yahoo - 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="com.example.yahoo.MainActivity">

    <EditText
        android:id="@+id/txtName"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="@string/txtName"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/btnProceed"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/btnProceed"
        app:layout_constraintTop_toBottomOf="@id/txtName" />

    <ListView
        android:id="@+id/lstCustomers"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintTop_toBottomOf="@id/btnProceed" />

</android.support.constraint.ConstraintLayout>