如何在android studio中使用BottomNavigationViewEx更改或添加图标后面的形状

implementation 'com.github.ittianyu:BottomNavigationViewEx:2.0.4'

<com.ittianyu.bottomnavigationviewex.BottomNavigationViewEx
    android:id="@+id/bottom_navigation"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:itemIconTint="@color/bottom_nav_icon_color"
    app:itemTextColor="@color/bottom_nav_text_color"
    app:menu="@menu/bottom_nav_menu" />

BottomNavigationViewEx bottomNavigationView = findViewById(R.id.bottom_navigation);
bottomNavigationView.setItemShapeVisible(true);

bottomNavigationView.setItemShapeColor(Color.RED);

<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval">
    <solid android:color="@color/circle_color" />
</shape>

<item
    android:id="@+id/menu_item"
    android:icon="@drawable/ic_menu_item"
    android:title="Menu Item"
    app:showAsAction="always"
    app:actionLayout="@layout/custom_menu_item" />

<ImageView
    android:id="@+id/menu_item_icon"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/shape_circle"
    android:src="@drawable/ic_menu_item" />