I have created a view in Interface Builder with some labels and text as IBOutlets. I can view this screen perfectly when I segue to it from another view that I have defined in my Storyboard.
However, I have another XIB and an associated UIViewController that I want to access that view from. Because my XIB is not in the Storyboard, I cant segue to it. Instead I have to execute the transition programmatically.
PlantDetailViewController *plantDetailVC = [[PlantDetailViewController alloc] init];
[self.currentNavigationController pushViewController:plantDetailVC animated:YES];
When this code is executed it transitions to the view but the view is just blank. I have debugged the code and it enters viewDidLoad and viewWillAppear however all my IBOutlets are NIL....so nothing it showing up on screen!
Can anyone tell me why they might be NIL and how I can initialize them?
Thanks
Brian
It sounds like you're saying you have a PlantDetailViewController set up in your storyboard, and some OtherViewController that was created outside of your storyboard. Now you want OtherViewController to instantiate the PlantDetailViewController that was set up in your storyboard.
Let's say your storyboard is named MainStoryboard.storyboard.
First, you need to set the identifier of the PlantDetailViewController in your storyboard. You do this in the Attributes inspector, under the View Controller section. Let's say you set it to PlantDetail.
Then, in OtherViewController, this should work:
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:#"MainStoryboard" bundle:nil];
PlantDetailViewController *vc = [storyboard instantiateViewControllerWithIdentifier:#"PlantDetail"];
[self.currentNavigationController pushViewController:vc animated:YES];
-init doesn't load a nib file for you, if you want to load a nib use -initWithNibName:bundle:
If you use nib naming conventions you can pass nil to load a nib whose name matches your class and the default bundle, i.e. [[PlantDetailViewController alloc] initWithNibName:nil bundle:nil], see the docs for -nibName for details.
Related
I call a View to be presented with the following code:
#import "infoView.h"
...
infoView *viewInfo = [[infoView alloc] initWithNibName:nil bundle:nil];
viewInfo.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self presentModalViewController:viewInfo animated:YES];
But when it is presented in run-time the view that is loaded turns out black.
Currently I am using storyboard, but I need to use this code, for it is a lot more efficient in my case, because I am dealing with multiple views!
It works fine if I connect it via StoryBoard.
I should be seeing 2 labels, 1 UITextView, and 2 UIButton.
The view was created using StoryBoard, when the .m and .h files for the view where created I did not add a .xib for it. And also it is linked through the "Custom Class" section in StoryBoard.
Thanks, hope someone can help!
It's generally pretty bad form to mock people who are taking the time and effort to help you.
Naming is important it makes your code easier to work with and allows other people to use it. Not following the conventions for the language you are working in is dangerous and means that your code is not compatible with other developers as things are interpreted differently.
If you look at the docuemntation for UIViewController you'll see this note in the initWithNibName:bundle: method description
If your app uses a storyboard to define a view controller and its associated views, your app never initializes objects of that class directly. Instead, view controllers are either instantiated by the storyboard—either automatically by iOS when a segue is triggered or programmatically when your app calls the storyboard object’s instantiateViewControllerWithIdentifier: method. When instantiating a view controller from a storyboard, iOS initializes the new view controller by calling its initWithCoder: method instead. iOS automatically sets the nibName property to a nib file stored inside the storyboard.
Therefore you are instantiating your controller wrong, the storyboard should be instantiating it. Which is done like this (naming corrected)
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:#"MainStoryboard" bundle:[NSBundle bundleForClass:[self class]]];
InfoViewController *infoViewController = [storyboard instantiateViewControllerWithIdentifier:#"InfoViewController"];
infoViewController.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self infoViewController animated:YES];
Side note
infoView is a bad name for the class not only because you didn't start with a capital but also because it's completely deceiving. Anyone reading this would assume that InfoView is a subclass of UIView not UIViewController.
I'm programming a complex storyboard application and I'm encountering some issues when it comes to code re-use across view controllers and different application paths.
Can I segue to a ViewController that is not directly connected to the current one?
How do I segue out from a button to several ViewControllers conditionally? Connecting both does not work.
Can I enter the ViewController sequence from an arbitrary position in the application?
Just a few questions that come up. Anybody have any ideas or good examples?
Can I segue to a ViewController that is not directly connected to the current one?
Not with a segue. But you can push or present a viewController from a storyboard modally, like you did with .xib files.
// if self was created from code or from a .xib:
UIStoryboard *storyBoard = [UIStoryboard storyboardWithName:#"MainStoryBoard" bundle:nil];
// if self was instantiated from within a storyboard:
UIStoryboard *storyBoard = self.storyboard;
MyFancyViewController *viewController = [storyboard instantiateViewControllerWithIdentifier:#"MyFancyViewControllerIdentifier"];
[self presentModalViewController:viewController animated:YES];
But you have to set the identifier first. Select the viewController in the storyboard and do that in the attributes inspector.
Once the MyFancyViewController is visible you can use all its segues. It might feel strange to switch between code and storyboard segues, but there is nothing wrong with that. It makes the whole storyboard thing really usable.
How do I segue out from a button to several ViewControllers conditionally? Connecting both does not work.
Add two or more segues that start from the viewController (not from a button or any other view. E.g. start your control-drag at the statusbar) to the target viewControllers. Set identifiers for them and use some code like this:
if (someState) {
[self performSegueWithIdentifier:#"MyFirstSegueIdentifier" sender:somethingOrNil];
}
else {
[self performSegueWithIdentifier:#"MySecondSegueIdentifier" sender:somethingOrNil];
}
Can I enter the ViewController sequence from an arbitrary position in the application?
Yes, if you use "old school" view controller management. Similar to the first part. Instantiate your viewController and present it with code.
I have built up a UITableViewController inside my storyboard and now need to present it modally programatically (I can't link the transition/segue inside my storyboard).
I have linked my custom UITableViewController class to the controller I made in the storyboard and imported where required and trying to present it like so in my code:
AddEventViewController *vc = [[AddEventViewController alloc] init];
[self.navigationController pushViewController:vc animated:YES];
However, it picks up nothing I have done in the storyboard, purely basing what is shown by the class contents.
Turns out I just needed to use this instead:
[self performSegueWithIdentifier:#"addEventTVC" sender:self];
Silly me.
I tried looking for a similar problem but I could not find a similar question.
I am loading a UINavigationController in a UIView which is not (as in most examples) the MainWindow.
I created one new .xib called DocumentsViewController which is subclass of UIView (it has the related .m and .h files). And I created a DocumentsRootViewController.xib, which is a subclass of UITableViewController, which is supposed to be the UINavigationController's RootViewController.
I moved to DocumentsViewController and added a UINavigationController object in Interface Builder. Then I went to code, and added it as in IBOutlet, and connected it to the object.
In the ViewDidLoad, I execute the following lines:
DocumentsRootViewController *rootViewController = [[[DocumentsRootViewController alloc] init] autorelease];
rootViewController.title = #"Documents";
[navigationControllerDocuments initWithRootViewController:rootViewController];
[self.view addSubview:navigationControllerDocuments.view];
It shows the table as intended, but it shows a "Back" button to the "Root View Controller" (as in picture below).
Why? Shouldn't it already know that the rootviewcontroller has been set?
Thank you in advance to the ones that clarify this doubt
Giovanni
When you add the UINavigationController via the Nib it actually creates an instance of a UINavigationController inside the nib file with a default RootViewController set (of type UIViewController) and with a default title of RootViewController.
When you load the nib, this object is being created as part of loading the nib (i.e when you initialise DocumentsViewController) - so the navigationControllerDocuments outlet is already initialised as a UINavigationController with the default ViewController already set on it.
What I think is happening is when you call 'initWithRootViewController' - you are calling this on an already initialised object - so it is running the initialisation code again - pushing the second view controller (the DocumentRootViewController) onto the stack, but the default one that was created in the nib is already there.
What you should probably do is forget about creating one in the nib and initialise the whole thing programatically.
i.e. where you do:
[navigationControllerDocuments initWithRootViewController:rootViewController];
I suggest that you do an alloc and init instead:
[[navigationControllerDocuments alloc] initWithRootViewController:rootViewController];
Since you are doing this you really don't need to have the navigation controller added to the nib so if this works you should remove it from the nib since you are replacing it with this one in code.
I have an iPhone app that shows a simple view (View 1) that has a button. When the user presses this button, View 2 slides into view using the call
[self presentModalViewController:self.view2 animated:YES];
I want View 2 to support a navigation controller. All the code I find tells you how to set up a Navigation Controller App, but I can't figure out how to set this up using IB.
What I have done is to create a plain view2.xib file. I set the file's owner class to view2.
I add a navigation Controller to the XIB. I create an IBOutlet called view2Nav in view2.h for a UINavigationController. I link view2Nav to the NavigationController in view2.xib.
I then create a view3 class with view3.xib. I set the RootViewController in view2.xib to be of class view3 and set its NIB name to view3.
Then I go back and run the program. When I press my button on view 1, the app crashes as it tries to create view 2.
I know I must be missing a setting or something.
MySecondViewController *secondVC = [[MySecondViewController alloc] initWithNibName:#"MySecondViewController" bundle:nil];
UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:secondVC];
[self presentModalViewController:navigationController animated:YES];
[secondVC release];
[navigationController release];
Forget about IB. Do anything in code :) It is faster and you will exactly know why and how it works.
I'm not sure whether you can pass a self.view2 to presentModalViewController. If self.view2 is a subclass of UIViewController, you can. If it is a simple UIView, you shouldn't. If fact you can't at all.