How to use ViewTreeObserver on map marker object?

Question

I have a custom map marker that I would like to scale based on the text of the marker. I want to retrieve the width of this marker. The issue I am facing is that when the app is first launched, the width value is 0. I am getting the width too early. But I am unable to get ViewTreeObserver to actually work. What am I doing wrong, is it possible I am not referencing the correct view?

        // custom marker
        mCustomMarkerView = ((LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE)).inflate(R.layout.custom_map_marker, null);
        tvCustomMarkerTitle = (FontedTextView) mCustomMarkerView.findViewById(R.id.tv_marker_title);
        ivCustomMarker = (ImageView) mCustomMarkerView.findViewById(R.id.iv_marker_bg);
        rlCustomMarkerWrapper = (RelativeLayout) mCustomMarkerView.findViewById(R.id.rl_custom_marker_wrapper);

        rlCustomMarkerWrapper.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                // do some work
            }
        });

The XML looks like the following

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

    <RelativeLayout
        android:id="@+id/rl_custom_marker_wrapper"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">

        <!-- custom marker image -->
        <ImageView
            android:id="@+id/iv_marker_bg"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@drawable/custom_marker"/>

        <!-- custom marker title -->
        <TextView
            android:id="@+id/tv_marker_title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:textSize="@dimen/font_size_14"/>

    </RelativeLayout>

</FrameLayout>

Thank you in advanced!