main_res_layout_activity_profile.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/colorPrimaryDark"
    tools:context="com.example.harsh.freechat.ProfileActivity">

    <TextView
        android:id="@+id/profile_displayName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="20dp"
        android:text="@string/display_name"
        android:textColor="@android:color/white"
        android:textSize="30dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/profile_picture" />

    <de.hdodenhof.circleimageview.CircleImageView
        android:id="@+id/profile_picture"
        android:layout_width="155sp"
        android:layout_height="155sp"
        android:layout_marginEnd="126dp"
        android:layout_marginStart="126dp"
        android:layout_marginTop="80dp"
        android:src="@drawable/default_avatar"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/profile_status"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/profile_displayName"
        android:layout_centerHorizontal="true"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:text="@string/current_user_status"
        android:textColor="@android:color/white"
        android:textSize="18dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/profile_displayName" />

    <Button
        android:id="@+id/profile_send_req_btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/profile_decline_btn"
        android:layout_alignBottom="@+id/profile_decline_btn"
        android:layout_marginBottom="128dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_toStartOf="@+id/profile_status"
        android:background="@color/colorAccent"
        android:padding="5dp"
        android:paddingBottom="2dp"
        android:paddingTop="2dp"
        android:text="Send Friend Request"
        android:textColor="@android:color/white"
        android:textSize="12sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

    <Button
        android:id="@+id/profile_decline_btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_below="@+id/profile_status"
        android:layout_marginBottom="68dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:background="@color/colorAccent"
        android:padding="5dp"
        android:paddingBottom="2dp"
        android:paddingTop="2dp"
        android:text="@string/decline_friend_request"
        android:textColor="@android:color/white"
        android:textSize="12sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />
</android.support.constraint.ConstraintLayout>