Android: Align button to bottom-right of screen using FrameLayout?

Actually it's possible, despite what's being said in other answers. If you have a FrameLayout, and want to position a child item to the bottom, you can use android:layout_gravity="bottom" and that is going to align that child to the bottom of the FrameLayout.

I know it works because I'm using it. I know is late, but it might come handy to others since this ranks in the top positions on google

It can be achieved using RelativeLayout

<RelativeLayout 
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

   <ImageView 
      android:src="@drawable/icon"
      android:layout_height="wrap_content"
      android:layout_width="wrap_content"
      android:layout_alignParentRight="true"
      android:layout_alignParentBottom="true" />

</RelativeLayout>

I also ran into this situation and figured out how to do it using FrameLayout. The following output is produced by the code given below.

              <FrameLayout
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content" >

                    <ImageView
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:src="@drawable/contactbook_icon"
                        android:layout_gravity="center" />

                    <TextView
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:text="140"
                        android:textSize="12dp"
                        android:textColor="#FFFFFF"
                        android:layout_gravity="bottom|right"
                        android:layout_margin="15dp" />
                </FrameLayout>

Change the margin value to adjust the text position over the image. Removing margin might make the text to go out of the view sometimes.