太简单。

1.创建layer-list Drawable名为“ icon_check”的文件

<layer-list 
    xmlns:android="http://schemas.android.com/apk/res/android">

    <item                                           //for the round white background
        android:bottom="10dp"                       //margin, "<size>" tag doesn't work
        android:end="10dp"
        android:start="10dp"
        android:top="10dp">

        <shape 
            android:shape="oval">

            <solid 
                android:color="@color/white" />

        </shape>

    </item>

    <item
        android:drawable="@drawable/check"          //check mark from built-in asset
        android:bottom="14dp"                       //margin, extra 4dp is prefered
        android:end="14dp"
        android:start="14dp"
        android:top="14dp" />

</layer-list>

2.创建selector Drawable名为“ foreground_check”

<selector
    xmlns:android="http://schemas.android.com/apk/res/android">

    <item
        android:drawable="@drawable/icon_check"             //layer-list created above
        android:state_selected="true" />

    <item
        android:drawable="@android:color/transparent"       //key point, 【"@null" doesn't work!!】
        android:state_selected="false" />

</selector>

3.设定 CardView

<androidx.cardview.widget.CardView                  //【MaterialCardView doesn't work!!】
    android:id="@+id/cardView"
    android:layout_width="40dp"
    android:layout_height="40dp"
    android:foreground="@drawable/foreground_check" //apply layer-list drawable
    app:cardBackgroundColor="@color/black"
    app:cardCornerRadius="20dp" />                  //half of side length

4.设置Ui控制器

cardView.setOnClickListener {
    it.isSelected = !it.isSelected
}

结果：