I have a segue that navigates from FirstViewController to SecondViewController. This happens by the press of a button. The code for the button is
- (IBAction)segue:(id)sender {
[self performSegueWithIdentifier:#"myIdentifier" sender:self];
}
This happens correctly when i press the button.
What i am trying to do is fire this method from another view. I tried doing
FirstViewController fvc = [[FirstViewController alloc] init];
[fvc segue:nil];
When i try this, I get the error message, Reciever has no segue with identifier 'myIdentifier'
How do i fire this segue programatically from another view?
There are a few issues here, but they boil down to a couple of key points:
Segues are a storyboard thing, so view controllers only "know" about segues if they're instantiated from a storyboard.
A view controller must be onscreen to perform a segue.
Segues are transitions from one specific view controller to another specific view controller.
So, in your snippet:
FirstViewController fvc = [[FirstViewController alloc] init];
[fvc segue:nil];
The first problem is that alloc-init-ing gives you an instance of FirstViewController that doesn't know anything about the storyboard it came from, so it doesn't know anything about segues. (This alone could be fixed using [instantiateViewControllerWithIdentifier:][1], but that doesn't solve your whole problem.) A second problem is that this instance doesn't fit anywhere into the UI hierarchy -- it hasn't been presented as a modal view controller, it's not the top view controller in the current navigation controller, it's not the visible window's root view controller, etc. In order to transition the screen from one view to another, the first view needs to be onscreen.
What it sounds like you want to do is transition from what's currently onscreen to the target of this segue. But the notion of a storyboard segue isn't just a transition with a destination -- it's a source, a destination, and a transition or relationship between them. If you have a different source view, you need a different segue. So, if you already have a segue from FirstViewController to SecondViewController, and you want to make a similar transition from OtherViewController (assuming that's the one onscreen now) to SecondViewController, you need to make a second segue connecting OtherViewController to SecondViewController.
Related
For some reason, when I try to open a view controller via modal segue, it opens up two of the same type. Why is this happening?
Warning: Attempt to present <ModalViewController: 0x7fa062c5edd0>
on <HomeViewController: 0x7fa062e16e40> which is already presenting
<ModalViewController: 0x7fa062fb9780>
This is causing problems because I try to use delegates, but my main view controller never gets the correct delegate.
The issue occurs when I click the the button which triggers showModalView
HomeViewController
- (IBAction)showModalView:(UIButton *)sender {
ModalViewController *modalView = [[ModalViewController alloc] init];
[self presentViewController:modalView animated:YES completion:nil];
}
I tried this solution here and here and a dozen other ones, but none seem to work for me.
Why is this happening?
The problem you're having, is because you've connected a segue to the button, and are also presenting the controller in code; you should be doing one or the other. When you removed the segue, you got a black screen because you're using alloc init to create your controller. If you made the controller in a storyboard, then you should use instantiateViewControllerWithIdentifier: instead.
However, the easier way would be to leave the segue connected to the button, and delete the code you have in the button's action method. The button doesn't need an action method, if you have it hooked directly to a segue. All of this is covered in Apple's document, "View Controller Programming Guide for iOS". You should read it.
Please see the following attached image for more understanding.
The scenario is : I have five view controllers
Each view navigate to next viewController on push
Now the MidContainerViewController has got the Container which embeds the FirstViewController.
Bottom of MidContainerViewController is a static view which should not change while navigating further.
On navigation The FirstViewController should be of size equal to container
Also when I navigate to SecondViewController from FirstViewController, it should also be of size of Container.
Objective 1 : 'FirstViewController' and 'SecondViewController' should not take whole screen overlapping the bottomView image on MidContainerViewController.
Objective 2 : I must pop to root "View Controller" on last 'push' on SecondViewController.
Solutions :
1) Currently As I have embedding the root "View Controller" to navigationController. No problem with objective 2. It successfully navigates back to root. But can't achieve objective 1
2) If I embed the "First View Controller" too with navigationController the objective 1 is achieved but start facing problem for objective 2. It pop back till 'MidContainerViewController' only.
Any suggestion are highly appreciated.
Thanks,
Assuming your are manually handling push/pop events without using storyboard, I recommend you to not push the FirstViewController from MidContainerViewController. Add the next view controller as child view controller through following code:
FirstViewController *firstViewController = [[FirstViewController alloc] initWithNibName:#"FirstViewController" bundle:[NSBundle mainBundle]];
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:firstViewController];
[self addChildViewController:navController];
[navController.view setFrame:CGRectMake(0.0f, 0.0f, _containerView.frame.size.width, _containerView.frame.size.height)];
[_containerView addSubview:navController.view];
[navController didMoveToParentViewController:self];
From the above code you'll achieve your first objective. In the above code, the FirstViewController gets initiated on its own separate navigation controller object, so it will have different navigation stack. So if you further push and pop from FirstViewController & SecondViewController, your view will not take the whole screen. But if you call popToRootViewController from last view controller, your root view controller would be FirstViewController in that specific container view.
To achieve second objective, you'll have to create a public property to contain reference of main navigation controller object in your AppDelegate class. Create your root view controller from that navigation controller object. In your last view controller, you'll then have to get reference of that navigation controller property from your AppDelagate class and then call popToRootViewController from that object.
i think you must present your root view controller from the secondView Controller rather that embedding to root view controller.
Thank you everyone.
The problem is solved and both the objectives are achieved.
I kept only one navigation controller as root view controller.
I created one customContainerViewController.
This class has instances of all the children it is supposed to show.
This class acts as delegate for each of its childViewController. Make customContainerViewController as deleagte of each childViewController.
I updated the chilren using delegation method and using UIView transition method in UIKit.
This worked for me.
I have a multi-player game where I want it to start after I press a button in the menu. The problem is I don't know how to transit from the menu to the game directly after I start multiplayer.
In ViewController.m
- (IBAction)multiplayer:(id)sender {
[Nextpeer launchDashboard];
}
In AppDelegate.m
-(void)nextpeerDidTournamentStartWithDetails:(NPTournamentStartDataContainer *)tournamentContainer {
UIStoryboard *storyboard = self.storyboard;
ArcadeView *svc = [storyboard instantiateViewControllerWithIdentifier:#"arcade"];
[self presentViewController:svc animated:YES completion:nil];
srandom(tournamentContainer.tournamentRandomSeed);
[tournamentContainer tournamentIsGameControlled];
}
I'm getting the error of
"Property'storyboard'not found on object of type 'AppDelegate *' and
"No visible #interface for 'AppDelegate' declares the selector
'presentViewController:animated:completion:'"
How do I change from one ViewController to another ViewController using storyboard?
Normally in cocos2d, I would do like this:
CCScene *gameplayScene = [CCBReader loadAsScene:#"GamePlay"];
[[CCDirector sharedDirector] replaceScene:gameplayScene];
What's the equivalent?
How do i change from one ViewController to another ViewController using storyboard?
Typically, you'd use a segue to switch from one view controller to another. You can create a segue in your storyboard, connect it to a button, and the button will automatically trigger the segue and transition to the next view controller. As part of the segue process, the existing view controller will get a chance to "prepare" for the segue, at which point it can clean up after itself as necessary and also provide any information that the next view controller might need. Read all about it in the docs for -[UIViewController prepareForSegue:sender:].
There are a number of different ways that you can transition from one view controller to another, of course. You can push a new view controller onto a navigation stack, have a tab bar controller switch between several view controllers, present a view controller, simply remove one view controller's view hierarchy from the window and install the new one, and so on. Many of the possible transitions are provided by existing segue types, but you can also create your own custom transitions by creating your own segues.
If all this is new to you, you should probably spend some time reading through View Controller Programming Guide for iOS.
I am working with Parse, and one thing I have implemented in my app is their built in PFLogInViewController. This controller will be presented at two times in the application - when the app first starts and the user is not logged in, and when the user taps the "Log out" button of my application (logging out takes them back to the PFLogInViewController, as you are required to sign in to use the app). I would like to set this up using Storyboard, as that is how the rest of my app is laid out. How could I set up a central view controller (a PFLogInViewController) that is accessed at these two times? I have already Subclassed PFLogInViewController and set it up, I just need advice on how to place it in Storyboard and how to connect it to my views. To make this question help as many people as possible, the general theme of my question is how does one establish a central Login/ViewController that can be accessed at different points in the application using Storyboard. Attached is the basic idea of what I'm trying to accomplish. I haven't been able to successfully segue to the initial TabBarController, and I'm not sure how I should make the LoginController the initial ViewController if I can't segue. I am programming in Swift, if it matters.
There are a few ways to do this depending upon your application. One way is drop a UIViewController onto the storyboard, but don't wire it up to anything (no segue). Create a storyboard id for it such as "MyLoginVC". Do the necessary subclassing of UIViewController and attach the class to your VC. Then, when you want to display the VC simply do the following or wire this up to your logout button
id destinationVC = [self.storyboard instantiateViewControllerWithIdentifier:#"MyLoginVC"];
[self.navigationController pushViewController:destinationVC animated:YES];
In addition, if you want to show the login VC as the very first VC when you launch your app, then perhaps in your AppDelegate
// Load Root view controller
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:#"Main" bundle:nil];
self.rootVC = [storyboard instantiateInitialViewController];
self.window.rootViewController = _rootVC;
[self.window makeKeyAndVisible];
// Load Login view controller
id initialVC = [storyboard instantiateViewControllerWithIdentifier:#"MyLoginVC"];
[initialVC setModalPresentationStyle:UIModalPresentationFullScreen];
[_rootVC presentModalViewController:initialVC animated:NO];
When you finish with your login VC (i.e. successful login) then within login VC
[self dismissViewControllerAnimated:NO completion:nil];
and alternatively instantiate your first VC with something similar to the following from within login VC. Note, since you loaded the root VC above first, it is already there with the login VC sitting over it. When you dismiss login VC, the underlying root VC should be ready to rock and roll. Otherwise you can do the following:
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
RootTabBarController *tbController = (RootTabBarController *)[self.storyboard instantiateViewControllerWithIdentifier:#"rootTabBarController"];
[self presentViewController:tbController animated:YES completion:NULL];
}
I think what you want is an unwind segue. Here are the instructions I follow for an unwind segue: https://github.com/bradley/iOSUnwindSegueProgramatically
If the link dies, here is what it said:
In your storyboard create two view controllers.
Subclass UIViewController twice, once for each of the view controllers in your storyboard.
Connect these view controllers to the view controllers in your storyboard.
Make a segue between the first view controller and the second by control+dragging from the first to the second.
Click on the segue you created and give it an identifier in the attributes inspector.
Make a button on the first view controller and link it to an IBAction in its UIViewController subclass.
When this button is pressed, the second storyboard should appear. To make this happen (we are doing it programatically) put the following into the implementation of the action you just created:
[self performSegueWithIdentifier:#"nameOfTheSegueBetweenOneAndTwo" sender:self];
Create a second method in the implemention of the first view controller with the following:
- (IBAction)returnToStepOne:(UIStoryboardSegue *)segue {
NSLog(#"And now we are back.");
}
This method will work to unwind any view controller back to this view controller. Notice that we implement the method in the view controller we wish to return to.
Go back to the storyboard. Focus in on the second view controller. If it is active, you should see a dark bar beneath it with 3 symbols on it. One of these is orange and when hovered over will show the name of the UIViewController subclass that this view controller represents. Control drag from this symbol woth the green symbol that means 'Exit'. You should see all available segue unwinds, which XCode automatically enumerates when you create segue unwind implementations inside UIViewController subclasses that you have shown on your stroryboard. Hence, you should see the segue 'returnToStepOne' as an option. Select it.
In your storyboard's document outline, find the section for the second view controller. You should see an item listed below it with a grey symbol that says something like "Unwind segue from ... to Exit." Click on this item.
Important and easily missed step follows!
On the right side of your storyboard, in the attributes inspector, you should see two fields. One for 'Identifier' and one for 'Action'. In most cases, the 'Action' field will have the text 'returnToStepOne:', which is what we want, but the 'Identifier' field will be blank. Fill this field with the text: 'returnToStepOne' (note that we leave out the colon).
Create a button on the second view controller and link it to an IBAction in its UIViewController subclass.
In the implementation for the method you just created, put the following code:
[self performSegueWithIdentifier:#"returnToStepOne" sender:self];
Run the application. You should now be able to unwind from the second view controller to the first.
I have an application that has a login page. It then moves to a navigation controller that has a collection view as its root view controller. When the app starts and there is only one item in the collection, I want to have the navigation controller automatically push to that item and allow the user to use 'back' to view the collection. This is the same behavior that is in 'Notes' from Apple.
The idea is to allow the user to immediately start to use the app and only 'discover' the need for the collection view after using the app for some time.
I am using IB, storyboards, and segues for my view transitions.
If I programmatically have the root view controller do a performSegue in its viewWillLoad: I get an error about causing a transition while a transition is still in process.
If I move the code calling performSegue into the didLoad, then the user sees a double transition.
A navigation controller usually manages the underlying stack itself. That is, you pass it an initial view controller, and then through segues or pushViewController:animated: the stack is altered. However, there is nothing stopping you from manually altering the stack. In prepareForSegue:sender:, you can check the number of items, and if it's 1, do something like this:
UIViewController *singleItemViewController = [self.storyboard instantiateViewControllerWithIdentifier:#"SingleItem"];
NSMutableArray *viewControllers = [sender.destinationViewController.viewControllers mutableCopy];
[viewControllers addObject:singleItemViewController];
sender.destinationViewController.viewControllers = viewControllers;
Now instead of starting at the first view controller of the stack, you start at the second one, with a back button to navigate back.
Actually, I found that the following worked the best for me.
if (/* reason to change back list*/) {
UIViewController * rootViewController = [[UIStoryboard storyboardWithName:#"Main" bundle:nil] instantiateViewControllerWithIdentifier:#"backViewController"];
NSArray * viewControllers = #[rootViewController, self];
[self.navigationController setViewControllers:viewControllers animated:NO];
}
setViewControllers seems to be the best way to manipulate the stack.