How add pin on map?

问题

I have a view in which i have a map. On that view i have a tool bar. In tool bar i have a button for drop pin on map. Now i want to get methods for detecting pin drop and latitude and longitude of that point. For example when user click on button then a pin drop on center of map view. And when user click on pin then show title as the address of that point where that pin drop. What function i use for that so that i can set that event on my map view? How do that?

Thanks in advance...