Migrating Existing iOS Applications to Swift 3

In 2014, Apple introduced a new compiled programming language called Swift for iOS, macOS, watchOS, and tvOS app development. The company subsequently made Swift an open source programming language. In addition to being an expressive, powerful, and modern programming language, Swift is also fully compatible and interoperable with Objective-C. The iOS app developers also have option to combine both Objective-C and Swift code seamlessly in a single project. Hence, they can use Swift for writing new iOS apps and upgrade existing iOS apps written in Objective-C.

Apple recently announced Swift 3 with an array of improvements and refinements at its 2016 Worldwide Developers Conference (WWDC). The new API conventions provided by Swift 3 enable app developers to work with commonly used frameworks more efficiently. Likewise, the version 3 of the programming language also comes with several new language features to make it easier for programmers to keep the app code natural and consistent. Hence, the developers can easily enhance the performance and user experience of the existing iOS apps by migrating them to Swift 3. However, they must focus on some simple points to move their existing iOS apps to Swift 3 quickly and efficiently.

How to migrate your existing iOS Apps to Swift 3 successfully?

Prepare the Project for Migration

When you decide to move an existing iOS app to Swift 3, it becomes essential to prepare the project perfectly for migration. For instance, you have to upgrade to Xcode 8 to take advantage of the new features included in Swift 3. Likewise, the project must be managed under source control. The source control will help you to review the changes made to the app during migration, and discard the changes that are irrelevant.

There are always chances that your iOS app may be designed with multiple schemes. You must integrate various schemes used by the iOS app, and create a single scheme to make the app migration process smoother. The migration assistant tool will process only the changes included in the unified scheme. However, you still have option to review the changes being processed by the tool, and ensure that the scheme includes all targets and associated unit tests.

Use Swift Migration Assistant

You can always move an existing iOS app to Swift 3 efficiently by taking advantage of the Swift Migration Assistant included in Xcode 8. The migration assistant tool allows you to migrate the iOS app to either Swift 2.3 or Swift 3. Apple recommends you to move the app directly to Swift 3 to take advantage of the new features provided by most recent versions of Swift and Xcode. Many iOS app developers still find it more convenient to move their apps initially to Swift 2.3, and then migrate the app again to Swift 3.

The migration assistant further allows you to choose from a comprehensive list of targets to be migrated. Once you chose the targets, the tool will implement the source changes by initiating a migration build. Also, it will display you all changes that will be applied to the iOS app once you click on the save button. Once you click on the save button, the migration assistant will apply the source changes to the original files. After the changes are applied, you can check the source code of the existing iOS app converted into version 3 of Swift programming language.

Identify and Resolve Migration Errors

The migration assistant will enable you to move an existing iOS app to Swift 3 without putting extra time and effort. But the migration process can be impacted by a variety of errors and issues. Hence, you must identify the migration issues and resolve them properly to make the app migration project successful. You can always refer to the list of migration errors and issues shared by Apple to understand the common problems in migrating an existing iOS app to Swift 3. However, you still need to understand the enhancements and refinements included in the most recent version of Swift to resolve the new migration errors efficiently.

However, the developers must remember that Swift 3.0 is currently available as a part of Xcode 8. Hence, they have to upgrade to the most recent version of Xcode before moving their apps to Swift 3. Also, they must not forget to test the iOS application thoroughly after migrating to the latest version of Swift programming language.