===========按钮状态=============用来设置控件的background属性值
<?xml version="1.0" encoding="utf-8"?>
<!--按钮的状态显示设置-->
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_pressed="true" android:drawable="@drawable/shape"></item>
<item android:state_focused="true" android:drawable="@drawable/shapenomal"></item>
<item android:drawable="@color/colorAccent"></item>
</selector>
=============shape自定义形状============
<?xml version="1.0" encoding="utf-8"?>
<!--自己定义形状-->
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
<corners android:radius="5dp"/>
<!--<gradient android:startColor="#ff0000" android:endColor="#0000ff"/>-->
<solid android:color="#44000000"/>
<!--<stroke android:color="#000000" android:width="5dp" android:dashWidth="10dp" android:dashGap="2dp"/>-->
</shape>