Скачать или смотреть How to Return a String in SwiftUI

Learn how to return a simple string in SwiftUI from a function, troubleshoot common errors, and improve your code structure.
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This video is based on the question https://stackoverflow.com/q/63521120/ asked by the user 'RussellHarrower' ( https://stackoverflow.com/u/275414/ ) and on the answer https://stackoverflow.com/a/63521295/ provided by the user 'rraphael' ( https://stackoverflow.com/u/3256795/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Return a String in SwiftUI: A Comprehensive Guide

When developing applications with SwiftUI, you may encounter scenarios where you need to return values from functions, particularly strings. This guide will guide you through the process of returning a string from a function in Swift, particularly when dealing with asynchronous calls, like fetching data from an API.

The Problem

You may want to return a String value in a SwiftUI view, but you could run into confusion, especially if you are familiar with returning JSON data. For instance, you might have a function designed to fetch a podcast's currently playing episode, but when you attempt to return a plain string, it doesn’t seem to work. This leads you to question how to structure your SwiftUI code to handle such cases correctly.

Let’s dive into the provided code snippets to highlight the issues and solutions.

Understanding the Code Structure

Original Code Breakdown

Here's a simplified version of the class and how it's supposed to function:

[[See Video to Reveal this Text or Code Snippet]]

In the Podcasts view, you want to retrieve a string and display it:

[[See Video to Reveal this Text or Code Snippet]]

Issues Identified

Incorrect Type in Completion Handler:
The completion handler currently expects an array of nowplaying, which is not appropriate when you're working with a simple String.

Data Type for State Variable:
The state variable nowplaying is declared as an array, but it needs to be a String to be displayed properly in the Text view.

Unused Variable:
The line let nowplaying: String is unnecessary and can be removed.

Incorrect Syntax in onAppear:
The syntax used in onAppear is incorrect and can cause issues when the view attempts to load.

The Solution

Let's resolve these issues step-by-step:

Step 1: Modify the API Function

Instead of expecting an array in your completion block, change it to a String:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Update the View State Variable

Change your state variable in the Podcasts view to hold a String value instead of an array.

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Clean up Unused Variables

Remove any redundant code that isn't necessary. For example, the initial let nowplaying: String can be removed from the nowplaying.swift file.

Step 4: Correct the onAppear Syntax

Make sure to correctly use the closure syntax in onAppear like so:

[[See Video to Reveal this Text or Code Snippet]]

Final Complete Example

After applying these fixes, your modified code should look like this:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

Returning a simple String in a SwiftUI application is straightforward once you adjust the parameters and structure correctly. By following the outlined steps, you can manage your functions and state variables effectively, resulting in a clean and functional code design. Happy coding!