swiftUI code preview fatally crashing.

Question

TSHKS OP

Created Nov ’23

Replies 3

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Hello!

Being a beginner in creating and editing views using swiftUI, I am unsure of the current situation that I am presently in, and would be grateful for any advice or suggestions for the below problem.

For some context, I have recently begun exploring the "Capturing depth using the LiDAR camera" Documentation using AVFoundation and intend to change its ContentView file which is currently written in swiftUI.

The problem: I am unable to preview the SwiftUI code. When I try to resume the Preview Pane on the right

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Answer 1

TSHKS OP

Nov ’23

The error message: Cannot preview in this file. Fatal error in Cameracontroller.swift

An additional doubt that I would like cleared is whether the possibility of the below causes the preview to crash:

The requirement of a Camera device and LiDAR [Included in the main setup function]No initial view to present.

Thanks in advance!

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Answer 2

ssmith_c OP

Dec ’23

You didn't post any code so I'm making an educated guess here. Your ContentView contains a PreviewPane which is dependent on data from a LiDAR camera. You're developing on a Mac which doesn't have a LiDAR camera. The Preview runs on your Mac, not on the phone, so if it expects a LiDAR camera it isn't going to work.

Previews aren't magic, they are conveniences which enable you to see what your UI would look like under various circumstances. But if your UI is tied to dependencies which cannot be represented in the context of a preview, it is going to be difficult to preview. You're going to have to change your preview so that it isn't dependent on LiDAR. That probably means that your preview will just show a static image as a placeholder, and you're going to have to get the static image from somewhere and explicitly refer to it in your preview.

This is a problem I run into all the time because a lot of example code uses in-memory data structures for brevity, but the real world is much messier.

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Answer 3

TSHKS OP

Dec ’23

Hello ssmith_c!

Thank you for your response and my apologies for not posting any code.

As stated above, I understand that the initial view dependencies need to be changed to support non-LiDAR devices.

I will edit the documentation code by adding an initial static image as preview.

Are there any other things that I need to look out for while using swiftUI? would be happy to gain a little advice from someone who is experienced.

Thanks for the help.

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