Button按钮点击变颜色

Button布局,背景设为btn_bg

  <Button         android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="登陆"        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>