I want to implement CalendarView / DatePicker button into my Google Map How can i do it ?

On click of this button i want a small calendar to open and enable to pick a date from the calendar,when the date is picked i want to execute a function that i wrote.

Thank you !

**The area marked with red doesn't exist right now :

I want this button to open a datePicker

https://imagizer.imageshack.us/v2/390x695q90/633/VyWT4l.jpg

my activity xml right now looks like:

<fragment xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/map"
    tools:context=".MapsActivity"
    android:name="com.google.android.gms.maps.SupportMapFragment"/>