I am trying to add a registration page & a verification page to my app that has a 3 views that can be switched to and from using a UITabBarController. The registration page should only be shown once in this app's life time. Once a user is registered, this view will go away and be replaced by a verification page. Once a users identity is verified, a user can use the app.
Now in AppDelegate I have the following code to present the registration page to the user:
RegistrationPage *registration = [[RegistrationPage alloc] initWithNibName:#"RegistrationPage" bundle:nil];
[self.window.rootViewController presentViewController:registration animated:YES completion:nil];
After the user filled the registration page and pressed the submit button, the following code is used to dismiss the registration page and present the verification page:
VerificationPage *verification = [[VerificationPage alloc] initWithNibName:#"VerificationPage" bundle:nil];
[self dismissViewControllerAnimated:YES completion:^{
[self addVerificationPage];
}];
-(void) addVerificationPage
{
VerificationPage *verification = [[VerificationPage alloc] initWithNibName:#"VerificationPage" bundle:nil];
[self presentViewController:verification animated:YES completion:nil];
}
However the verification page just never shows up. Can someone help me with this?
I have also tried this in the registration page, does not work either:
VerificationPage *verification = [[VerificationPage alloc] initWithNibName:#"VerificationPage" bundle:nil];
[self dismissViewControllerAnimated:YES completion:^{
[[UIApplication sharedApplication].keyWindow.rootViewController presentViewController:verification animated:YES]
}];
Most likely is an issue caused by attempting to present the VerificationPage at the same time as you dismiss the RegistrationPage. From the Apple documentation:
Dismissing a view controller dismisses not only that view controller but also any view controllers it presented.
As a result, there's two possible orders, either of which will result in failure - either the VerificationPage is created and presented, then the RegistrationPage is dismissed - taking the presented VerificationPage with it. Alternatively, the RegistrationPage is dismissed and destroyed, then the presentViewController call is sent through to it - resulting in failure as the RegistrationPage is no longer a valid ViewController.
To resolve, either leave the RegistrationPage open and present the VerificationPage over it (not ideal, but it will work), or signal the AppDelegate or a ViewController higher up the chain (you can use self.presentingViewController) to do the presenting instead.
Related
My app is crashing when I dismiss a ModalViewController via:
[self.parentViewController dismissModalViewControllerAnimated:YES];
This modal view-controller ("MVC") is presented when a user clicks on one of the cells of a UINavigationController ("NavRoot") - here's the code for that:
MVC *modalView = [[MVC alloc] initWithNibName:#"MVC" bundle:nil];
[self.navigationController presentModalViewController: modalView animated:YES];
[modalView release];
The "modalView" which is loaded contains only 2 objects: a UIWebView object and a "DONE" button, which when clicked-on does the dissmissing via:
[self.parentViewController dismissModalViewControllerAnimated:YES];
Except when I click on "DONE" - the app crashes.
When I run Instruments with NSZombies I do see the retain count reaches -1 but I can't tell what's causing this over-release.
The only thing I found which solves the problem is to either add a "[modalView retain]" statement in "NavRoot" - which is the viewController doing the presenting of modalView:
MVC *modalView = [[MVC alloc] initWithNibName:#"MVC" bundle:nil];
[self.navigationController presentModalViewController: modalView animated:YES];
[modalView retain]; // <<== new 'retain' statement
[modalView release];
or just simply never releasing modalView in the first place:
MVC *modalView = [[MVC alloc] initWithNibName:#"MVC" bundle:nil];
[self.navigationController presentModalViewController: modalView animated:YES];
// commenting out the 'release':
// [modalView release];
Both of these options throw flags when I run "Analyze" ("Potential leak of an object allocated on line 34"...) but they do fix the problem.
Still, I worry about this causing the app to be rejected by Apple from the App Store.
Any ideas on what may be causing the over-release? Or how I might further try to isolate / identify the problem?
attaching an image of Instruments/Zombies report:
Are u using iOS 5? I had the same problem when I switched an app from ios4 to 5.
ParentViewController is now called presentingViewController
What you can do though is in your modal view just call [self dismissModalViewController] and it should dismiss itself. I'm not 100% about that and can't check as I'm not near my mac, but I recall reading it in the docs,
If you do
[self.navigationController presentModalViewController: modalView animated:YES];
Then you should dismiss it like
[self.navigationController dismissModalViewControllerAnimated:YES];
Rather than
[self.parentViewController dismissModalViewControllerAnimated:YES];
Where are you trying to dismiss the view from? The actual modalView or the parentView? It seems to me that you are trying to dismiss a modal view that has already been dismissed and subsequently released.
To dismiss a modalViewController I simply just do: [self dismissModalViewControllerAnimated:YES];.
[self dismissModalViewControllerAnimated:YES] does not work on iOS 5.
I have built a category that add presentingViewController on iOS 4. (It disables itself on iOS 5.)
Just include 2 files, and it works seamlessly.
Please see backward-modal.
I hope this benefits you as much as it does to me; It makes your code more clean!
I am using a tab based application that shows a presentModalViewController called "overview" that has 2 buttons on it .
In order to call it I am using the following code in app delegate:
Overview *overview = [[Overview alloc] initWithNibName:#"Overview" bundle:nil];
[self.tabBarController presentModalViewController:overview animated:YES];
When overview shows up, it has a button called that gets clicked and I am using the following code:
-(IBAction) btnLoginPressed{
[self dismissModalViewControllerAnimated:YES]; //get rid of view
Login *login = [[Login alloc] initWithNibName:#"Login" bundle:nil];
[self.tabBarController presentModalViewController:login animated:YES];
[login release];
}
However the login prsentModalViewController never shows up. Can someone explain why and what I can do to show it?
Thanks
When you present a modal view controller, you do it from the view controller currently in the view.
Assuming your second modal display of a view controller is happening in Overview.m change your code to the following:
-(IBAction) btnLoginPressed {
Login *login = [[Login alloc] initWithNibName:#"Login" bundle:nil];
[self presentModalViewController:login animated:YES];
[login release];
}
You don't need to dismiss Overview first, and in fact you shouldn't as it the animations won't work in conjunction with each other.
When you ultimately dismiss login (or however deep you want to go), you send dismissModalViewController:animated: as high up as you need to. To get back to the tab bar's controller use:
[self.tabBarController dismissModalViewController:animated]
It would be well beyond the scope of your question and the time I have to answer but you should take some time and really study the docs on implementing View Controllers. I definitely recommend following Apple's code style guidelines as one suggestion to make your code much more readable (e.g. overviewViewController vs overview). It's also clear you're just learning so keep at it.
In my iPhone app, I have the unique identifier for eah project. I want that when the user logs in the unique identifier be accessible on every page.
I am using NSUserDefaults to do that. But the problem is that Login is not the first page. So if I access some page which requires unique id, then it shows "unknownkey".
How can I work around this problem?
Also, I can't add the login screen as first screen as the user can access some portions without login.
try something like
if (![[NSUserDefaults standardUserDefaults] objectForKey: #"uniqueid"]) {
//...user is not logged in..
} else {
//...user is logged in...
}
I guess that this is a design problem rather than a programming problem?
You could probably either move your login screen to the startup screen or leave the tab bar as it is until the user logs in, or even re-design the whole thing differently.
If the login is necessary for everything (e.g. your app is a dropbox client), present the login viewController modally at application start.
And don't dismiss it until you have a successful login.
In your RootViewController's viewDidLoad method, you need to check the saved NSUserDefault via an IF statement. Easy.
-(void)viewDidLoad {
if(![[NSUserDefaults standardDefaults] objectForKey:#"uniqueid"]) {
// here you'll want to present a view modally inside a new navigation controller.
LoginViewController *lvc = [[LoginViewController alloc] initWithNibName:#"LoginViewController" bundle:nil];
UINavigationController *controller = [[UINavigationController alloc] initWithRootViewController:lvc];
[self.navigationController presentModalViewController:controller animated:YES];
} else {
// this is where you'd set up the client if the user is already logged in.
}
}
I've an iPhone application:
When you open the app you see the "LoginView". If you login into application you see a TabBarController. In the third and last tab there is "Logout" button. If you click you see the "LoginView" again. My problem is that if you login again you see the "old" tabbar and the selected tab is the third and not the one, and there is a "Logout" button. Also, if a user login with a different user, see the old data of the previous user (very dangerous).
Here's the code:
- Delegate.h:
UITabBarController *tabBarController;
LoginViewController *loginView;
- Delegate.m (didFinishLaunchingWithOptions):
[self.window makeKeyAndVisible];
loginView = [[LoginViewController alloc] init];
if (YES) { /* if the user is not already logged */
[self.window addSubview:loginView.view];
}
Delegate.m (methods):
- (void)loginComplete {
[loginView dismissModalViewControllerAnimated:YES];
[window addSubview:tabBarController.view];
}
- (void)logoutComplete {
[[tabBarController view] removeFromSuperview];
[tabBarController release];
[window addSubview:loginView.view];
}
And here's the two methods in two different viewcontrollers:
- (IBAction)login:(id)sender {
TabNavisAppDelegate *delegate =
(TabNavisAppDelegate *) [[UIApplication sharedApplication] delegate];
[delegate loginComplete];
}
(the logout method is the same)
Guys, how can I solve this painful problem?
So, here's a list of application that do what I want: "Foursquare", "Brightkite" and others.
Each one have a login screen, a tabbar view and a logout button.
Thanks # everyone.
For login-logout-login situations where all kinds of things need to reset themselves at the logout or the next login, I like to create a notification, something like "NewUserReset." Everything that needs to reset itself to an original state listens for the notification and runs a method that does whatever kind of resetting it needs. The tabbar would change the button title to logout, temporary data structures nil/zero/release themselves, etc.
It's nicely decouples the logout from all of the things that have to be done so you're not trying to manipulate view controllers and data storage and view appearances from the the controller that received the logout tap.
Sending a notification is easy. When the user taps the Logout button you'll send out a notification like this:
[[NSNotificationCenter defaultCenter] postNotificationName:#"JMUserLogout"
object:nil];
You don't have to call it JMUserLogout, you just need a string that you'll recognize and something -- I used your initials -- to help ensure you don't accidentally send a notification that has the same name as a notification something you're unaware of is listening for.
When that notification goes out, any object that has registered with the defaultCenter to listen for #"JMUserLogout" will perform any actions you choose. Here's how your object registers (this should be located in some place like ViewWillLoad or the initialization method of the object):
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(resetForNewUser:)
name:#"JMUserLogout"
object:nil];
The selector there, resetForNewUser:, is just the name of a method you want to run when the notification goes out. That method looks like this:
- (void)resetForNewUser:(NSNotification *)notif {
// DO SOMETHING HERE
}
Where it says // DO SOMETHING HERE you'll add the code specific to your app. For example, you can add the tab bar as an observer of the JMUserLogout notification. In its resetForNewUser: method you'd change the name of the logout button to Login.
In a ViewController or View or data store that holds old data from the previous user the resetForNewUser method would delete all of that data and set things back to the way they should be fore a new user. For example, if the previous user entered data into a UITextField you would delete the text, yourTextFieldName.text = #"";
Lastly, it's important that you also remove your object as an observer before it's deallocated. In your Dealloc method of each object that registered to receive the notification you add this:
[[NSNotificationCenter defaultCenter] removeObserver:self];
Hopefully that makes sense. The Apple documentation for NSNotificationCenter explains more and they provide several sample apps that use notifications.
Seems like tabBarController is not getting released. [ retain count should be 1 before releasing] tabBarController might be retain somewhere. check the retain count of it.
If you want to reset the old data from the previous user after you log out.. all you have to do is reset the UITabBarController's viewControllers property.
So if you are subclassing UITabBarController the following code should restore your app to its original state.
self.viewControllers = #[self.viewControllerOne, self.viewControllerTwo, self.viewControllerThree];
From the documentation:
If you change the value of this property at runtime, the tab bar controller removes all of the old view controllers before installing the new ones. The tab bar items for the new view controllers are displayed immediately and are not animated into position.
The tabBarController object may have been retained somewhere. Try to remove that.
And use the following code for Login, Logout methods
- (void)loginComplete {
// initialize the tabBarController here. like the following
if(tabBarController == nil){
tabBarController = [[UITabBarController alloc] init];
}
[loginView dismissModalViewControllerAnimated:YES];
[window addSubview:tabBarController.view];
}
- (void)logoutComplete {
[[tabBarController view] removeFromSuperview];
[tabBarController release];
tabBarController = nil;
[window addSubview:loginView.view];
}
So that your problem will be solved.
i am trying and trying.... but no result yet.
i have a view with a navigationcontroller and -bar. in addition there is a tableview.
if you click on a row, the iphone email function is getting startet by using the email example from apple (MailComposerViewController.h and .m).
it opens and i am able to send or cancel the mail. after that the "dismissModalViewControllerAnimated" methode is dismissing the emailing view. everything looks right, i am in the previous view now, BUT:
when i want to use buttons from the navigationitem or if i want to add rows to the tableview, the app is crashing without any error message.
do i have to set something back or to "remove" something which is still there because of the mailing view?
it's really strange and i am searching now for hours....... :-(
thank you very much in advance!
hopefully someone has an idea.
EDIT:
ok, here i have the code now:
in a tableview which is included in a navcontroller i have following lines to open first a Subclass of UIViewController:
- (IBAction)Action:(id)sender
{
DetailViewController *editViewController = [[DetailViewController alloc] initWithNibName:#"TripDetailViewController" bundle:nil];
// ...
// Pass the selected object to the new view controller.
[self.navigationController pushViewController:editViewController animated:YES];
editViewController.navigationItem.prompt = #"Details";
[editViewController release];
}
in the DetailViewController following action is processed when the user clicks on the button:
- (IBAction)mailTrip:(id)sender {
MailComposerViewController *mailComposer = [[MailComposerViewController alloc] init];
[[[self view] window] addSubview:[mailComposer view]];
[mailComposer showPicker:sender];
}
when i press the related button, the MailComposerViewController pushes up correctly. all functions of the MailComposerViewController are working correct.
but when i send or cancel the mail and the MailComposerViewController disappears, my previous view doesn't work anymore.
in the MailComposerViewController-Example from apple the MailComposerViewController just disappear and the previous view is working fine again.... :-(
ok, i found the stupid simple problem.
the MailComposer-View was after dismissing it still over the previous view.
i did set the propert hidden after dismissing and now it works...
[self dismissModalViewControllerAnimated:YES];
[[self view] setHidden:YES];
but i am really not sure if this is the right way to do it...