Question

I have this simple LinearLayout that shows up fine in Graphical Layout but when I build the project I get this console error (What am I missing here?):

No resource identifier found for attribute ‘layout_weightSum’ in package ‘android’

Here is the layout:

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

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_weightSum="3"
    android:baselineAligned="false"
    android:orientation="horizontal" >

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1" >

        <TextView
            android:id="@+id/tvSpine"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Spine"/>
    </LinearLayout>

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1" >

        <TextView
            android:id="@+id/tvPage"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Page"/>
    </LinearLayout>

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1" >

        <TextView
            android:id="@+id/tvThick"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Thick"/>
    </LinearLayout>
</LinearLayout>

Answer 1

Change:

android:layout_weightSum="3"

To:

android:weightSum="3"

There is no layout prefix to this parameter.