I have a custom UITableView subclass in which I override +accessInstanceVariablesDirectly to return NO in order to ensure attributes with no setter cannot be set using KVC.
When removing this table view from the view hierarchy, the app crashes - sometimes - and now for the weird part: only if Accessibility is enabled! (i.e. the Accessibility Inspector is visible, or you have Accessibility enabled on a physical device)
If I do not override +accessInstanceVariablesDirectly, everything works fine. I figured maybe UITableView relies on accessing some instance variables directly - but then what is the point of this method, if I can break superclasses by using it? Is there a way to specify this behavior per-attribute, like +automaticallyNotifiesObserversForKey:? However I am baffled by the fact that this issue only exists when Accessibility is enabled.
I tried analyzing the project with various Instruments, but without success.
You can find a minimal project reproducing the issue here. I would greatly appreciate any pointers on why this is happening or how to achieve what I want nonetheless.
This issue appears to be fixed in iOS 9.
Related
While compiling a couple of projects with XCode 12 (beta 5 is the latest version at the moment) and running them on iOS14, I've noticed that UIButton, UITextField, and many other selectable objects are not responding to user input when inside of a UITableViewCell.
In some cases, it is possible to work around the issue by bringing the object to the front (object.bringToFront()), but this is not working for all the cases I'm facing. I've also noticed an empty view (layer) on top of the components of the cell when I use the "Debug View Hierarchy" Tool. This view is not present on XCode 11 builds. Is this some new cell configuration that I'm missing? Is there a standard way of disabling this behavior or will I have to be hacky to fix this?
PS: The issues were not present on the same projects when compiled with XCode 11 (or previous), even when running on iOS14.
All the select response issue may caused by adding subview on UITableviewCell. The right way is add on UITableViewCell.contentView, check it first.
I have been working on this app for months now and from as far back as I can remember I have never had an issue with segues. The code is unchanged in terms of calling performSegueWithIdentifier but since my recent update to Xcode 7 and iOS 9 I have not been able to tack this issue.
I have tried:
Deleting button and creating new button w/ segue link
Using a direct segue from button to view, without the use of performSegueWithIdentifier
Connecting button to new blank viewController
When I press the button, no initial load functions are called on the destination VC (Ex: ViewDidLoad, ViewWillAppear, etc). When I connect it to a blank view, the segue works fine with the same code in place.
Since the code never stops, or breaks, and just seems to "freeze" in place while still running on Xcode I can't seem to even narrow this down to whats causing the issue. I have a similar segue that is also called from another button on the same ViewController that has no issues whatsoever.
Any thoughts on the matter are greatly appreciated!
EDIT: I have narrowed the issue down to the UITextView's causing the problem. Once the Text Views were removed the page loads fine via segue. I wonder what changed between iOS 8 and iOS 9 in terms of UITextView as I will have to remove the text views and completely re add new text views.
So basically the segue was freezing because of the UITextView's I was using in the destinationViewController. The following fixed the issue:
Delete all UITextView's
Add new UITextView's
you must leave the default lorem imposed text and change this programmatically in the viewDidLoad()
This was the fix for me, and from the research I have done on the issue it seems this is a bug in iOS 9 and Xcode 7.
Cheers!
NOTE: Removing the text in the UITextView (or making it longer then ~12 characters) is sufficient to work around it, no need to delete and recreate them. This is fixed in Xcode 7.1.1 and later.
I ran into the same issue and the fixes in this post (Xcode 7 crash: [NSLocalizableString length] 30000) solved the issue for me.
The first is to enable a localisation other than the base for the storyboard (see https://stackoverflow.com/a/32688815/3718974)
The second is to turn off the base localisation (see https://stackoverflow.com/a/32719247/3718974)
I think I have the same problem: I have a UITabelView with cells created from a nib file, when a user tap a cell this method is called:
and when I have the following method prepareForSegue:: the application crashes:
if I delete the line 129 Everything is ok , the method prepareForSegue:: open the right view and the label contactName is shown with its default text.
If I modify the method as follows prepareForSegue:: get exactly what you expect, without having any type of error:
let me know if you also get the same result
Any one who is facing this issue, i solved it by turning off the "Optimize rendering for windows scale" option in Debug of simulator window. I already had tried all of the above answers but could not solve the issue.
In the method in the first viewController where you activate the segue, do you have beginIgnoringInteractionEvents anywhere? If so the screen you segue to will be frozen and will ignore interaction events like you describe. If this is the case you can fix this by adding an endIgnoringInteractionEvents method before your segue method:
UIApplication.sharedApplication().endIgnoringInteractionEvents()
self.performSegueWithIdentifier("editItemToMyGearSegue", sender: self)
I realize this is an old topic, but appears to be still relevant. I was facing the same problem in Xcode 9, iOS11. My UITextViews are embedded inside UITableViewCells. Same symptoms as described here. The tricks with default text and placeholders did nothing for me, but I solved it by turning off the scrolling indicators for the text view in the xib. They were on by default, I guess, though unused.
Edit: this is probably an important detail... the views that were hanging all had an image NSTextAttachment in the attributed string of the text view. I think the image was wider than the available table cell content. With scrolling turned off, they appear to downscale.
After a recent upgrade of Xcode (6.1) I am no longer able to see the properties of objects in the debug area. Does anyone know how to return this functionality to Xcode?
Xcode has never shown properties per se in the Variables view. If the property had a backing ivar, and there was debug information for the backing ivar, then that would be shown. But to present the correct property view it would have to call the property accessor for every property of all the disclosed objects, and that's too expensive.
It happened to me before. Turn out, it was just because a tiny mistake.
So, I think you need to check two things:
Whether the break points you are setting are able to discover your properties. It's all about the scope problem.
To check whether you filter it out accidentally.
I have an iPad app that has been running fine until iOS7. This issue seems to be only on ipad 2nd gen models and earlier when iOS7 is installed. Anyway, I've been tearing my hair out trying to figure out where this error is coming from, but have had no luck. The console in xcode (5) reports the following error after I perform a logged in segue:
2013-11-18 11:17:31.768 MyApp[400:60b] *** -[UIToolbar backdropView:willChangeToGraphicsQuality:]: message sent to deallocated instance 0x18ec23e0
I can't lookup the address for more info (image lookup -a 0x18ec23e0) it just returns nothing.
In instruments running zombies, it reports that a message was sent to a UIToolbar like so:
When I inspect the instance, I get the following:
How do I debug this? I have no idea where this call is being made and it seems dependent upon a physical deivce (doesn't happen on the iPad mini or ipad 3/4)
I was struggling with a very similar error, also with a UIToolbar, that I couldn’t figure out until a couple hours ago. I also had to use and try to understand the zombies’ instrument but without any luck.
What I did was to pay a close attention to the call stack that was presented when the Exception Breakpoint was activated as described in the following tutorial:
http://www.raywenderlich.com/10209/my-app-crashed-now-what-part-1
Even though the call stack didn’t point me to the exact code line, I noticed that the app was trying to add a UIToolbar to a ViewController. Turns out that what I was doing was creating a local UIToolbar inside of a method and adding it to the presented UIView. After have modified this behavior, I stopped having the annoying sudden crash. It was difficult for me to find the issue because looking at the code of the ViewController that caused the crash, there was no code that created or used a UIToolbar; however this VC included a custom view that did exactly that, as I explained before.
Have said all of this I recommend you to closely inspect the VC that generates the crash. If you need to create a UIToolbar programmatically I recommend you to declare it as a strong property to maintain the memory reference as long as needed.
I hope this helps you.
I struggled with this for a while today. I had two storyboards, one for login/signup (set as the main storyboard for the project) and another with the rest of the application. The app delegate would detect if a user was logged in and instantiate the root view controller of the other storyboard. The root view controller of the login storyboard is a navigation controller and after after some investigation with instruments I realized there was a UIToolbar being instantiated from the nib. Opening up the storyboard file revealed an off-screen UIToolbar object in the root view controller. I deleted it and I'm not crashing any more.
I should also mention this crash was only occurring when I was using MKMapView.
I have a custom button that is a subclassed UIButton. When I try to drag it into a UIScrollView in IB Xcode immediately crashes. What gives?
I have this custom button working inside a UIScrollView in at least one other location in my app. Any ideas?
UPDATE:
Uncheck "Use Autolayout" in the File Inspector fixes this problem. See answer below.
I have this custom button working inside a UIScrollView in at least
one other location in my app. Any ideas?
I could crash several Java editor like this. The problem it was in my custom component code:
I have added code, which the designer ( Interface builder) have executed to show my component.
Take extra care at init, viewDidLoad methods in your Button code.
Do not know exactly, But once the same kind of issue happened with me.
My problem was that some of my drawing methods were being called recursively, causing the Xcode to crash. I handled those recursive calls and issue got fixed.
SOLUTION: Uncheck "Use Autolayout" in the File Inspector
Thanks to #BornCoder I decided to try running this on my laptop running Xcode 4.4. When I tried to build I got an error saying this version of Xcode doesn't support Autolayout. I didn't intend to use Autolayout, it looks like Xcode 4.5 does automatically. Unchecking the box fixed it.