shape selector 实现按钮效果（圆边按钮、背景翻转）

//这里写代码片 selector 代码
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/town_ship_village_community_gray_press_button_border" android:state_pressed="true"/>
    <item android:drawable="@drawable/town_ship_village_community_gray_button_border"/>
</selector>

//shape代码 按下
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <corners android:radius="@dimen/margin5"/>
    <stroke android:width="1dp" android:color="@color/gray7"/>
    <padding android:bottom="1dp" android:left="1dp"
        android:right="1dp" android:top="1dp"/>
    <solid android:color="#ffe6e6e6"/>
</shape>

//shape代码 未按下
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <corners android:radius="@dimen/margin5"/>
    <stroke android:width="1dp" android:color="@color/gray7"/>
    <padding android:bottom="1dp" android:left="1dp"
        android:right="1dp" android:top="1dp"/>
    <solid android:color="#00000000"/>
</shape>