Creating a custom UIControl object

So far, you have been using the user interface objects provided by Apple, such as labels and buttons. All you need to do is click the Object library button, search for the object you want, and drag it into the storyboard. However, there will be cases where the objects provided by Apple are either not suitable or don't exist. In such cases, you will need to build your own. Let's review the Restaurant Detail screen that you saw in the app tour, which can be seen in the following screenshot:

Here, you can see a group of five stars, just above the Add Review button. At the moment, the Restaurant Detail View Controller Scene in RestaurantDetail.storyboard and the Table View Controller Scene in ReviewForm.storyboard have blank view objects where the stars should be. You will build RatingsView, a custom subclass of a UIControl object, that...