Synchronous image loading on a background thread with Picasso - without .get()

Question

I have a custom viewgroup (that contains Picasso-loaded images) that can be reused in two places:

1. Displayed to the user in the application (on the UI thread)

Answer 1

Here is my solution:

/**
 * Loads the request into an imageview.
 * If called from a background thread, the request will be performed synchronously.
 * @param requestCreator A request creator
 * @param imageView The target imageview
 * @param callback a Picasso callback
 */
public static void into(RequestCreator requestCreator, ImageView imageView, Callback callback) {
  boolean mainThread = Looper.myLooper() == Looper.getMainLooper();
  if (mainThread) {
    requestCreator.into(imageView, callback);
  } else {
    try {
      Bitmap bitmap = requestCreator.get();
      imageView.setImageBitmap(bitmap);
      if (callback != null) {
        callback.onSuccess();
      }
    } catch (IOException e) {
      if (callback != null) {
        callback.onError();
      }
    }
  }
}

Answer 2

Perfect answer by Jacob Tabak

Here is small addition that handles the case if you load image into Target. I haven't found a way to get the origin of image to pass appropriate LoadedFrom argument.

 public static void into(RequestCreator requestCreator, Drawable placeHolder, Drawable errorDrawable, Target target) {
        boolean mainThread = Looper.myLooper() == Looper.getMainLooper();
        if (mainThread) {
            requestCreator.into(target);
        } else {
            try {
                target.onBitmapFailed(placeHolder);
                Bitmap bitmap = requestCreator.get();
                target.onBitmapLoaded(bitmap, Picasso.LoadedFrom.MEMORY);
            } catch (IOException e) {
                target.onBitmapFailed(errorDrawable);
            }
        }
    }