安卓:使用圆形锚定FAB为BottomAppBar添加圆角

<com.google.android.material.bottomappbar.BottomAppBar
    android:id="@+id/bottomAppBar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:fabAlignmentMode="center"
    app:fabCradleMargin="8dp"
    app:fabCradleRoundedCornerRadius="16dp"
    app:fabCradleVerticalOffset="8dp">

    <!-- 添加其他底部应用栏的内容 -->

</com.google.android.material.bottomappbar.BottomAppBar>

<com.google.android.material.floatingactionbutton.FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_margin="16dp"
    app:layout_anchor="@id/bottomAppBar"
    app:srcCompat="@drawable/ic_add" />

BottomAppBar bottomAppBar = findViewById(R.id.bottomAppBar);
float cornerRadius = getResources().getDimension(R.dimen.bottom_app_bar_corner_radius);
MaterialShapeDrawable shapeDrawable = (MaterialShapeDrawable) bottomAppBar.getBackground();
shapeDrawable.setShapeAppearanceModel(
    shapeDrawable.getShapeAppearanceModel()
        .toBuilder()
        .setTopRightCorner(CornerFamily.ROUNDED, cornerRadius)
        .setTopLeftCorner(CornerFamily.ROUNDED, cornerRadius)
        .build());