Getting ready

The UITabBarController class provides a way to display different view controllers on the same hierarchy level divided into a tab-like interface. Create a new iPhone Empty Project in Xamarin Studio and name it TabControllerApp.

How to do it…

Perform the following steps to provide controllers in tabs:

How it works...

The UITabBarController class displays one tab for each of the controllers it manages. That tab is of the UITabBarItem type that can accept both text and images. We set the controllers it will display through its SetViewControllers property, as follows:

tabController.SetViewControllers(new UIViewController[] {
  mainController,
  settingsController
}, true);

After we have added the controllers, we can access its tab bar items through the TabBar property. In this case, we set the tab's Title attribute:

tabController.TabBar.Items[0].Title = "Main";

Each UIViewController contains a TabController property. Similar to the NavigationController property, when the controller is part of a tab controller, the property will return the instance of that tab controller.

There's more...

The controller can accept as many controllers as we want but if we add six or more, four will be displayed with their tabs, while a fifth predefined More tab will represent all the remaining controllers. This is to keep the interface easily accessible to the user by keeping the tabs to a specific size suitable for human fingers. When we add more than six controllers in a tab bar controller interface, by default, the object provides an Edit button on top in the More tab that allows the user to rearrange the order of controllers. If we want to exclude some controllers from this functionality, we have to remove it from the CustomizableViewControllers array.

tabController.ViewControllerSelected += (sender, e) => {
  // Do something with e.ViewController.
};

See also