Скачать или смотреть Solving the Fade In and Fade Out Animation Issue in SwiftUI

Learn how to create smooth `opacity` animations in SwiftUI. This guide addresses common mistakes and provides a clear solution to implement fade in and fade out transitions successfully.
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This video is based on the question https://stackoverflow.com/q/63187785/ asked by the user 'rayaantaneja' ( https://stackoverflow.com/u/13299183/ ) and on the answer https://stackoverflow.com/a/63187822/ provided by the user 'Asperi' ( https://stackoverflow.com/u/12299030/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding the Fade In and Fade Out Animation in SwiftUI

When working with animations in SwiftUI, one might encounter challenges that can be frustrating, especially when it comes to simple animations like fading in and out. You may find yourself asking, Why isn't this simple opacity animation working as intended? Let's dive into this common issue and explore how to resolve it effectively.

The Problem: Jumping Between Opacity States

In the case posed, the developer attempted to create a fade in and fade out animation for a text element, but instead of a smooth transition, the text simply jumps between fully visible and completely invisible states. This lack of smoothness can diminish the user experience and is something we want to avoid.

The code snippet that led to this hiccup is as follows:

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

Here, the problem arises because the animation is being applied at the wrong point in the code, specifically only to the text element itself.

The Solution: Moving the Animation to the Parent View

To achieve a smooth fade in and fade out effect, you need to adjust the placement of the animation. Instead of applying the animation directly to the Text view, it should be applied to the parent VStack. This way, the animation can properly recognize changes in the view hierarchy and animate accordingly.

Corrected Code

Here's the corrected version of the code:

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

Explanation of the Changes

Placement of .animation Modifier: By moving the .animation(.easeInOut) to the VStack, the entire stack, which includes the conditional text, now observes changes in its contents. When showing toggles, the VStack animates this change smoothly, allowing for the intended fade in and fade out effect to occur.

Using transition(.opacity): The .transition(.opacity) modifier cleverly informs SwiftUI to apply an opacity transition whenever the Text element is added or removed from the view. This must be paired with the appropriate animation on the container view to succeed.

Conclusion

In SwiftUI, successfully implementing a fade in and fade out animation requires careful positioning of your animation modifiers. Always remember that the context in which you apply animations can greatly affect the output. By placing animation modifiers at the parent view level, you open the door to a smoother and more visually appealing experience for your users.

Now that you know how to fix that jumping issue, go ahead and enhance your SwiftUI applications with smooth transitions! Happy coding!