在Android上使用Fresco显示Gif预览（例如，作为第一帧）

Question

I use Fresco library to show animated gif files in RecyclerView and android. My code is pretty simple, I do this in onBindViewHolder():

 DraweeController controller = Fresco.newDraweeControllerBuilder()
                .setUri(url)
                .setAutoPlayAnimations(true)
                .build();
 simpleDraweeView.setController(controller);

Everything is fine, but it looks like GIF images are not cached and reloaded when I scroll up or down. So I decided to show preview for GIF files just like simple images. Seems to setLocalThumbnailPreviewsEnabled(true) for ImageRequest doesn't work for GIF images. Then I tried to use ImageDecodeOptionsBuilder with setForceStaticImage(true) - it displays GIFs as static images (almost what I need, but I need to start animation after static image is loaded). Here is the all my code:

    Uri imageUri = Uri.parse(url);
    ImageDecodeOptionsBuilder decodeOptionsBuilder = new ImageDecodeOptionsBuilder();
    decodeOptionsBuilder.setForceStaticImage(true);
    decodeOptionsBuilder.setDecodePreviewFrame(true);
    ImageDecodeOptions imageDecodeOptions = new ImageDecodeOptions(decodeOptionsBuilder);
    ImageRequest request =  ImageRequestBuilder.newBuilderWithSource(imageUri)
            .setImageDecodeOptions(imageDecodeOptions)
            .setLocalThumbnailPreviewsEnabled(true)
            .build();

    DraweeController controller = Fresco.newDraweeControllerBuilder()
            .setImageRequest(request)
            .setAutoPlayAnimations(true)
            .build();
    simpleDraweeView.setController(controller);

I also tried to play with setAutoPlayAnimations(true/false) and other parameters (like decodeOptionsBuilder.setDecodePreviewFrame(true)) but still without success.

So my question is: how I can show the static images as preview images (like placeholders) for GIFs? If It's first(or some other) frame from GIF it would be cool. Any help is appreciated.

Answer 1

The easiest way to do this is as you described:

Set the GIF where you force the static image. Once you want to play the animation (eg on tap), set the image again but this time with setAutoPlayAnimations .

As an alternative, you can also not start the animation automatically but start it on tap, see https://github.com/facebook/fresco/blob/master/samples/animation/src/main/java/com/facebook/samples/animation/MainActivity.java#L131

Basically, you build your controller like this:

DraweeController gifController = Fresco.newDraweeControllerBuilder()
    .setUri(animatedGifUri)
    .setControllerListener(new BaseControllerListener<ImageInfo>() {
      @Override
      public void onFinalImageSet(
          String id,
          ImageInfo imageInfo,
          Animatable anim) {
        if (anim != null) {
          // start the animation with anim.start() whenever you want
        }
      }
    })
    .build();

Unfortunately, there is currently no better way to do this. However, we're looking into improving the animation API for Fresco in the future.