How to dynamically update bitmap with rounded corners on Widget root layout? - android-layout

Question

I need to dynamically update a picture with rounded corners in the root layout of the Widget. There is only a simple setImageViewBitmap API for viewing related documents, but the exact size of the widget is required to draw the specified radius; this problem is easy to implement on Android 12 (refer to https://medium.com/androiddevelopers/updating-your-widget-for-android-12-92e7de87424c), but I see that some apps are also implemented on devices lower than Android 12, there should be other ways to achieve this problem
As I know is:
Before Android 12, I can't get real size of widget root view
Many APIs of RemoteViews are only supported in API 31 and above，including setClipToOutline, etc.
The View supported by RemoteViews is very limited and does not support custom View
my widget layout file：
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/fl_root_view"
android:layout_width="match_parent"
android:layout_height="155dp">
// widget background
<ImageView
android:id="#+id/iv_root_view_bg"
android:src="#drawable/big_most_played_widget_layout_bg"
android:layout_width="match_parent"
android:layout_height="match_parent" />
// widget content
<LinearLayout
android:layout_height="match_parent"
android:layout_width="match_parent"
android:orientation="horizontal">
...
</LinearLayout>
</FrameLayout>
one of the background files：
//#drawable/big_most_played_widget_layout_bg.xml
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<corners android:radius="24dp"/>
<solid android:color="#182327"/>
</shape>
And i have tried:
Update the layout background directly, the rounded shape will be lost
Generate a bitmap with the approximate width and height of the widget and use PorterDuff.Mode.SRC_IN to draw rounded corners, which has great uncertainty on various devices (the bitmap cannot completely fit the widget size)
override RemoteViews.apply(), but it not work
override fun apply(context: Context?, parent: ViewGroup?): View {
val result = super.apply(context, parent)
val colors = IntArray(2) { (0xff000000).toInt() or Random.nextInt(0x00ffffff) }
val bgDrawable = GradientDrawable(GradientDrawable.Orientation.TOP_BOTTOM, colors).apply {
cornerRadius = 42f
}
result.setBackgroundDrawable(bgDrawable)
return result
}
I want to know:
In addition, is there a way to get the real width and height of the widget on devices lower than Android 12?
Other better implementation methods?