This is a follow on to

The view has a big question mark hanging over it; it is a subclass of a WKWebView, which is the big change here. I'm using it here as for regular UIView capability, of acting as a container for a bunch of CAShapeLayers. This is working exactly as it was before, when it was a UIView.

The reason for the change is that I want to be able to display html content in the same view as the CAShapeLayers, as a way of having html interleaved between different drawn elements on the screen; think of text with the dark purple shape behind it and the lighter one in front. In this, I'm following a question I asked which was answered here.

In any case, referring to the container in the next line, where the mask is set to nil does not cause the crash; so it seems to have to do with the layer of the WKWebView, and the sublayers of it. They exist, and I've checked that, but setting them to nil seems to blow this up, in this weird way.

I'm sure I'm missing something; I haven't used WebViews before, so I'm expecting that maybe that's the issue; but it's not intuitive to me what could be going wrong, and I've tried multiple strategies for debugging this. The one that has gotten me the closest to pinpointing the problem is what I've shown here, where I can locate it in the one line; but it seems pretty unproblematic to me...am I missing something obvious?

Thanks in advance for your ideas and insights.

CodePudding user response：

It would appear that @Larme was on the right track: I eventually traced it to the line where the view's layer's sublayers were set to nil. This was the problem. Iterating through the sublayers if present and removing them individually from the parent layer caused the crash to disappear.

The same problem cropped up in a second view, also a WKWebView, where applying the same solution caused a similar crash. In both cases, the error message was entirely unhelpful. In the second case, I simply commented out all the code related to sublayer, and things worked fine. I suspect that this might cause problems at a later stage when I need to update the view with other sublayer information, but I am not in a situation to test that right now.

I'm travelling right now without access to my original project, so sorry for no code to show; but the basic iteration through the layer's sublayers should not be too hard to work out.