Android : Location On Screen Coordinates Of A View?

I am developing a game in android and i want to capture screen coordinates of a view(ImageView) which is embedded in frame.

Hierarchy is <LinearLayout android android:layout_height="fill_parent" android:layout_width="fill_parent" > <RelativeLayout android:layout_height=fill_parent" android:layout_width="fill_parent" > <FrameLayout android:layout_height="wrap_content" android:layout_width="wrap_content" android:id="@+id/frame14"></ FrameLayout> </RelativeLayout> </LinearLayout>

At run time i am attaching two image views for frame layout.I wanted to capture screen coordinates of frame layout.But Couldnt do it.if i say

(FrameLayout) f=(FrameLayout)findViewById(R.id.frame14); int[] loc = new int[2]; f.getLocationOnScreen(loc); System.out.println(loc[0]); System.out.println(loc[1]);

I get Null Pointer Exception for getLocationOnScreen() method.

If I try to get f.getLeft() and f.getRight() they return as 0 coordinates.

Can anyone please tell me how to find location on screen of a view.