Скачать или смотреть How to Fix UITableViewCell Transparency Issues in Swift

Learn the solution to make your `UITableViewCell` partially transparent in Swift using `alpha` property correctly.
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This video is based on the question https://stackoverflow.com/q/63553736/ asked by the user 'pizza7' ( https://stackoverflow.com/u/722984/ ) and on the answer https://stackoverflow.com/a/63556404/ provided by the user 'pizza7' ( https://stackoverflow.com/u/722984/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Addressing UITableViewCell Transparency Issues in Swift

When developing iOS applications, you might encounter a situation where you need your UITableViewCells to be partially transparent. In a common use case, you may want cells that start with an alpha value of 0.85, so that the content behind them shows through slightly. However, this can become tricky, as cells often default back to being fully opaque.

In this guide, we will explore why UITableViewCells might not respect the opacity settings as expected, and we’ll provide a streamlined solution to ensure your cells maintain the desired transparency effect.

Understanding the Problem

You might have tried to set the alpha property of the UITableViewCell inside the cellForRowAt method, like this:

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

While this looks good, you may notice that when the table view is displayed, the cells appear as fully opaque. The reason lies in how UITableView manages its cells, particularly with the alpha property.

The Underlying Issue

Re-Setting Alpha

After the cellForRowAt method is executed, UITableView may modify or reset the cell's alpha and other properties before the cell is displayed on the screen. This behavior can lead to confusion, as it seems that the alpha value you set is being ignored.

The Solution

To address this challenge, we can utilize another method provided by the UITableViewDelegate. The method tableView(_:willDisplay:forRowAt:) is called just before the cell is displayed, making it the perfect place to set the alpha property. Here is how you can implement it:

Step-by-Step Implementation:

Conform to UITableViewDelegate: Ensure your view controller conforms to the UITableViewDelegate protocol.

Implement the willDisplay Method: Add the following method to set the alpha just before the cell is shown.

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Complete Example

Putting it all together, your view controller might look something like this:

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

Conclusion

By using the willDisplay method, you can ensure that your UITableViewCell maintains the desired alpha value all the way through to when it is displayed on the screen. This technique not only resolves the opacity issue but also provides a great level of control over your interface.

Now you can implement transparent UITableViewCells seamlessly in your projects! Happy coding!