OnboardingFragment.java 文件源码

@Override
protected void onPageChanged(final int newPage, int previousPage) {
    if (mContentAnimator != null) {
        mContentAnimator.end();
    }
    ArrayList<Animator> animators = new ArrayList<>();
    Animator fadeOut = createFadeOutAnimator(mContentView);

    fadeOut.addListener(new AnimatorListenerAdapter() {
        @Override
        public void onAnimationEnd(Animator animation) {
            mContentView.setImageDrawable(getResources().getDrawable(pageImages[newPage]));
            ((AnimationDrawable) mContentView.getDrawable()).start();
        }
    });
    animators.add(fadeOut);
    animators.add(createFadeInAnimator(mContentView));
    AnimatorSet set = new AnimatorSet();
    set.playSequentially(animators);
    set.start();
    mContentAnimator = set;
}