Making a stackable, square graph with text labels - android-layout

Question

For my first venture into Android-land, I have what seems to me to be a simple project. I want to display a square graph with text in its four corners. I want to be able to display a single graph, or four, grouped 2 x 2.
Quad graph example
So far, the only means I've found to overlay the four TextViews on my custom GraphView is to put the GraphView in a RelativeLayout, and position the TextViews relative to it.
<?xml version="1.0" encoding="utf-8"?>
<com.companyname.graph.GraphLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
>
<com.companyname.graph.GraphView
android:id="#+id/graph_single_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#color/colorGraphBackground"
/>
<TextView
android:id="#+id/label_top_left"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/graph_single_view"
android:layout_alignStart="#+id/graph_single_view"
android:layout_alignTop="#+id/graph_single_view"
android:layout_gravity="top|start"
android:gravity="top|start"
android:hint="#string/placeholder_top_left"
/>
<TextView
android:id="#+id/label_top_right"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignEnd="#+id/graph_single_view"
android:layout_alignRight="#+id/graph_single_view"
android:layout_alignTop="#+id/graph_single_view"
android:layout_gravity="top|end"
android:gravity="top|end"
android:hint="#string/placeholder_top_right"
/>
<TextView
android:id="#+id/label_bottom_left"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/graph_single_view"
android:layout_alignLeft="#+id/graph_single_view"
android:layout_alignStart="#+id/graph_single_view"
android:layout_gravity="bottom|start"
android:gravity="bottom|start"
android:hint="#string/placeholder_bottom_left"
/>
<TextView
android:id="#+id/label_bottom_right"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/graph_single_view"
android:layout_alignEnd="#+id/graph_single_view"
android:layout_alignRight="#+id/graph_single_view"
android:layout_gravity="bottom|end"
android:gravity="bottom|end"
android:hint="#string/placeholder_bottom_right"
/>
</com.companyname.graph.GraphLayout>
To keep the GraphView square, I'm doing this in the GraphView class:
#Override
protected void onMeasure( int widthMeasureSpec, int heightMeasureSpec )
{
super.onMeasure( widthMeasureSpec, heightMeasureSpec );
int size = Math.min( getMeasuredWidth(), getMeasuredHeight() );
setMeasuredDimension( size, size );
}
(stolen from here).
I'm running into problems, though, in displaying the group of four. GridLayout loses its tiny mind at the thought (it puts every GraphView in an area the width of the entire screen). I ended up using two horizontal LinearLayouts in a vertical LinearLayout, sized using layout_weight, which works, but won't let me do the animated transition that I want. I'd like a single graph simply to expand to cover the entire area, clipping its unchanging siblings as it goes, and back again.
So far I've settled on animating the layout_weights in the LinearLayouts, but the effect isn't something you'd show off to your friends.
I'm using height and width of WRAP_CONTENT for everything except 1dip-wide/tall separator lines between the graphs in the two rows, and between the rows in the quad view.
So my (first) question is - is there a better way to make my graph-plus-text widget?