Behind the graphical layout we just made is the XML file that actually defines the views. We're a

<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"
    tools:context=".LoginActivity" >

    <EditText
        android:id="@+id/usernameField"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:ems="10"
        android:hint="Username" >

        <requestFocus />
    </EditText>

    <EditText
        android:id="@+id/passwordField"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/usernameField"
        android:layout_below="@+id/usernameField"
        android:ems="10"
        android:hint="Password"
        android:inputType="textPassword" />

    <Button
        android:id="@+id/button1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/passwordField"
        android:layout_below="@+id/passwordField"
        android:text="Sign In" />

    <TextView
        android:id="@+id/signUpTextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/loginButton"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="52dp"
        android:text="Sign Up for Ribbit" />

</RelativeLayout>