I have an app with several views. Taking into consideration the large main view, called MyView1, it is controlled by MyView1Controller. Within MyView1, there is a button that causes a modal segue to another view, whose controller is also MyView1Controller. This modal view has a couple UILabels, and a button that terminate the modal view, bringing the user back to MainView1.
Here is the problem... Let's say in my modal view there is a UILabel called sampleLabel. While in MyView1, a button is pressed, which executes the code:
sampleLabel.text = #"changed";
Since the UILabel named sampleLabel is not on screen for MyView1, and instead is part of the modal view from MyView1, nothing happens. However, when I click on the button to view the modal view from MyView1, the UILabel hasn't changed.
This is even more puzzling since the main MyView1 and the modal view that segues off of MyView1 are controlled by the same view controller, MyView1Controller.
Can someone please tell me how I can make code that executes during the user's interaction with MyView1 change things in the modal view, so that when they press the button and segue to the modal view, the UILabel's have already been changed?
Thanks!
First of all, Apple recommends (and it makes life a lot easier) to have one view controller for each view. So you should have a second view controller. In the second view controller you would have a property called sampleLabel. In the first view controller you could use different methods to set the sampleLabel.text. I would probably create a separate sampleLabelText property in the first view controller (could be an NSString *) and set it to the text you want when the user presses a button. Then in your
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
you would get your second view controller and set its property like this:
SecondViewController *svc = [segue destinationViewController];
svc.sampleLabel.text = self.sampleLabelText;
That's it. Hope this helps.
So I have had a similar issue that I resolved through 'delegation' but not through a segue schema. Here is a link to the stackoverflow question and my answer. Delegation
Hopefully this gets you going in the right path. Instead of modally presenting a view, I push a new viewcontroller onto a navigation stack but the same answer should apply, hopefully :P
Related
How do I create a custom back button on one of my storyboards, when I do a segue and I say push it creates a back button on Mac with but when I do a modal or model it does not create a back button?
Modally presented view controllers do not automatically get close buttons.
self.navigationController.leftBarButtonItem = ...
A pushed view controller will automatically create a back button if the navigation controller is shown.
You will have to create your own back button. In the view controller that you have presented via the modal transition, you have to put a toolbar on it. Put it at the top and if using autolayout set the constraints top, both sides and height. Then place a barbuttonitem in the toolbar. You can select a system button like done or cancel. Make sure the new view controller is the class that you created. Now you can control drag from the barbuttonitem to your .h file and connect an IBAction. Call it dismiss or something like that. In that method call [self dismiss viewcontroller:animated completion:nil]. This will bring you back to the original view controller. I am not a my computer right now so I am not sure the exact wording of the dismiss method, but it will auto fill for you. Good luck.
As Douglas explained, you need to create property of the button (UIButton or BarButtonItem) and in the viewcontroller .m file connect
- (IBAction)backButton:(id)sender
{
[self dismissViewControllerAnimated:YES completion:nil];
}
with the button. This will dismiss the current view controller and bring you back to the previous one :)
I have a super simple presentation for iPad with few modal views. At every View user makes a simple action (like dragging a slider), after that appears UIButton "Next" what presents new modal View above previous. Button in last view connects with first view by a modal segue. So app needs to work in recursive way. But after first time presentation goes (from the second loop starts), all Views presented with all actions done in them. So I want that all app ModalViewControllers reloads to the default state every time user taps button on the last View.
Can I implement this behaviour only set it in -prepareForSegue of UIButton in last ModalViewController or it's a more global issue? If so, how to implement that?
Implement viewWillAppear in every ViewController will give you an opportunity to reset the view before the view gets to the screen. When you come back to a ViewController from another viewController, viewWillAppear gets called.
-(void)viewWillAppear:(BOOL)animated
{
NSLog(#"viewWillAppear");
[super viewWillAppear:animated];
//Reset your view (i.e. hide next button etc.)
}
I've set up a really simple project using storyboards including two views as shown here: http://i.stack.imgur.com/iRx21.png. The navigation can be done by either selecting a cell in the custom table view or hitting the back button labelled with "<<". Everything works fine except the following:
when I switch between the views, every time an instantiation happens. The profiling shows an increasing number of view objects. I would like to keep only one of each view and instantiation should be happen only once. What am I doing wrong? (I'm using ARC.)
Thanks in advance!
You should not link your back button to the parent view controller. This is what causes the new instantiation.
The way to go is to embed the table view into UINavigationController (in IB, choose Editor -> Imbed In -> Navigation Controller. Then change your segue to a Push segue. You can of course hide the navigation bar etc. to make things look exactly as you like. Then, link the back button to the controller with an IBAction and in the handler do a simple
[self.navigationController popViewControllerAnimated:YES];
This would be the appropriate logic of what you are doing. Of course, you can also push the web view modally and then handle the button click with
[self dismissModalViewControllerAnimated:YES];
Hi there and thank you in advice for your help. I have a really strange problem while working with ViewControllers in Xcode4. First of all I have to say that I'm not using storyboards and I prefer to create any UI element programmatically. So I've set a UIButton and I want that, when pressed, it brings me to a new view controller. This is the code I'm using for a button:
-(void)settingsAndExportHandle:(UIButton *)buttonSender {
SettingsViewController* settingView = [[SettingsViewController alloc] initWithNibName:#"SettingsViewController" bundle:nil];
settingView.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self presentModalViewController:settingView animated:YES];
}
This buttons is initialized and allocated in the viewDidLoad method of the RootViewController. I want to switch to the other view controller (in this case SettingsViewController) when I press the button.
The strange thing is that when I press the button, the animation that flips the controllers goes well, but when it finishes I obtain the EXACT same things that I had on the RootViewControllers (same custom views, same buttons, same all!). The question is: what I'm missing?? I have to say that I use ARC (automatic reference counting) so I can't release or dealloc the views and buttons I've created on my RootViewController.
Any help will be appreciated. Thank you all!
Pushing and and modally presenting view controllers does not deallocate the view controller that presented them. It simply adds the additional view controller to the stack. You'll need to implement a callback method so that when the user hits the button to flip back to root view controller, your settings view controller lets the root view controller know what's about to happen so you can call a method you've written to reset the interface back to whatever state you need it at. You may also be able to use viewWillAppear: but that's a little messy.
However, according to the Apple Human Interface Guidelines, the user expects that when they push a view controller or modally present it, the view controller they were on will save state and be exactly the way they left it when they came back. It's disconcerting and annoying when state is not preserved while in a navigation controller context. It is especially annoying when it's modally presented.
Think about this - A user is in a hypothetical Mail app. They start typing out an email and set a font size and a color. They tap on the add attachment button, which brings up a modal view controller that allows them to select a picture. They select the picture and the modal view is dismissed, and in your implementation, the mail composing interface would have reset and the email content would be gone or at the very least the selected font size and color would be back to the default. That's not a good experience.
How can I achieve this? Basically I have first a view controller that lists some items, if I touch one Item it will push another viewcontroller on the stack for a detailed view of that item, then if I choose "edit" it will present a modal viewcontroller, in this modal view controller I have the option to delete the item. If I choose to delete I want to dismiss the modal view controller and be taken back to the lists of items.
So for clarity ListViewController, DetailedViewController, EditViewController.
I would recommend using the DetailedViewController for editing as well, like the Contacts.app.
If you don't want to omit the EditViewController, then you could solve it with a delegate pattern, which pops the DetailedViewController before you dismiss the edit controller.