MacRuby: The Definitive Guide

Chapter 10. Geolocation

The example in this chapter shows how to write an application that uses the user’s geographical location and a location web service. To do that, we are going to use the CoreLocation framework, the gowalla.com web API (offering location information based on coordinates), and a TableView instance.

As before, we start by creating a MacRuby application using Xcode. Start Xcode and choose the MacRuby template. In the template settings, set the Product Name to “AroundMe” and disable the Document-Based and Core Data options.

User Interface

In this example, the UI will be very simple. We are going to work with just an NSTableView instance and a bunch of columns (NSTableColumn).

Edit your .xib file and resize the main window to be 640 pixels by 440 pixels (use the Size Inspector in the Utilities panel). Now drag and drop a Table View from the Object Library inside the Window’s view. Using the grid guides, scale the table to use most of the window’s real estate.

At this point, make sure the AroundMe scheme is selected and click Run. The app should look like Figure 10-1.

Figure 10-1. Blank Table View

We are going to use the Gowalla API to find the locations (called spots in Gowalla’s jargon) around our users. You can see the type of information the API provides us by going to the following page: http://gowalla.com/api/explorer#/spots?lat=30.2697&lng=-97.7494&radius=50.

We can’t ...