Android——Glide加载Gif图片监听加载回调函数onResourceReady问题

Glide相比Picasso来说有一个优势不错就是可以很方便的加载Gif图。
比如这样：

            Glide.with(activity).load(gifUrl).placeholder(R.drawable.plugmain_no_banner).diskCacheStrategy(DiskCacheStrategy.SOURCE).into(imgEg);

如果图片是gif格式，那么可以自动显示GIf动画，很不错。
但是如果现在需要进入页面的时候先显示加载转圈，等gif图片加载ok的时候取消转圈，这个时候我们就需要监听加载回调函数了，网上大部分是这样的。

 Glide.with(activity).load(gifMakeTypeResponse.getGifExampleUrl()).
                placeholder(R.drawable.plugmain_no_banner).
                diskCacheStrategy(DiskCacheStrategy.SOURCE).
                into(new SimpleTarget<GlideDrawable>() {
                    @Override
                    public void onResourceReady(GlideDrawable resource, GlideAnimation<? super GlideDrawable> glideAnimation) {
                  
                        imgEg.setBackground(resource);
                    }
                });

对于静态图来说，这个很对，没啥问题，但是我们会发现gif图不动了。

这是为啥？我们跟一下glide的源码into进去看看，然后我们会跟进到GlideDrawableImageViewTarget的onResourceReady函数，我们看下如果只是传了一个imageview人家内部是咋处理的。

   /**
     * {@inheritDoc}
     * If no {@link com.bumptech.glide.request.animation.GlideAnimation} is given or if the animation does not set the
     * {@link android.graphics.drawable.Drawable} on the view, the drawable is set using
     * {@link android.widget.ImageView#setImageDrawable(android.graphics.drawable.Drawable)}.
     *
     * @param resource {@inheritDoc}
     * @param animation {@inheritDoc}
     */
    @Override
    public void onResourceReady(GlideDrawable resource, GlideAnimation<? super GlideDrawable> animation) {
        if (!resource.isAnimated()) {
            //TODO: Try to generalize this to other sizes/shapes.
            // This is a dirty hack that tries to make loading square thumbnails and then square full images less costly
            // by forcing both the smaller thumb and the larger version to have exactly the same intrinsic dimensions.
            // If a drawable is replaced in an ImageView by another drawable with different intrinsic dimensions,
            // the ImageView requests a layout. Scrolling rapidly while replacing thumbs with larger images triggers
            // lots of these calls and causes significant amounts of jank.
            float viewRatio = view.getWidth() / (float) view.getHeight();
            float drawableRatio = resource.getIntrinsicWidth() / (float) resource.getIntrinsicHeight();
            if (Math.abs(viewRatio - 1f) <= SQUARE_RATIO_MARGIN
                    && Math.abs(drawableRatio - 1f) <= SQUARE_RATIO_MARGIN) {
                resource = new SquaringDrawable(resource, view.getWidth());
            }
        }
        super.onResourceReady(resource, animation);
        this.resource = resource;
        resource.setLoopCount(maxLoopCount);
        resource.start();
    }

最主要看最后两句：

 resource.setLoopCount(maxLoopCount);
 resource.start();

原来GlideDrawable resource对象对于gif图片等动图有相关处理，这样我们就这样改一下：

 Glide.with(activity).load(gifMakeTypeResponse.getGifExampleUrl()).
                placeholder(R.drawable.plugmain_no_banner).
                diskCacheStrategy(DiskCacheStrategy.SOURCE).
                into(new SimpleTarget<GlideDrawable>() {
                    @Override
                    public void onResourceReady(GlideDrawable resource, GlideAnimation<? super GlideDrawable> glideAnimation) {
                        if (resource.isAnimated()) {
                            resource.setLoopCount(GifDrawable.LOOP_FOREVER);
                            resource.start();
                        }
                        imgEg.setBackground(resource);
                        loadingDailog.dismiss();
                    }
                });

这样bug就fixed了。