Android 自定义Button控件实现按钮点击变色

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_pressed="true">
<shape android:shape="rectangle">
<solid android:color="#73c4f3" />
<stroke android:width="2dp" android:color="#ffffff" />
<corners android:radius="20dp" />
<padding android:bottom="5dp" android:left="10dp" android:right="10dp" android:top="5dp" />
<gradient android:angle="270" android:endColor="#8accf2" android:startColor="#8accf2" android:type="sweep" />
</shape>
<shape>
<solid android:color="#3fb3f6" />
<stroke android:width="2dp" android:color="#ffffff" />
<corners android:radius="20dp" />
<padding android:bottom="5dp" android:left="10dp" android:right="10dp" android:top="5dp" />
</shape>
</item>
</selector>

<style name="rectangle">
<item name="android:layout_width">match_parent</item>
<item name="android:layout_height">wrap_content</item>
<item name="android:textSize">15sp</item>
<item name="android:textColor">#ffffff</item>
<item name="android:background">@drawable/buttonclickstyle</item>
</style>

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.ly.blogtest.MainActivity">
<Button
android:id="@+id/button"
style="@style/rectangle"
android:text="@string/btn1" />
</RelativeLayout>