Samples/ActivityFeed/activityfeed/src/main/res/layout/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: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=".activities.MainActivity"
    android:background="@color/lightBlue">

    <ImageView
        android:layout_width="125dp"
        android:layout_height="125dp"
        android:id="@+id/imageView"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:src="@drawable/usergridguy"
        android:layout_marginTop="20dp"
        android:adjustViewBounds="true" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/usernameText"
        android:minWidth="250dp"
        android:background="@android:color/white"
        android:height="40dp"
        android:layout_below="@+id/imageView"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="30dp"
        android:hint="Username"
        android:paddingStart="10dp"
        android:singleLine="true"
        android:minLines="1"
        android:maxLines="1"
        android:minHeight="30dp"
        android:paddingEnd="10dp"
        android:maxWidth="250dp" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/passwordEditText"
        android:minWidth="250dp"
        android:background="@android:color/white"
        android:height="40dp"
        android:layout_marginTop="15dp"
        android:layout_below="@+id/usernameText"
        android:layout_alignStart="@+id/usernameText"
        android:hint="Password"
        android:paddingStart="10dp"
        android:singleLine="true"
        android:maxLines="1"
        android:minLines="1"
        android:minHeight="30dp"
        android:maxWidth="250dp"
        android:paddingEnd="10dp"
        android:inputType="textPassword" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Sign In"
        android:id="@+id/signInButton"
        android:layout_below="@+id/passwordEditText"
        android:layout_alignEnd="@+id/passwordEditText"
        android:layout_marginTop="25dp"
        android:minWidth="250dp"
        android:background="@color/colorPrimary"
        android:textColor="@android:color/white" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Create Account"
        android:id="@+id/createAccountTextView"
        android:layout_below="@+id/signInButton"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="30dp"
        android:textColor="@color/colorPrimary"
        android:clickable="true" />

</RelativeLayout>