Android 按钮按下效果

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android" >
    
 <item android:state_pressed="true" android:drawable="@drawable/bus_s" />
 
<item android:state_pressed="false" android:state_focused="false"
  android:drawable="@drawable/bus_u" />

<item android:state_focused="true" android:drawable="@drawable/bus_s" />

<item android:state_focused="false" android:drawable="@drawable/bus_u" />

<item android:state_checked="true" android:drawable="@drawable/bus_s"></item>

</selector>

2./res/layout/team_unit_view.xml
<?xml version="1.0" encoding="utf-8"?>
<Button 
    android:layout_width="400dp"
    android:layout_height="135dp"
    android:background="@drawable/selector"
    android:orientation="horizontal" >
</button>