Android XML: Centering Horizontally On Bottom

Question

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" 
    >

<TextView 
    android:text="Title" 
    android:id="@+id/TextView01" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:textSize="30px" 
    android:textStyle="bold" 
    >
</TextView>

<LinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="fill_parent"
    android:layout_height="60px">

<Button 
    android:text="Choose a Story" 
    android:id="@+id/choose" 
    android:layout_width="150px" 
    android:layout_height="wrap_content"  
    android:layout_gravity="bottom" 
    android:layout_marginBottom="1px">
</Button>

<Button 
    android:text="Info" 
    android:id="@+id/info" 
    android:layout_width="150px" 
    android:layout_height="wrap_content"  
    android:layout_gravity="bottom" 
    android:layout_marginBottom="1px">
</Button>

</LinearLayout>
</LinearLayout>

In this code, as you can see, there is a title, 2 linear layouts, and 2 buttons that are inside a linear layout. What I'm trying to do is center the 2 buttons. No matter what I do, I can never get the 2 buttons to be centered at the bottom with a height of 60px.

In the end I'm trying to make the text centered both vertically and horizontally, and have the 2 buttons on the bottom centered horizontally. What do I need to change?

Heres a picture of what it looks like in the Layout Editor.

Answer 1

On your inner linear layout, set the layout_gravity.

Here's one solution

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" 
    >
<TextView 
    android:text="Title" 
    android:id="@+id/TextView01" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:textSize="30dip" 
    android:textStyle="bold" 
    />

    <LinearLayout 
        android:orientation="horizontal"
        android:layout_width="fill_parent"
        android:layout_height="60dip"
        android:layout_gravity="bottom|center_horizontal"
        android:layout_marginBottom="1dip"
        >

    <Button 
        android:text="Choose a Story" 
        android:id="@+id/choose" 
        android:layout_width="0dip" 
        android:layout_height="wrap_content"
        android:layout_weight="1"
        />

    <Button 
        android:text="Info" 
        android:id="@+id/info" 
        android:layout_width="0dip"
        android:layout_weight="1" 
        android:layout_height="wrap_content"
        />

    </LinearLayout>
</FrameLayout>

In general, you should style the outermost component (container) which will then position all of its children accordingly. As a side not, this layout would be achieved using just a single (or pair, depending on exactly what you're trying to do) or FrameLayouts, which would significantly reduce the layout overhead. While there's nothing wrong with LinearLayout, it is surprisingly computationally expensive.