I am trying to follow this tutorial : http://developer.android.com/training/basics/firstapp/building-ui.html as I am new to android developing and this is what my "activity_main.xml" file looks like : <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="horizontal"> <EditText android:id="@+id/edit_message" android:layout_weight="1" android:layout_width="0dp" 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" /> When I click run I get an error that says "No XML content. Please add a root view or layout to your document." and I noticed there is a new file generated called "activity_main.out.xml". What could I be doing wrong?