iOS 7 Programming Cookbook

9.10. Displaying Directions on the Map

Problem

You want to display directions on a map to show the user how to get from point A to point B.

Solution

Instantiate an object of type MKDirections and issue the calculateDirectionsWithCompletionHandler: instance method of that object. The completion handler will get called and will pass you an object of type MKDirectionsResponse. Use the directions response object to open the Maps app on your device, as you will soon learn.

Discussion

Directions to walk or drive can be displayed only in the Maps app on a device, so you cannot display them inside an instance of a map view in your app. The way we will go about displaying directions is very straightforward. In order to display the directions on the Maps app, we need to create an instance of the MKDirections class. This class will require us to have already prepared an instance of the MKDirectionsRequest.

In addition, to create the directions request, you need to create instances of the MKMapItem. Every map item will represent a point on the map. So the bottom line is that if you want to display directions from point A to point B on the map, you need to represent them as map items, create a request out of that, and then use the MKDirections class to receive the directions. After receiving the directions, you have two choices:

• Process the directions yourself. For instance, using the technique that you learned earlier in this chapter (see Recipe 9.4), you may want to retrieve all the gas stations ...