<android.support.v7.widget.GridLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:myns="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:ignore="HardcodedText">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="1"
        foobar:layout_column="1" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        <error descr="Wrong namespace; with v7 `GridLayout` you should use myns:layout_column">android:la<caret>yout_column="1"</error>
        android:text="2" />

</android.support.v7.widget.GridLayout>