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In contrast to what we saw earlier, here is an example using LinearLayout just to center TextView (creating the same effect as the layout_center parameter of RelativeLayout):

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:orientation="horizontal" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:gravity="center"> 
    <LinearLayout 
        android:layout_width="0dp" 
        android:layout_height="wrap_content" 
        android:layout_weight="1" 
        android:gravity="center" > 
        <TextView 
            android:id="@+id/imageButton_speak" 
            android:layout_width="wrap_content" 
            android:layout_height="wrap_content" 
            android:text="Centered" /> 
    </LinearLayout> 
</LinearLayout> 

Notice this layout is one level deeper than the equivalent RelativeLayout (which is LinearLayout nested within the parent LinearLayout.) Though a simple example, it's a good idea to avoid unnecessary nesting as it can impact performance, especially when a layout is being repeatedly inflated (such as ListItem).