Скачать или смотреть Solving the Issue of Showing and Hiding a Custom Alert in SwiftUI

Discover how to correctly implement a `Custom Alert` in SwiftUI that can be shown and hidden with dynamic buttons using best practices!
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This video is based on the question https://stackoverflow.com/q/75405087/ asked by the user 'tech_human' ( https://stackoverflow.com/u/697033/ ) and on the answer https://stackoverflow.com/a/75405452/ provided by the user 'timbre timbre' ( https://stackoverflow.com/u/5318223/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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SwiftUI: How to Show and Hide a Custom Alert Effectively

In the world of SwiftUI, creating a reusable Custom Alert modifier can elevate your app's user experience significantly. However, many developers, especially those new to SwiftUI, encounter challenges when it comes to showing and dismissing alerts. This post tackles a common predicament: you have successfully set up an alert, but clicking the button to dismiss it seemingly does not work. Let's break down the issue and explore an effective solution.

The Problem

You have a custom alert set up using a ViewModifier, but when you click the button labeled "Click Me," the alert does not dismiss. You suspect the problem lies in how you're managing the isPresented binding variable. Let's look closer at the relevant code snippet to understand the situation:

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The Root Cause

Upon closer examination, there are two primary issues causing the alert to stay visible even after tapping the button:

Binding Declaration: The isPresented variable is declared as a standard property, rather than as a SwiftUI @ Binding property. This is essential for the alert to reactively update its presentation state.

Constant Binding: The use of .constant(viewModel.showAlert) in the customAlert function means you're passing a constant value, rather than a dynamic binding that reflects the changing states managed by your ViewModel.

The Solution

To resolve the issues and ensure the alert can be shown and dismissed correctly, follow these steps to modify your CustomAlertView:

Step 1: Use @ Binding for isPresented

Start by changing the declaration of isPresented in your CustomAlertView:

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Step 2: Initialize the Binding Correctly

Update the initializer to set the _isPresented:

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Step 3: Pass the Correct Binding

In your main view (MyView), instead of passing a constant value, make sure to pass the actual binding to the showAlert property:

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Final Implementation

With these modifications, your final implementation for the CustomAlertView should look like this:

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And in your main view:

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Conclusion

By ensuring the correct use of @ Binding and passing dynamic bindings to your modifier, you can easily manage the visibility of alerts in SwiftUI. This approach empowers you to create customizable alerts that seamlessly integrate into your application, enhancing user interaction. With this newfound understanding, you're well on your way to mastering alert presentations in SwiftUI!

Remember, SwiftUI's reactive nature is powerful, and learning to leverage bindings is key to creating dynamic interfaces. Stay curious and keep experimenting with what SwiftUI has to offer!