How to center a view using RelativeLayout?

Question

I wanted to know how to center a View between two other views (or between a view and the parent edge) using RelativeLayout.

For example, if I have the following...

How do I vertically center the Button between the ImageView and the bottom of the screen using RelativeLayout?

I'm looking for a solution where...

• the Button is not stretched in any way
• there are no nested layouts

And I'm trying to do this in the XML layout (not programmatically).

Answer 1

You can use following:

<RelativeLayout 
        android:layout_below="@id/theImageView"
        android:align_parentBottom="true"
        android:layout_width="match_parent"
        android:layout_height="200dp" >    


        <Button 
            android:id="@+id/btn"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerHorizontal="true"
            android:layout_centerVertical="true"            
            android:onClick="onClickButton"
            android:textSize="20sp"
            android:text="Go"/>

    </RelativeLayout>

Answer 2

There's unfortunately no easy way to do this. You can either nest layouts, or do it at runtime. The simplest way is to nest layouts:

<LinearLayout
    android:width="match_parent"
    android:height="match_parent"
    android:orientation="vertical">
    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/my_top_image"/>
    <RelativeLayout
        android:layout_width="fill_parent"
        android:layout_height="0dip"
        android:layout_weight="1">
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:text="@string/my_button_label"/>
    </RelativeLayout>
</LinearLayout>

This puts the image at the top. Below that, the layout_height=0 and layout_weight=1 attributes on the RelativeLayout cause it to take up all the remaining space. You can then center the button in the RelativeLayout. You can play with padding on the button to get it to the size you want.