（4.2.28）项目中使用的gif开源组件----android-gif-drawable

前言：

1. GifView：已知bug : 如果图档过大，会出现OOM为了解决图档太大时的OOM，我想把gif解析时的图片先存入到文件中，在显示时直接从文件中读入，但这样的话，显示的效果不好。
2. android-gif-drawable并没有此问题，底层解码使用C实现，极大的提高了解码效率，同时很大程度上避免了OOM现象出现。
   

GifView——Android显示GIF动画

作者：ant.cy.liao

主页： http://code.google.com/p/gifview/

下载： http://code.google.com/p/gifview/downloads/list

简介：android中现在没有直接显示gif的view,只能通过mediaplay来显示，且还常常不能正常显示出来，为此写了这个gifview，其用法和imageview一样

使用方法：

1-把GifView.jar加入你的项目。

2-在xml中配置GifView的基本属性，GifView继承自View类，和Button、ImageView一样是一个UI控件。如：

<com.ant.liao.GifView android:id="@+id/gif2"
  android:layout_height="wrap_content" android:layout_width="wrap_content"
  android:paddingTop="4px" android:paddingLeft="14px" android:enabled="false" />

3-在代码中配置常用属性：

// 从xml中得到GifView的句柄
    gf1 = (GifView) findViewById(R.id.gif1);
    // 设置Gif图片源
    gf1.setGifImage(R.drawable.gif1);
    // 添加监听器
    gf1.setOnClickListener(this);
    // 设置显示的大小，拉伸或者压缩
    gf1.setShowDimension(300, 300);
    // 设置加载方式：先加载后显示、边加载边显示、只显示第一帧再显示
    gf1.setGifImageType(GifImageType.COVER);

GifView的Jar包共有四个类：

GifAction.java:

观察者类，监视GIF是否加载成功

package com.ant.liao;  
public interface GifAction {
/**
  *gif解码观察者
  * @hide
  * @param parseStatus 解码是否成功，成功会为true           
  * @param frameIndex 当前解码的第几帧，当全部解码成功后，这里为-1           
  */     
public void parseOk(boolean parseStatus,int frameIndex);  }

GifFrame.java

里面三个成员：当前图片、延时、下张Frame的链接。

package com.ant.liao;
import android.graphics.Bitmap;
public class GifFrame { 
/**
* 构造函数 
* @param im 图片 
* @param del 延时 
*/        
public GifFrame(Bitmap im, int del) {  
image = im;         
delay = del;     
}           
public GifFrame(String name,int del){   
imageName = name;         
delay = del;        
}               
/**图片*/      
public Bitmap image;   
/**延时*/        
public int delay;  
/**当图片存成文件时的文件名*/ 
public String imageName = null;      
/**下一帧*/      
public GifFrame nextFrame = null; 
}

GifDecoder.java

http://code.google.com/p/gifview/source/browse/trunk/src/com/ant/liao/GifDecoder.java

GifView.java

主类，包括常用方法，如GifView构造方法、设置图片源、延迟、绘制等。

http://code.google.com/p/gifview/source/browse/trunk/src/com/ant/liao/GifView.java

Android开源项目：android-gif-drawable——Android显示GIF动画

android-gif-drawable

View s and Drawable for animated GIFs in Android.

项目地址： https://github.com/koral--/android-gif-drawable

Bundled GIFLib via JNI is used to render frames. This way should be more efficient than WebView or Movie classes. 
Animation starts automatically and run only if View with attached GifDrawable is visible.

Latest release downloads

Gradle (Android Studio)

Insert the following dependency to build.gradle file of your project.

dependencies {
    compile 'pl.droidsonroids.gif:android-gif-drawable:1.0.+'
}

Note that Maven central repository should be defined eg. in top-levelbuild.gradle like this:

buildscript {
  repositories {
    mavenCentral()
  }
}
allprojects {
  repositories {
    mavenCentral()
  }
}

SDK with API level 19 is needed. If you don't have it in your local repository, download maven-android-sdk-deployer and install SDK level 19: mvn install -P 4.4 (from maven-android-sdk-deployer directory). Then add dependency inpom.xml of your project:

<dependency>
    <groupId>pl.droidsonroids.gif</groupId>
    <artifactId>android-gif-drawable</artifactId>
    <version>insert latest version here</version>
    <type>aar</type>
</dependency>

• Android 1.6+ (API level 4+)

Building from source

• Android NDK needed to compile native sources

The simplest way is to use GifImageView (or GifImageButton ) like a normalImageView :

<pl.droidsonroids.gif.GifImageView  android:layout_width="match_parent"  android:layout_height="match_parent"  android:src="@drawable/src_anim"
 android:background="@drawable/bg_anim"
 />

If drawables declared by android:src and/or android:background are GIF files then they will be automatically recognized as GifDrawable s and animated. If given drawable is not a GIF then mentioned Views work like plain ImageView andImageButton .

GifTextView allows you to use GIFs as compound drawables and background.

<pl.droidsonroids.gif.GifTextView  android:layout_width="match_parent"  android:layout_height="match_parent"  android:drawableTop="@drawable/left_anim"
 android:drawableStart="@drawable/left_anim"
 android:background="@drawable/bg_anim"
 />

GifImageView , GifImageButton and GifTextView have also hooks for setters implemented. So animated GIFs can be set by callingsetImageResource(int resId) and setBackgroundResource(int resId)

GifDrawable can be constructed directly from various sources:

//asset file
  GifDrawable gifFromAssets = new GifDrawable( getAssets(), "anim.gif" );

  //resource (drawable or raw)
  GifDrawable gifFromResource = new GifDrawable( getResources(), R.drawable.anim );

  //byte array
  byte[] rawGifBytes = ...
  GifDrawable gifFromBytes = new GifDrawable( rawGifBytes );

  //FileDescriptor
  FileDescriptor fd = new RandomAccessFile( "/path/anim.gif", "r" ).getFD();
  GifDrawable gifFromFd = new GifDrawable( fd );

  //file path
  GifDrawable gifFromPath = new GifDrawable( "/path/anim.gif" );

  //file
  File gifFile = new File(getFilesDir(),"anim.gif");
  GifDrawable gifFromFile = new GifDrawable(gifFile);

  //AssetFileDescriptor
  AssetFileDescriptor afd = getAssets().openFd( "anim.gif" );
  GifDrawable gifFromAfd = new GifDrawable( afd );

  //InputStream (it must support marking)
  InputStream sourceIs = ...
  BufferedInputStream bis = new BufferedInputStream( sourceIs, GIF_LENGTH );
  GifDrawable gifFromStream = new GifDrawable( bis );

  //direct ByteBuffer
  ByteBuffer rawGifBytes = ...
  GifDrawable gifFromBytes = new GifDrawable( rawGifBytes );

InputStreams are closed automatically in finalizer if GifDrawable is no longer needed so you don't need to explicitly close them. Calling recycle() will also close underlaying input source.

Note that all input sources need to have ability to rewind to the begining. It is required to correctly play animated GIFs (where animation is repeatable) since subsequent frames are decoded on demand from source.

Animation control

GifDrawable implements an Animatable and MediaPlayerControl so you can use its methods and more:

• stop() - stops the animation, can be called from any thread
• start() - starts the animation, can be called from any thread
• isRunning() - returns whether animation is currently running or not
• reset() - rewinds the animation, does not restart stopped one
• setSpeed(float factor) - sets new animation speed factor, eg. passing 2.0f will double the animation speed
• seekTo(int position) - seeks animation (within current loop) to givenposition (in milliseconds) Only seeking forward is supported
• getDuration() - returns duration of one loop of the animation
• getCurrentPosition() - returns elapsed time from the beginning of a current loop of animation

Using MediaPlayerControl

Standard controls for a MediaPlayer (like in VideoView ) can be used to control GIF animation and show its current progress.

Just set GifDrawable as MediaPlayer on your MediaController like this:

@Override
  protected void onCreate ( Bundle savedInstanceState )
  {
    super.onCreate( savedInstanceState );
    GifImageButton gib = new GifImageButton( this );
    setContentView( gib );
    gib.setImageResource( R.drawable.sample );
    final MediaController mc = new MediaController( this );
    mc.setMediaPlayer( ( GifDrawable ) gib.getDrawable() );
    mc.setAnchorView( gib );
    gib.setOnClickListener( new OnClickListener()
    {
      @Override
      public void onClick ( View v )
      {
        mc.show();
      }
    } );
  }

Retrieving GIF metadata

• getLoopCount() - returns a loop count as defined in NETSCAPE 2.0 extension
• getNumberOfFrames() - returns number of frames (at least 1)
• getComment() - returns comment text ( null if GIF has no comment)
• getFrameByteCount() - returns minimum number of bytes that can be used to store pixels of the single frame
• getAllocationByteCount() - returns size (in bytes) of the allocated memory used to store pixels of given GifDrawable
• getInputSourceByteCount() - returns length (in bytes) of the backing input data
• toString() - returns human readable information about image size and number of frames (intended for debugging purpose)

• recycle() - provided to speed up freeing memory (like inandroid.graphics.Bitmap ).
• getError() - returns last error details

This library uses code from GIFLIB 5.0.5 and SKIA .