MessageActivity.java 文件源码

public void executeTransition() {
    postponeEnterTransition();

    final View decorView = getWindow().getDecorView();
    getWindow().getDecorView().getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
        @Override
        public boolean onPreDraw() {
            decorView.getViewTreeObserver().removeOnPreDrawListener(this);
            supportStartPostponedEnterTransition();
            return true;
        }
    });

    MyTransition transition = new MyTransition();
    transition.setPositionDuration(300);
    transition.setSizeDuration(300);
    transition.setPositionInterpolator(new FastOutLinearInInterpolator());
    transition.setSizeInterpolator(new FastOutSlowInInterpolator());
    transition.addTarget("message");

    getWindow().setSharedElementEnterTransition(transition);
}