Use of include tags in android

<?xml version= "1.0" encoding= "Utf-8"?>
<relativelayout android:layout_width= "fill_parent" android:layout_height= "fill_parent" style= "@style/ Stylelayoutmain "mce_style=" @style/stylelayoutmain "
Xmlns:android= "Http://schemas.android.com/apk/res/android" >

<!--include tags cannot set relativelayout properties, such as Android:layout_alignparentbottom, because it does not work--
<!--the id attribute in the Include tag (ANDROID:ID), the id attribute in the layout layouts referenced does not work, and it is suspected that the layout outer layer of its reference is wrapped in an include tag
Or a property that overrides its contents id-->
<!--If there is no include tag, all layout code is written in an XML file, and the interface appears redundant and poorly readable. And when the interface is loaded in order, the previous layout cannot
Call the layout ID that follows it. With include, you can refer to the layout id attribute in an include after
<include android:id= "@id/titlelayout" layout= "@layout/app_title"/>

<include layout= "@layout/app_tradelogin"/>

<include layout= "@layout/app_bottom"/>

</RelativeLayout>

App_title App_tradelogin App_bottom Three each represents a layout file

Use of include tags in android