I'm using a UISplitviewController as a template.
action for edit button:
newExViewController *editWindow =[[newExViewController alloc]initWithNibName:#"newExViewController" bundle:nil];
UINavigationController *navBar=[[UINavigationController alloc]initWithRootViewController:editWindow];
navBar.modalPresentationStyle = UIModalPresentationFormSheet;
navBar.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self presentModalViewController:navBar animated:YES];
[navBar release];
[editWindow release];
navBar has a UIBarButton for saveButton. This is called when you press SaveButton
[self dismissModalViewControllerAnimated:YES];
now is the problem:
any idea how to reload the data for both the main NavigationConteroller and the detailViewController when the modalView is dismissed??
I have no clue
thnx
You should look into NSNotificationCenter. In your view with the UITableView, create the notification listener. Then in the view that dismisses, call that notification.
To be more specific, the Notification will call a method that should contain reloadData.
Example
The following should go with the UITableView you want to reload:
This could go along with your [self dismissModalViewControllerAnimated:YES];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(someMethodToReloadTable) name:#"reloadTable" object:nil];
This is how you will call the notification center to reload the table:
[[NSNotificationCenter defaultCenter] postNotificationName:#"reloadTable" object:self];
Example of the notification method:
- (void)someMethodToReloadTable:(NSNotification *)notification
{
[myTableView reloadData];
}
And don't forget to remove the notificaiton observer:
-(void)viewDidUnload
{
[[NSNotificationCenter defaultCenter] removeObserver:self name:#"reloadTable" object:nil];
}
In controllers, that contains view you want to reload, you should decline following method which will be called when the modalView will be dismissed (or when controller's main view will be first time loaded):
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
// here you can reload needful views, for example, tableView:
[tableView reloadData];
}
Related
In sesssion inactivity implementation for my project. I have created a NSNotification in RootViewController class of project.
- (void)viewDidLoad
{
[super viewDidLoad];
self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithTitle: #"Close"
style: UIBarButtonItemStyleDone
target: self
action: #selector(closeModal)];
UIImage *image = [UIImage imageNamed:#"fidelity_logotype"];
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, image.size.width, image.size.height)];
[imageView setImage:image];
[self.navigationItem setTitleView:imageView];
self.navigationController.view.backgroundColor = [UIColor fidelityGreen];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(applicationDidTimeout:) name:#"ApplicationTimeout" object:nil];
}
- (void) applicationDidTimeout:(NSNotification *) notif
{
NSLog(#"I m here");
BCDSessionInactivityViewController *sessionView=[[UIStoryboard storyboardWithName:#"Main" bundle:nil] instantiateViewControllerWithIdentifier:#"InactivityViewController"];
sessionView.modalPresentationStyle = UIModalPresentationFormSheet;
sessionView.preferredContentSize = CGSizeMake(838,340);
[[self topViewController] presentViewController:sessionView animated:YES completion:nil];
}
and in logoutviewcontroller, i am removing this observer written below
- (IBAction)logoutbtn:(id)sender
{
NSLog(#"logout is called");
[sessionTimer invalidate];
sessionTimer = nil;
[[BCDTimeManager sharedTimerInstance]stopIdleTimer];
//[self dismissViewControllerAnimated:YES completion:nil];
[[NSNotificationCenter defaultCenter] removeObserver:self name:#"ApplicationTimeout" object:nil];
[self performSegueWithIdentifier:#"Thankyoupage" sender:self];
}
This is code where i posting the notification.
- (void)idleTimerExceeded {
NSLog(#"idle time exceeded");
[[NSNotificationCenter defaultCenter]
postNotificationName:#"ApplicationTimeout" object:nil];
}
for first time login, it works fine whenever timer exceeds, i post a notification and model view is presesnted perfectly, but once user logs out, after that whenever the notification is posted, selector method is getting called twice
I am pretty sure that notification is getting posted only once.
Should i create notification in every view controller and then remove it when view unloads?
what i am doing wrong here?
You are adding the notification in RootViewController and trying to remove it from LogoutViewController. So that notification observer added to the RootViewController never gets removed. So each time you logout and login, the observer call will get increased by one. For fixing the issue, you need to remove the observer from the RootViewController object.
For fixing the issue you mentioned in your comment,
If I remove the observer in RootViewController , then if timers
exceeds in some other views, and notification observer is not called.
Also, i can't add observer on app delegate because we want timer
notification to be fired only after reaching rootviewController
Write two public methods in AppDelegate
One for adding observer (addObserver)
One for removing observer (removeObserver)
When you reach RootViewController, call the addObserver method for adding the observer
When logout is pressed, call the removeObserver for removing the observer
I am communicating between two classes with NSNotificationCenter. My problem is that although I tap a button once (and that button only fires off once) I am unintentionally producing increasing numbers of notifications from only one call to the NSNotificationCenter.
Here is a better explanation of the problem, with code:
My two classes are the mainView class and the Menu class.
When a view in the mainView class is tapped, it launches a view created and governed by the Menu class. This code is called when the mainView is initialized:
menu=[[MyMenu alloc] init];
UITapGestureRecognizer * tap=[[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(onTapped:)];
[tap setNumberOfTapsRequired:1];
[container addGestureRecognizer:tap];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(onChangeItem:) name:#"ItemChange" object:nil];
This Gesture Recognizer fires off this method, also in the mainView class:
- (void) onTapped: (UIGestureRecognizer*) recognizer {
NSLog(#"tap");
[menu displayMenu];
}
This is how the Menu class initializes:
- (MyMenu*) init {
self=[super init];
UICollectionViewFlowLayout * layout=[[UICollectionViewFlowLayout alloc] init];
menuView=[[UICollectionView alloc] initWithFrame:CGRectMake(0, 0, 200, 200) collectionViewLayout:layout];
[menuView setDataSource:self];
[menuView setDelegate:self];
[menuView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:#"cell"];
[menuView setAutoresizesSubviews:YES];
[menuView setAutoresizingMask:UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth];
[menuView setBackgroundColor:[UIColor clearColor]];
[menuView setIndicatorStyle:UIScrollViewIndicatorStyleWhite];
return self;
}
And this is the displayMenu method inside the Menu class:
- (void) displayMenu {
[viewForMenu addSubview:menuView];
}
The Menu class also has a clearMenu method:
- (void) clearMenu {
[menuView removeFromSuperview];
}
This is the code for each cell in the UICollectionView, contained within my Menu class:
- (UICollectionViewCell*) collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
UICollectionViewCell * cell=[collectionView dequeueReusableCellWithReuseIdentifier:#"cell" forIndexPath:indexPath];
[cell setTag:indexPath.row];
UITapGestureRecognizer * tap=[[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(onButtonTapped:)];
[tap setNumberOfTapsRequired:1];
[cell addGestureRecognizer:tap];
NSLog(#"button tapped : %d",indexPath.row);
return cell;
}
This calls the onButtonTapped: method, also within my Menu class:
- (void) onButtonTapped:(UIGestureRecognizer*) recognizer {
NSInteger buttonTapped=[[recognizer view] tag];
[[NSNotificationCenter defaultCenter] postNotificationName:#"ItemChange" object:nil userInfo:#{#"selected":#(buttonTapped)}];
[self clearMenu];
}
This notification is picked up by my mainView class with this code:
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(onChangeItem:) name:#"ItemChange" object:nil];
This calls the onChangeItem: method, inside my mainView class:
- (void) onChangeItem: (NSNotification*) notification {
NSLog(#"change item to %d",[[[notification userInfo] objectForKey:#"clock"] intValue]);
}
So that's the code.
OK, here's the problem: the first time the menu displays I get this in my log:
...[43023:11f03] tap
...[43023:11f03] button tapped : 1
...[43023:11f03] change item to 1
And this is fine, this is what I expect. However second time around I get this:
...[43023:11f03] tap
...[43023:11f03] button tapped : 1
...[43023:11f03] change item to 1
...[43023:11f03] change item to 1
Third time around I get this:
...[43023:11f03] tap
...[43023:11f03] button tapped : 1
...[43023:11f03] change item to 1
...[43023:11f03] change item to 1
...[43023:11f03] change item to 1
...[43023:11f03] change item to 1
And so on. Each successive tap on a menu item doubles the amount of notification calls.
To begin with I thought I was adding multiple views, and thus resulting in multiple button taps, and therefore multiple notifications calls.
However as you can see from my logs, this is not the case. The buttons are only receiving 1 tap event - this is firing off only 1 notification - but receiving class gets sent multiple notifications.
Can anyone explain this to me?
Sorry for the lengthy post!
Well, I am assuming that [[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(onChangeItem:) name:#"ItemChange" object:nil]; are being added more than once.
I like to remove any potential observer before adding an observer, like so:
[[NSNotificationCenter defaultCenter] removeObserver:self name:#"ItemChange" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(onChangeItem:) name:#"ItemChange" object:nil];
That way there will ever only be one observer callback.
Issue: I faced same problem, observer was calling twice, sometimes thrice.
Scenario
A user taps logout button
HomeViewController was dismissed and LoginViewController screen was presented
When user signed in again for second time
Observer was called twice (sometimes thrice)
The issue was [[NSNotificationCenter defaultCenter] removeObserver:self]; in dealloc method of my HomeViewController was not called at all, which actually removes an object from the notification center all together.
ℹ️ dealloc is an Objective-C selector that is sent by the
Objective-C runtime to an object when the object is no longer owned by
any part of the application.
Solution: Made your own method dispose and call it when user tap logout.
- (void)dealloc {
[[NSNotificationCenter defaultCenter] removeObserver:self];
// ....
}
- (void)dispose {
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
- (void)logoutTapped {
[self dispose];
// ....
}
I have a TableViewController embedded in a NavigationController, at some point I use a Segue to push to a new ViewController. When I navigate back from the ViewController I want to reload the tableView in the TableViewController.
I followed the solution posted here and here. For some reason it does not work. I miss something but I can't see it at the moment.
Has anybody a glue, why the code does not work? What do I have to do to get it work?
TableViewController.m
- (id)initWithStyle:(UITableViewStyle)style
{
self = [super initWithStyle:style];
if (self) {
// notification when comeing back from the cameraView
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(reloadMagazine:) name:#"reloadTable" object:nil];
}
return self;
}
//[...]
// notification reload
-(void)reloadMagazine:(NSNotification *)notification {
NSLog(#"notification reload");
[self.tableView reloadData];
}
//[...]
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
[[NSNotificationCenter defaultCenter] postNotificationName:#"reloadTable" object:self];
}
ViewController.m
-(void)uploadData:(id)sender {
// Upload and navigate back to the tableViewController
[[NSNotificationCenter defaultCenter] postNotificationName:#"reloadTable" object:self];
[self dismissViewControllerAnimated:YES completion:nil];
[self.navigationController popViewControllerAnimated:YES];
}
This does not answer your question "why the code does not work?", but the easiest
method to reload the table view when navigating back to it could be to
call reloadData in viewWillAppear.
I suspect that the code above does not work because initWithStyle is not being called. Put a breakpoint there to test my theory. If that is the case, then move that code to viewDidLoad.
It is easy.
Suppose I have two views: firstView and SecondView.
firstView is the ROOT view.
I load secondView from firstView:
secondView *secondViewController;
secondViewController = [[SecondView alloc]
initWithNibName:#"SecondView" bundle:nil];
[self.view addSubview:SecondViewController.view];
I added a "Back" button in secondView.
When I click that button I go back to firstView:
[self.view removeFromSuperView];
Here is the question:
When firstView -> secondView, viewDidLoad in secondView is triggered.
How can I trigger an event to inform firstView when I go back using removeFromSuperView in secondView?
What do you want to do exactly ? maybe you just want to go from your first view controller to your second view controller ? and then go back to your first view controller ? in this case just do like this, if your first controller is already embbeded in a navigation controller:
[self.navigationController pushViewController:secondViewController animated:YES];
But if you just want to create a view from Interface Builder and then add it above your first view, you can use the notification center to post an event when you click on your Back button from your second view:
- (void) backButtonClicked:(id)sender {
[self.view removeFromSuperView];
[[NSNotificationCenter defaultCenter] postNotificationName:#"back"
object:self.view];
}
You can then add an observer for this event in your first view controller, like this:
- (void) pushSecondViewController {
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(secondViewDidGoBack:)
name:#"back"
object:secondViewController.view];
SecondView *secondViewController = [[SecondView alloc] initWithNibName:#"SecondView"
bundle:nil];
[self.view addSubview:secondViewController.view];
}
- (void) secondViewDidGoBack:(NSNotification *)notification {
[[NSNotificationCenter defaultCenter] removeObserver:self];
NSLog(#"My Second View Did Go back !");
}
I hope this will help you !
I have a view controller (view A) presenting a modal view (B) when the user pushed a button and the view B has itself a button to present view C. My problem is that if the user exits the application when the view B or C is shown, the same view will appear next time the application is launched. Is there a way to dismiss the views B and C on exit or to show view A when the application starts?
Thanks for your help
I assume by close you mean when the application enters the background.
In your app delegate you can via the applicationDidEnterBackground: method dismiss your controller.
Best way would probably be to add an observer in your view controller class:
- (void) viewDidLoad {
[super viewDidLoad];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(appClosing) name:#"appClosing" object:nil];
}
- (void) dealloc
{
[[NSNotificationCenter defaultCenter] removeObserver:self name:#"appClosing" object:nil];
[super dealloc];
}
- (void) appClosing
{
[self dismissModalViewControllerAnimated:YES];
}
And post the notification in your app delegate:
- (void)applicationDidEnterBackground:(UIApplication *)application
{
[[NSNotificationCenter defaultCenter] postNotificationName:#"appClosing" object:nil];
}