-fundamentals-phone-sms/tree/master/PhoneCallingSampleChallenge

IntentcallIntent=newIntent(Intent.ACTION_DIAL);callIntent.setData(Uri.parse(phoneNumber));

Forphonepermission,addthefollowingtotheAndroidManifest.xmlfile:

Tomakeaphonecall,createanimplicitintentwithACTION_CALL,andsetthephonenumberURIasthedatafortheintentwithsetData():

IntentcallIntent=newIntent(Intent.ACTION_CALL);callIntent.setData(Uri.parse(phoneNumber));

Tocheckiftelephonyisenabled,usethestringconstantTELEPHONY_SERVICEwithgetSystemService()toretrieveaTelephonyManager,whichgivesyouaccesstotelephonyfeatures.UsecheckSelfPermission()todeterminewhetheryourapphasbeengrantedaparticularpermissionbytheuser.Ifpermissionhasnotbeengranted,usetherequestPermissions()methodtodisplayastandarddialogfortheusertograntpermission.TomonitorthephonestatewithPhoneStateListener,registeralistenerobjectusingtheTelephonyManagerclass.Forphonemonitoringpermission,addthefollowingtotheAndroidManifest.xmlfile:

Tomonitorphonestates,createaprivateclassthatextendsPhoneStateListener,andoverridetheonCallStateChanged()methodofPhoneStateListenertotakedifferentactionsbasedonthephonestate:CALL_STATE_RINGING,CALL_STATE_OFFHOOK,orCALL_STATE_IDLE.

RelatedconceptPhoneCalls

LearnmoreAndroiddeveloperdocumentation:

CommonIntentsTelephonyManager


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https://developer.android.com/reference/android/content/Context.html#TELEPHONY_SERVICEhttps://developer.android.com/reference/android/content/Context.html#getSystemService(java.lang.String)https://developer.android.com/reference/android/telephony/TelephonyManager.htmlhttps://developer.android.com/reference/android/support/v4/content/ContextCompat.html#checkSelfPermission(android.content.Context,%20java.lang.String)https://developer.android.com/reference/android/support/v4/app/ActivityCompat.html#requestPermissions(android.app.Activity,%20java.lang.String[],%20int)https://developer.android.com/reference/android/telephony/PhoneStateListener.htmlhttps://developer.android.com/reference/android/telephony/TelephonyManager.htmlhttps://developer.android.com/reference/android/telephony/PhoneStateListener.htmlhttps://developer.android.com/reference/android/telephony/PhoneStateListener.html#onCallStateChanged(int,%20java.lang.String)https://developer.android.com/guide/components/intents-common.htmlhttps://developer.android.com/reference/android/telephony/TelephonyManager.html

PhoneStateListenerRequestingPermissionsatRunTimecheckSelfPermissionRunAppsontheAndroidEmulatorIntentsandIntentFiltersIntent

StackOverflow:HowtoformataphonenumberusingPhoneNumberUtils?Howtomakephonecallusingintentinandroid?RingingmyselfusingandroidemulatorFakeIncomingCallAndroidSimulatingincomingcallorsmsinAndroidStudio

Other:User(beginner)tutorial:HowtoMakePhoneCallswithAndroidDeveloperVideo:HowtoMakeaPhoneCall


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https://developer.android.com/reference/android/telephony/PhoneStateListener.htmlhttps://developer.android.com/training/permissions/requesting.htmlhttps://developer.android.com/reference/android/support/v4/content/ContextCompat.html#checkSelfPermission(android.content.Context,%20java.lang.String)https://developer.android.com/studio/run/emulator.htmlhttp://developer.android.com/guide/components/intents-filters.htmlhttp://developer.android.com/reference/android/content/Intent.htmlhttp://stackoverflow.com/questions/6106859/how-to-format-a-phone-number-using-phonenumberutilshttp://stackoverflow.com/questions/4275678/how-to-make-phone-call-using-intent-in-androidhttp://stackoverflow.com/questions/2577785/ringing-myself-using-android-emulatorhttp://stackoverflow.com/questions/4964703/fake-incoming-call-androidhttp://stackoverflow.com/questions/27638462/simulating-incoming-call-or-sms-in-android-studiohttp://www.beginandroid.com/phonecall.shtmlhttps://youtu.be/3PHDcQOGFtg

2:SMSMessagesContents:

SendingandreceivingSMSmessagesUsinganintenttolaunchanSMSappSendingSMSmessagesfromyourappReceivingSMSmessagesRelatedpracticalLearnmore

AndroiddevicescansendandreceivemessagestoorfromanyotherphonethatsupportsShortMessageService(SMS).AndroidofferstheMessengerappthatcansendandreceiveSMSmessages.Ahostofthird-partyappsforsendingandreceivingSMSmessagesarealsoavailableinGooglePlay.

ThischapterdescribeshowtouseSMSinyourapp.Youcanaddcodetoyourappto:

LaunchanSMSmessagingappfromyourapptohandleallSMScommunication.SendanSMSmessagefromwithinyourapp.ReceiveSMSmessagesinyourapp.

Note:TheSMSprotocolwasprimarilydesignedforuser-to-usercommunicationandisnotwell-suitedforappsthatwanttotransferdata.YoushouldnotuseSMStosenddatamessagesfromawebservertoyourapponauserdevice.SMSisneitherencryptednorstronglyauthenticatedoneitherthenetworkorthedevice.

SendingandreceivingSMSmessagesAccesstotheSMSfeaturesofanAndroiddeviceisprotectedbyuserpermissions.Justasyourappneedstheuser'spermissiontousephonefeatures,soalsodoesanappneedtheuser'spermissiontodirectlyuseSMSfeatures.

However,yourappdoesn'tneedpermissiontopassaphonenumbertoaninstalledSMSapp,suchasMessenger,forsendingthemessage.TheMessengerappitselfisgovernedbyuserpermission.

YouhavetwochoicesforsendingSMSmessages:

UseanimplicitIntenttolaunchamessagingappsuchasMessenger,withtheACTION_SENDTOaction.

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https://developer.android.com/reference/android/content/Intent.htmlhttps://developer.android.com/reference/android/content/Intent.html#ACTION_SENDTO

Thisisthesimplestchoiceforsendingmessages.Theusercanaddapictureorotherattachmentinthemessagingapp,ifthemessagingappsupportsaddingattachments.Yourappdoesn'tneedcodetorequestpermissionfromtheuser.IftheuserhasmultipleSMSmessagingappsinstalledontheAndroidphone,theAppchooserwillappearwithalistoftheseapps,andtheusercanchoosewhichonetouse.(Androidsmartphoneswillhaveatleastone,suchasMessenger.)Theusercanchangethemessageinthemessagingappbeforesendingit.TheusernavigatesbacktoyourappusingtheBackbutton.

SendtheSMSmessageusingthesendTextMessage()methodorothermethodsoftheSmsManagerclass.

Thisisagoodchoiceforsendingmessagesfromyourappwithouthavingtouseanotherinstalledapp.Yourcodemustasktheuserforpermissionbeforesendingthemessageiftheuserhasn'talreadygrantedpermission.Theuserstaysinyourappduringandaftersendingthemessage.YoucanmanageSMSoperationssuchasdividingamessageintofragments,sendingamultipartmessage,getcarrier-dependentconfigurationvalues,andsoon.

ToreceiveSMSmessages,thebestpracticeistousetheonReceive()methodoftheBroadcastReceiverclass.TheAndroidframeworksendsoutsystembroadcastsofeventssuchasreceivinganSMSmessage,containingintentsthataremeanttobereceivedusingaBroadcastReceiver.YourappreceivesSMSmessagesbylisteningfortheSMS_RECEIVED_ACTIONbroadcast.

Mostsmartphonesandmobilephonessupportwhatisknownas"PDUmode"forsendingandreceivingSMS.PDU(protocoldataunit)containsnotonlytheSMSmessage,butalsometadataabouttheSMSmessage,suchastextencoding,thesender,SMSservicecenteraddress,andmuchmore.Toaccessthismetadata,SMSappsalmostalwaysusePDUstoencodethecontentsofaSMSmessage.ThesendTextMessage()andsendMultimediaMessage()methodsoftheSmsManagerclassencodethecontentsforyou.WhenreceivingaPDU,youcancreateanSmsMessageobjectfromtherawPDUusingcreateFromPdu().

UsinganintenttolaunchanSMSappTouseanIntenttolaunchanSMSapp,yourappneedstoprepareaUniformResourceIdentifier(URI)forthephonenumberasastringprefixedby"smsto:"(asinsmsto:14155551212).Youcanuseahardcodedphonenumber,suchasthephonenumberof

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https://developer.android.com/reference/android/telephony/SmsManager.html#sendTextMessage(java.lang.String,%20java.lang.String,%20java.lang.String,%20android.app.PendingIntent,%20android.app.PendingIntent)https://developer.android.com/reference/android/telephony/SmsManager.htmlhttps://developer.android.com/reference/android/content/BroadcastReceiver.html#onReceive(android.content.Context,%20android.content.Intent)https://developer.android.com/reference/android/content/BroadcastReceiver.htmlhttps://developer.android.com/reference/android/provider/Telephony.Sms.Intents.html#SMS_RECEIVED_ACTIONhttps://developer.android.com/reference/android/telephony/SmsManager.html#sendTextMessage(java.lang.String,%20java.lang.String,%20java.lang.String,%20android.app.PendingIntent,%20android.app.PendingIntent)https://developer.android.com/reference/android/telephony/SmsManager.html#sendMultimediaMessage(android.content.Context,%20android.net.Uri,%20java.lang.String,%20android.os.Bundle,%20android.app.PendingIntent)https://developer.android.com/reference/android/telephony/SmsManager.htmlhttps://developer.android.com/reference/android/telephony/SmsMessage.htmlhttps://developer.android.com/reference/android/telephony/SmsMessage.html#createFromPdu(byte[],%20java.lang.String)https://developer.android.com/reference/android/content/Intent.html

asupportmessagecenter,orprovideanEditTextfieldinthelayouttoenabletheusertoenteraphonenumber.

Tip:FordetailsaboutusingmethodsinthePhoneNumberUtilsclasstoformataphonenumberstring,seetherelatedconceptPhoneCalls.

Useabutton(suchasanImageButton)thattheusercantaptopassthephonenumbertotheSMSapp.Forexample,anappthatenablesausermakeaphonecalland/orsendamessagetothephonenumbermightofferasimplelayoutwithaphoneiconbuttonforcalling,andamessagingiconbuttonforsendingamessage,asshowninthefigurebelow.

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https://developer.android.com/reference/android/telephony/PhoneNumberUtils.html

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TocallamethodsuchassmsSendMessage()thatwouldlaunchamessagingappwithaphonenumber,youcanaddtheandroid:onClickattributetothebuttonforsendingamessage:

InthesmsSendMessage()method,youwouldconvertthephonenumbertoastringprefixedby"smsto:"(asinsmsto:14155551212).UseanimplicitintentwithACTION_SENDTOtopassthephonenumbertotheSMSapp,andsetthephonenumberandmessagefortheintentwithsetData()andputExtra.

Tip:The"smsto:"prefixwithACTION_SENDTOensuresthatyourintentishandledonlybyatextmessagingapp(andnotbyotheremailorsocialapps).

IftheuserhasseveralSMSmessagingapps,theusercanchoosewhichonetoopen.TheSMSappopenswiththesuppliedphonenumberandmessage,enablingtheusertotapabuttontosendthemessage,orchangethenumberandmessagebeforesending.TheSMSappthensendsthemessage.

Thefollowingcodedemonstrateshowtoperformanimplicitintenttosendamessage:

publicvoidsmsSendMessage(Viewview){//FindtheTextViewnumber_to_callandassignittotextView.TextViewtextView=(TextView)findViewById(R.id.number_to_call);//Concatenate"smsto:"withphonenumbertocreatesmsNumber.StringsmsNumber="smsto:"+textView.getText().toString();//Findthesms_messageview.EditTextsmsEditText=(EditText)findViewById(R.id.sms_message);//Getthetextofthesmsmessage.Stringsms=smsEditText.getText().toString();//Createtheintent.IntentsmsIntent=newIntent(Intent.ACTION_SENDTO);//Setthedatafortheintentasthephonenumber.smsIntent.setData(Uri.parse(smsNumber));//Addthemessage(sms)withthekey("sms_body").smsIntent.putExtra("sms_body",sms);//Ifpackageresolves(targetappinstalled),sendintent.if(smsIntent.resolveActivity(getPackageManager())!=null){startActivity(smsIntent);}else{Log.e(TAG,"Can'tresolveappforACTION_SENDTOIntent.");}}

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Notethefollowingintheabovecode:

Themethodgetsthephonenumberfromthenumber_to_callTextView,andconcatenatesitwiththesmsto:prefix(asinsmsto:14155551212)beforeassigningittosmsNumber.ItalsogetsthemessageenteredintotheEditTextview.TolaunchanSMSmessagingapp,useanimplicitintent(smsIntent)withACTION_SENDTO,andsetthephonenumberandmessagefortheintentwithsetData()andputExtra.

TheputExtra()methodneedstwostrings:thekeyidentifyingthetypeofdata("sms_body")andthedataitself,whichisthetextofthemessage(sms).FormoreinformationaboutcommonintentsandtheputExtra()method,seeCommonIntents:TextMessaging.

Youneedtosupplyachecktoseeiftheimplicitintentresolvestoapackage(anapp),andifitdoes,youneedtostartthesmsIntentactivity.Ifitdoesn't,displayalogmessageaboutthefailure.

SendingSMSmessagesfromyourappTosendanSMSmessagefromyourapp,usethesendTextMessage()methodoftheSmsManagerclass.Performthesestepstoenablesendingmessagesfromwithinyourapp:

1. AddtheSEND_SMSpermissiontosendSMSmessages.2. Checktoseeiftheusercontinuestograntpermission.Ifnot,requestpermission.3. UsethesendTextMessage()methodoftheSmsManagerclass.

Checkingforuserpermission

BeginninginAndroid6.0(APIlevel23),usersgrantpermissionstoappswhiletheappisrunning,notwhentheyinstalltheapp.Thisapproachstreamlinestheappinstallprocess,sincetheuserdoesnotneedtograntpermissionswhentheyinstallorupdatetheapp.Italsogivestheusermorecontrolovertheapp'sfunctionality.However,yourappmustcheckforpermissioneverytimeitdoessomethingthatrequirespermission(suchassendinganSMSmessage).IftheuserhasusedtheSettingsapptoturnoffSMSpermissionsfortheapp,yourappcandisplayadialogtorequestpermission.

Tip:Foracompletedescriptionoftherequestpermissionprocess,seeRequestingPermissionsatRunTime.

AddtheSEND_SMSpermissiontotheAndroidManifest.xmlfileafterthefirstline(withthepackagedefinition)andbeforethesection:

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https://developer.android.com/reference/android/content/Intent.html#putExtra(java.lang.String,%20java.lang.String)https://developer.android.com/guide/components/intents-common.html#Messaginghttps://developer.android.com/reference/android/telephony/SmsManager.html#sendTextMessage(java.lang.String,%20java.lang.String,%20java.lang.String,%20android.app.PendingIntent,%20android.app.PendingIntent)https://developer.android.com/reference/android/telephony/SmsManager.htmlhttps://developer.android.com/training/permissions/requesting.html

Becausetheusercanturnpermissionsonoroffforeachapp,yourappmustcheckwhetheritstillhaspermissioneverytimeitdoessomethingthatrequirespermission(suchassendinganSMSmessage).IftheuserhasturnedSMSpermissionofffortheapp,yourappcandisplayadialogtorequestpermission.

Followthesesteps:

1. AtthetopoftheactivitythatsendsanSMSmessage,andbelowtheactivity'sclassdefinition,defineaconstantvariabletoholdtherequestcode,andsetittoaninteger:

privatestaticfinalintMY_PERMISSIONS_REQUEST_SEND_SMS=1;

Whytheinteger1?Eachpermissionrequestneedsthreeparameters:thecontext,astringarrayofpermissions,andanintegerrequestCode.TherequestCodeistheintegerattachedtotherequest.Whenaresultreturnsintheactivity,itcontainsthiscodeandusesittodifferentiatemultiplepermissionresultsfromeachother.

2. Intheactivitythatmakesaphonecall,createamethodthatusesthecheckSelfPermission()methodtodeterminewhetheryourapphasbeengrantedthepermission:

privatevoidcheckForSmsPermission(){if(ActivityCompat.checkSelfPermission(this,Manifest.permission.SEND_SMS)!=PackageManager.PERMISSION_GRANTED){Log.d(TAG,getString(R.string.permission_not_granted));//Permissionnotyetgranted.UserequestPermissions().//MY_PERMISSIONS_REQUEST_SEND_SMSisan//app-definedintconstant.Thecallbackmethodgetsthe//resultoftherequest.ActivityCompat.requestPermissions(this,newString[]{Manifest.permission.SEND_SMS},MY_PERMISSIONS_REQUEST_SEND_SMS);}else{//Permissionalreadygranted.Enablethemessagebutton.enableSmsButton();}}

ThecodeusescheckSelfPermission()todeterminewhetheryourapphasbeengrantedaparticularpermissionbytheuser.Ifpermissionhasnotbeengranted,thecodeusestherequestPermissions()methodtodisplayastandarddialogfortheusertograntpermission.

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https://developer.android.com/reference/android/support/v4/content/ContextCompat.html#checkSelfPermission(android.content.Context,%20java.lang.String)https://developer.android.com/reference/android/support/v4/app/ActivityCompat.html#requestPermissions(android.app.Activity,%20java.lang.String[],%20int)

UseyourcheckForSmsPermission()methodtocheckforpermissionatthefollowingtimes:

Whentheactivitystarts—initsonCreate()method.Everytimebeforesendingamessage.SincetheusermightturnofftheSMSpermissionwhiletheappisstillrunning,callthecheckForSmsPermission()methodinthesmsSendMessage()methodbeforeusingtheSmsManagerclass.

Requestinguserpermission

Ifpermissionhasnotbeengrantedbytheuser,usetherequestPermissions()methodoftheActivityCompatclass.TherequestPermissions()methodneedsthreeparameters:thecontext(this),astringarrayofpermissions(newString[]{Manifest.permission.SEND_SMS}),andthepredefinedintegerMY_PERMISSIONS_REQUEST_SEND_SMSfortherequestCode.

WhenyourappcallsrequestPermissions(),thesystemshowsastandarddialogtotheuser,asshowninthefigurebelow.

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https://developer.android.com/reference/android/support/v4/app/ActivityCompat.html#requestPermissions(android.app.Activity,%20java.lang.String[],%20int)

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WhentheuserrespondstotherequestpermissiondialogbytappingDenyorAllow,thesysteminvokestheonRequestPermissionsResult()method,passingittheuserresponse.Yourapphastooverridethatmethodtofindoutwhetherthepermissionwasgranted.

ThefollowingcodedemonstrateshowyoucanuseaswitchstatementinyourimplementationofonRequestPermissionsResult()basedonthevalueofrequestCode.Theuser'sresponsetotherequestdialogisreturnedinthepermissionsarray(index0ifonlyonepermissionisrequestedinthedialog).Thisiscomparedtothecorrespondinggrantresult,whichiseitherPERMISSION_GRANTEDorPERMISSION_DENIED.

Iftheuserdeniesapermissionrequest,yourappshoulddisablethefunctionalitythatdependsonthispermissionandshowadialogexplainingwhyitcouldnotperformit.Thecodebelowlogsadebugmessage,displaysatoasttoshowthatpermissionwasnotgranted,anddisablesthemessageiconusedasabutton.

@OverridepublicvoidonRequestPermissionsResult(intrequestCode,Stringpermissions[],int[]grantResults){switch(requestCode){caseMY_PERMISSIONS_REQUEST_SEND_SMS:{if(permissions[0].equalsIgnoreCase(Manifest.permission.SEND_SMS)&&grantResults[0]==PackageManager.PERMISSION_GRANTED){//Permissionwasgranted.}else{//Permissiondenied.Log.d(TAG,getString(R.string.failure_permission));Toast.makeText(MainActivity.this,getString(R.string.failure_permission),Toast.LENGTH_SHORT).show();//Disablethemessagebutton.disableSmsButton();}}}}

UsingSmsManagertosendthemessage

UsethesendTextMessage()methodoftheSmsManagerclasstosendthemessage,whichtakesthefollowingparameters:

destinationAddress:Thestringforthephonenumbertoreceivethemessage.scAddress:Astringfortheservicecenteraddress,ornulltousethecurrentdefaultSMSC.AShortMessageServiceCenter(SMSC)isanetworkelementinthemobiletelephonenetwork.Themobilenetworkoperatorusuallypresetsthecorrectservice

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https://developer.android.com/reference/android/support/v4/app/ActivityCompat.OnRequestPermissionsResultCallback.html#onRequestPermissionsResult(int,%20java.lang.String[],%20int[])https://developer.android.com/reference/android/telephony/SmsManager.html#sendTextMessage(java.lang.String,%20java.lang.String,%20java.lang.String,%20android.app.PendingIntent,%20android.app.PendingIntent)https://developer.android.com/reference/android/telephony/SmsManager.html

centernumberinthedefaultprofileofsettingsstoredinthedevice'sSIMcard.

Tip:YoucanfindthedefaultSMSCinanAndroidsmartphone'shiddenmenu.OpenthePhoneappanddial##4636##toopenthetestingmenu.TapPhoneinformation,andscrolltothebottom.TheSMSCnumbershouldappearblank.TapRefreshtoseethenumber.

smsMessage:Astringforthebodyofthemessagetosend.sentIntent:APendingIntent.Ifnotnull,thisisbroadcastwhenthemessageissuccessfullysentorifthemessagefailed.deliveryIntent:APendingIntent.Ifnotnull,thisisbroadcastwhenthemessageisdeliveredtotherecipient.

FollowthesestepstousethesendTextMessage()method:

1. CreateanonClickhandlerforabuttonthatsendsthemessage.2. Getthestringsforthephonenumber(destinationAddress)andthemessage

(smsMessage).3. DeclareadditionalstringandPendingIntentparameters:

...//Settheservicecenteraddressifneeded,otherwisenull.StringscAddress=null;//Setpendingintentstobroadcast//whenmessagesentandwhendelivered,orsettonull.PendingIntentsentIntent=null,deliveryIntent=null;...

4. UsetheSmsManagerclasstocreatesmsManager,whichautomaticallyimportsandroid.telephony.SmsManager,andusesendTextMessage()tosendthemessage:

...//UseSmsManager.SmsManagersmsManager=SmsManager.getDefault();smsManager.sendTextMessage(destinationAddress,scAddress,smsMessage,sentIntent,deliveryIntent);...

ThefollowingcodesnippetshowsasampleonClickhandlerforsendingamessage:

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https://developer.android.com/reference/android/app/PendingIntent.htmlhttps://developer.android.com/reference/android/app/PendingIntent.htmlhttps://developer.android.com/reference/android/telephony/SmsManager.html#sendTextMessage(java.lang.String,%20java.lang.String,%20java.lang.String,%20android.app.PendingIntent,%20android.app.PendingIntent)https://developer.android.com/reference/android/telephony/SmsManager.html

publicvoidsmsSendMessage(Viewview){EditTexteditText=(EditText)findViewById(R.id.editText_main);//SetthedestinationphonenumbertothestringineditText.StringdestinationAddress=editText.getText().toString();//Findthesms_messageview.EditTextsmsEditText=(EditText)findViewById(R.id.sms_message);//GetthetextoftheSMSmessage.StringsmsMessage=smsEditText.getText().toString();//Settheservicecenteraddressifneeded,otherwisenull.StringscAddress=null;//Setpendingintentstobroadcast//whenmessagesentandwhendelivered,orsettonull.PendingIntentsentIntent=null,deliveryIntent=null;//Checkforpermissionfirst.checkForSmsPermission();//UseSmsManager.SmsManagersmsManager=SmsManager.getDefault();smsManager.sendTextMessage(destinationAddress,scAddress,smsMessage,sentIntent,deliveryIntent);}

ReceivingSMSmessagesToreceiveSMSmessages,usetheonReceive()methodoftheBroadcastReceiverclass.TheAndroidframeworksendsoutsystembroadcastsofeventssuchasSMS_RECEIVEDforreceivinganSMSmessage.YoumustalsoincludeRECEIVE_SMSpermissioninyourproject'sAndroidManifest.xmlfile:

Touseabroadcastreceiver:

1. AddthebroadcastreceiverbychoosingFile>New>Other>BroadcastReceiver.TheOther>BroadcastReceiver.Makesure"Exported"and"Enabled"arechecked.The"Exported"optionallowsyourapptorespondtooutside

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https://developer.android.com/reference/android/content/BroadcastReceiver.html#onReceive(android.content.Context,%20android.content.Intent)https://developer.android.com/reference/android/content/BroadcastReceiver.html

broadcasts,while"Enabled"allowsittobeinstantiatedbythesystem.

AndroidStudioautomaticallygeneratesatagintheapp'sAndroidManifest.xmlfile,withyourchosenoptionsasattributes:

Registeringthebroadcastreceiver

Inordertoreceiveanybroadcasts,youmustregisterforspecificbroadcastintents.IntheIntentdocumentation,under"StandardBroadcastActions",youcanfindsomeofthecommonbroadcastintentssentbythesystem.

Thefollowingintentfilterregistersthereceiverfortheandroid.provider.Telephony.SMS_RECEIVEDintent:

ImplementingtheonReceive()method

Onceyourapp'sBroadcastReceiverinterceptsabroadcastitisregisteredfor(SMS_RECEIVED),theintentisdeliveredtothereceiver'sonReceive()method,alongwiththecontextinwhichthereceiverisrunning.

ThefollowingshowsthefirstpartoftheonReceive()method,whichdoesthefollowing:

Retrievestheextras(theSMSmessage)fromtheintent.Storesitinabundle.DefinesthemsgsarrayandstrMessagestring.GetstheformatforthemessagefromthebundleinordertouseitwithcreateFromPdu()tocreatetheSmsMessage.

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https://developer.android.com/reference/android/content/Intent.htmlhttps://developer.android.com/reference/android/telephony/SmsMessage.html#createFromPdu(byte[],%20java.lang.String)https://developer.android.com/reference/android/telephony/SmsMessage.html

Theformatisthemessage'smobiletelephonysystemformatpassedinanSMS_RECEIVED_ACTIONbroadcast.Itisusually"3gpp"forGSM/UMTS/

Documents

Android Apps – Phone Calls and SMS · Android telephony features you can use from within your app by launching the Phone app with an implicit intent. You can add code to your app