activity_main.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"
    tools:context=".MainActivity">


    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginBottom="0dp"
        android:layout_marginEnd="0dp"
        android:layout_marginLeft="0dp"
        android:layout_marginRight="0dp"
        android:layout_marginStart="0dp"
        android:layout_marginTop="0dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <Button
            android:id="@+id/CreateWalletBtn"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentStart="true"
            android:layout_alignParentTop="true"
            android:layout_marginStart="133dp"
            android:layout_marginTop="106dp"
            android:text="Create Wallet" />

        <Button
            android:id="@+id/connectEthereumClientBtn"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerHorizontal="true"
            android:layout_marginTop="10dp"
            android:layout_below="@id/CreateWalletBtn"
            android:text="Connect Ethereum" />

        <Button
            android:id="@+id/loadCredentialsBtn"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerHorizontal="true"
            android:layout_marginTop="10dp"
            android:layout_below="@id/connectEthereumClientBtn"
            android:text="Load Credentials" />

        <Button
            android:id="@+id/transferFundsBtn"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerHorizontal="true"
            android:layout_marginTop="10dp"
            android:layout_below="@id/loadCredentialsBtn"
            android:text="Transfer Funds" />
    </RelativeLayout>
</android.support.constraint.ConstraintLayout>