I have in my objective-c application a loginViewController from where I display the homeViewController after the user logged in successfully. This is how I display the home:
-(void) displayHome {
UIViewController * home = [self.mainStoryboard instantiateViewControllerWithIdentifier:#"homeViewController"];
_window.rootViewController = publicHome;
[_window makeKeyAndVisible];
}
The displayHome function is in the AppDelegate. After that, in the homeViewController i present some view controllers using
[self presentViewController:controller animated:false completion:nil];
Sometimes I have to redirect the user to the loginViewController so I call this VC the same as I do for the home (by setting the rootViewController) in order to remove all the other views. But when I use the 3d debugger I see that the presented views are there.
Why when I set the rootViewController with the loginViewController, the presented views are not removed even if there are attached to the homeViewController that is as the rootViewController?
Edit
An example:
Suppose that from the homeViewController(that is the rootViewController) I go to the viewController1 (viewController1 is presented). Now when I press a button in the viewController1 I have to return to the loginViewController. In the button action, this is what I do:
I call
[self dismissViewControllerAnimated:false completion:nil];
and [appDelegate displayLogin];
//AppDelegate
-(void) displayLogin {
UIViewController * login = [self.mainStoryboard instantiateViewControllerWithIdentifier:#"homeViewController"];
_window.rootViewController = publicHome;
[_window makeKeyAndVisible];
}
When I debug, I find that the viewController1 is still here. It under the login. Why is the viewController1 here even if I set the rootViewController?
Maybe you should first check whether the method -dealloc has been executed in you UIViewControllers. Try add this code in viewController1:
- (void)dealloc {
NSLog(#"ViewController %# dealloc", NSStringFromClass([self class]));
}
If this method hasn't been invoked, then check whether there is still any strong reference pointing to viewController1 after you called [self dismissViewControllerAnimated:false completion:nil];
This usually happens due to the retaincount, check your implementation and make sure there is no completion block or something which is not letting dealloc get called. Once your dealloc gets called all views will get removed
Related
I have the whole app embedded in UINavigationController. Now there is the Home Screen that has several modules for user to choose. Now, when the user clicks on the module it is NAVIGATED and if user desires to choose some another module from any other modules available, there is a button in navigation bar, which PRESENTS the HomeViewController modally on top of the current module and then user can choose any module from there which will NOT BE PRESENTED instead they will NAVIGATE.
Now what I have done is made a delegate called navigate on HomeViewController and will be override by viewcontrollers of each module and it will take the reference of the new ViewController with it. Then when this method is called I have first dismissViewController the HomeViewController and then navigated to the new ViewController that I have the reference.
Now, what the real issue is that SOMETIMES there is a jerk when navigating from one module to other and sometime it works fine. That why I am not able to debug also. The jerk is that when a module is clicked from HomeViewController, the home screen disappears and the appears again and then it actually navigates.
The code for navigating to a module from HomeViewController is
RadiusSearchViewController *rad = [self.storyboard instantiateViewControllerWithIdentifier:#"RadiusSearchViewController"];
[self.delegate navigate:rad];
This navigation overrided method in all modules is
-(void)navigate:(UIViewController*)uiViewController{
NSLog(#"inside navigate method");
[self.presentedViewController dismissViewControllerAnimated:YES completion:nil];
[self.navigationController pushViewController:uiViewController animated:YES];
}
I assure you that it is coming in this method.
Now the code that presents the HomeViewController modally is
ViewController *vc = [self.storyboard instantiateViewControllerWithIdentifier:#"HomeVC"];
vc.view.backgroundColor = [[UIColor whiteColor]colorWithAlphaComponent:0];
vc.delegate = self;
vc.providesPresentationContextTransitionStyle = YES;
vc.definesPresentationContext = YES;
vc.modalPresentationStyle = UIModalPresentationOverCurrentContext;
vc.fromOutside = true;
NSLog(#"Presneting...");
[self presentViewController:vc animated:NO completion:nil];
The reason for PRESENTING and NOT NAVIGATING the HomeViewController is that it comes on the top of the current module in transparent form which is necessary.
REMEMBER: It happens sometimes not all of the time. Like you can say half of the times.
[self.presentedViewController dismissViewControllerAnimated:YES completion:nil];
[self.navigationController pushViewController:uiViewController animated:YES];
this should be changed to...
[self.presentedViewController dismissViewControllerAnimated:YES
completion:^{
[self.navigationController pushViewController:uiViewController animated:YES];
}];
this will make sure navigation view controller will be called after dismiss is done. check and see if it solves your problem.
I have 4 view controllers: loginVC -> homeVC -> aVC -> bVC.
Let's assume the user is currently at bVC view controller and decided to switch to another app. When the user switch back to my app, I want to present the loginVC to authenticate the user. Once authenticated, the previous bVC view controller is to be presented to the user to continue whatever he/she was doing. I'm not using Navigation Controller in my project.
In applicationDidBecomeActive: method, I was able to present the loginVC view controller, but once the user is authenticated, what do I do present the bVC view controller? I assume bVC is still on the stack when the app resign from active?
// AppDelegate.m
-(void) applicationDidBecomeActive: (UIApplication*) application {
NSString *storyboardId = #"LoginIdentifier";
self.window.rootViewController = [self.window.rootViewController.storyboard instantiateViewControllerWithIdentifier:storyboardId];
}
// loginVC.m
-(void)authenticateSuccessful {
// This doesn't do anything... as I want to present bVC
[self dismissViewControllerAnimated:YES completion:nil];
}
1 Instantiate and show your LoginVC as modal one
2 Dismiss it when a user is authenticated
//AppDelegate.m
- (UIViewController *)visibleViewController:(UIViewController *)rootViewController
{
if (rootViewController.presentedViewController == nil)
{
return rootViewController;
}
if ([rootViewController.presentedViewController isKindOfClass: [UINavigationController class]])
{
UINavigationController *navigationController = (UINavigationController *)rootViewController.presentedViewController;
UIViewController *lastViewController = [[navigationController viewControllers] lastObject];
return [self visibleViewController:lastViewController];
}
if ([rootViewController.presentedViewController isKindOfClass:[UITabBarController class]])
{
UITabBarController *tabBarController = (UITabBarController *)rootViewController.presentedViewController;
UIViewController *selectedViewController = tabBarController.selectedViewController;
return [self visibleViewController:selectedViewController];
}
UIViewController *presentedViewController = (UIViewController *)rootViewController.presentedViewController;
return [self visibleViewController:presentedViewController];
}
-(void) applicationDidBecomeActive: (UIApplication*) application {
NSString *storyboardId = #"LoginIdentifier";
UIViewController *lvc = [self.window.rootViewController.storyboard instantiateViewControllerWithIdentifier:storyboardId];
// I.e show it modally instead of putting to rootViewController
UIViewController *visibleVC = [self visibleViewController:self.window.rootViewController];
[visibleVC presentViewController:lvc animated:NO completion:NULL];
}
// loginVC.m
-(void)authenticateSuccessful {
[self.presentingViewController dismissViewControllerAnimated:YES completion:nil];
}
I believe what you need to do is to present (or Modal) a temporary viewController over the current View controller (which is bVC in this case) when the application becomes active.
When a viewcontroller is presented, the object or your bVC is not destroyed and hence you could simply dismiss the loginView once the user is authenticated.
[[NSNotificationCenter defaultCenter]addObserver:self
selector:#selector(yourMethod)
name:UIApplicationDidBecomeActiveNotification
object:nil];
Adding a notification like this could be helpful if you need to present a LoginView from any requiredView Controller
Please refer the documentation on PresentingView controllers
You can do that by presenting your loginViewController as a modal one, as said before, but I think that this 'feature' will make your users to go away of your app, because they want the login part done once in their user's life (at their first use of your app).
If you really need the user to be logged in your app (or server) every time he comes back to your app, I advise you to chose to store the user's login informations in an NSUserDefaults.
Keep in mind that the user wants things to be done as seamlessly as possible, they really don't want to type their login/password every time they just go back to your app :)
EDIT
After some more digging around it has become apparent that if i try to call a segue from the view controller class after a fast application switch to/from Safari i get an exception stating that the segue does not exist. It definitely does, in the VC that is loaded on screen, and i have checked the spelling and it's 100% correct.
What makes it even weirder is that if i call that exact same method from an IBAction it works fine.
Here's the code i am using:
-(void)goToPhotoPage{
[self performSegueWithIdentifier:#"twitterAuthComplete" sender:self];
}
If i call this when the app resumes i get an exception, however if i call it from this IBAction, attached to a UIButton, with doing nothing different the segue works as expected and no exception.
- (IBAction)twitterToPhoto:(id)sender
{
[self goToPhotoPage];
}
Arrrrgrghrhhgrgrg!
ORIGINAL QUESTION
I am working on an iPad application that uploads user photos to Facebook/Twitter.
As part of the process i have to jump to Safari to do OAuth for twitter, the app then jumps back via a specific URL and get's the tokens e.t.c
However for some reason when the application re-awakes i cannot trigger any segue's or manually load any VC's.
I have a success block in my AppDelegae which get's called when the upload is complete which calls a method in the VC to close a spinner and segue to the success view.
The spinner stops as expected, but no matter what i try i cannot get the segue to work.
Everything is hooked up, the segue has an ID and i get no error or exceptions in the console, just nothing happens. The only way i can get code triggered segue to work after this point is to use a user trigger one connect to a UIButton, after that one complete they start to work again.
Here is the code with callback in my AppDelegate:
- (void)postToTwitter:(NSString*)postText image:(UIImage*)image
{
NSData *data = UIImageJPEGRepresentation(image, 0.5);
[_twitter postStatusUpdate:postText
mediaDataArray:#[data]
possiblySensitive:nil
inReplyToStatusID:nil
latitude:nil
longitude:nil
placeID:nil
displayCoordinates:nil
uploadProgressBlock:^(NSInteger bytesWritten, NSInteger totalBytesWritten, NSInteger totalBytesExpectedToWrite) {
} successBlock:^(NSDictionary *status) {
ViewController * vc = [[ViewController alloc]init];
[vc triggerSuccess];
} errorBlock:^(NSError *error) {
ViewController * vc = [[ViewController alloc]init];
[vc uploadFail:error];
}];
}
in the VC i have tried the following:
- (void)triggerSuccess
{
[self segueToSuccess];
}
- (void)segueToSuccess
{
[self hideMessage];
[self.navigationController performSegueWithIdentifier:#"approveSegue" sender:self];
}
As well as:
- (void)triggerSuccess
{
[self segueToSuccess];
}
- (void)segueToSuccess
{
[self hideMessage];
UIViewController *controller = [self.storyboard instantiateViewControllerWithIdentifier:#"done"];
[self.navigationController pushViewController:controller animated:YES];
}
In a moment of pure desperation i even tried:
- (void)triggerSuccess
{
[self segueToSuccess];
}
- (void)segueToSuccess
{
[self hideMessage];
//[self.navigationController performSegueWithIdentifier:#"approveSegue" sender:self];
[self dismissViewControllerAnimated:NO completion:nil];
[self.navigationController popToRootViewControllerAnimated:NO];
[self performSelector:#selector(segueToSuccessPart2) withObject:nil afterDelay:0.25];
}
- (void)segueToSuccessPart2
{
UIViewController *controller = [self.storyboard instantiateViewControllerWithIdentifier:#"done"];
[self.navigationController pushViewController:controller animated:YES];
}
I've obviously missed something, and i'm guessing it's to do with the application going into the background and the VC being "unloaded" from memory, and needing re-instatiating, but i'm not sure where to begin with that.
Any help would be greatly appreciated as i'm about to throw the computer out of the window . .
Thanks
Gareth
Edit 1
After doing some more troubleshooting it appears that during this call in the VC:
[self dismissViewControllerAnimated:NO completion:nil];
[self.navigationController popToRootViewControllerAnimated:NO];
self.navigationController is nil . . .
I'm guessing that is likely the cause of the issues i'm seeing?
Edit 2
So as suggested by Kelin, i am trying to make sure i retain the Navigation Controller.
I have done the following in AppDelegte:
#property (nonatomic, strong) UINavigationController *navController;
and
#synthesize navController;
But when i try to access this from the VC using the below code, it's still nil . .
AppDelegate *appDelegate = [[UIApplication sharedApplication]delegate];
UINavigationController *navController = appDelegate.navController;
[self dismissViewControllerAnimated:NO completion:nil];
[navController popToRootViewControllerAnimated:NO];
Edit 3
I have also added this to the AppDelegate, which means the Navigation Controller is no longer nil. But still nothing happens . . .
if (!self.navController)
{
self.navController = [[UINavigationController alloc]initWithNibName:#"Main" bundle:nil];
}
The problem is you trying to perform segue from storyboard using programmatically created View Controller.
You use -performSegueWithIdentifier: sender: completely wrong. In this method "sender" is a button, or any other control which action initialises segue, but not the view controller to be pushed.
Usually segue is created with storyboard. But if you really need to create it manually, call:
-[UIStoryboardSegue initWithIdentifier:source:destination:]
where source and destination are view controllers.
Read this: https://developer.apple.com/library/ios/recipes/xcode_help-interface_builder/articles-storyboard/StoryboardSegue.html
or this (about custom segues):
You can not do both dismiss and pop together either you have to pop or dismiss the view controller and
Every ViewController have it's own NavigationController which is default point out to navigation controller you added to AppDelegate.
So, You also can access it by self.navigationController (Edit 3)
Also check whether you initialised navigation controller in
AppDelegate
self.navController = [[UINavigationController alloc] initWithRootViewController:firstVC];
I'm developing a single view iOS 5.0+ app and I'm going to navigate throw my ViewControllers this way:
SearchViewController* search =
[[SearchViewController alloc] initWithNibName:#"SearchViewController"
bundle:nil];
[self presentViewController:search
animated:NO
completion:nil];
My question is, if I'm opening SearchViewController from HomeViewController, is HomeViewController dismissed after SearchViewController is shown?
I have a lot of UIViewControllers and I don't know if all of them will be on memory while user is navigating between them.
If You want to Present Only one Viewcontroller you can try like,
SearchViewController* search =
[[SearchViewController alloc] initWithNibName:#"SearchViewController"
bundle:nil];
[self dismissViewControllerAnimated:NO completion:^{
[self presentViewController:search
animated:NO
completion:nil];
}];
When you present a ViewController from another ViewController, they never get released from memory. To release them from memory you need to explicitly dismiss them.
The method presentViewController:animated:completion: sets the
presentedViewController property to the specified view controller,
resizes that view controller’s view and then adds the view to the view
hierarchy.
So you see you are getting a stack of ViewControllers and adding a View on top of another.
This one is tricky. I have a subclass of UINavigationController that overrides pop/push and present/dismiss methods. Here I customise the behaviour to set the correct size if the UINavigationController subclass is contained in a popover. Nothing too fancy, but I do it this way to don't write subclasses of all my ViewControllers and use Autolayout.
However, the completion blocks of the presentViewController:animated:completion: and dismissViewControllerAnimated:completion: are not being executed. And this is the weird part: the exact same code on iPhone works correctly, but on iPad is not executing the blocks. Here is a code sample.
#interface SBNavigationController : UINavigationController
#end
#implementation SBNavigationController
- (void) presentViewController:(UIViewController *)viewControllerToPresent animated:(BOOL)flag completion:(void (^)(void))completion
{
if ([viewControllerToPresent isKindOfClass:[UINavigationController class]])
{
UINavigationController *nav = (UINavigationController *) viewControllerToPresent;
[nav.topViewController setContentSizeForViewInPopover:kFullSizePopover];
} else
{
[viewControllerToPresent setContentSizeForViewInPopover:kFullSizePopover];
}
viewControllerToPresent.modalPresentationStyle = UIModalPresentationCurrentContext;
[super presentViewController:viewControllerToPresent animated:flag completion:completion];
}
- (void)dismissViewControllerAnimated:(BOOL)flag completion:(void (^)(void))completion ;
{
[super dismissViewControllerAnimated:flag completion:completion];
}
#end
And the code using it is this:
#implementation SBInviteFBContactViewController
...
- (void) createInviteByMailViewController
{
SBInviteMailViewController *mailInvite = [[SBInviteMailViewController alloc] initWithDelegate:self userInfo:_userInfo];
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:mailInvite];
[self.navigationController presentViewController:navController
animated:YES
completion:^{
NSLog(#"presentViewController:");
}];
}
#pragma mark SBInviteMailProtocol
- (void) invitedMailContacts:(NSArray *)contacts;
{
[self.navigationController dismissViewControllerAnimated:YES
completion:^{
NSLog(#"animation Ended");
if (contacts) {
[self.delegate invitedMailContact:contacts];
[self popViewControllerAnimated:YES];
}
}];
}
...
#end
Any ideas?
This seems to be a huge bug. Please report it to Apple (and I am about to do the same). I found my way here because I just discovered the same bug myself, and did a google search to see if anyone else was talking about it.
I've created a very small demonstration project, whose architecture is like this:
ViewController - the main view controller
Its view contains a button Tap Me.
PopoverViewController - presented in popover
When you tap Tap Me in the main ViewController, it creates a UIPopoverController with this vc, PopoverViewController, as its content view controller; its view, too, contains a button Tap Me.
PopoverViewController2 - presented "modally" in same popover
PopoverViewController2 has its modalPresentationStyle set to UIModalPresentationCurrentContext so it can appear inside the popover. When you tap Tap Me in the popover, PopoverViewController calls presentViewController:....
Here's the code:
- (IBAction)doTapMe:(id)sender {
NSLog(#"about to present view controller");
[self presentViewController:[PopoverViewController2 new] animated:YES completion:^{
NSLog(#"in completion handler"); // never called!
}];
NSLog(#"did present view controller");
}
The log reads "about to present view controller" and "did present view controller", but "in completion handler" never appears, even though the "modal" view controller's view appears in the popover just fine.
(Moreover, changing to animated:NO not only doesn't fix it, it causes a visual glitch.)
The UIModalPrsentationCurrentContext style is only available if you are compiling against iOS 3.2 or greater. Can't imagine that is the issue though.
The docs for UIModalPrsentationCurrentContext also say:
When presenting a view controller in a popover, this presentation style is supported only if the transition style is UIModalTransitionStyleCoverVertical. Attempting to use a different transition style triggers an exception. However, you may use other transition styles (except the partial curl transition) if the parent view controller is not in a popover.
This is a strange one.
Any chance you're running a different version of iOS on the iPhone and the iPad?