I'm running into some really strange behaviour when running this (test) layout on my OnePlus6T but it works fine when i run it in the emulator.
There is a gray bar appearing below the FrameLayout which increases/decreases in size depending on the elevation (smaller elevation means wider but less tall bar).
It only occurs when using a combination of an elevation and corner specific radius (using plain android:radius instead of bottomRightRadius makes it appear normal). Also, when I change the outlineProvider from background to something else, it works as well.
Can anyone confirm this behaviour on other phones and/or is it a known bug? I tried it on a friends Moto X4 and it works fine there.
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#DCDCDC"
tools:context=".MainActivity">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginStart="40dp"
android:layout_marginTop="40dp"
android:layout_marginEnd="40dp"
android:layout_marginBottom="40dp"
android:background="@drawable/background_rounded"
android:outlineProvider="background"
android:elevation="100dp">
</FrameLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
@drawable/background_rounded.xml
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<solid android:color="@android:color/white" />
<corners android:bottomRightRadius="64dp" />
</shape>
Screenshot from my 6T
Screenshot from API28 Emulator
