This is an example that uses dynamic proxies to trace method calls (in logging) and print out elapsed times for them. Because dynamic proxies can only be generated for interfaces, the service classes must be implemented with interface-implementation pairs. Create services A and B. A.java : public interface A { public void service1()... AImpl.java : import java.util.Random; public class AImpl... B.java : public interface B { public void service1()... BImpl.java : public class BImpl implements B { public vo... The call trace proxy: import java.lang.reflect.*; class TraceProx... The performance proxy: import java.lang.reflect.*; class Performan... The service factory: import java.lang.reflect.*; public class Se... The test class: public class Test { public static void main... The output: Entering AImpl.service1 Entering BImpl.service1... The above example has no information...

Dynamic proxy can be used to eliminate the need to stub out unused interface methods. This is an example for a simple SAX content handler for XML parsing. The org.xml.sax.ContentHandler interface requires 11 methods be implemented but we only need three: import java.io.IOException; import java.util.Ar... With a dynamic proxy, we don't need the empty blocks for the unused methods: import java.io.IOException; import java.util.Ar... Equivalently (with anonymous inner class): import java.io.IOException; import java.util.Ar... demo.xml : <breakfast-menu> <food> <name>Belgian W...

This is an odd-ball content provider in that it doesn't provide database records, but provides a resource as a stream. It can be used to provide media files or XML resources. Start the project with: tools/android create project --package com.android... Create assets directory and add an XML file ( assets/demo.xml ): <? xml version="1.0" encoding="UTF-8"?> <people... Edit the layout ( res/layout/main.xml ): <?xml version="1.0" encoding="utf-8"?> <LinearL... Edit src/com/android/cptest/Dummy.java : package com.android.cptest; import java.io.... Add content provider ( src/com/android/cptest/XmlResource.java ): package com.android.cptest; import java.io.... Update AndroidManifest.xml : <?xml version="1.0" encoding="utf-8"?> <manifes... Add this section to the end of build.xml : <target name="-package-resources"> <ech... Build and install: ant install Screenshot: Remove the Dummy activity ( AndroidManifest.xml ): <?xml version="1.0" encoding="utf-8"?> <manifes... Create a new project for...

This example uses an Intent with Uri scheme tel: to invoke the phone dialer. Create a new project with: $ ~/android-sdk-linux_86/tools/android create proj... Update the layout res/layout/main.xml to add a text field and a button: <?xml version="1.0" encoding="utf-8"?> <LinearL... Update the Java class src/com/android/intenttest/CallPhone.java to handle button click and start the built-in phone dialer with Intent : package com.android.intenttest; import andr... Update AndroidManifest.xml to add CALL_PHONE permission: <?xml version="1.0" encoding="utf-8"?> <manifes... Install to the emulator and test: ant install The phone dialer will be invoked when you click the "Call" button. So how did this happen? The CallPhone activity creates an Intent with action Intent.ACTION_CALL and Uri tel:<a number> and sends it off to Android. Android starts the activity com.android.phone.OutgoingCallBroadcaster because the intent matches the...

Create new project $ tools/android create project \ > --package co... Edit res/values/string.xml , add strings for the main screen. <?xml version="1.0" encoding="utf-8"?> <resourc... Add widgets to main layout ( res/layout/main.xml ). <?xml version="1.0" encoding="utf-8"?> <LinearL... Edit src/com/android/apkinfo/GetAPKPermissions.java and change contents to: package com.android.apkinfo; import android... Install the debug package to the emulator: ant install The screen should look like: Add display permissions activity. Start by creating a new layout res/layout/display_permissions.xml : <?xml version="1.0" encoding="utf-8"?> <LinearL... Add the strings used by the new Activity ( res/values/strings.xml ): <?xml version="1.0" encoding="utf-8"?> <resourc... Add the Display Permissions Activity ( src/com/android/apkinfo/DisplayPermissions.java ): package com.android.apkinfo; import android... Change src/com/android/apkinfo/GetAPKPermissions.java to invoke the Display Permissions Activity: package com.android.apkinfo; import android... Declare Display Permissions Activity in AndroidManifest.xml : <?xml version="1.0" encoding="utf-8"?> <manifes......

Generate android project $ ~/android-sdk-linux_86/tools/android create proj... Create XML file res/xml/books.xml : <?xml version="1.0"?> <catalog> <book id=... Edit layout ( res/layout/main.xml ): <?xml version="1.0" encoding="utf-8"?> <Lin... Edit code ( src/com/android/xmlres/XMLResource.java ): package com.android.xmlres; import java.io.... Change activity label from app_name to booklist ( AndroidManifest.xml ): <?xml version="1.0" encoding="utf-8"?> <manifes... Add value for string resource ( res/values/string.xml ): <?xml version="1.0" encoding="utf-8"?> <resourc... Deploy and test: ant install

Follow these steps to build your first app that allows you to enter input and click a button: Start from the Hello World example. Edit res/layout/main.xml , change the contents to: <?xml version="1.0" encoding="utf-8"?> <LinearL... This adds a text input field and a button to the screen. It also declaratively binds an event handler ( onClick="sayHi" ) to the button. Add the string resources ( res/values/strings.xml ): <?xml version="1.0" encoding="utf-8"?> <resourc... Implement the event handler ( src/com/android/helloworld/HelloWorld.java ): package com.android.helloworld; import andr... Change the Activity label to Greeting ( AndroidManifest.xml ): <?xml version="1.0" encoding="utf-8"?> <manifes... Reinstall the debug package to the emulator: ant install The screen should look like this:

The android.util.Log class provide facilities for applications to send log output. For example, after adding two log lines to the HelloWorld class: package com.android.helloworld; import andr... the messages will be printed out to the system log when the HelloWorld application is launched. This can be verified by running adb logcat : I/ActivityManager( 60): Start proc com.android.h...