Android app widgets background shape change color opacity programmatically

I have developed an app widget with round corners. I've basically set a background drawable to the root of the app widget layout.

Now I'm trying to change its background opacity without losing round corners.

I know that RemoteViews are pretty limited.

Right now I'm using this code: views.setInt(R.id.root_layout_widget, "setBackgroundColor", ColorUtils.setAlphaComponent(Color.WHITE, opacity))

But this way I lose rounded corners. If I wasn't using RemoteViews I would get the background of the element and set its alpha.

My root element is a LinearLayout and my background drawable is the following:

<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
    <solid android:color="@android:color/white" />
    <corners android:radius="2dp" />
</shape>

Do you know of any ways to do it? Thanks

To solve this I removed the background from my root LinearLayout and place the ShapeDrawable to an ImageView and rearranged my layout like this:

Before:

<LinearLayout
  android:background="@drawable/round_corners">
    .....
    .....
</LinearLayout>

After:

<FrameLayout>
    <ImageView
        android:id="@+id/background"
        android:src="@drawable/round_corners"/>
    <LinearLayout>
        .....
        .....
    </LinearLayout>
</FrameLayout>

And to change the background opacity without losing the round corners:

remoteViews.setInt(R.id.background, "setImageAlpha", alpha)

The alpha value should be an integer between 0 and 255 (inclusive).