When I first setup my app I had some issues getting a single navigation controller to work.
I have several screens behind each tab item. I think the problem I was getting was that view controllers would show within the wrong tabs, when switching between them. I'm not bothered about keeping the last view controller used open within each tab, in fact I hide the tab bar to stop this anway now.
So at the moment I have navigation controller files for each of my tabs. I have them assigned in IB, in the mainWindow.
And I use them like this...
CategorySelTableViewController *nextController =
[[[CategorySelTableViewController alloc] initWithNibName:
#"CategorySelTableView" bundle:nil] autorelease];
nextController.hidesBottomBarWhenPushed = YES;
MyAppDelegate *delegate = (MyAppDelegate *)[[UIApplication sharedApplication]
delegate];
[delegate.billsndepsNavController pushViewController:nextController animated:YES];
However, I have some leaks.
I can't release my delegate, it causes an error.
My colleuge suggests that I should just be using self.navigationcontroller.
But this is a big change for me, I'd like to know definetively if I'm doing this wrong before I make the changes ?
When a view controller is pushed into the stack, it has two ways to access the navigation controller:
Using self.navigationController.
Accessing the navigation controller ivar in the delegate:
[UIApplication sharedApplication].delegate.navigationController
Both are equivalent but the first one is shorter, so it tends to be used more. There is no benefit from switching from one to the other. The only reason to do the extra typing is when you are not in a pushed view controller, eg: a view controller used in an independent GUI component, or an object that is not a view controller.
The delegate shouldn't be released because it exists during the whole life of the application.
Related
I can't find the correct method on how to reload a modal view controller from within itself. I'm developing a very simple UI based app but I'm not sure how to do this.
I open the modal view with the following:
MainView *mainmview = [[MainView alloc] initWithNibName:#"submod" bundle:nil];
mainmview.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
[self mainmview animated:YES];
and then can dismiss it depending on iOS version. However this has no effect when used on what i need to be a simple restart button. Any help is appreciated.
You will have to implement your own "refresh" functionality - define a "refresh" method inside the modal view controller's class and do whatever needs to be done inside it - if for instance you have a tableview that requires a reload or to refresh your views depending on new data, etc...
I have a UINavigationController with a UIViewController as the RootViewController.
The view controller cycles through 3 different view controllers (screen) depending on a popover selected. The cycling is working fine. Now I know that the Nav Controller is supposed to update it's title based on the title attribute being set for it's current controller on the stack, but I'm thinking because of how I've got it set up this could be the cause of my issues.
But I don't know how to get around it. I've a few different things but this seemed most correct:
iNephroCareAppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
appDelegate.navController.navigationItem.title = #"Test Title";
I'm trying to set this from one of the view controllers (screens).
Still, nothing. Anyone have any ideas? Help much appreciated.
If every view controller is pushed rather than adding it's view as subview, then you can use the below line of code in viewDidLoad or viewWillAppear of all view controllers
self.title = #"Navigation title";
i am unable to get the pushViewController to work on a View Based Application on the iPhone. On my 'ProjectViewController' i have a IBAction with the following code :
-(IBAction)switchAugmented
{
ARViewController *viewController = [[ARViewController alloc] initWithDelegate:self];
[self.navigationController pushViewController:viewController animated:YES];
[viewController release];
}
When i run the program and press ibaction nothing happens. Besides that statement above do i need to do anything else to make the view appear? what am i missing?
(...) on a View Based Application (...)
You just have no UINavController! Try to embed your main view in UINavigationController and everything will start working.
Double check to make sure that the button you are pressing is connected to the right method in interface builder. Also try putting an NSLog statement in the switchAugmented to see if the method is getting called.
You also have to check and see if you have a UINavigationController instance, otherwise you won't be able to push a new view controller.
You won't be able to push a new view controller in a View Based Project. You need to create a Navigation Based Project or add an instance of the UINavigationController in your Main.nib (if your using a nib file) only then will the push view controller will work
i am designing an app that has a login screen. it is a UIView with username/password and a button to submit. once the user authenticated successfully, i want to load a new xib file that holds a navigation controller and a navigation bar. below the bar i want to load a tableView and switch between other views as i move along with the programming of it.
what i did is create a new class that inherits from UINavigationController and assembled the xib file to include the navigation controller. i hooked it back up to file's owner and i'm loading the navigation controller modally like this:
myNavController* navVC = [[myNavController alloc] initWithNibName:#"navXibFile" bundle:nil];
[self presentModalViewController:navVC animated:YES];
[navVC release];
this works okay as the navigation controller shows up. however, it shows up with no title, even though i've set one up in IB. moreover, the tableView's delegates are hooked up via IB but i cannot even see empty lines. all i see is an empty navigation bar at the top and blank view (one piece) below it.
thank you for your help.
so i figured it out... first it's a design decision right? is the app being managed by a navigation controller? if so (which is my case), expect the main (first) view, that is a login page, all you need to do is to hide the navigation bar in your ViewdidLoad for the main view:
[self.navigationController setNavigationBarHidden:YES animated:YES];
once the user logs in and you push the next view like this:
MainTableViewController* mainTableVC = [[MainTableViewController alloc]
initWithNibName:#"MainTableViewController" bundle:nil];
[self.navigationController pushViewController:mainTableVC animated:YES];
[mainTableVC release];
and lastly, in the ViewDidLoad of the next view controller:
[self.navigationController setNavigationBarHidden:NO animated:YES];
in case your app needs a navigation controller for a specific section of the app but not all if it, you will need to use the VC to manage this, in a similar way the appDelegate manages the sample navigation based sample app.
i hope this helps anyone struggling with wrapping their minds around the design patterns implemented here.
cheers.
I am trying to create a reusable "picker". It is basically like a keypad of a phone. Since I will be using this a lot in my iPhone app, I have been frustrated with trying to make it appear.
It is in its own XIB file and has its own UIViewController subclass as the FileOwner.
However, when I instantiate this with:
MonthPickerViewController *mpvc
= [[MonthPickerViewController alloc] initWithNibName:#"MonthPicker"
bundle:nil];
Nothing happens on the screen. Yet is does fire the -viewWillAppear methods, etc.
So, what am I doing wrong either in code or in InterfaceBuilder that is preventing my view to appear?
Are you pushing the view controller?
[[self navigationController] pushViewController:mpvc animated:YES];
Or are you adding the view controller's view as a subView of your current view?
First, make sure you've hooked everything up right inside Interface Builder. An easy gotcha is to forget to connect the View object up to the view outlet of your UIViewController subclass.
Then, as Adam says, you need to actually display the view. Assuming you're doing this inside the code of another view controller, you'd need something like the following if you just wanted the new view to appear ontop of your current view:
[self.view addSubview:mpvc.view];
Of if you are using a navigation controller to stack views:-
[[self navigationController] pushViewController:mpvc animated:YES];