activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical"
   tools:context="p.testwebviewcommunicate.MainActivity">

    <Button
       android:id="@+id/button"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:text="Native android button"/>

    <WebView
       android:id="@+id/webView1"
       android:layout_width="match_parent"
       android:layout_height="0dp"
       android:layout_weight="1" >

    </WebView>

    <WebView
       android:id="@+id/webView2"
       android:layout_width="match_parent"
       android:layout_height="0dp"
       android:layout_weight="1" />
</LinearLayout>