Fade In Fade Out Android Animation in Java

2019-01-04 05:25发布

I want to have a 2 second animation of an ImageView that spends 1000ms fading in and then 1000ms fading out.

Here's what I have so far in my ImageView constructor:

Animation fadeIn = new AlphaAnimation(0, 1);
fadeIn.setDuration(1000);

Animation fadeOut = new AlphaAnimation(1, 0);
fadeOut.setStartOffset(1000);
fadeOut.setDuration(1000);

AnimationSet animation = new AnimationSet(true);
animation.addAnimation(fadeIn);
animation.addAnimation(fadeOut);
this.setAnimation(animation);

When I run that animation, nothing shows up. However, when I remove one of the alpha animations, the behavior works as expected.

Things I have already tried:

  • Every conceivable combination of setFillBefore, setFillAfter, and setFillEnabled.
  • Adding a LinearInterpolator to the AnimationSet.

10条回答
迷人小祖宗
2楼-- · 2019-01-04 06:04

As I believe in the power of XML (for layouts), this is the equivalent for the accepted answer, but purely as an animation resource:

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:interpolator="@android:interpolator/accelerate_decelerate"
    android:fillAfter="true">
    <alpha
        android:fromAlpha="0"
        android:toAlpha="1"
        android:duration="1000" />
    <alpha
        android:fromAlpha="1"
        android:toAlpha="0"
        android:duration="1000"
        android:startOffset="1000"/>
</set>

The fillAfter is for the fade to remain after completing the animation. The interpolator handles interpolation of the animations, as you can guess. You can also use other types of interpolators, like Linear or Overshoot.

Be sure to start your animation on your view:

yourView.startAnimation(AnimationUtils.loadAnimation(co‌​ntext, R.anim.fade));
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一纸荒年 Trace。
3楼-- · 2019-01-04 06:06

AnimationSets don't appear to work as expected at all. In the end I gave up and used the Handler class's postDelayed() to sequence animations.

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小情绪 Triste *
4楼-- · 2019-01-04 06:08

Here is what I used to fade in/out Views, hope this helps someone.

private void crossFadeAnimation(final View fadeInTarget, final View fadeOutTarget, long duration){
    AnimatorSet mAnimationSet = new AnimatorSet();
    ObjectAnimator fadeOut = ObjectAnimator.ofFloat(fadeOutTarget, View.ALPHA,  1f, 0f);
    fadeOut.addListener(new Animator.AnimatorListener() {
        @Override
        public void onAnimationStart(Animator animation) {
        }

        @Override
        public void onAnimationEnd(Animator animation) {
            fadeOutTarget.setVisibility(View.GONE);
        }

        @Override
        public void onAnimationCancel(Animator animation) {
        }

        @Override
        public void onAnimationRepeat(Animator animation) {
        }
    });
    fadeOut.setInterpolator(new LinearInterpolator());

    ObjectAnimator fadeIn = ObjectAnimator.ofFloat(fadeInTarget, View.ALPHA, 0f, 1f);
    fadeIn.addListener(new Animator.AnimatorListener() {
        @Override
        public void onAnimationStart(Animator animation) {
            fadeInTarget.setVisibility(View.VISIBLE);
        }

        @Override
        public void onAnimationEnd(Animator animation) {}

        @Override
        public void onAnimationCancel(Animator animation) {}

        @Override
        public void onAnimationRepeat(Animator animation) {}
    });
    fadeIn.setInterpolator(new LinearInterpolator());
    mAnimationSet.setDuration(duration);
    mAnimationSet.playTogether(fadeOut, fadeIn);
    mAnimationSet.start();
}
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Bombasti
5楼-- · 2019-01-04 06:09

You can also use animationListener, something like this:

fadeIn.setAnimationListener(new AnimationListener() {
    @Override
    public void onAnimationEnd(Animation animation) {
        this.startAnimation(fadeout);
    }
});
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