Fresco设置GIF只播放一次，播放完后显示其他view

Fresco对gif可以设置自动播放，但是播放次数没有设置播放的方法，只有get方法，在GifImage

 public int getLoopCount() {
    // If a GIF image has no Netscape 2.0 loop extension, it is meant to play once and then stop. A
    // loop count of 0 indicates an endless looping of the animation. Any loop count X>0 indicates
    // that the animation shall be repeated X times, resulting in the animation to play X+1 times.
    final int loopCount = nativeGetLoopCount();
    switch (loopCount) {
      case LOOP_COUNT_FOREVER:
        return AnimatedImage.LOOP_COUNT_INFINITE;
      case LOOP_COUNT_MISSING:
        return 1;
      default:
        return loopCount + 1;
    }
  }

这个通过获取gif中设置的循环次数来获取播放次数
而官网上面对于gif播放只给出了简单的使用方法
手动控制动画图播放，监听图片是否加载完毕，然后才能控制动画的播放：

ControllerListener controllerListener = new BaseControllerListener<ImageInfo>() {
    @Override
    public void onFinalImageSet(
        String id,
        @Nullable ImageInfo imageInfo,
        @Nullable Animatable anim) {
        if (anim != null) {
          // 其他控制逻辑
          anim.start();
        }
    }
};

Uri uri;
DraweeController controller = Fresco.newDraweeControllerBuilder()
    .setUri(uri)
    .setControllerListener(controllerListener)
    // 其他设置（如果有的话）
    .build();
mSimpleDraweeView.setController(controller);

自动播放设置，图片下载完之后自动播放，同时，当View从屏幕移除时，停止播放，只需要在 image request 中简单设置

Uri uri;
DraweeController controller = Fresco.newDraweeControllerBuilder()
    .setUri(uri)
    .setAutoPlayAnimations(true)
    . // 其他设置（如果有的话）
    .build();
mSimpleDraweeView.setController(controller);

gif只播放一次可以将gif中播放次数设置为一次，但是播放后如何替换呢，我百度后看到https://www.imooc.com/article/15274
这个文章很久了，使用的是fresco很早的版本，可以获取循环次数和播放时间，我找了下，没有AbstractAnimatedDrawable，也没有AnimatedDrawable了，只有AnimatedDrawable2，里面也没有次数设置了，但是我看了下代码有个

private static final AnimationListener NO_OP_LISTENER = new BaseAnimationListener();

public void setAnimationListener(@Nullable AnimationListener animationListener) {
    mAnimationListener = animationListener != null
        ? animationListener
        : NO_OP_LISTENER;
  }

这个AnimationListener可以实现了对动画的监听
于是监听动画播放结束时，替换相应的图片，就实现了

fun SimpleDraweeView?.loadGifOnce(aniImageUrl: String?, staticImageUrl: String?) {
    if (this == null) return
    val uri = if (aniImageUrl.isNullOrEmpty()) null else Uri.parse(aniImageUrl)
    controller = Fresco.newDraweeControllerBuilder()
        .setUri(uri)
        .setOldController(controller)
        .setAutoPlayAnimations(false)
        .setControllerListener(object : BaseControllerListener<ImageInfo>(){
            override fun onFinalImageSet(id: String?, imageInfo: ImageInfo?, animatable: Animatable?) {
                if (animatable != null && !animatable.isRunning){
                    animatable.start()
                    val animatedDrawable2 = animatable as AnimatedDrawable2
                    animatedDrawable2.setAnimationListener(object : AnimationListener {
                        override fun onAnimationRepeat(drawable: AnimatedDrawable2?) {
                        }

                        override fun onAnimationStart(drawable: AnimatedDrawable2?) {
                        }

                        override fun onAnimationFrame(drawable: AnimatedDrawable2?, frameNumber: Int) {
                        }

                        override fun onAnimationStop(drawable: AnimatedDrawable2?) {
                            setImageURI(staticImageUrl)
                        }

                        override fun onAnimationReset(drawable: AnimatedDrawable2?) {
                        }

                    })
                }
            }
        })
        .build()
}

这个listener简直打开了gif功能的另一个天地

public interface AnimationListener {

  /**
   * Called when the animation is started for the given drawable.
   *
   * @param drawable the affected drawable
   */
  void onAnimationStart(AnimatedDrawable2 drawable);

  /**
   * Called when the animation is stopped for the given drawable.
   *
   * @param drawable the affected drawable
   */
  void onAnimationStop(AnimatedDrawable2 drawable);

  /**
   * Called when the animation is reset for the given drawable.
   *
   * @param drawable the affected drawable
   */
  void onAnimationReset(AnimatedDrawable2 drawable);

  /**
   * Called when the animation is repeated for the given drawable.
   * Animations have a loop count, and frame count, so this is called when
   * the frame count is 0 and the loop count is increased.
   *
   * @param drawable the affected drawable
   */
  void onAnimationRepeat(AnimatedDrawable2 drawable);

  /**
   * Called when a frame of the animation is about to be rendered.
   *
   * @param drawable the affected drawable
   * @param frameNumber the frame number to be rendered
   */
  void onAnimationFrame(AnimatedDrawable2 drawable, int frameNumber);
}

若gif的循环播放次数只有一次，可以在onAnimationStop进行操作，如果是循环，那可以在onAnimationRepeat进行设置，repeat是帧数为0，播放次数加1的时候。