A new version of the Swift programming language is coming: Swift 5.0. It’s slated to be released early 2019, with a fair number of changes. How does this Swift update affect practical iOS development? And who’s making these changes anyway?
In this article, we’ll walk through some of the proposed and accepted changes for Swift 5.0. We’ll also discuss how the process of making changes to the Swift language works, and why that’s relevant for iOS developers.
Version 5 of Apple’s Swift language used for iOS and MacOS application development will arrive in 2019 with ABI (application binary interface) stability in the standard Swift library a primary focus.
ABI stability is half of what is needed to support binary frameworks. The other half, module stability, will be a “stretch goal” for Swift 5 and may not make it into the release, Apple’s roadmap notes.
Deep linking basically enables you to open an app from another app or a website while passing on parameters. This mechanism works with custom URL schemes which you can define in the .plist of your app.
Why deep linking?
If you have an app with lookup functionality (e.g. an app for finding song lyrics) you might want to perform a lookup without having to navigate to the designated screen and typing in the query. This can be achieved by opening the following example URL MyAppScheme://myAction=lookup&myQuery=What%20is%20the%20meaning%20of%20life in another app of the browser. In this case the app is programmed to read the ‘myAction’-parameter on startup to determine the action and the ‘myQuery’-parameter for the search query. Often, deep linking doesn’t go as planned and you might need to debug your app.
Why is debugging this difficult?
Deep linking might occur in three kinds of scenarios:
The app hasn’t been installed yet
The app is running in the background (or foreground for that matters)
The app is installed but not running at all
Scenario 1 is irrelevant in this case, so we’ll skip this one. Scenario 2 should be no problem since the app is running on the device (or simulator) while in a debug session. Scenario 3 requires you not to have the app running, but you need the debug session to be able to debug. This is a problem because Xcode starts the app automatically when starting a debug session. Instead of letting Xcode start the app, you want to do it yourself using the deep link URL.
So… tell me how to do this
There is a convenient option which enables you to start a debug session by manually starting the app. To achieve this, go to the ‘Edit scheme’ screen and tick the ‘Wait for MyApp.app to be launched manually’ option on in the ‘Run’ configuration.
Whenever you run the target in Xcode, the app doesn’t automatically starts and the debug session will only start when you manually start the app.
An action is a piece of code that’s linked to some kind of event that can occur in your app. When that event takes place, the code gets executed. You can define an action to accomplish anything from manipulating a piece of data to updating the user interface. You use actions to drive the flow of your app in response to user or system events.
You define an action by creating and implementing a method with an IBAction return type and a senderparameter.
The sender parameter points to the object that was responsible for triggering the action. The IBAction return type is a special keyword; it’s like the void keyword, but it indicates that the method is an action that you can connect to from your storyboard in Interface Builder (which is why the keyword has the IB prefix).
Outlets provide a way to reference objects from your interface—the objects you added to your storyboard—from source code files. You create an outlet by Control-dragging from a particular object in your storyboard to a view controller file. This creates a property for the object in your view controller file, which lets you access and manipulate that object from code at runtime. For example, in the second tutorial, you’ll create an outlet for the text field in your ToDoList app to be able to access the text field’s contents in code.