android - change layout in proportion to background image on orientation

Question

I have a layout with Viewgroup as parent containing a relativelayout with background image. I am adding controls dynamically to relativelayout and able to zoom and scroll it. When I change the orientation the background image shrink to fit landscape. I want to change the relativelayout controls in proportion to the background image. Iam a newbie to android so not clear where to start??

Layout

 <com.example.pdoc.zoomablepdf.ZoomableViewGroup
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:foregroundGravity="center"
 android:id="@+id/zoomLayout"
 xmlns:android="http://schemas.android.com/apk/res/android">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:background="@drawable/sample1pdf"
        android:id="@+id/RelLayout">            
    </RelativeLayout>
  </com.example.pdoc.zoomablepdf.ZoomableViewGroup>

Answer 1

You can create different layout for different orientation. In that way it is easy to maintain the UI part for any orientation.

Answer 2

I think you could use a onConfigurationChanged Listener. Something like this

    @Override
        public void onConfigurationChanged(Configuration newConfig) {
            super.onConfigurationChanged(newConfig);

            // Checks the orientation of the screen
            if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE) {

                //Make your layout changes
            } else if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT){
                //other Changes (to default)
            }
        }

You can look here for more information: How to detect orientation