介绍两个Android开源项目：Android显示GIF动画

浏览数：202 / 时间：2015年06月11日

Android开源项目：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

解码线程类

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

Views and Drawable for animated GIFs in Android.

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

Overview

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

Download

Latest release downloads

Setup

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-level build.gradle like this:

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

Maven dependency

SDK with API level 19 is needed. If you don‘t have it in your local repository, downloadmaven-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>

Requirements

Android 1.6+ (API level 4+)

Building from source

Android NDK needed to compile native sources

Usage

From XML

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 asGifDrawables and animated. If given drawable is not a GIF then mentioned Views work like plainImageView and ImageButton.

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"
    />

From Java code

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. Callingrecycle() 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

UsingMediaPlayerControl

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)