利用XML设定按钮在不同状态下的表现样式

首先在res/drawable下自行定义一个xml，分别设定按钮获得焦点、按钮按下、常规状态下的按钮表现样式

drawable/mButton.xml

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

然后在main.xml中将mButton赋值给Button组件中的background属性

layout/main.xml

<Button
    android:id="@+id/mButton1"
    android:background="@drawable/mButton"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="MyButton"
    />