i am making a very complicated app with a lot of classes.
my app worked great and i worked on it for the last month.
the last time i worked on it i added a function and it worked great, i saved the app and ran it a few times since and it worked. the last time i turned my computer on, it prompted me that an update for xcode is available. i updated it, and since then every time i run my app it runs with no errors but on ios simulator it shows a black screen. what can i do? i worked really hard on that app. thanks for the help in advance.
There's few issues that could happened, withou detailed description of this issue, you can try following solutions:
reset simulator
check if your initial controller is set up in storyboard(select controller and press attribute inspector, select is initial view controller):
if you're setting initial view controller programmatically, check if that controller is not nil in app delegate
another tip - try to use UI debugger, that helps a lot:
Any debug messages in the Xcode output? That usually will give a clue.
One thing I can think of, is that in your
- (void) applicationDidFinishLaunching:(UIApplication*)application
delegate, try setting the window's root view controller to your view controller. Example:
[window setRootViewController:viewController];
[window makeKeyAndVisible];
Again, the Xcode debug output will confirm if this is indeed the case though.
Related
I currently have multiple views open as children to my navigation controller through the method navigation controller.push(). When you rotate the device it automatically goes back all the way to the root view controller, as if you called poptorootview().
I am wondering why it is doing this and how to stop this from happening. I have not modified UINavigationController class in any way.
Thank you!
In case anyone else is looking for any workaround .I had this really annoying issue in iOS 11.1 only but everything was looking good in iOS 10 and below.
Finally I got it fixed by updating my Xcode to 9.2 and the problem has been disappeard, still I have no idea what caused that, but it take 3 days to me to get rid of it!
Sometimes, when I run app, I got white screen. But I know app is still running (coz I need to play sound).
Somehow, the view hierarchy mess up I guess. Problem is that I never see white screen if I run from Xcode. If I see, I will know how is the hierarchy.
dispatch_async(dispatch_get_main_queue(), ^{ //need to run in main thread.
self.window.rootViewController = self.defaultVC;
[self.window makeKeyWindow];
self.window.hidden = NO;
});
Is it because of view hierarchy? Or any other reason which can produce white screen?
There is an awesome little tool called PonyDebugger which enables view-based debugging. You just throw it all in your project and start it in your AppDelegate and you can see at anytime exactly what view is displayed.
You can basically step through the hierarchy like in "chrome F12".
This helped me solve WhiteScreen-problems in the past.
Check your Copy Bundle Resources (found within Build Phases) and make sure that all of your .xib files are correctly listed (e.g. that they are indeed there).
Also is there a specific reason you are creating that window programmatically instead of using setRootViewController?
I'm coding a video processing app and was just about to submit it to the app store when ios 8.1 came out. I updated my iPhone as well as XCode and all hell broke loose. In my simple single viewcontroller interface nothing is rotating anymore except for the statusbar, which also doesn't get automatically hidden anymore in landscape mode...
I figured it was because I was using the deprecated willAnimateRotationToInterfaceOrientation: for what little custom rotation actions I had, so I implemented traitCollectionDidChange: and viewWillTransitionToSize: to specs instead. However viewWillTransitionToSize never gets called in my app and traitCollectionDidChange: is only called once, at startup. The device simply isn't telling the app that the device has rotated.
After googling I've also tried using name:UIDeviceOrientationDidChangeNotification. At least my selector does get called for that one but I don't know how to manually handle all rotation.
My didFinishLaunching... and viewDidLoad are very simple. alloc UIWindow, storyboard, set my viewcontroller from there, make it rootviewcontroller, makekeyandvisible. All based on one of Apple's AVFoundation demo apps.
Then in didload I add some subviews and a toolbar etc, nothing out of the ordinary and obviously it did work on 8.0 and 8.0.2 on all kinds of devices as well as the 7.1 simulator etc. Still runs flawlessly on my iPad with 8.0.2... Reason I haven't posted any code is I'm 100% sure everything is correct on that end.
Main weird thing is I can't seem to find anyone with this problem.
No errors in console or elsewhere either.
Does anyone have any idea of what might be causing this? I didn't think a point release would make such massive differences and again, no one else seems to be having this. Could it be an issue/bug in the actual storyboard file?
And, mainly, since I can get rotation notifications through UIDeviceOrientationDidChangeNotification, how do I manually handle all rotation/resizing stuff? I have been looking all over for answers but to no avail and am out of time to spend on this project currently :(
Cheers!
alloc'ing UIWindow will be the problem.
First, Make sure your navigation controller (or whatever you're using) is set as "Initial View Controller" in your storyboard.
Secondly, in your AppDelegate.m file, remove any references to UIWindow and rootViewController that appear in application didFinishLaunchingWithOptions. In my case, removing the following two lines fixed my issues.
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
[self.window makeKeyAndVisible];
You also don't need to set the window's rootViewController if using storyboards.
They're simply not needed when using storyboards, but until 8.1 there was never any harm using them. It took my 2 days to figure this out, so hopefully it will help you and others too.
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'm presenting an MFMessageComposeViewController which works fine with iOS4 and iOS 5 but has problems with iOS6.
The view is presented ok but if its dismissed and then represented it doesn't display correctly - only the To: line is displayed, the body and keyboard are missing. (Sorry I can't post a screen shot at the moment as XCode crashes when I take a shot, I'm downloading an older version of XCode as I type).
Stepping through the code in the debugger I noticed that the problem may originate earlier than the re-presenting - I noticed than when dismissViewControllerAnimated: gets called the entire view does not get dismissed immediately, rather it is the message body and keyboard that gets dismissed leaving behind the To:, the same thing that is displayed when the view is re-presented.
It might be easier to describe with screenshot, I'll post some shortly.
I'm using presentViewController: and dismissViewControllerAnimated: to present/dismiss the MFMessageComposeViewController.
+++ UPDATE +++
I've found the problem can be solved if instead of using the same MFMessageComposeViewController object to re-present the view I first delete it and then create a new one.
That seems a little inefficient though, and it should not be necessary I'd have though, like i mentioned it worked on iOS5.
In iOS 6 apple introduced a new feature "remote view controller". Some external view controllers are no longer part of your app, and the messaging controller is one of them.
I guess that is the problem in your case.
you can read more about it there: http://oleb.net/blog/2012/10/remote-view-controllers-in-ios-6/