View over another View

I have some Popups on my screen, and need something not so common.

I Layout my popup with Header + Content + Footer into a LinearLayout. But I need a little arrow to show on my component.

When the popup is above the anchor and the arrow is down, I use the following code to have it drawed.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/content" android:orientation="vertical"
android:layout_width="wrap_content" android:layout_height="wrap_content">

<LinearLayout android:id="@+id/header" android:background="@drawable/background_header"
    android:orientation="horizontal" android:layout_width="match_parent"
    android:layout_height="wrap_content">
</LinearLayout>

<HorizontalScrollView android:background="@drawable/background"
    android:layout_width="wrap_content" android:layout_height="match_parent"
    android:scrollbars="none">

</HorizontalScrollView>

<ImageView an开发者_C百科droid:id="@+id/arrow_down" android:layout_width="wrap_content"
    android:layout_height="wrap_content" android:layout_marginTop="-3dip"
    android:src="@drawable/quickcontact_arrow_down" />
</LinearLayout>

In runtime I'm able to place the arrow exactly above the anchor with the following code.

    ViewGroup.MarginLayoutParams param = (ViewGroup.MarginLayoutParams) mArrowDown
            .getLayoutParams();
    param.leftMargin = root.getMeasuredWidth()
            - (screenWidth - anchor.getLeft());

And it's show correctly.

Now I need do the same thing but the arrow needs to show in the up side. My problem is that the arrow need overlap a little over the other View (cause the backgrounds color match them), so this is why it's need to be draw after.

I tried with a FrameLayout and letting "content" has some topMargin, but it's not working.

I know it's can be done with AbsoluteLayout, but I'm avoiding it at all costs.

EDIT:

Following Josh answer, I wrote the following code.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content" android:layout_height="wrap_content">
<LinearLayout android:id="@+id/content"
    android:orientation="vertical" android:layout_width="wrap_content"
    android:layout_height="wrap_content" android:fadingEdgeLength="0dip">

    <RelativeLayout android:id="@+id/header"
        android:background="@drawable/background_header" android:orientation="horizontal"
        android:layout_width="match_parent" android:layout_height="wrap_content">
    </RelativeLayout>

    <HorizontalScrollView android:background="@drawable/background"
        android:layout_width="wrap_content" android:layout_height="wrap_content"
        android:scrollbars="none">
    </HorizontalScrollView>
</LinearLayout>
<ImageView android:id="@+id/arrow_up" android:layout_above="@id/content"
    android:layout_width="wrap_content" android:layout_height="wrap_content"
    android:src="@drawable/quickcontact_arrow_up" />
</RelativeLayout>

But I don't know why, the arrow is not show now.

---

I won't pretend to have read all that xml. I think what you want is RelativeLayout, though. You should be able to use this technique to place any little arrow view where ever you like, relative to the bounds of the RelativeLayout which encompasses it.

If you wrap everything you have in a single RelativeLayout, for instance, and then add, say, a Button as the second item, you can give the button attributes like alignParentRight=true and layout_marginRight=10dp to place the button 10dp from the right edge of the screen, ON TOP of whatever views are already there.