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iOS 17 Programming for Beginners - Eighth Edition

You're reading from  iOS 17 Programming for Beginners - Eighth Edition

Product type Book
Published in Oct 2023
Publisher Packt
ISBN-13 9781837630561
Pages 604 pages
Edition 8th Edition
Languages
Author (1):
Ahmad Sahar Ahmad Sahar
Profile icon Ahmad Sahar

Table of Contents (34) Chapters

Preface 1. Part 1: Swift
2. Exploring Xcode 3. Simple Values and Types 4. Conditionals and Optionals 5. Range Operators and Loops 6. Collection Types 7. Functions and Closures 8. Classes, Structures, and Enumerations 9. Protocols, Extensions, and Error Handling 10. Swift Concurrency 11. Part 2: Design
12. Setting Up the User Interface 13. Building Your User Interface 14. Finishing Up Your User Interface 15. Modifying App Screens 16. Part 3: Code
17. Getting Started with MVC and Table Views 18. Getting Data into Table Views 19. Passing Data between View Controllers 20. Getting Started with Core Location and MapKit 21. Getting Started with JSON Files 22. Getting Started with Custom Views 23. Getting Started with the Camera and Photo Library 24. Getting Started with Search 25. Getting Started with Collection Views 26. Part 4: Features
27. Getting Started with SwiftData 28. Getting Started with SwiftUI 29. Getting Started with Widgets 30. Getting Started with visionOS 31. Testing and Submitting Your App to the App Store 32. Other Books You May Enjoy
33. Index

Exploring error handling

When you write apps, bear in mind that error conditions may happen, and error handling is how your app would respond to and recover from such conditions.

First, you create a type that conforms to Swift’s Error protocol, which lets this type be used for error handling. Enumerations are normally used, as you can specify associated values for different kinds of errors. When something unexpected happens, you can stop program execution by throwing an error. You use the throw statement for this and provide an instance of the type conforming to the Error protocol with the appropriate value. This allows you to see what went wrong.

Of course, it would be better if you could respond to an error without stopping your program. For this, you can use a do-catch block, which looks like this:

do {
   try expression1
   statement1
} catch {
   statement2
}

Here, you attempt to execute code in the do block using the try keyword. If an error is thrown...

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