I have three viewcontroller. when I get to the third viewcontroller, I use poptorootviewcontroller to pop to my first view controller, but when I use popviewcontroller in my third viewcontroller (i want to go back to my second viewcontroller) its poping but all the info that I edit in my second viewcontroller are there, and I want the secondviewcontroller to be new (reset this viewcontroller), like this viewcontroller to be reloaded.
here is my code in the third viewcontroller:
-(IBAction)playAgain:(id)sender
{
[self.navigationController popViewControllerAnimated:YES];
}
how can I do it?
thanks!
In the second viewcontroller, you should write a method viewWillAppear like below,
-(void) viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
//set initial values here
}
This method will call when your controller is about to appear. So while third viewcontroller will get popped, this method will get called and you can reset values.
Related
This has been a headache for few hours now and I finally found out what is actually happening, but I don't know how to solve this issue.
I've got List.h with UITableView properly connected from storyboard:
#property (strong, nonatomic) IBOutlet UITableView *tableView;
Then there's List.m where I set delegates and datasource for my UITableView:
// Set tableview datasource and register class for cell reuse
self.tableView.dataSource = self;
[self.tableView registerClass:[TableViewCell class] forCellReuseIdentifier:#"cell"];
// Set tableview delegate
self.tableView.delegate = self;
// Set tableview cells style
self.tableView.separatorStyle = UITableViewCellSeparatorStyleNone;
self.tableView.backgroundColor = [UIColor colorWithWhite:0.1f alpha:1.0f];
// Set tableview frame
self.tableView.frame = CGRectMake(0.0, 35.0, self.tableView.frame.size.width, self.tableView.frame.size.height-35.0);
Then on NSNotification I'm trying to [self.tableView reloadData]:
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(doUpdateAppBefore:) name:UIApplicationWillEnterForegroundNotification object:nil];
Also I'm reloading data of tableView on every UIApplicationBecomeActive notification.
Before I close my app and open it up from background to find out if it's reloads the data, I'm moving to another UIViewController and going back, which causes that somehow identifier of my self.tableView changes. I'm checking it in:
NSLog(#"Calling reloadData on : %#");
and at the beginning it gives me:
Calling reloadData on <UITableView: 0x9b09400;....
but after I segue back from another UIViewController it gives me:
Calling reloadData on <UITableView: 0x9b4b000;
which causes that it doesn't actually reload the data after I open up the app from the background state.
I've been thinking... when I segue back from another viewcontroller, viewDidLoad fires again, is it possible that it somehow sets tableView.delegate again and changes something? Just thinking...
Thank you very much for your answers.
It sounds like you have a view controller, push a modal view on top of it, and then want to go back to the original view controller when you're done. So, you set up a modal segue in your storyboard, and then a second modal segue to go back. The problem is that your second modal segue doesn't return to the original view controller, but it creates a new instance of that view controller, and now your have the original view controller, the second view controller, and an unwanted third view controller. Instead of creating a segue, which creates the third view controller, you need to dismiss the second view controller, which then gets you back to your original view controller, and therefore also your original table view. So what you want to do is get rid of the second segue and replace it with an IBAction, put something like
- (IBAction)goBack:(id)sender;
in your .h file. Connect that to your button or whatever you're using to trigger the segue now. Then, in your implementation file, dismiss the modal view like so:
- (IBAction)goBack:(id)sender
{
[self dismissViewControllerAnimated:YES completion:nil];
}
That should get you what you want.
Alternately, and this is probably better, you can use an unwind segue as well. Go to List.h, and create this method:
- (IBAction)unwind:(UIStoryboardSegue *)segue;
Then just implement it, you can leave it blank for now. Then, drag from the button that currently triggers the segue to Exit, and select the Action Segue unwind. That will also get you back.
... I guess.
This is the situation:
here a simple method, in a view controller, where we can push a botton to go in another view:
- (IBAction)actionNext:(UIButton *)sender {
self.numeriUtiliListaViewController = [[ALCNumeriUtiliListaViewController alloc] init];
[self.numeriUtiliListaViewController.view setTag:[sender tag]];
[self.delegate vai:self.numeriUtiliListaViewController title:#"Numeri Utili"];
}
the delegate's method is:
- (void)vai:(id)view title:(NSString *)title
{
ALCParentViewController *viewController = (ALCParentViewController *)view;
viewController.delegate = self;
NSLog(#"tag: %d",[viewController.view tag]);
[self.myNavigationController pushViewController:viewController animated:YES];
}
This system works well, but the only thing is the tag that i've logged in this last method, here it was print correctly, but in the view loaded by the navigation controller, when i try to catch the value in the viewDidLoad, it's 0.
Any ideas?
Thanks in advance
Update 1 2013-01-30:
if i try to print the the tag in the viewWilAppear method of the viewcontroller pushed in the navigationcontroller, i'll give the right value... why? i don't know
Whats happening here is that in your actionNext method, when you are setting the tag of the viewController's view using : self.numeriUtiliListaViewController.view, as soon as you access the view propert of the viewController, viewDidLoad method is called in the viewController. So even before the setTag function is executed, viewDidLoad has already been executed, and it is showing tag = 0. But your viewWillAppear/viewDidAppear methods will be called only when the actual view appears and by then setTag has been executed, so it shows correct value.
Makes sense? Hope this helps
I am very new to iPhone app development.
I am developing one example application for iPhone emulator using Objective-C++ and std CPP.
I have two views in my application, on some events from CPP code i am displaying second view using following code from the first view controller.
// Defined in .h file
secondViewScreenController *mSecondViewScreen;
// .mm file Code gets called based on event from CPP (common interface function between Objective-C++ and CPP code)
mSecondViewScreen = [[secondViewScreenController alloc] initWithNibName:nil bundle:nil];
[self presentModalViewController:mSecondViewScreen animated:YES];
I am able to see second view coming on screen, but problem is that i am unable to end/remove second view controller from first view controller.
How can i remove second view controller from first view controller using second view controller's pointer or using any other method.
To remove second view i have following code in second view controller file, which gets called on button click event of second view.
// In .mm of second view controller.
- (IBAction)onEndBtnClicked:(UIButton *)sender
{
[self dismissModalViewControllerAnimated:NO];
[self.navigationController popViewControllerAnimated:YES];
}
Above code works perfectly, when i click on the seconds view's end button it removes the second view controller from the screen and navigets to first view, how can i use same code to remove second view from the first view controller.
I tied to use NSNotificationCenter to send event from first view to second view to call the function onEndBtnClicked but it is not working.
What is the proper way of doing it?
OSX version: 10.5.8 and Xcode version: 3.1.3
In the secondViewController create a protocol like:
#protocol SecondViewScreenControllerDelegate <NSObject>
- (void)secondViewScreenControllerDidPressCancelButton:(UIViewController *)viewController sender:(id)sender;
// Any other button possibilities
#end
Now you have to add a property in the secondViewController class:
#property (weak, nonatomic) id<SecondViewScreenControllerDelegate> delegate;
You sinthesize it in the secondViewController implementation:
#synthesize delegate = _delegate;
Finally all you have to do is implement the protocol in your firstViewController and set the secondViewController properly prior presenting it:
#interface firstViewController : UIViewController <SecondViewScreenControllerDelegate>
...
#implementation firstViewController
- (void)secondViewScreenControllerDidPressCancelButton:(UIViewController *)viewController sender:(id)sender
{
// Do something with the sender if needed
[viewController dismissViewControllerAnimated:YES completion:NULL];
}
Then when presenting the secondViewController from the first:
UIViewController *sec = [[SecondViewController alloc] init]; // If you don't need any nib don't call the method, use init instead
sec.delegate = self;
[self presentViewController:sec animated:YES completion:NULL];
And ready. Whenever you want to dismiss the secondViewController from the first, just call: (inside the secondViewController implementation)
[self.delegate secondViewScreenControllerDidPressCancelButton:self sender:nil]; // Use nil or any other object to send as a sender
All that happens is that you send a pointer of the secondViewController that you can use from the first. Then you can work with it without problem. No C++ needed. In Cocoa you won't need C++. Almost everything can be done with Objective-C, and it's more dynamic.
If there are only two views in your application then use
- (IBAction)onEndBtnClicked:(UIButton *)sender
{
[self dismissModalViewControllerAnimated:NO];
}
remove line below:
[self.navigationController popViewControllerAnimated:YES];
as it is you are dismissing second view then why you want to remove it from first view.
I connected mainViewController and customTableViewController with a "push" segue. The mainViewController pass an array of data to customTableViewController in prepareForSegue. If the array is empty, customTableViewController should automatically pop back to the mainViewController.
My code looks like this:
//customTableViewController.m
- (void) viewDidload
{
if (self.array.count == 0) {
[self.navigationController popViewControllerAnimated: YES];
}
}
But all i got is a blank and black view if the array is empty, not the mainViewController.
If i call popViewControllerAnimated manually (such as pushing a button), everything just works as i expected. So, what should i do?
Thank you all in advance.
Try to use your code in -viewDidAppear:(BOOL)animated
I have a main UITableView, when cell is pressed it goes to another UITableView and when a cell is pressed there it goes to a DetailView of that cell.
I want the middle UITableView to behave differently depending on if the detailView got popped or the UITableView itself got pushed. If the view got pushed on from the main table I want to scroll to the top, if it is shown after a DetailView got popped I want it to stay at the same position.
Any suggestions?
you could call a scrollToTop method on the DetailViewController after you have pushed it to the navigationController.
Something like that:
if (!detailViewController) {
detailViewController = [[DetailViewController alloc] initWithNibName:nil bundle:nil];
}
[self.navigationController pushViewController:detailViewController animated:YES];
[detailViewController scrollToTop];
// or use the tableView directly:
// [detailViewController.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:0] atScrollPosition:UITableViewScrollPositionTop animated:YES];
In your Middle View Controller, examine which view is next-to-display directly from the UINavigationController stack:
- (void)viewWillDisappear:(BOOL)animated
{
if ([self.navigationController.topViewController isEqual:(UITableViewController *)tvcDetailView]) {
// Detail view has been pushed onto the UINavigationController stack
}
else {
// Middle view has been popped from the UINavigationController stack
}
}
Create a BOOL #property on your middle UIViewController property called wasPushed or something similar, and when you initialise it from UIViewController 1, set the property on the new instance, push it onto the nav stack and you can then use your property in your middle view controller's loadView, viewDidLoad, viewWill/DidAppear methods.
As soon as you've used it, set it back to FALSE or NO (or whatever) and when you end up coming back to it due to popping off your 3rd view controller you'll have it as FALSE/NO in your loadView, viewDidLoad etc.. methods.