@Nullable
  public Bitmap updateBitmap(String id, @Nullable Bitmap bitmap) {
    ImageAssetManager bm = getImageAssetManager();
    if (bm == null) {
      Log.w(L.TAG, "Cannot update bitmap. Most likely the drawable is not added to a View " +
          "which prevents Lottie from getting a Context.");
      return null;
    }
    Bitmap ret = bm.updateBitmap(id, bitmap);
    invalidateSelf();
    return ret;
  }
@ Nullable public Bitmap updateBitmap ( String id , @ Nullable Bitmap bitmap ) { ImageAssetManager bm = getImageAssetManager ( ) ; if ( bm == null ) { Log . w ( L . TAG , "Cannot update bitmap. Most likely the drawable is not added to a View " + "which prevents Lottie from getting a Context." ) ; return null ; } Bitmap ret = bm . updateBitmap ( id , bitmap ) ; invalidateSelf ( ) ; return ret ; }
Allows you to modify or clear a bitmap that was loaded for an image either automatically
through {@link #setImagesAssetsFolder(String)} or with an {@link ImageAssetDelegate}.

@return the previous Bitmap or null.