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iOS Enhance a Weather App with Table Views Custom Table View Cells Pull To Refresh

Posted by tate
tate
13,435 Points

Refresh control zPosition crashing the app?

Ok so I was following the pull to refresh video and then I tried typing refreshControl?.layer.zPosition = tableView.backgroundView!.layer.zPosition + 1 but it just crashed my app? The error that it comes up with is: "fatal error: unexpectedly found nil while unwrapping an Optional value"

Leonardo Santos
Leonardo Santos
5,290 Points

It must be tableView.backgroundView?.layer.zPosition + 1

The app is unwrapping a null value. If you use "?", the unwrap process will be silently interrupted in case of null value.

2 Answers

Konstantin Mishukov
Konstantin Mishukov
7,707 Points
Konstantin Mishukov
Konstantin Mishukov
7,707 Points

I've got the same problem.

I have a custom tableView, and this must be the problem. When i tried optional sign "?" xCode automatically corrects the line like this:

self.refreshControl.layer.zPosition = (self.mainTableView.backgroundView?.layer.zPosition)! + 1

The error is EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subside=0x0)

Konstantin Mishukov
Konstantin Mishukov
7,707 Points
Konstantin Mishukov
Konstantin Mishukov
7,707 Points

Also i have a problem in a custom tableView, i made myself a refresh control, which was introduced in weather app course. Everything works fine, but i don't understand, how can i make refreshControl appear above tableView, i want it to be pulled down, not appear behind the tableView.