Multiple root tags in Android Studio [duplicate]

Answer 1

Since in Android every xml file there must be only one root layout. Just add the EditText and Button inside the LinearLayout. Right code is shown below

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <EditText  
        android:id="@+id/edit_message"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:hint="@string/edit_message" />

    <Button    
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/button_send" />

</LinearLayout>