Android development

Jinhua Chen

1.2.2011

Outline• Introduction

– Android features– Android architecture

• Android Application Development– Installing and hello android example– Android project structure– Activity and lifecycle

• Android User Interface– View and View group

• Android Example– Login system

• MOPSI Related Development– Camera, location and maps– MOPSI Android demos

Outline

• Introduction• Android Application Development• Android User Interface• Android Example• MOPSI Related Development

What is Android?• Android is a mobile operating system initially

developed by Android Inc., a company bought by Google in 2005

• Open, free mobile platform based on Linux kernel • Released in Nov. 2007• Developed by Open Handsets Alliance• Run on a Dalvik virtual machine • Applications written in Java

Open Handsets Alliance

Why android?

• Android Dominate the Mobile Market– 33% worldwide, 44% in US

• More Type and Stronger Sales– Motorola Droid, HTC Hero, Samsung Gallery, Huawei...

• Larger Space For Different Kinds and Ideas– Full access to entire platform source for developers

• Easy access to Google applications– Google Search, Google Maps, Gmail, Google Calendar

Android Market Share

Android Features• Application framework enabling reuse and replacement of components• Dalvik virtual machine optimized for mobile devices• Integrated browser based on the open source WebKit engine• Optimized graphics powered by a custom 2D graphics library; 3D graphics

based on the OpenGL ES 1.0 specification (hardware acceleration optional)• SQLite for structured data storage• Media support for common audio, video, and still image formats (MPEG4,

H.264, MP3, AAC, AMR, JPG, PNG, GIF)• GSM Telephony (hardware dependent)• Bluetooth, EDGE, 3G, and WiFi (hardware dependent)• Camera, GPS, compass, and accelerometer (hardware dependent)• Rich development environment including a device emulator, tools for

debugging, memory and performance profiling, and a plugin for the Eclipse IDE

Android Architecture

Linux Kernel• Relies on Linux kernel version 2.6• Acts as an abstraction layer between the hardware and

the rest of the software stack• Provides core system services:

– Security– Memory management– Process management– Network stack– Driver model

Libraries

• C/C++ libraries used by various Android components• Developers can user their capabilities through the

application framwork• Includes:

– Media Libraries: MPEG4, H.264, MP3, AAC, AMR, JPG…– LibWebCore: Web browser engine– SQLite: Relational database engine– Libraries/engines for 2D and 3D graphics

Android Runtime

• Core libraries provide most functionalities using Java• Devices can run multiple Dalvik VMs, every Android

application runs with its own instance of Dalvik VM• Dx-tool transforms compiled Java-files into dex-files

Application Framework/Applications

• Developers have full access to the same framework APIs used by the core applications including contacts, phone, browser, maps

• Simplifies the reuse of components• Any application can publish its capabilities and any other

application may then make use of those capabilities

What are we going to do?

Develop fantastic Android applications!

Outline

• Introduction• Android Application Development• Android User Interface• Android Example• MOPSI Related Development

Installing Android SDK

• Follows the instruction from Android document– http://developer.android.com/sdk/installing.html

• JDK 1.6• IDE Eclipse 3.5 or newer• Android SDK including docs, tools and examples• ADT Plugin for Eclipse

Hello Android Ⅰ

• File->New->Android Project

Hello Android Ⅱ

• Fill in the project details with the following values: – Project name: HelloAndroid

– Application name: Hello, Android

– Package name: com.example.hello (or your own private namespace)

– Create Activity: HelloAndroid

• Select Build Target– Android 2.2 version

• Click on “Finish”

Hello Android Ⅲ

Hello Android Ⅳ

• Run->run

Android Project Structure

Android Manifest

• The manifest presents essential information about the application to the Android system, information the system must have before it can run any of the application's code

Android Manifest Permissions

• A permission is a restriction limiting access to a part of the code or to data on the device.

• Includes– Internet– Location using GPS or Network– Writing data– …

<uses-permission android:name="android.permission.INTERNET" />

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

Android Application Components

• Activities– An activity presents a visual user interface for one focused

endeavor the user can undertake

• Services– A service doesn't have a visual user interface, but rather runs in

the background for an indefinite period of time

• Broadcast receivers– A broadcast receiver is a component that does nothing but

receive and react to broadcast announcements.

• Content providers– A content provider makes a specific set of the application's data

available to other applications.

Activity

• Single, focused thing or task• An application may have one or more activities• Refers to a single screen, displays a UI, interacts with

user, responses to events• Activities managed by activity stack• New activity put on top of stack• 3 states: active/running, paused, stopped • Activated by intent

– Context.startActivity() – Activity.startActivityForResult()

Activity Lifecycle

Activity Lifetime

• Entire lifetime of an activity happens between the first call to onCreate() through to a single final call to onDestroy()– Does initial setup in onCreate()– Releases all remaining resources e.g. stops thread

• Visible lifetime of an activity happens between a call to onStart() until a corresponding call to onStop()– User can see the activity on-screen – Maintain resources that are needed

• Foreground lifetime of an activity happens between a call to onResume() until a corresponding call to onPause()– Activity is in front of all other activities on screen and is interacting

with the user

Outline

• Introduction• Android Application Development• Android User Interface• Android Example• MOPSI Related Development

User Interface/View

• The user interface is built using view and viewgroup • View objects are the basic units of user interface

expression• A View object handles its own measurement, layout,

drawing, focus change, scrolling, and key/gesture interactions

• Read-made views: buttons, text fields, menu items, scroll bars and check boxes

Programmatic UI Layout

• Construct and build the UI of application directly from source code

• Drawback: small changes in layout can have a big effect on the source code

package com.android.hello;

import android.app.Activity;import android.os.Bundle;import android.widget.TextView;

public class HelloAndroid extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); TextView tv = new TextView(this); tv.setText("Hello, My Android!"); setContentView(tv); }}

Upgrading UI to XML Layout

• Inspired by web development model where the presentation of the application’s UI is separated from the logic

• Two files to edit– Java file: application logic– XML file: user interface

Upgrading UI to XML Layout

XML Layout

Common Layout Objects

• FrameLayout• LinearLayout• TableLayout• RelativeLayout

FrameLayout

• Simplest Layout Objects• Basically a blank space on your screen that you can later

fill with a single object — for example, a picture that you'll swap in and out

• All child elements of the FrameLayout are pinned to the top left corner of the screen

• Cannot specify a different location for a child view

LinearLayout

• Aligns all children in a single direction — vertically or horizontally

• All children are stacked one after the other, so a vertical list will only have one child per row, no matter how wide they are, and a horizontal list will only be one row high (the height of the tallest child, plus padding)

TableLayout

• Positions its children into rows and columns• Does not display border lines for rows, columns, or cells• TableRow, a child view, defines a single row in the table

<?xml version="1.0" encoding="utf-8"?><TableLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:stretchColumns="1">    <TableRow>        <TextView            android:text="@string/table_layout_4_open" android:padding="3dip" />        <TextView            android:text="@string/table_layout_4_open_shortcut"            android:gravity="right" android:padding="3dip" />    </TableRow>    <TableRow>        <TextView            android:text="@string/table_layout_4_save“ android:padding="3dip" />        <TextView            android:text="@string/table_layout_4_save_shortcut"            android:gravity="right" android:padding="3dip" />    </TableRow></TableLayout>

RelativeLayout

• Lets child views specify their position relative to the parent view or to each other (specified by ID)

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android  android:layout_width="fill_parent" android:layout_height="wrap_content"   android:background="@drawable/blue“ android:padding="10px" >

    <TextView android:id="@+id/label"         android:layout_width="fill_parent" android:layout_height="wrap_content"         android:text="Type here:" />

    <EditText android:id="@+id/entry"         android:layout_width="fill_parent" android:layout_height="wrap_content"         android:background="@android:drawable/editbox_background"        android:layout_below="@id/label" />     <Button android:id="@+id/ok"         android:layout_width="wrap_content" android:layout_height="wrap_content"         android:layout_below="@id/entry" android:layout_alignParentRight="true"        android:layout_marginLeft="10px" android:text="OK" />

    <Button android:layout_width="wrap_content"         android:layout_height="wrap_content“ android:layout_toLeftOf="@id/ok"        android:layout_alignTop="@id/ok“ android:text="Cancel" /></RelativeLayout>

Important View Groups

• Gallery: A horizontal scrolling display of images, from a bound list

• GridView: Displays a scrolling grid of m columns and n rows

• ListView: Displays a scrolling single column list• ScrollView: A vertically scrolling column of elements

• More resources:– http://developer.android.com/guide/topics/ui/layout-objects.html

Handling UI Events

• Capture the events from the specific View object that the user interacts with

public class ExampleActivity extends Activity implements OnClickListener {    protected void onCreate(Bundle savedValues) {        ...        Button button = (Button)findViewById(R.id.corky);        button.setOnClickListener(new OnClickListener() { public void onClick(View v) { // do something when the button is clicked }});    }    ...}

Outline

• Introduction• Android Application Development• Android User Interface• Android Example• MOPSI Related Development

Login Example

Login: Create Project

• File->New->Android Project• Fill in the project details with the

following values: – Project name: Login – Application name: Login, Demo – Package name:

com.example.login– Create Activity: Login

• Select Build Target– Android 2.2 version

• Click “Finish”

Login: Create colors.xml

• Create colors.xml to set color for text, background, ect

• Login->res->values, right click->New-> Android XML File

Login Example – Create colors.xml

• Fill the file name– colors.xml

• Select type– Values

• Click on “Finish”

Login: colors.xml and AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?><resources><color name="white">#ffffff</color><color name="blue">#3366cc</color></resources>

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.android.login" android:versionCode="1" android:versionName="1.0"> <application android:icon="@drawable/icon" android:label="@string/app_name"> <activity android:name=".Login" android:label="@string/app_name"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> <uses-permission android:name="android.permission.INTERNET" /></manifest>

Login: Main.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:background="@color/white" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <TextView android:id="@+id/login_user“ android:layout_width="wrap_content“ android:layout_height="wrap_content“ android:text="@string/username“ android:textColor="@color/blue“ android:gravity="left“ android:layout_marginLeft="12px“ android:layout_marginTop="10px" /><EditText android:id="@+id/txt_username" android:layout_width="fill_parent“ android:layout_height="wrap_content" android:hint="Username“ android:singleLine="true" android:textSize="18sp"android:layout_marginLeft="10px" android:layout_marginRight="10px" /><TextView android:id="@+id/login_pwd" android:layout_width="wrap_content“ android:layout_height="wrap_content" android:text="@string/password“ android:textColor="@color/blue" android:gravity="left“ android:layout_marginLeft="12px" /><EditText android:id="@+id/txt_password" android:layout_width="fill_parent“ android:layout_height="wrap_content" android:hint="Password“ android:singleLine="true" android:textSize="18sp" android:password="true"android:layout_marginLeft="10px" android:layout_marginRight="10px" /><Buttonandroid:layout_width="100px" android:layout_height="wrap_content"android:layout_marginTop="10px" android:layout_marginRight="15px"android:id="@+id/button_login" android:text="Login"android:layout_gravity="right" /> <TextView android:id="@+id/txt_response" android:layout_width="wrap_content“ android:layout_height="wrap_content" android:textSize="18sp" android:textColor="@color/blue" android:layout_marginLeft="10px" /></LinearLayout>

Login: Login.java

F:\Work\android\eclipse\Login\src\com\and

public class Login extends Activity {private static final String TAG = "Login";private ProgressDialog dialog;private Thread thrd;private EditText etxt_user;private EditText etxt_pass;private TextView tv_rp; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); etxt_user = (EditText) findViewById(R.id.txt_username);etxt_pass = (EditText) findViewById(R.id.txt_password);tv_rp = (TextView) this.findViewById(R.id.txt_response); Button loginin = (Button) findViewById(R.id.button_login);loginin.setOnClickListener(new OnClickListener() {public void onClick(View v) {dialog = ProgressDialog.show(Login.this, "","Singing in. Please wait...", true);

thrd = new Thread(new Runnable() {public void run() {tryLogin(); } });thrd.start(); }}); }

Login: Login.javapublic void tryLogin() {Log.v(TAG, "Trying to Login");String username = etxt_user.getText().toString();String password = etxt_pass.getText().toString();Log.v(TAG, "username:" + username + "password:" + password);String httpQuery = "http://cs.joensuu.fi/paikka/web/inc/mobilelogin.php?username="+ username + "&password=" + password;try {HttpGet request = new HttpGet(httpQuery);HttpClient httpClient = new DefaultHttpClient();HttpResponse response = httpClient.execute(request);Message login_msg = new Message();if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {String result = EntityUtils.toString(response.getEntity());

if (!result.equals("incorrect")) { // login successJSONObject json = new JSONObject(result);int userid = Integer.parseInt(json.getString("userid"));username = json.getString("username");Log.v(TAG, "userid:" + userid + "username:" + username);login_msg.obj = "SUCCESS";} else {login_msg.obj = "INCORRECT";}} else {login_msg.obj = "FAILED";}handler.sendMessage(login_msg);} catch (Exception e) {dialog.dismiss();Log.v(TAG, "login error:"+e.getMessage());}}

Login: Login.java/** * Use Handle to update UI */private Handler handler = new Handler() {

@Overridepublic void handleMessage(Message msg) {// close dialoguedialog.dismiss();String loginmsg = (String) msg.obj;Log.v(TAG, loginmsg);if (loginmsg.equals("SUCCESS")) {tv_rp.setText("Success!");//moving to other screen} else if (loginmsg.equals("INCORRECT")) {tv_rp.setText("Account is incorrect!");} else if (loginmsg.equals("FAILED")) {tv_rp.setText("No connection!"); }}};}

Login User Interface

Login User Interface

Outline

• Introduction• Android Application Development• Android User Interface• Android Example• MOPSI Related Development

MOPSI Related Development• Invoke device camera• Location and maps

Use Device Camera• android.hardware.Camera

– set image capture settings, start/stop preview, snap pictures, and retrieve frames for encoding for video

– declare the CAMERA permission in your Android Manifest • android.provider.MediaStore.ACTION_IMAGE_CAPTURE

– Invokes the camera application in your device

– Returns a small size image If the EXTRA_OUTPUT is not present

– Writes a full size image to the Uri if EXTRA_OUTPUT is present

Camera Hardware and Application

Camera hardware Camera application

Invoke Camera Application

// Invoke the camera of system and take photo, then go to send photo screenprivate void takePhoto() {Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);startActivityForResult(cameraIntent, CAMERA_PIC_REQUEST);}

//Process the image data from the cameraprotected void onActivityResult(int requestCode, int resultCode, Intent data) {try {if (requestCode == CAMERA_PIC_REQUEST && resultCode == RESULT_OK) {Bundle extras = data.getExtras();Bitmap thumbnail = (Bitmap) extras.get("data");// instantiate Intent, indicate the intent to be invokedIntent intent = new Intent();intent.setClass(this, SendPhoto.class);// instantiate Bundle, set the parameters to be passedintent.putExtra("image", thumbnail);// start the new intent without responsethis.startActivity(intent);}} catch (Exception e) {Log.v(TAG, e.getMessage());}}

Location and Maps

• Get location– GPS: accurate, slow, only for outdoors– Network: using cell tower or Wi-Fi, not very accurate, fast– Set permission

• <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

• Get Maps– Maps external library that includes the com.google.android.maps

package – http://code.google.com/android/add-ons/google-apis

Get Location

private LocationManager mLocationManager;// Acquire a reference to the system Location ManagermLocationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);// Register the listener with the Location Manager to receive location updatesmLocationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, minTime, minDist, networkListener);mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,0, 0, gpsListener);// Define a listener that responds to location updatespublic final LocationListener networkListener = new LocationListener() {

public void onLocationChanged(Location location) {double lat = location.getLatitude()double lon = location.getLongitude()

double alt = location.getAltitude()//doLocationUpdated(location); // do other things}public void onStatusChanged(String provider, int status, Bundle extras) {}public void onProviderEnabled(String provider) {}public void onProviderDisabled(String provider) {}

};

MOPSI Android: Main Screen

Login UI Main UI Setting UI

MOPSI Android: Taking Photo

Camera Add description Photo uploading

MOPSI Android: Tracking Route

Route tracking Options in tracking Saved tracking routes

Thank you!

jinhuachen1982@gmail.com