Center multiple items in a RelativeLayout without putting them in a container?

Question

I have a RelativeLayout containing a pair of side-by-side buttons, which I want to be centered within the layout. I could just put the buttons in a LinearLayout and center that in the RelativeLayout, but I want to keep my xml as clean as possible.

Here's what I tried, this just puts the "apply" button in the center and the "undo" button to the left of it:

<RelativeLayout     android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:layout_marginTop="15sp">   <TextView     android:id="@+id/instructions"     android:text="@string/instructions"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:layout_marginBottom="15sp"     android:layout_centerHorizontal="true"     />   <Button     android:id="@+id/apply"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:layout_centerInParent="true"     android:text="@string/apply"     android:textSize="20sp"     android:layout_below="@id/instructions"     />   <Button     android:id="@+id/undo"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:layout_centerInParent="true"     android:text="@string/undo"     android:textSize="20sp"     android:layout_toLeftOf="@id/apply"     android:layout_below="@id/instructions"     /> </RelativeLayout> 

Answer 1

android:gravity will align the content inside the view or layout it is used on.

android:layout_gravity will align the view or layout inside of his parent.

So adding

android:gravity="center" 

to your RelativeLayout should do the trick...

Like this:

<RelativeLayout     android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:gravity="center"     android:layout_marginTop="15sp">  </RelativeLayout> 

Answer 2

Here is an extension of BrainCrash's answer. It is a non nested option that groups and centers all three horizontally and vertically. In addition, it takes the top TextView and centers it horizontally across both buttons. If desired, you can then center the text within the TextView with android:gravity="center". I also removed the margins, added color, and set the RelativeLayout height to fill_parent to highlight the layout. Tested on API 11.

<RelativeLayout   android:layout_width="fill_parent"   android:layout_height="fill_parent"   android:gravity="center"   android:background="@android:color/black"   >   <TextView     android:id="@+id/instructions"     android:text="TEST"     android:textSize="20sp"     android:background="@android:color/darker_gray"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:layout_centerHorizontal="true"     android:layout_alignLeft="@+id/undo"     android:layout_alignRight="@+id/apply"     android:gravity="center"     />   <Button     android:id="@+id/apply"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:layout_centerInParent="true"     android:text="APPLY"     android:textSize="20sp"     android:layout_below="@id/instructions"     />   <Button     android:id="@+id/undo"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:layout_centerInParent="true"     android:text="UNDO"     android:textSize="20sp"     android:layout_toLeftOf="@id/apply"     android:layout_below="@id/instructions"     /> </RelativeLayout>