Android: Fixing vertical/horizontal scrolling for nested maps.

fragment_my_fancy_map.xml

<?xml version="1.0" encoding="utf-8"?>
    <android.support.v4.widget.NestedScrollView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/actionbar"
        android:id="@+id/scrollView"
        android:descendantFocusability="afterDescendants">
        
         <RelativeLayout
                android:id="@+id/mapsContainer"
                android:layout_width="match_parent"
                android:layout_height="127dp"
                android:layout_below="@+id/gravatar"
                android:layout_marginLeft="@dimen/activity_horizontal_margin"
                android:layout_marginRight="@dimen/activity_horizontal_margin"
                android:layout_marginTop="20dp">

                <fragment
                    android:id="@+id/map"
                    android:name="com.google.android.gms.maps.SupportMapFragment"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    tools:context=".MainActivity"
                    tools:layout="@layout/map_preview" />

                <ImageView
                    android:id="@+id/transparentImage"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:src="@android:color/transparent" />
            </RelativeLayout>

    </android.support.v4.widget.NestedScrollView>

MyMapFragment.kt

/**
 * @see [nested scrolling workaround](http://stackoverflow.com/a/17317176)
 */
private fun fixMapScrolling() {
    transparentImage.setOnTouchListener { v, event ->
        when (event.action) {

            MotionEvent.ACTION_DOWN -> {
                // Disallow ScrollView to intercept touch events.
                scrollView.requestDisallowInterceptTouchEvent(true)
                // Disable touch on transparent view
                false
            }
            MotionEvent.ACTION_UP -> {
                // Allow ScrollView to intercept touch events.
                scrollView.requestDisallowInterceptTouchEvent(false)
                true
            }
            MotionEvent.ACTION_MOVE -> {
                scrollView.requestDisallowInterceptTouchEvent(true)
                false
            }
            else -> {
                true
            }
        }
    }
}