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.
Related
I am a newbie to iOS world and have started building custom code on top of a templated code.
So excuse me for the obvious.
The View chain starts with a MainWindow.xib which contains a App Delegate Object, a Window Object and Application ViewController. I dont understand why those objects are needed over there. But what I understand, I need to mention starting ViewController in the "Nib Name" Property to initiate my custom View Controller (called "EmptyViewController"). Its a dummy view controller, just there to avoid crash to happen as a result of missing valid viewcontroller.
I initiate a separate Modal View Controller(MainViewController) inside didFinishLaunchingWithOptions.
Code for initiating modal View Controller --
self.window.rootViewController = self.viewController;
mainView = [[MainViewController alloc] initWithNibName:#"MainViewController" bundle:nil];
// present the viewcontroller
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:mainView];
[self.viewController presentModalViewController:navController animated:NO];
// release it, because it's retained as modalViewController
[navController release];
I do not put this MainViewController inside MainWindow.xib as I want to have navigation at the root of MainViewController.
Inside MainViewController, I push HelpViewController when "help" button is pressed.
But HelpViewController does not show any navigation bar. I do not understand why?
Code for Pushing Navigation bar --
HelpViewController *helpVC = [[HelpViewController alloc] init];
[self.navigationController pushViewController:helpVC animated:YES];
[helpVC release];
So I would like to understand --
1) Why is MainWindow.xib needed? Can I remove it? (Note: I tried to remove it, but then I get blank screen)
1.a) Why are all the controls/objects App Delegate Object, a Window Object and Application ViewController objects needed?
2) Why doesnt HelpViewController show Navigation bar?
3) Another thing I noticed, if I say self.presentingViewController, EmptyViewController handle is returned while popViewController returns me back to MainViewController.
Thanks
The App Delegate simply implements some app-level 'callbacks' by which iOS communicates with your own code. In main.m you can see how iOS is told which of your classes implements UIApplicationDelegate. iOS creates an instance of this class and call these delegate methods ('callback') whenever appropriate (e.g. when the app goes to background).
The Window is something iOS provides, your app needs to tell what to display on it. And, as you saw, this is usually done in didFinishLaunchingWithOptions (which is called by iOS to inform your app things are ready to get started).
A View Controller is a class that handles states of stuff you show on the Window. You don't show stuff directly on the Window, but instead use Views. Every View Controller has a View with UI elements.
The XIB or NIB is a UI description/layout file. A XIB and View are linked together; you need to tell the XIB to which View Controller member (e.g. a UILabel) a UI element belongs, and you tell the XIB which View Controller method to call on a certain UI event (e.g. user taps on a button).
These are the basics. I'm aware it does not answer all your questions; I suggest you read the very good Apple documentation. Don't try to understand everything immediately as things, as you're experiencing, indeed can seem illogical at start.
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.
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 want to know that can in switch between two views in an iPhone application if I have chosen the application as window based application in the Xcode or it is only possible to switch between views in view based application only.
How to design interface for changing the views in such appliocations as I am not able to design the second view in the interface builder after designing the first view.
Your view controller can present any other view controller like this
[firstViewController presentModalViewController:secondViewController animated:YES];
This will take you to second view controller.
To come back to first view controller, in second view controller you say
[secondViewController.parentViewController dismissModalViewControllerAnimated:YES];
Please refer to the documentation here
The main problem i think you have here is the perception of what each project type does.
A Window based application provides just a window and no "default" view controller for you to use.
A View based application provides a window AND a view controller and xib file for you to create your UI.
If you want to see how to add a view to a window based application create an empty view based application and look at the code that is auto added to the didFinishLaunchingWithOptions method in the appdelegate. This is essentially what you need to do with your window based application.
Add a view controller with a xib file for user interface, then look at how the view based application loads this view and displays it (using initWithNibName and then adding the view to the window)
i'd say you need to do more reading: take a look at cocoa fundamentals for iOS - in the documentation and then the view controller programming guide) these are both essential areas of reading. Then have a root around in the standard project types and take a look at how they are set up, this is really useful because you'll see what apple intend you to do when setting up your app
When you have your class which controls the UIWindow, you add objects in that window. One or some of these objects are Navigation Controllers or Views. in you windowController.h, you should define a view:
#property (nonatomic, retain) IBOutlet UIView *mainView;
and in the .m-file, synthesize it:
#synthesize mainView;
Then use it:
MainView *mainView = [[MainView alloc] initWithNibName:nil bundle:nil];
mainView.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
[self presentModalViewController:mainView animated:YES];
[mainView release];
That is one of the two things that could possibly be your question.
Another question you could ask is: how to switch from my window-based application to a view-based application?
You can just create new classes with corresponding .xib-files, being UIView's. Adapt your appDelegate classes and you should be fine.
Switching from one view to other in view based application
FirstViewController *firstViewController = [[UIViewController alloc] initWithNibName:#"FirstViewController" bundle:[NSBundle mainBundle]];
[self.view addSubview:firstViewController.view];
or you can also use this.
FirstViewController *firstViewController = [[UIViewController alloc] initWithNibName:#"FirstViewController" bundle:[NSBundle mainBundle]];
[self presentModalViewController:firstViewController animated:YES]; // this is deprecated in ios6.0
When I open the new file dialog I see only 3 Cocoa Touch Classes: Objective-C class, Objective-C test case class, UIViewController subclass. When I last worked with Xcode, before I updated it, I remember there were more than 3 options, which included what I'm looking for: UINavigationController.
So where can I find this template to create a UINavigatonController subclass?
Apple's made a lot of changes to Xcode's file creation screen and they've caught me of guard as well. I'm not exactly sure what your navigation controller is attempting to accomplish, but this post at the iPhoneDevSDK forum explains why you shouldn't subclass UINavigationController and instead present your view modally.
iPhoneSDK Forum UINavigation Controller Subclassing
In addition to the discussion in the forum about modal view controllers, here is source code from Apple's View Controller programming guide that explains how accomplish this.
YourViewController *viewController = [[YourViewController alloc] initWithNibName:#"YourView" bundle:nil];
viewController.delegate = self;
UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:viewController];
[self presentModalViewController:navigationController animated:YES];
There are no required methods found in the header file protocols for UINavigationController. I'm unsure what the old template used to look like, but you could try re-creating one using one of your old classes, or just examine the header file for the methods you want to commonly implement and store your own template for it.