activity_roll_number.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_roll_number"
    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.darshanbshah.odsystem.RollNumber">

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="textPersonName"
        android:ems="10"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="167dp"
        android:id="@+id/rollNumberEditText"
        android:hint="Amrita Roll Number"
        android:textAlignment="center" />

    <Button
        android:text="Sign Out"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/button3"
        style="@style/Widget.AppCompat.Button.Borderless.Colored"
        android:layout_alignParentTop="true"
        android:layout_alignParentEnd="true"
        android:onClick="signOut" />

    <Button
        android:text="Continue"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="42dp"
        android:id="@+id/continueButton"
        style="@style/Widget.AppCompat.Button.Colored"
        android:layout_below="@+id/rollNumberEditText"
        android:layout_centerHorizontal="true"
        android:onClick="nextAct" />
</RelativeLayout>