Understanding View Controller Orientation in iOS 8

In iOS development, handling the orientation of view controllers is crucial for providing a seamless user experience. Before iOS 8, handling orientation could be controlled through setting properties or implementing specific delegate methods. However, iOS 8 introduced changes that require a more thorough understanding of how to effectively manipulate view controller orientation.

This article explores the methods and techniques to force and manage view controller orientation in iOS 8.

Key Principles of Orientation in iOS 8

Prior to iOS 8, `shouldAutorotate` and `supportedInterfaceOrientations` in the `UIViewController` were primary means for controlling orientation. With iOS 8, these methods have less control due to changes that emphasize reliance on the root view controller.

1. Orientation in iOS 8:
   • The control largely moved to the `UINavigationController` or `UITabBarController`.
   • Orientation is now primarily determined by the root view controller in a window.
2. View Controller Lifecycle:
   • Methods like `viewDidLoad`, `viewWillAppear`, and `viewWillDisappear` are valuable entry points for orientation setup.
3. Face Up and Locked Modes:
   • Faced with restrictions, one might need to creatively manage face up and device-locked scenarios.

Forcing Orientation with Code

When you need to lock a view controller to a specific orientation or trigger a rotation, you can enforce orientation using specific mechanisms. Here's a technical walkthrough on how to achieve this:

Step 1: Set Supported Orientation

Most of the orientation work is done in the `AppDelegate`:

• `supportedInterfaceOrientations`: Indicates the orientations supported by this view controller.
• `preferredInterfaceOrientationForPresentation`: Specifies the initial orientation when the view controller is presented.
• `shouldAutorotate`: Enables the ability to rotate to supported orientations.
• `UIDevice.current.setValue`: Provides a way to enforce orientation at the device level (use cautiously).
• `UINavigationController.attemptRotationToDeviceOrientation`: Signals UIKit to reevaluate orientations.
• Design Insights: Design your user interface to adapt to different orientations using auto-layout, size classes, and vector graphics.
• Testing: Test thoroughly across various devices to ensure consistent behavior.
• User Interruptions: Keep in mind user expectations and test scenarios where an orientation change might disrupt interactions or gameplay.