android 动画的实现

animatorSet = new AnimatorSet();
ObjectAnimator alphaAnimator = ObjectAnimator.ofFloat(img_bg, "alpha", 1.0f, 0.5f, 0.5f);
ObjectAnimator alphaAnimator2 = ObjectAnimator.ofFloat(img_bg, "alpha", 0.5f, 1.0f, 1.0f);
ObjectAnimator scaleAnimatorY = ObjectAnimator.ofFloat(img_bg, "scaleY", 1.0f, 1.2f, 1.2f);
ObjectAnimator scaleAnimatorX = ObjectAnimator.ofFloat(img_bg, "scaleX", 1.0f, 1.2f, 1.2f);

animatorSet.play(scaleAnimatorY).with(scaleAnimatorX).with(alphaAnimator2);
animatorSet.play(alphaAnimator).after(scaleAnimatorX);
animatorSet.setDuration(8000);
animatorSet.addListener(new AnimatorListener() {

@Override
public void onAnimationStart(Animator animation) {
//　
// Intent intent = new Intent(Constants.CONFIG_BROADCAST_ACTION_INTENT);
// LocalBroadcastManager.getInstance(getActivity()).sendBroadcast(intent);
}

@Override
public void onAnimationRepeat(Animator animation) {

}

@Override
public void onAnimationEnd(Animator animation) {
animatorSet.start();
}

@Override
public void onAnimationCancel(Animator animation) {

}
});
animatorSet.start();