android 带文字阴影的按钮

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    <!-- 文字阴影的按钮 -->
    <Button android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="文字带阴影的按钮"
        android:textSize="12sp"
        android:shadowColor="#aa5"
        android:shadowRadius="1"
        android:shadowDx="5"
        android:shadowDy="5"
        />

</LinearLayout>