With the introduction of SceneDelegate in iOS 13, developers have been given more power and flexibility in managing multiple window UIs and scenes. SceneDelegate is a new class that works alongside the AppDelegate to define the window and scene-based architecture of an iOS app. In this article, we’ll explore what SceneDelegate is, why it’s useful, and how to implement it in your app.
What is SceneDelegate?
SceneDelegate is a new class introduced in iOS 13 that is responsible for managing one or more windows and their associated scenes. Each scene represents an instance of your app’s UI that can be displayed independently of other scenes. A scene can be thought of as a “mini-app” that runs within your app.
One of the main functions of SceneDelegate is to create and configure the UIWindow object for each scene. The UIWindow is the main container for your app’s user interface and is responsible for displaying the views and controls of your app. When a scene is created, its UIWindow is created and configured by the SceneDelegate.
Why use SceneDelegate?
SceneDelegate is useful for managing multiple windows and scenes within an app. In previous versions of iOS, apps were limited to a single window and UI instance. With SceneDelegate, developers can create multiple windows and scenes, each with their own UI and state. This allows for more flexibility in managing complex UIs and user workflows.
SceneDelegate also allows for better integration with iPadOS and macOS. With the introduction of multi-window support on iPadOS and Catalyst apps on macOS, SceneDelegate provides the necessary tools to manage multiple windows and scenes across different platforms.
How to implement SceneDelegate
Implementing SceneDelegate in your app involves a few steps. First, you need to create a new file for your SceneDelegate class. This file should inherit from UIResponder and adopt the UIWindowSceneDelegate protocol.
Next, you’ll need to update your app’s Info.plist file to indicate that it supports multiple windows and scenes. Specifically, you’ll need to add the "Application Scene Manifest" key and specify the classes and storyboards for each scene in your app.
Once your app is set up to support multiple scenes, you can use the SceneDelegate to create and manage each scene’s UI and state. This can be done by implementing the various methods of the UIWindowSceneDelegate protocol, such as scene(:willConnectTo:options:) and sceneDidDisconnect(:).
Best practices for managing multiple windows and scenes
When working with multiple windows and scenes in your app, it’s important to follow some best practices to ensure a smooth user experience. One important practice is to use the proper transition styles when presenting and dismissing scenes. This can help maintain the user’s mental model of the app’s UI and reduce confusion.
Another best practice is to use separate UI hierarchies for each scene instead of trying to share views between scenes. This can help avoid conflicts and unexpected behavior when managing multiple scenes.
Finally, it’s important to properly manage the state of each scene when the app enters the background or is terminated. This can be done by implementing the appropriate methods of the SceneDelegate and saving and restoring the scene’s state as needed.
In conclusion, SceneDelegate is a powerful tool for managing multiple window UIs and scenes in iOS apps. By implementing SceneDelegate in your app, you can create more flexible and powerful UIs that work seamlessly across different platforms. By following best practices for managing multiple scenes, you can ensure a smooth and intuitive user experience.