How to place an imageview on top of another imageview in android

FrameLayout is what you need. You can simply merge the parent layout that is a FrameLayout too. Take a look at the Android Developers Blog: http://android-developers.blogspot.it/2009/03/android-layout-tricks-3-optimize-by.html

<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center">

    <ImageView
        android:id="@+id/outside_imageview" 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:scaleType="fitXY"/>

    <ImageView
        android:id="@+id/inside_imageview" 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" 
        android:layout_marginTop="5dip"
        android:layout_marginBottom="5dip"
        android:src="@drawable/frame" />
</merge>

    <RelativeLayout
      xmlns:android="http://schemas.android.com/apk/res/android"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent"
      android:background="@color/white" >

    <ImageView
        android:id="@+id/inside_imageview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="5dip"
        android:layout_marginTop="5dip"
        android:src="@drawable/frame" />

      <ImageView
         android:id="@+id/outside_imageview"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_alignTop="@id/inside_imageview"
         android:layout_alignBottom="@id/inside_imageview"
         android:layout_alignLeft="@id/inside_imageview"
         android:layout_alignRight="@id/inside_imageview"            
         android:scaleType="fitXY" />
  </RelativeLayout>

The layout_align[Top|Bottom|Left|Right] attribute in RelativeLayout is used to align views based on their respective x and y values within the margin. The second ImageView will now be aligned to the top, bottom, left, and right of the first ImageView based on the margins. Padding is ignored in the alignment.