I have a UITableView with various posts, that the user can comment on. Once the user taps on the comment button in the cell, the comments view controller is loaded, and viewwillappear is called but before presenting the view, the app freezes. I am making an API call to fetch the comments in viewDidLoad and reloading the table once the API call is finished. I am not able to figure where iOS 11 is doing things differently. Any help will be much appreciated.
Call API in background thread
let dispatchTime: DispatchTime = DispatchTime.now() + Double(Int64(0.1 * Double(NSEC_PER_SEC))) / Double(NSEC_PER_SEC)
DispatchQueue.main.asyncAfter(deadline: dispatchTime, execute: {
DispatchQueue.main.async{
//Call API function here
}
})
The issue seemed to be with the Navigation Controller, like most issues on iOS 11 transition.
I was setting the right bar buttons for the viewcontroller in viewDidLoad. Commented that line of code and moved it to viewDidAppear and the app wasn't freezing.
But this gave rise to another freeze when user taps on the back button. So I recreated the segues in XCode 9 and did not set the right bar buttons on the navigation item at all. This seemed to fix the issue and there isn't any freeze right now. Hope this helps somebody else.
Related
Working in an app with Objective-C I got the next problem:
I have a code that executes an animation in a UIViewController that is called with input from the user and also when a push notification comes from other user using this app.
The matter is that the first time i enter this UIViewController it works fine, but when unwind-segue and segue again to this UIViewController the animation that is executed with the notification code stops working. The code is being executed but the animation isn't showing. The segues are working modally.
If you need to see some code please tell me.
Thanks T_77 i found the solution to this problem.
It seems like i have some timers that wasn't being invalidated. Invalidating them at ViewWillDessapear did the fix.
With iOS8, I noticed that a view controller was no longer receiving a UIKeyboardWillSHowNotification, when it previously was with iOS7.
Here's the scenario:
1.) View Controller A is displaying a keyboard, and pushes View Controller B without resigning first responder
2.) View Controller B has a control that becomes first responder during its viewDidLoad call, while it's being created by VCA, before it's pushed onto the nav controller
3.) If VC A is NOT displaying a keyboard when pushing B, the notifications work fine. However, if A is still editing when pushing B, then B does not get a keyboard will show notification.
Without the keyboard notification, VC B is not resizing / repositioning and does not look right.
The workaround I'm using until I find a solution is to do the following from any view controllers that might be editing when pushing another view controller that might be editing:
i.e., before pushing another view controller, be sure to call:
[self.view endEditing:YES];
While it works, it doesn't seem good that the view controller (B) can be 'broken' by the state of the app prior to displaying it.
Question: Am I doing something wrong here?
As far as I can tell, one of 3 things are possible:
A.) I should be getting the notifications, but I'm not b/c I'm doing something wrong
B.) I should be getting the notifications, but I'm not b/c of a bug
C.) I can't rely on always getting the notifications...But if I don't get the notifications in VC B when it appears, I need to be able to get the keyboard dimensions of the displayed keyboard without relying on the keyboard notification info. All the apple docs say to use the notifications though (as far as I can find).... which points back to options A.) or B.).
I can create and upload sample code later tonight / early tomorrow to try and isolate / for you all to test/reproduce to see what I'm doing.
I can see the same issue with iOS8 / xCode6 (works with iOS7 and xCode5). In my case, I'm observing a systemStatus property on the model in my AppDelegate so as to log the user out and bring the user back to the login screen when the user logs out from anywhere in the app. I'm doing that by setting the window.rootViewController to the loginViewController in my App Delegate observeValueForKeyPath: method.
This works fine on iOS7 / xCode5 but on iOS8 / xCode6, I loose the keyboard in the way. Looks like my loginViewController might be registering for keyboard notifications (in its ViewWillAppear method) before the window's rootViewController switch is complete (in iOS8) thus registering to the old window's notification center...
I moved the registration for keyboard notifications to the ViewDidAppear: method instead and that seems to fix it but somehow this seems to be called twice for some reason.
I am going to tear my hair out because I cannot think of a logical reason why this occurs on 5 but not 6. So basically, I have a view presented in modal fashion with a navigation bar and a Cancel button (UIBarButtonItem - no custom anything on it, just a standard button) in the navigation bar. When this Cancel button is tapped, I want the modal view to disappear. This works just fine in iOS 6. But for iOS 5 it refuses to work for 2 out of 3 places I have it in my code. What's odd to me is that it works on one but not the other two.
Using storyboards, I right click the button, click on "selector" under Sent Actions, and drag over to the appropriate IBAction method in my view controller's .h file. The link is successfully confirmed with the little blinking animation in Xcode. When I run the app on iOS 6 (simulator or device doesn't matter), the method is successfully executed upon button tap and my modal view dismissed. However, on iOS 5, the method is never even called (I set breakpoints inside the method to see if they would be hit). I've even tried switching the argument in my IBAction method from id to UIBarButtonItem *. No cigar, though.
I've also tried programmatically (in viewDidLoad) setting the cancel button's action to a selector. I've even set the target to the VC. No cigar again. Here is a screenshots of my current setup:
Please note the IBAction methods.
Is there some magical clause in the documentation that I missed? Something awfully special I need to do in order to get it to work in iOS 5? It sure seems like a bug to me, but I'm still fairly new to this stuff so what do I know.
I am using Xcode 4.5.2 and storyboards, and targeting iOS 5 and iOS 6 for the release.
Your help is appreciated, thank you.
I think there may be problem of using GestureRecognizer please comment that code and try it...
I added a separate UIView that resides under my textfields and button and below the navigation bar/title. I added the tap gesture to that programmatically, and that seems to recognize both my tap and the cancel button's action. I still would like to know why the tap gesture swallows up the UIBarButtonItem's action if the gesture is on the root view. This question helped me figure this out. Thanks.
you can exclude view/control from gesture recognizer using following delegate method.
// UIGestureRecognizerDelegate
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch
{
// exclude your view from gesture recognizer
if(yourView == touch.view)
{
return NO;
}
//
return YES;
}
Okay, so I'm building an universal iOS app with an initial login view (view controller named LoginVC), just a plain simple UIViewController. If the login is successful the app segues to an navigation controller (MainNavigationVC). I created this segue through the storyboard gui of XCode, so no programmatic creation of the nav controller is done. The nav controller is presented modally in fullscreen, so the rest of the app is run atop the login view, with this nav controller as the centerpiece of everything.
The navigation controller contains a view (with a view controller named UserStartPageVC), and in its navigation bar is a logout button. This button sends an target action to UserStartPageVC, with the goal of dismissing the nav controller thus bringing the user back to the login view.
So far everything works fine. I can login and use the app as intended. But! When I log out and then re-login XCode tells me this:
Warning! Attempt to present <MainNavigationVC: 0x753110> on
<LoginVC: 0x756fcf0> while a presentation is in progress!
I suppose this means that the login view is trying to modally display a MainNavigationVC navigation controller, but another one is already displayed, right? But how? Can a view be presented without showing?
And how can I get rid of the old nav controller when logging out? I've tried several ways of dismissing the modal view, for instance:
from within UserStartpageVC running
[x dismissViewControllerAnimated:YES completion:NULL]
[x dismissModalViewControllerAnimated:YES]
where x is either self, self.parentViewController or self.presentingViewController.
setting the LoginVC as a property in UserStartpageVC and running
[self.loginVC dismissViewControllerAnimated:YES completion:NULL]
and so on.
All of the tested calls actually brings me back to the login screen, so it's kind of working.
Any ideas? Relevant code samples can be provided if necessary, I just couldn't figure out which pieces that were of interest. The seguing to the navigation controller has no code (except for a performSegueWithIdentifier:sender:), and the code for dismissing it is the part I cannot seem to get straight.
As a sidenote. So far this isn't a REAL problem; the app runs, and it IS possible to logout and re-login without any other side-effects than an error message in XCode. But I suppose this will be a memory leak if users logout and login multiple times, and I'm not in the mood of an unnecessary rejection from Apple.
I discovered another way to get the exact same error message. Lucky me!
If you created a segue at one point and had it tied to a button (click button -> new view) and then later give that segue a name and invoke it directly using
[self performSegueWithIdentifier:#"identifierName" sender:self];
then you can get this error because you can effectively trigger the segue twice. I thought making the button invoke an IBAction would turn off the segue I had set up in the first place, but apparently not. Hitting the button triggered the segue twice, but after I deleted the segue and re-created it as a manual segue on the view with the same identifier then I was able to invoke it via the above code and not get the warning message.
Hoopla! My bad.
Seemed I had set up the notification observing from the login API call in a stupid way. For every time the user triggered a login (or re-login), it added itself as an observer for the notification; the result was that it performed one more segue for every time a login was done.
And doing multiple segues at the same time, is... well, obviously bad.
iPhone/iPad dev newb here...
I am using MonoTouch to create a universal iPad/iPhone storyboard app. In the primary view controller (RootViewController) the default auto-generated behavior is a table with a single cell "Detail" in it, which hardwires you to the next destination (DetailViewController).
I'd like to change this RootViewController to instead show a login control I've made extending UIViewController (LoginView). I have had some success putting the LoginView inside the RootViewController, but can't figure out how to make it 'segue' to DetailViewController. And upon watching how the iPad app works, where there is no segue (that I can see) between the two, am I going about this wrong?
To summarize: How do I enhance this storyboard app with a preceding login screen, reusing its contents/xib between the iPad and iPhone variant?
Apologies if this is a bit unclear and muddled.......
I have not tried a storyboard app in Monotouch yet, but I did spend a lot of time working out the best approach for a login screen for my application. What I ended up doing, which could work in your situation as well, is presenting the login screen as a Modal view. Once the user has successfully logged in, we then push the next appropriate view.
So if you are automatically pushed into the detail view by the storyboard viewcontroller, you could display the login dialog as a modal dialog from the detail view's DidLoad or DidAppear methods.