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:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/activity_main"
        android:layout_marginTop="@dimen/activity_vertical_margin"
        android:layout_marginBottom="@dimen/activity_vertical_margin"
        android:layout_marginRight="@dimen/activity_vertical_margin"
        android:layout_marginLeft="@dimen/activity_vertical_margin"
        >


    <VideoView
            android:layout_width="350dp"
            android:layout_height="250dp"
            android:id="@+id/videoView"
            android:layout_centerVertical="true"
            android:layout_alignParentLeft="true"
            android:layout_alignParentStart="true"/>
</RelativeLayout>