先上效果图
1.activity_main.xml
<?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:id=@+id/activity_main
android:layout_width=match_parent
android:layout_height=match_parent
a
