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Presented at SpringOne 2GX 2011
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• Roy Clarkson & Josh LongSpringSource, a division of VMware
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Native Android Development Practices
@royclarkson
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About Roy Clarkson (Spring Android Lead)
@royclarkson
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About Roy Clarkson (Spring Android Lead)
@royclarkson
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About Roy Clarkson (Spring Android Lead)
@starbuxman
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About Josh Long (Spring Developer Advocate)
Spring Mobile
• Provides support for developing mobile web applications– Builds on Spring MVC, focuses on server-side support– Compliments client-side mobile frameworks
• Key Features– Device Detection– Site Preference Management– Site Switcher
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Device Detection
• Useful when requests by mobile devices need to be handled differently from requests made by desktop browsers
• Introspects HTTP requests to determine the device that originated the request.– Achieved by analyzing the User-Agent header and other
request headers– In contrast to “Feature Detection” where client detects
available features
• Spring Mobile provides a DeviceResolver abstraction and interceptor
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Device Detection Demo
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Site Preference Management
• Device detection is often used to determine which "site" will be served to the user– Mobile site vs. desktop site
• Spring Mobile also provides support for “site preference management”
• Allows the user to indicate whether he or she prefers the mobile site or the normal site
• Remembers the user’s preference for their session
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Site Preference Demo
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Site Switcher
• Some applications may wish to host their "mobile site" at a different domain from their "normal site"– For example, Google will switch you to m.google.com if you
access google.com from your mobile phone
• SiteSwitcherHandlerInterceptor can be used to redirect mobile users to a dedicated mobile site
• Supported SiteSwitchers– mDot - m.example.com– dotMobi - example.mobi
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Site Switcher Demo
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Limitations of Mobile web sites
• they can’t access the native capabilities of the phone• they require network access (no offline support)• formatting an application to look mobile is different than
actually being a mobile application
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Agenda
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Agenda
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Agenda
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An Introduction to Android!
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More than 500,000 activations every day
An Introduction to Android!
• Huge and growing ecosystem ofapplications and a market to boot
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8.1 billion app downloadsAndroid Market PlaceApple App Store 6 billion
* http://news.cnet.com/8301-1035_3-20103230-94/android-to-overtake-apple-in-app-downloads/
Expected downloads in 2011
Easy to get started
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• Programs are written in Java ( )
Easy to get started
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• Programs are written in Java ( )
Easy to get started
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• Programs are written in Java ( )
Easy APIs and concepts
• no real “applications,” only loosely coupled components
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Activities describes the unit of work for one screen
Services does background work like synchronization with a cloud service
Content Providers component that knows how to render and manipulate content of a certain type
Broadcast Receivers knows how to receive and respond to system-wide events like screen shutoff.
* http://developer.android.com/guide/topics/fundamentals.html
A Simple Activity
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package org.springframework.android.activities;
import android.app.Activity;import android.os.Bundle;
public class HelloAndroid extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); }
}
You *must* extend Android classes to build proper components
A Simple Activity
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package org.springframework.android.activities;
import android.app.Activity;import android.os.Bundle;
public class HelloAndroid extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); }
}
You *must* extend Android classes to build proper components
R.* refers to constants that Android code generates for you that correspond to “resources”
A Simple Activity
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package org.springframework.android.activities;
import android.app.Activity;import android.os.Bundle;
public class HelloAndroid extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); }
}
Declaring the Simple Activity
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<?xml version="1.0" encoding="utf-8"?><TextView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/textview" android:layout_width="fill_parent" android:layout_height="fill_parent" android:text="@string/hello"/>
/res/layout/main.xml
<?xml version="1.0" encoding="utf-8"?><resources> <string name="hello">Hello, Android! I am a string resource!</string> <string name="app_name">Hello, Android</string></resources>
/res/values/strings.xml
Lifecycle
• Android controls lifecycles of these components• Registered in manifest
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<activity android:name=".activities.HelloAndroid android:label="@string/app_name" android:theme="@android:style/Theme.NoTitleBar"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter></activity>
Class is set relative to root package specified in manifest
Lifecycle
• Android controls lifecycles of these components• Registered in manifest
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<activity android:name=".activities.HelloAndroid android:label="@string/app_name" android:theme="@android:style/Theme.NoTitleBar"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter></activity>
you specify that an Activity is the primary one like this
Class is set relative to root package specified in manifest
Lifecycle
• Android controls lifecycles of these components• Registered in manifest
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<activity android:name=".activities.HelloAndroid android:label="@string/app_name" android:theme="@android:style/Theme.NoTitleBar"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter></activity>
Android Sample Demo
• How to use STS and the Android Eclipse plugin
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How can Maven help?
• Android4Maven– This project compiles android.jar from source and pulls out
source and resource files to replicate android.jar in the SDK– http://sourceforge.net/projects/android4maven/
• Maven Android SDK Deployer– If you need to use Google maps, then you have to go this
route– https://github.com/mosabua/maven-android-sdk-deployer
• Maven Android Plugin– Provides support for Maven dependency management within
Android projects– http://code.google.com/p/maven-android-plugin/
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Maven Android Plugin Configuration
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<plugins> <plugin> <groupId>com.jayway.maven.plugins.android.generation2</groupId> <artifactId>maven-android-plugin</artifactId> <version>2.8.4</version> <configuration> <sdk> <platform>3</platform> </sdk> <emulator> <avd>3</avd> </emulator> <deleteConflictingFiles>true</deleteConflictingFiles> <undeployBeforeDeploy>true</undeployBeforeDeploy> </configuration> <extensions>true</extensions> </plugin>
m2eclipse Support
• Maven Integration for Android Development Tools– An Eclipse plugin that adds support for integrating
m2eclipse, Android Developer Tools, and the Maven Android Plugin
– http://code.google.com/a/eclipselabs.org/p/m2eclipse-android-integration/
• Maven Android archetypes– This projects provides several Maven archetypes for
Android. These archetypes allow you to quickly bootstrap a Maven project to develop an android application.
– https://github.com/akquinet/android-archetypes
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http://blog.springsource.com/2010/12/17/spring-android-and-maven-part-1/http://blog.springsource.com/2010/12/17/spring-android-and-maven-part-2/
Running the simple Activity
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Running the simple Activity
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...what about something a bit more non-trivial?
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Spring’s aim:
bring simplicity to java development
modern web data access integration mobile social security
tc ServerTomcatJetty
lightweightCloudFoundry
Google App EngineAmazon Web Services
BeanStalkHeroku
the cloud: WebSphereJBoss ASWebLogic
(on legacy versions, too!)
traditional
The Spring framework
security
Enter Spring Android!
What problem are we trying to solve?
• Concerns– REST has become a popular choice for architecting both
public and private web services– The Android runtime provides HTTP clients capable of
making HTTP connections and requests, but it does not have a fully featured REST client
• Spring Android Solution– The goal of Spring Android Rest Template is to provide an
easy to use, and functional REST client that supports marshaling objects from XML and JSON.
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REST
• Origin– The term Representational State Transfer was introduced and
defined in 2000 by Roy Fielding in his doctoral dissertation.• His paper suggests these four design principles:
– Use HTTP methods explicitly.• POST, GET, PUT, DELETE• CRUD operations can be mapped to these existing methods
– Be stateless.• State dependencies limit or restrict scalability
– Expose directory structure-like URIs.• URI’s should be easily understood
– Transfer XML, JavaScript Object Notation (JSON), or both.• Use XML or JSON to represent data objects or attributes
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Basic Rest Template Example
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RestTemplate restTemplate = new RestTemplate();String url = "https://ajax.googleapis.com/ajax/services/search/web?v=1.0&q={query}";String result = restTemplate.getForObject(url, String.class, "SpringSource");
RestTemplate restTemplate = new RestTemplate();String url = "http://example.com/hotels/{hotel}/bookings/{booking}";String result = restTemplate.getForObject(url, String.class, "42", “21”);
§ Google search example
§ Multiple parameters
Demo
• Using Spring Android to communicate with a RESTful web service (Google Search Demo)
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Spring Android Rest Template
• Based on SpringFramework– The majority of the supporting classes are pulled from
SpringFramework.– Modifications were made to support Android.
• RestTemplate class is the heart of the library– Entry points for the six main HTTP methods
• DELETE - delete(...)• GET - getForObject(...)• HEAD - headForHeaders(...)• OPTIONS - optionsForAllow(...)• POST - postForLocation(...)• PUT - put(...)• any HTTP operation - exchange(...) and execute(...)
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Spring Android Rest Template
• Http Client– The HttpComponents HttpClient is a native HTTP client
available on the Android platform.– HttpComponentsClientHttpRequestFactory
• Message Converters– MappingJacksonHttpMessageConverter - object to
JSON marshaling supported via the Jackson JSON Processor
– SimpleXmlHttpMessageConverter - object to XML marshaling supported via the Simple XML Serializer
– SyndFeedHttpMessageConverter - RSS and Atom feeds supported via the Android ROME Feed Reader
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Spring Android Showcase
• Examples– HTTP GET
• JSON• XML
– HTTP GET with Parameters• JSON• XML
– HTTP POST• String• JSON• XML• MultiValueMap
– HTTP and GZIP
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Spring Android Demos
• Spring Android Showcase Demo
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Spring Social on Android
• Supports connecting to supported Spring Social services• uses same RESTful connectivity based on RestTemplate
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Enter Spring Android!
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do NOT reinvent the Wheel!
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Dependency Injection on Android
• Problems with DI on Android– hard reliance on base classes– hard reliance on Android to manage the runtime lifecycle
• a POJO peer system would have been onerous
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Dependency Injection on Android
• Lots of options– RoboGuice– Android Annotations– the Android way
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Dependency Injection on Android
• RoboGuice (http://code.google.com/p/roboguice/)– Pros:
• requires you to extend RoboApplication• You must configure your beans using the
AbstractAndroidModule• Each Activity must extend from RoboActivity
– Cons:• no AOP• not small, at all!
– (400kb to a mobile application may as well be 400MBs to your enterprise application!)
public class MyActivity extends Activity { private TextView label; private Drawable image; private SearchManager searchManager; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.myactivity); this.label = (TextView) findViewById(R.id.mylabel); this.image = getResources().getDrawable(R.drawable.myimage); this.searchManager = (SearchManager) getSystemService(Activity.SEARCH_SERVICE); }}
before RoboGuice
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Dependency Injection on Android
• RoboGuice (http://code.google.com/p/roboguice/)
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Dependency Injection on Android
• RoboGuice (http://code.google.com/p/roboguice/)
public class MyActivity extends RoboActivity { @InjectView(R.id.mylabel) TextView label; @InjectResource(R.drawable.myimage) Drawable image; @Inject SearchManager searchManager; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.myactivity); }}
with RoboGuice
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Dependency Injection on Android
• RoboGuice (http://code.google.com/p/roboguice/)
used to inject other widgets or “views”
public class MyActivity extends RoboActivity { @InjectView(R.id.mylabel) TextView label; @InjectResource(R.drawable.myimage) Drawable image; @Inject SearchManager searchManager; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.myactivity); }}
with RoboGuice
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Dependency Injection on Android
• RoboGuice (http://code.google.com/p/roboguice/)
used to inject Resources
used to inject other widgets or “views”
public class MyActivity extends RoboActivity { @InjectView(R.id.mylabel) TextView label; @InjectResource(R.drawable.myimage) Drawable image; @Inject SearchManager searchManager; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.myactivity); }}
with RoboGuice
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Dependency Injection on Android
• RoboGuice (http://code.google.com/p/roboguice/)
used to inject other objects
used to inject Resources
used to inject other widgets or “views”
public class MyActivity extends RoboActivity { @InjectView(R.id.mylabel) TextView label; @InjectResource(R.drawable.myimage) Drawable image; @Inject SearchManager searchManager; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.myactivity); }}
with RoboGuice
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Dependency Injection on Android
• RoboGuice (http://code.google.com/p/roboguice/)
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Dependency Injection on Android
• RoboGuice (http://code.google.com/p/roboguice/)– Pros:
• requires you to extend RoboApplication• You must configure your beans using the
AbstractAndroidModule• Each Activity must extend from RoboActivity
– Cons:• no AOP• not small, at all!
– (400kb to a mobile application may as well be 400MBs to your enterprise application!)
• runtime inefficiency
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Beyond Dependency Injection
• Android Annotations(http://code.google.com/p/androidannotations/)– Pros:
• compile-time code generation means no runtime cost• can be used side-by-side with RoboGuice
– Cons:• extra build step• some redundancy with RoboGuice
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Beyond Dependency Injection
• Android Annotations(http://code.google.com/p/androidannotations/)
@EActivity(R.layout.myactivity) public class MyActivity extends Activity { @InjectView TextView mylabel; @DrawableRes(R.drawable.myimage) Drawable image; @SystemService SearchManager searchManager;}
sets the layout
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Beyond Dependency Injection
• Android Annotations(http://code.google.com/p/androidannotations/)
@EActivity(R.layout.myactivity) public class MyActivity extends Activity { @InjectView TextView mylabel; @DrawableRes(R.drawable.myimage) Drawable image; @SystemService SearchManager searchManager;}
sets the layout
Inject another widget or “view”
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Beyond Dependency Injection
• Android Annotations(http://code.google.com/p/androidannotations/)
@EActivity(R.layout.myactivity) public class MyActivity extends Activity { @InjectView TextView mylabel; @DrawableRes(R.drawable.myimage) Drawable image; @SystemService SearchManager searchManager;}
sets the layout
Inject another widget or “view”
specify a resource id (it is optional)
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Beyond Dependency Injection
• Android Annotations(http://code.google.com/p/androidannotations/)
@EActivity(R.layout.myactivity) public class MyActivity extends Activity { @InjectView TextView mylabel; @DrawableRes(R.drawable.myimage) Drawable image; @SystemService SearchManager searchManager;}
sets the layout
Inject another widget or “view”
specify a resource id (it is optional)
Inject objects configured manually
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Beyond Dependency Injection
• Android Annotations(http://code.google.com/p/androidannotations/)
@EActivity(R.layout.myactivity) public class MyActivity extends Activity { @InjectView TextView mylabel; @DrawableRes(R.drawable.myimage) Drawable image; @SystemService SearchManager searchManager;}
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Dependency Injection on Android
• The Android way – android applications all have required access to a single
“Application” class– You can override the Application class– Thus, instant singleton!
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Dependency Injection on Android
• The Android way public class MainApplication extends Application { private MyService service; @Override public void onCreate() { super.onCreate(); service = new MyServiceImpl(); } public MyService getMyService() { return this.service; }}
extend the Application
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Dependency Injection on Android
• The Android way public class MainApplication extends Application { private MyService service; @Override public void onCreate() { super.onCreate(); service = new MyServiceImpl(); } public MyService getMyService() { return this.service; }}
register your global singleton services
extend the Application
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Dependency Injection on Android
• The Android way public class MainApplication extends Application { private MyService service; @Override public void onCreate() { super.onCreate(); service = new MyServiceImpl(); } public MyService getMyService() { return this.service; }}
public class MainActivity extends Activity { private MyService service; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); MainApplication app = (MainApplication) getApplication(); service = app.getMyService(); }}
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Dependency Injection on Android
• The Android way
get a pointer to the Application
public class MainActivity extends Activity { private MyService service; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); MainApplication app = (MainApplication) getApplication(); service = app.getMyService(); }}
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Dependency Injection on Android
• The Android way
access your service
get a pointer to the Application
public class MainActivity extends Activity { private MyService service; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); MainApplication app = (MainApplication) getApplication(); service = app.getMyService(); }}
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Dependency Injection on Android
• The Android way
Additional Resources
• Project Home– http://www.springsource.org/spring-android– http://www.springsource.org/spring-mobile
• Sample Code– https://github.com/SpringSource/spring-android-samples.git– https://github.com/SpringSource/spring-mobile-samples.git
• Blog Posts– http://blog.springsource.org
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© 2011 SpringOne 2GX 2011. All rights reserved. Do not distribute without permission.
Q&A
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