I'm not sure why but in Xcode 5 working on a project of IOS6.1 I have a button connected to a IBAction in which I'm trying to navigate to a new view controller.
I've tried two different codes to create the viewController and then push it to the navigation in both cases the view controller is not nil and both cases the viewController doesn't appear.
first try: with story Id - I've set the story id of the view controller to imageCapture and set the class to VSImageCaptureViewController
VSImageCaptureViewController* imageCaptureViewController = (VSImageCaptureViewController*)([self.storyboard instantiateViewControllerWithIdentifier:#"imageCapture"]);
[self presentViewController:imageCaptureViewController animated:NO completion:nil];
second try: with the name of the viewcontroller
VSImageCaptureViewController *imageCaptureViewController = [[VSImageCaptureViewController alloc] initWithNibName:#"VSImageCaptureViewController" bundle:nil];
[self.navigationController pushViewController:imageCaptureViewController animated:YES];
can you see something wrong or do you think I forgot to initialize something
Check to see if self.navigationController is nil.
If it is nil that means that you are not running within the context of a UINavigationController (the system sets this property for you when the UIViewController is added to a nav stack).
If this is the case then you have not properly set up a UINavigationController.
Note that you can not set the navigationController property yourself. The systems sets it for you when the UIViewController is added to a UINavigationController's stack (and sets it to nil when it is removed from the stack).
To set this up you will usually create a UINavigationController instance right after you create your main view controller.
UIViewController *mainViewController = ...;
UINavigationController *mainNavController = [[UINavigationController alloc] initWithRootViewController:mainViewController];
// now present the mainNavController instead of the mainViewController
If you are using storyboards you would drag out a UINavigationController instance and replace the default root view controller with an instance of your mainViewController.
Related
I'm writting my first app using a storyboard. Before I had the following code to go from one view controller to another. But..this code needs a NibName. How would I do this going from screens created in a storyboard?
if (mDisplayCard==nil)
{
mDisplayCard = [[cDisplayCard alloc]
initWithNibName:#"cDisplayCard"
bundle:[NSBundle mainBundle]];
}
// [ mDisplay SetUp];
[self.navigationController pushViewController: mDisplayCard animated:YES];
A line like the following will instantiate a new view controller from a storyboard:
UIViewController *newViewController = [self.storyboard instantiateViewControllerWithIdentifier:#"<identifier-from-storyboard>"];
It is assumed that your current view controller was instantiated from the same storyboard, so that self.storyboard is not nil. For the view controller that you want to instantiate, you'll have to make sure that you set a storyboard ID for it, which is what you'll put in for the identifier.
In my app I've added a label to a view, connected it to an outlet but nothing shows up when I first assign this outlet from another view controller and then call pushViewController to display it. Here's the code before pushing next view that display the label:
CustomViewController *vc = [[CustomViewController alloc] init];
vc.lbl_price.text = self.label_price.text; // lbl_price is defined as a property in CustomViewController and label_price is defined in current view controller
[self.navigationController pushViewController:vc];
In the CustomViewController viewDidLoad method I added this instruction to see if it should work
NSLog(#"Price=%#",lbl_price); // it actually prints out what was previously assigned
But it doesn't show into the label!
Any idea why ?
Stephane
Even if view controller is created its view hierarchy may not (and so all subviews will still be nil), for optimization reasons it may not be loaded until you try to actually access controller's view. You have two options to solve your problem:
Store all values in separate non-UI variables and assign them to UI components with controller is going to appear:
// Before push controller
vc.myPriceText = self.label_price.text;
// In controller's viewWillAppear:
self.lbl_price.text = self.myPriceText;
Make [vc view] call to force controller to load its view hierarchy:
CustomViewController *vc = [[CustomViewController alloc] init];
[vc view];
vc.lbl_price.text = self.label_price.text;
[self.navigationController pushViewController:vc];
This is what I am doing. I have a tabBarControllerOne with 5 tabs. On clicking one of the tabs, I present a modal view controller, which has a navigationBar and a TabBarControllerTwo (with 3 tabs). These three tabs are the matter for concern here.
In the 5th Tab of tabBarController I show modalViewController as
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:self.nextTabView];
// navController.navigationBarHidden = YES;
navController.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
NSLog(#"Displauing the navcontroller before pushing %#", navController);
[self presentModalViewController:navController animated:NO];
Here, nextTabView is a tabBarController with 3 tabs. The views work. In the views, if I try something like.
self.navigationController.navigationBarHidden = YES;
[self.navigationController pushViewController: someController animated:YES];
// nothing works.
If I NSLog, it displays self.navigationController as (null)
Can someone tell me why this is not working ?
Embedding a UITabBarController inside a UINavigationController is not supported. Apple has a careful hierarchy of container view controllers, and a UITabBarController must be the root of its view controller hierarchy.
Additionally, as Joe points out, your views don't belong to the navigation controller; they belong to the tab bar controller, so their navigationController property is not set.
The modal view controller does not belong to a UINavigationController stack therefore the property is not set. You will want to use delegation to notify the creating controller when something is selected then that controller can properly push the next controller on to the stack.
UIViewController Reference:
Discussion
Only returns a navigation controller if the view controller
is in its stack. This property is nil if a navigation controller
cannot be found.
I have a View application with a Single UIViewController. I then add a UITableViewController through the IB, and I am trying to display the UITableViewController through a button press in the UIViewController (my main view). My button press (IBAction) contains the following code through which I am trying to push my UITableViewController view and display it:
DataViewController *dataController = [[DataViewController alloc] initWithNibName: #"DataViewController" bundle:nil];
[self.navigationController pushViewController:dataController animated:YES];
[dataController release];
My DataViewController is not at all getting pushed into the stack and displayed,
Also I have checked that in the code above, self.navigationController=nil
Probably this is the source of the problem. If so, how to rectify it?
Please help.
UINavigationController *navCtrlr = [[UINavigationController alloc]initWithRootViewController:yourfirstviewController];
[self.window setRootViewController:navCtrlr];
navCtrlr.delegate = self;
navCtrlr.navigationBarHidden = YES;
Create navigation controller in appdelegate.m then you can navigate to any uiviewcontroller
You need to actually create a UINavigationController. The navigationController property tells you whether your DataViewController is currently in a UINavigationController's hierarchy; if not (as in this case), the navigationController property returns nil.
I am creating a Navigation based iPhone application.
In that I have called a UiViewController using presentModalViewController. After that, the ViewController becomes visible. From that ViewController I need to call another ViewController using the sample presentModalViewController. Is this possible or not?
What do you mean by "call another uiviewcontroller"? (It really helps if you can be more detailed in your question.) If you mean, "slide in another view controller", then:
MyNewViewController *myNewViewController = [[MyNewViewController alloc] initWithNibName:#"MyNewViewController" bundle:nil];
[navigationController pushViewController:myNewViewController animated:YES];
[myNewViewController release];
...where:
MyNewViewController is the new view controller class that you want to slide in (the above code assumes you have an XIB file for the view controller class).
navigationController points to the current navigation controller. You'll have to replace it with something like [self navigationController], depending where you are in the view hierarchy.
U might be using following line to present a view controller.
//assume name of viewController which u want to present is "myViewController"
[self.navigationController presentModalViewController:myViewController animated:YES]
If you want to push an other ViewController or present an other ViewController then u will need to replace above line with following lines.
//[self.navigationController presentModalViewController:myViewController animated:YES];
UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:myViewController];
navigationController.navigationBarHidden = YES; //if u want to show navigation bar then remove this line
[self presentModalViewController:navigationController animated:YES];
After using above code you can present or push other view controllers within presented view controller.
Hope it will solve your problem :)