Xcode preview displays a bug in the content of the list view and its solution

summary

We know Xcode Preview of (Preview) It's development SwiftUI Edge tool of interface , It is manifested in ：

• Quick display SwiftUI View interface
• Quick test SwiftUI The function of the view

But unfortunately , so far Xcode There are still more or less problems with the preview function of , For example, when a list is displayed under certain conditions , among Cell Display of views (onAppear) And hide (onDisappear) The callback method will not be called ：

We hope that noname user Cell Show the user panel at the top of the main view when hidden , And Cell Hide the top user panel when displaying . But as shown above , In any case , None of the top panels show .

Include Xcode 13.4 And the latest Xcode 14beta All have this problem .

that , How to be in Xcode Fix this... In the preview Bug Well ？

Let’s dive in!

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Top panel shows and hides logic

As I said before , We hope the following results ：

• stay List in noname user Cell Display time , Hide the top user panel
• stay List in noname user Cell When hidden , Show the top user panel

This is by listening to users Cell Of onAppear and onDisappear Events to achieve