You know the Apple Map feature that lets you set a “Dropped Pin” on a Map View. I was wondering how they did it, and after a bit of research I found out:

It’s a clever combination of a long touch touch gesture recogniser, its “view-to-map-coordinate” method and your own class implementing the MKAnnotation protocol. It’s a bit complex so please bear with me.

Create an MKAnnotation Class

Let’s start from the end and work our way backwards: the MKAnnotation is an object that has the CLLocationCoordinate2D point of your map. This is the “red pin” you see on a map. Once you have it, you simply add it to your Map View.

Note that this object does not already exist which is a little weird – so we’ll have to create one first. I’ll call mine Pin and make it a subclass of NSObject. It needs to conform to the MKAnnotaion protocol, and as such it requires us to create three properties. Here’s the Pin.h file:

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We add our own class as the target and choose the selector we’ve setup in the previous step. We want to wait half a second before touches are converted into pins. The last line adds our touch gesture to the Map View.

And that’s it!

I have a working demo of this on GitHub. It includes several other Map Kit related features – take a look:

• https://github.com/versluis/Locations

Further Reading:

• http://jonathanfield.me/mkmapview-adding-pins-map-showing-annotations/
• https://developer.apple.com/library/ios/documentation/mapkit/reference/mkannotation_protocol/Reference/Reference.html