In my app delegate I have a navigationController property.
In my first view I have some buttons and tapping them will make another view appear when it is pushed on navController.
In this new view there is another button to open a UITableViewController by pushing it on the navController.
The problem is in the last view, UITableViewController, in fact in viewDidLoad, if I have no data, I try to pop it off the navigationController but my app crashes.
However, if I connect the pop to a button it works great.
I reference my app delegate instance in order to popViewControllerAnimated:, so what is the problem?
I'm not sure what's wrong with the code, can you post your viewDidLoad method?
Also, is it possible to check whether your table will have data BEFORE you push the tableView onto the nav stack? That would be a much cleaner UI, rather than showing and then immediately popping a view. If there is no data, disable the button that launches the table view.
Related
i've embed my first ViewController in an navigation controller. This auto generate an back button to all the ViewControllers.
The problem is that when i save a video into my core data it automatic go to a new ViewController, but then i'm able to go back to the ViewController where i added the video. Is there a way to like delete/reset the former ViewController that has presented and therefor control how far you can go back by clicking the back button?
Or what would be the best solution?
It's hard to offer advice without seeing your exact use case, but it sounds as though instead of pushing a viewController onto a navigation stack, you might want to do something like present a modal viewController.
Instead of doing pushViewController:animated, try [self presentViewController:newViewController animated:YES completion:nil]. If you're presenting your viewController via a segue in Interface Builder, change the segue type to 'modal'.
You'll also then need to add a button to dismiss your viewController - you can use the [self dismissViewController:animated:completion] method.
I'm doing a storyboard segue when tapping a navigation bar button item, from view controller A to view controller B, and it works fine with a push animation. But when I tap the back button (no custom code) the previous view (A) just pops into place without the sliding animation. The same happens when I do a [self.navigationController popViewControllerAnimated:YES], i.e. there's no animation. I've made sure that I'm only popping it once.
This has been tested in the simulator as well as on a device.
I suspect it has something to do with what happens when view controller B is being unloaded or something similar, but I can't put my finger on it. I am handling an ABRecordRef property in B, but I have tried to be careful to call CFRetain and CFRelease in the setter when appropriate. I'm doing calls to outlets in various setters and getters but again have been careful to only do it if the view is loaded in case that would cause the view to reload after being unloaded. No success.
Finally did a log in B's viewWillDisappear, and animated is set to false. Why's that?
I don't know what to do next, my segue has the "push" style in the storyboard.
I have an app I am working on that has a main screen with two buttons. One will take you to a view of a GPS (map) and then once there (new VC) it has options for setting that position or bringing up a list (tableview, another VC) of all locations already tagged.
At the list VC, if you click on the table cell, it will bring up the VC with the map. Problem is, this then adds the same VC bak on the stack. If a user clicks the Cancel button, they go back ones screen, then cancel goes back another screen, etc... until back to the main.
I know I can do the [self.navigationController popToRootViewControllerAnimated:YES]; to pop back to root but that is not always what I want.
Also, I know I can do: [[[self presentingViewController] presentingViewController] dismissModalViewControllerAnimated:YES];
I guess what I am saying is I want to "reuse" the GPS map view so I can call it from other VC's, so that is why I didn't go with the "pass back" to calling VC. So, is there away to either when a button is pressed and is to present a new VC, can I dismiss the prior one after the new one is shown? This way, a dismiss of current VC would take me back to where I need to be.
I hope makes sense and also that this question doesn't fall into the "Not an actual question" category.
Any help or better suggestions is greatly appreciated. Thx
Geo...
If you want to jump back some number of levels in a navigation controller's VC stack, you'll probably want to use its popToViewController:animated: method. To figure out if a particular view controller is on that stack, look at the navigation controller's viewControllers property. Be careful, though, as this kind of jumping around is a rather nonstandard UI behavior (even though there's API for it) which might confuse your users.
Also, using navigation controllers and presenting modally aren't the only ways to manage multiple view controllers -- you can always set the window's rootViewController yourself (and animate the change with UIView animations), even wrapping up your custom transition type in a custom UIStoryboardSegue if you like.
You can put a delegate in the table view. So that when a cell is pressed the info is passed to the delegate method in the VC which will dismiss the table view and reloads itself with the new info. You will have to implement refresh method in that VC.
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.