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Created by Fang on November 22, 2011 10:40:16
Last update: November 22, 2011 10:40:16
This is an example that uses tag handler, UI component and renderer together to support a custom taglib. The main purpose is to show how these components play together.
The tag renders
<ui:param name="extra" value="el interpreted"/>
...
as
<h3>my:foreach</h3>
<ul class="css class" extra...
These are the files:
The tag handler ( src/main/java/com/example/ForeachTagHandler.java ):
package com.example;
import java.util.Map;
...
The UI component ( src/main/java/com/example/UIForeach.java ):
package com.example;
import java.io.IOExcep...
The renderer ( src/main/java/com/example/ForeachRenderer.java ):
package com.example;
import java.io.IOExcep...
Faces config ( src/main/resources/META-INF/faces-config.xml ):
<?xml version="1.0" encoding="UTF-8"?>
<faces-c...
Taglib config ( src/main/resources/META-INF/foreach.taglib.xml ):
<?xml version="1.0" encoding="UTF-8"?>
<facelet...
Created by freyo on May 13, 2011 15:45:29
Last update: September 20, 2011 08:08:12
This is an Android app that dumps any binarized xml file as plain text - to the sdcard on the device or emulator.
build.xml :
<?xml version="1.0" encoding="UTF-8"?>
<project...
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<man...
res/layout/main.xml
<?xml version="1.0" encoding="utf-8"?>
<Lin...
res/values/strings.xml :
<?xml version="1.0" encoding="utf-8"?>
<res...
src/com/android/xmltool/DumpXml.java
package com.android.xmltool;
import java.ut...
Screenshot
Pre-built APK can be downloaded from: http://code.google.com/p/android-binxml-dump/
Created by freyo on July 27, 2011 12:13:52
Last update: July 27, 2011 12:13:52
Implement the provider. Put the initialization code in onCreate , implement the necessary query and update methods. This is a skeleton:
package my.package;
import android.content....
Declare the content provider in AndroidManifest.xml , with content authority (any string identifier):
<?xml version="1.0" encoding="utf-8"?>
<manifes...
Use the provider (content consumer code):
// import android.content.ContentResolver;
Cont...
Created by freyo on July 21, 2011 15:31:11
Last update: July 21, 2011 15:31:11
Override onSaveInstanceState to save the state of an Activity instance. Restore the state in onCreate :
@Override
public void onCreate(Bundle savedInst...
The state only exists while the application is still in the history stack. It is lost if the application is terminated (finalized).
Created by alfa on June 07, 2011 11:34:26
Last update: June 07, 2011 11:36:37
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...
Created by alfa on June 03, 2011 12:36:14
Last update: June 03, 2011 12:36:14
Thread local storage is typically used to associate state with a thread (e.g., a user ID or Transaction ID). This example, coming from Java API doc , assigns a unique id to each thread that calls getCurrentThreadId() . The actual usage is demonstrated with the Java concurrency package.
import java.util.concurrent.Future;
import java...
Created by alfa on June 03, 2011 09:41:03
Last update: June 03, 2011 09:41:03
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...
Created by alfa on June 02, 2011 15:26:37
Last update: June 02, 2011 15:26:37
While doing some Java reflection code, I noticed the method Class.isSynthetic() , which the JavaDoc says returns " true if and only if this class is a synthetic class as defined by the Java Language Specification". However, there's no definition of "synthetic class" in the JLS ! The only thing that I can find that remotely resembles a definition is in the JVM spec , where it defines the synthetic attribute : "The Synthetic attribute is a fixed-length attribute in the attributes table of ClassFile (§4.1), field_info (§4.5), and method_info (§4.6) structures. A class member that does not appear in the source code must be marked using a Synthetic attribute." By this definition, a default constructor, which does not appear in the source code, should...
Created by freyo on May 17, 2011 11:13:17
Last update: May 17, 2011 11:13:17
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...
Created by freyo on April 12, 2011 15:13:32
Last update: May 03, 2011 15:20:55
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......