Button佈局,背景設為btn_bg

  <Button 
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="登陸"
        android:onClick="login"
        android:background="@drawable/btn_bg"
        />

btn_bg的xml

<?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/btn1"></item>
    <item android:drawable="@drawable/btn2"></item>
</selector>