I'm trying to work out how I can get my UIBarButtonItem named "home" to return back to my first initial ViewController.
I have implemented my button within the viewDidLoad of my ViewControllerSecond:
#property (nonatomic, weak) UIBarButtonItem *homeProperty;
// Create a home button
UIBarButtonItem *homeButton = [[UIBarButtonItem alloc] initWithTitle:#"Home" style:UIBarButtonItemStylePlain target:self action:#selector(homeProperty)];
[self.navigationItem setLeftBarButtonItem:homeButton animated:NO];
Do I need to create an IBAction method for this? Also, is the UIBarButtonItem implemented in the correct method viewDidLoad
So to summarise I need to be able to go back to the ViewController from the ViewControllerSecond but I can't figure out how to do this.
Many thanks
How are you adding the second view controller to the first? Are you calling pushViewController or presentModalViewController? If you're using a UINavigationController, calling pushViewController should automatically create the back button for you on the navigation bar. Create a new project in XCode using the Master-Detail Application too see an example of how UINavigationController should work.
Related
I am studying Object-C and I am writing a test app to learn.
This is an easy app, where in the first View i press a button, go in the second View (I used a curl animation)fill a text field and then press a button, pass the content of the field in the first view.
So I created the 2 Views, placed a button and a Label in the first View and linked the button from the first View to the second View using the right mouse click and drag a line with action Modal.
In the second View, I wrote the following code:
ViewController2.h
#property (weak, nonatomic) IBOutlet UITextField *firstTextField;
#property (strong, nonatomic) NSString *stringFromVC2;
- (IBAction)passTextToVC2Button:(id)sender;
ViewController2.m
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
self.firstTextField.delegate = self;
}
- (IBAction)passTextToVC2Button:(id)sender {
ViewController *VC2 = [self.storyboard instantiateViewControllerWithIdentifier:#"wb_ViewController"];
VC2.stringFromTextField1 = self.firstTextField.text;
[self presentViewController:VC2 animated:YES completion:nil];
}
The app works, but when I press the button from ViewController2, and go back to ViewController, it doesn't animate the Curl animation, just it appears from the bottom of the page a new window (the ViewController) under the ViewController opened with the Curl animation.
I also tried to use:
[self dismissViewControllerAnimated:YES completion:nil];
instead of:
[self presentViewController:VC2 animated:YES completion:nil];
in this case, it closes the second view but the Label in the first View isn't display with the text I inserted in the second View.
As I told you, I am studying so I am a beginner, please be patient.
The way to do this is to define a delegate protocol that your first view controller conforms to, and your second view controller can send a message to to pass back the value.
I've had to answer this question a few times so I created an very simple example project to show exactly what I mean. Download it and see how to pass data back down the controller stack.
Update
I've changed the sample to an new project for iOS6 with ARC and Storyboards.
i have a TabBar with 5 ViewControllers. i am using that array of tabBarController to populating a SideBarMenu like in Facebook app.
When i use a viewController to set as RootViewController of UINavigationController, then this viewController gets removed from the array [self.tabBarController viewControllers].
Why is this happening and how can i prevent this?
return [[UINavigationController alloc] initWithRootViewController:
[[self.tabBarController viewControllers] objectAtIndex:0]];
the viewController at objectIndex 0 gets removed and the [self.tabbarcontroller viewControllers] is returning only 4 viewControllers.
A UIViewController can only have one parent. When you add the view controller from the tab bar to the navigation controller, the navigation controller detached the view controller from its previous parent and attaches it to itself. For more information about why this happens, read the Implementing a Container View Controller section of the UIViewController documentation.
I got a very interesting problem here. My iPhone app has an UITabbarController as rootViewController in the AppDelegate.
If the app is opened the first time, it must be configured basically. For this purpose I create an UINavigationController and tell the tabbarController to present it modally:
firstRun = [[firstRunViewController alloc] init];
navCtrl = [[UINavigationController alloc] initWithRootViewController:firstRun];
[[self tabBarController] presentModalViewController:navCtrl animated:NO];
When the configuration is done, I'd like to get rid of the firstRunViewController. I'm using this technique very often, using -dismissModalViewControllerAnimated:.
But in this constellation this doesn't work. It doesn't matter from what controller I'm calling the dismiss.
I tried it via the tabbarController, the rootViewController, the currently active viewController, of cause self and several other controllers.
EVERY TIME I call -dismissModalViewControllerAnimated: I get this exception:
'UIViewControllerHierarchyInconsistency', reason: 'presentedViewController for controller is itself on dismiss for: <UINavigationController:…
Can anybody help? Thanks in advance, with kind regards, Julian
EDIT
In my AppDelegate I'm using a UITabbarController as rootViewController for the main window:
self.window.rootViewController = self.tabBarController;
[self.window makeKeyAndVisible];
Then I'm creating an UINavigationController and tell the UITabbarController to present the modalViewController:
UINavigationController *navCtrl = [[UINavigationController alloc] initWithRootViewController:firstRun];
[[self tabBarController] presentModalViewController:navCtrl animated:NO];
When I now call -dismissModalViewControllerAnimated: on the firstViewController I'm getting the error from above.
In my opinion you are abusing UITabbarController. This class, even though a subclass of UIViewController, does not really use much of the UIViewController infrastructure.
What you want is a slight extension of what you have now. Create a new UIViewController subclass in your appDelegate, and add it as the single object to an array, and set the tabBar's viewControllers to this array. Set your subclass' hidesBottomBarWhenPushed to YES so it hides the tab bar when it becomes visible.
Now your app will launch and your UIViewController subclass will become the frontmost view. You can make this view the one you wanted to present modally, or you can present that view from your subclass using some kind of animation. Oh, and if you use the launch view as the background image for your subclass, you can really make this a smooth transition - I do this now.
When your modal view is done, then you can instantiate whatever views you want to then display, and set the UITabBarController to use those views with tabBarController.viewControllers (or the animated version). Poof, you UIViewController will get replaces (and under ARC just disappear).
I don't have a chance to test my hypothesis, but I suspect that this issue could depend on the fact that you are presenting the modal view too early, whereby too early means before the main window has had the chance to set up the tab bar controller. So, I would suggest this changes:
create a method to instantiate your navigation controller:
- (void)initializeAndPresentNavigationController {
UINavigationController *navCtrl = [[UINavigationController alloc] initWithRootViewController:firstRun];
[[self tabBarController] presentModalViewController:navCtrl animated:NO];
}
instead of presenting the navigation controller directly from appDidFinishLaunching, call the above method asynchronously:
[self performSelector:#selector(initializeAndPresentNavigationController) withObject:nil afterDelay:0.0];
Here the trick of calling the method as I do in 2 is that the call to initializeAndPresentNavigationController will be simply pushed on the main loop, and executed after your app has had the possibility to build its initial UI.
Hope it works for you.
I finally found the answer myself!
I just couldn't see the wood for the trees! I'm quite happy right now! :)
I did really silly things: In the last viewController of the setup viewControllers I had to change the tabars viewControllers corresponding to whether the user is administrator or not. So I did:
appDelegate.tabBarController.viewControllers = [NSArray arrayWithObjects:appDelegate.readState,
appDelegate.navCtrl,
appDelegate.settings, nil];
You can see that I was adding the AppDelegate's "navCtrl" to the tabbar's viewControllers. So I was trying to dismiss a viewController I just added to the parentViewControllers (UITabbarController) sub-controllers.
Dismissing something I want to present just in the same moment is NOT advisable! :))
I'm trying to "bookmark" (sort of) an object from one UIViewController so that it then shows on a different UIViewController. Currently, the only way I can get this to work is if I either push to the UIViewController that will display the bookmarks or if I perform a segue which is basically the same thing.
Is there a different approach to this?
if you just want to send a variable (without loading the view). This is how I do it.
DetailViewController *detailvc = [[[DetailViewController alloc] init] autorelease];
detailvc.event = [self.fetchedResultsController objectAtIndexPath:indexPath];
And another type of segue I've been doing (without the need of the whole function) i just ask the storyboard to go...
[self.storyboard instantiateViewControllerWithIdentifier:#"detailViewController"];
Just don't forget to name the identifier in the sotyboard, properties, identifier.
Hope it helps...
I've been having some trouble re-learning everything with the storyboard as well.
I am new to this and working thru a "teach yourself book". I have two questions. How to trouble-shoot this in the future and how to get the darn thing to work now.
I have a simple three Tab Bar app that points to three UIViewController. The three views work fine until I add a Webview to one of the XIBs. As soon as I bring up the view with the WebView included in the simulator, I am kicked out of the App.
The Debugger console says"'NSUnknownKeyException', reason: '[ setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key bannerView.'" I don't know what that means.
.h file code....
#interface ConvNavController : UIViewController {
IBOutlet UIWebView *bannerView;
}
-(IBAction)loadbannerView:(id)sender;
#property (nonatomic, retain)IBOutlet UIWebView *bannerView;
=========
.m file code
-(IBAction)loadbannerView:(id)sender{
NSURL *bannerURL;
NSString *bannerURLString;
bannerURLString=[[NSString alloc] initWithString:#"http://www.tak2000.com/banner_test.html"];
bannerURL =[[NSURL alloc] initWithString:bannerURLString];
[bannerView loadRequest:[NSURLRequest requestWithURL:bannerURL]];
[bannerURL release];
[bannerURLString release];
}
I used a simple button connected to loadbannerView.
Webview code worked great in a simple one view example. Why is it dying when I use it in multi UIViewController app? BTW: I used the "Windows Based App" template as a starting point. I also ensured the Class Identity was UIWebView.
Thanks in advance...
bannerView is a property, so it should be
[self.bannerView loadRequest ....]
and make sure in interface builder that you've connected your UIWebView to the bannerView outlet.