ImageView frameAnimation开始执行动画

this.mProgressBar = (ImageView) this.findViewById(R.id.businessvalue_webview_progressbar);this.mProgressBar.getViewTreeObserver().addOnPreDrawListener(new OnPreDrawListener() {@Overridepublic boolean onPreDraw() {final AnimationDrawable animationDrawable = (AnimationDrawable) BusinessValueBrowserActivity.this.mProgressBar.getBackground();animationDrawable.start();return true;}});