main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="horizontal">

    <EditText android:id="@+id/edit_message"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="@string/edit_message" />
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/button_send"
	android:onClick="sendMessage" />
</LinearLayout>