ImageFetcherActivityUIHandler.java

static class UIHandler extends Handler {
    private final WeakReference<ImageFetcherActivity> mActivityRef;
    
    UIHandler(ImageFetcherActivity activity) {
        mActivityRef = new WeakReference(activity);
    }
    
    @Override
    public void handleMessage(Message msg) {
        final ImageFetcherActivity activity = mActivityRef.get();
        if (activity == null) {
            return
        }
        
        switch (msg.what) {
            case MSG_SHOW_LOADER: {
                activity.progressIndicator.setVisibility(View.VISIBLE);
                break;
            }
            case MSG_HIDE_LOADER: {
                activity.progressIndicator.setVisibility(View.GONE);
                break;
            }
            case MSG_SHOW_IMAGE: {
                activity.progressIndicator.setVisibility(View.GONE);
                activity.imageView.setImageBitmap((Bitmap) msg.obj);
                break;
            }
        }
    }
}