Mobile app development

How to Switch the App from Objective-C to Swift?

Objective-C and Swift are two of the important programming languages for iOS app development. Although Swift came later, it has grown popular enough to compete with its counterpart. This is due to the fact that it offers an advantage of writing fewer code lines, less maintenance, fewer bugs, and strong security. And this has led developers to migrate from Objective-C to Swift. If you are also wishing to switch the app from Objective-C to Swift, then here are some tips for you.

Using modern Objective-C converter:

Xcode is the modern Objective-C converter that helps you convert to Switch language. However, it does not represent the semantics of the code and thus it is necessary to check for alterations manually. Here are the tips you can follow:

Converting one Class at a Time:

The best option is to convert one class at a time and not all at once. Although Swift cannot have subclasses, you can use two files that contain an interface section in the header file and implementation section in another.

Developing a Bridging Header:

Xcode develops a bridging head once the Objective-C file is added to the Swift target. It is nothing but the header file that has got the default name from the target but it can also be changed.

Performing Nil Checks:

Objective-C programming language returns a zero value whenever a message is sent to a nil object. It is necessary to perform these nil checks before converting from Objective C to Swift.  Generally, you get it in the form of a generic enum that has a value of wrapped type or value that doesn’t exist altogether.

Tuples:

To group several different values into a compound value, Apple has brought a new tool called Tuples.

Extensions:

All the extensions in Objective C are combined to form a single entity in Swift. There is no need to fetch the source code for the extending types even though it offers new functionality to the structure, class, and protocol.

Functions:

Swift follows an easy approach to the function syntax. Each function is formed with a type. The type contains function parameter types and return type. The developers can give a default value to the parameter.

Point to be considered while converting Objective-C to Swift:

  1. If you don’t want to convert the entire project in a single instance, then consider choosing a pair of .h and .m files to be migrated to Swift. However, if you wish to convert it entirely, then leave the AppDelegate class as it is.
  2. The next step is to locate the MyViewController.h file and eliminate the bridging header file.
  3. Now substitute the instances of MyViewController.h file. This can be done by adding a forward class declaration like @class MyViewController. Remember, this should be done for all the .h files.
  4. With the help of Finer extension that is provided by Swiftify in Xcode, you can translate the file from Objective-C to Swift. Also, you need to copy the contents of both .h and .m files into the Swift file by pressing on the ‘Convert the File’ option.
  5. Now you can replace the .h and .m files from the project with the required Swift format.
  6. Now that the conversion is done, the next step is compiling your code and finding bugs or errors, if any. Xcode offers auto-fix suggestions for fixing the errors. You can use it by navigating to Editor>Fix All in the Scope command. If in case the errors occur repeatedly, then you can optionally take the support of Swiftify.
  7. Now it’s time to run the project. If in case you get issues like ‘Class Not Found’ then you can search for the reference in the Editor. Enter the name of the class in Identity Inspector, then save and try once again.
  8. The AppDelegate class is intentionally kept last and if you wish to convert the entire project then it can be translated now. Now all the files have been switched from Objective-C to Swift, and there are no files left in the target.

Conclusion:

As Swift offer several advantages of developing iOS software, it has become a number one choice for developers. They are rapidly switching from using Objective-C language to Swift. However, transferring an entire project from Objective-C to Swift is a time-consuming and crucial project. It may cause you additional time and headache if not done with proper care and required steps. Consider hiring an experienced professional to perform the switch.

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