Скачать или смотреть Creating a Back Button for Your Image Gallery in Swift UI

A simple guide on how to implement a functional `back button` in your image gallery using Swift UI. Learn the best practices and common pitfalls to avoid.
---
This video is based on the question https://stackoverflow.com/q/62915335/ asked by the user 'Finotoni' ( https://stackoverflow.com/u/13928184/ ) and on the answer https://stackoverflow.com/a/62916396/ provided by the user 'DonMag' ( https://stackoverflow.com/u/6257435/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Swift UI - Button back on image gallery

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
A Guide to Creating a Functional Back Button for Your Image Gallery in Swift UI

When designing an image gallery in Swift UI, one common feature users expect is a functional back button that allows them to navigate through their collection of images seamlessly. If you've stumbled upon difficulties with implementing a back button, worry not! In this post, we’ll detail the solution and explain how to overcome common errors that arise when using arrays in Swift UI.

The Problem: Navigating Back in Image Gallery

Suppose you have an array of images, and you want to let users cycle through these images using both next and back buttons. The back button should take the user to the previous image. However, if not implemented correctly, it can lead to runtime errors—specifically when trying to access an array index that doesn't exist.

Example Scenario

Assuming you have the following images array:

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

If the current index i is 0 (pointing to the first image), pressing the back button executes the following:

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

This calculation will output a negative index, which is out of bounds for the array, causing an error. Our goal is to correctly transition from the first image back to the last one or stop the navigation if it’s already at the first image.

The Solution: Implementing the Back Button Correctly

Wrapping Around the Array

To ensure you can navigate backward from the first image back to the last one without errors, you can modify the back button's action like this:

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

This piece of code does the following:

Decreases the index i by 1.

Checks whether i has dropped below 0.

If so, it wraps around to point at the last image in the gallery (images.count - 1).

Finally, it updates the imageView to display the new image.

Stopping at the First Image

If you prefer to simply stop at the first image when the back button is pressed (rather than wrapping around), you could use this alternative approach:

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

In this case, the index will not wrap around. Pressing the back button will keep the index at 0, preventing any errors and maintaining the display of the first image.

Summary

Implementing a functional back button in your Swift UI image gallery can be done easily with these methods. Understanding how to manage array indices properly helps avoid runtime errors and create a more user-friendly experience. You can choose between wrapping the index around or stopping at the first image based on your application’s requirements.

Experiment with both methods to see which fits your design best, and happy coding!