1、Layer-list
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item>
<bitmap android:src="@drawable/android_red"
android:gravity="center" />
</item>
<item android:top="10dp" android:left="10dp">
<bitmap android:src="@drawable/android_green"
android:gravity="center" />
</item>
<item android:top="20dp" android:left="20dp">
<bitmap android:src="@drawable/android_blue"
android:gravity="center" />
</item>
</layer-list>
<ImageView
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:src="@drawable/layers" />
选择器 selector
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="@drawable/comment_down" android:state_pressed="true"/>
<item android:drawable="@drawable/comment_up"/>
</selector>
3、shape
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<solid android:color="#999"/>
</shape>
