Android中帧动画在Activity启动时自动运行的几种方式

第一种方式启动帧动画：（在Activity启动时会自动运行动画） 
AnimationDrawable ad； 
ImageView iv = (ImageView) findViewById(R.id.animation_view); 
iv.setBackgroundResource(R.drawable.animation); 
ad = (AnimationDrawable) iv.getBackground(); 
iv.getViewTreeObserver().addOnPreDrawListener(opdl); 
//当一个视图树将要绘制时产生事件，可以添加一个其事件处理函数 

OnPreDrawListener opdl=new OnPreDrawListener(){ 
@Override 
public boolean onPreDraw() { 
ad.start(); 
return true; //注意此行返回的值 
} 
}; 
第二种方式启动动画：（在Activity启动时会自动运行动画） 
ImageView image = (ImageView) findViewById(R.id.animation_view); 
image.setBackgroundResource(R.anim.oldsheep_wait); 
        animationDrawable = (AnimationDrawable) image.getBackground(); 
        RunAnim runAnim=new RunAnim(); 
        runAnim.execute(""); 

class RunAnim extends AsyncTask<String, String, String> 
{ 
        @Override 
        protected String doInBackground(String... params) 
        { 
            if (!animationDrawable.isRunning()) 
            { 
                animationDrawable.stop(); 
                animationDrawable.start(); 
            } 
            return ""; 
        } 
} 

第三种方式启动动画：（在Activity启动时会自动运行动画） 
ImageView image = (ImageView) findViewById(R.id.animation_view); 
image.setBackgroundResource(R.anim.oldsheep_wait); 
        animationDrawable = (AnimationDrawable) image.getBackground(); 
image.post(new Runnable() 
{ 
            @Override 
            public void run() 
            { 
                animationDrawable.start(); 
            } 
        }); 

第四种方式启动动画：（在Activity启动时会自动运行动画） 
ImageView image = (ImageView) findViewById(R.id.animation_view); 
image.setBackgroundResource(R.anim.oldsheep_wait); 
        animationDrawable = (AnimationDrawable) image.getBackground(); 

@Override 
    public void onWindowFocusChanged(boolean hasFocus) 
    { 
        animationDrawable.start(); 
        super.onWindowFocusChanged(hasFocus); 
    } 
这个ad.start不能直接写在onClick，onStart，onResume里面，是无效的，无法启动动画，只能写在比如事件监听当中