I'm writing an app that uses storyboarding and I want to update the labels in one view by clicking a button in a previous view.
_label.text = variable1;
is the line I would use to change the value of label, which is in the next view, when I click the button. Using this method I can easily change labels in the same view as the button but it does nothing when I go to the next view and see empty labels.
I've tried looking everywhere and found similar issues but couldn't find anything that worked for me so any solution would be very appreciated!
Unfortunately, it is not possible to connect IBOutlets between different scenes in storyboard.
It is difficult to suggest some precise solution because you have to provide more details about the setup which you have. Still, it is possible to outline some possible solutions:
Using prepareForSegue
If the view controller which you want to modify appears after the segue is performed you can customise its appearance in prepareForSegue function.
Using delegation
You can assign the view controller which wants to modify another view controller as its delegate. For example, if ViewController1 wants to modify ViewController2:
#interface ViewController1: UIViewController {}
#property (nonatomic,weak) ViewController2 *controllerThatIWantToModify;
with such setup you can call:
self.controllerThatIWantToModify.label.text = variable1;
You use storyboards, so there must be a segue from your first viewController (with the button) to your second (with labels in it).
If it is the case, you can set up the labels of the second view controller from the prepareForSegue method of your first view controller.
This method is called with a segue object which has a destinationViewController property which is your second view controller.
If you have several segue from this viewController, you should check if it is the right segue and then set it up.
To do that you need to set up outlets that gives you access to the labels from the viewController.
Then you can either write a setUpLabelsWith:(NSString)text1 ... method in your view controller, or directly access the outlets from the first view controller (supposing their are not private).
Yes this supposes your second view controller has a custom class.
Related
I need to navigate inside folders and files in directory (from server). The problem is that I don't know the number of folders so it's not possible to use performSegueWithIdentifier statically. How can I use navigation controller with dynamically number of view controllers in swift? I want to "push" a new view controller every time a user tap on a folder in order to list files/folders inside it and I want to do it with UINavigationController so the user have the possibility to go back with "previous" button.
Both storyboard and programmatically approaches are ok.
Thanks you
Storyboards and segues are just a crutch. Think about how you would do this without them. At each level, to go down a level, you would just instantiate a new view controller and push it onto the navigation controller stack with pushViewController:animated:.
https://developer.apple.com/library/ios/documentation/UIKit/Reference/UINavigationController_Class/#//apple_ref/occ/instm/UINavigationController/pushViewController:animated:
And in fact it takes only one view controller class to do this, since any instance can create and push another instance of its own class. The display of one folder is exactly like the display of any other.
So if you wanted to configure this notion in a storyboard, you would have a circular segue, that is, the view controller would have a push / show segue leading to itself.
I agree with #matt's answer, just create the controller and push it. For sake of completeness, you can do this in a Storyboard with a segue.
Here's how:
So that you can call the segue programmatically, add an additional prototype cell to your tableView. (You do this because you don't want the segue to be automatically triggered when the tableViewCell is selected. By using an additional prototype cell, the segue can be wired up, but it will never be triggered automatically since this prototype cell will never actually be instantiated.)
Control-drag from this prototype cell to the viewController icon at the top of the tableViewController. Select "Show" from the pop-up.
Find this segue in the Document Outline View and give it an identifier such as "showFolderSegue" in the Attributes Inspector.
Now, when you want to trigger the segue, call: self.performSegueWithIdentifier("showFolderSegue", sender: self)
You can use prepareForSegue to set up the new tableViewController as you normally would.
This method too works with a single tableViewController.
I'm using a storyboard. Let's say I have a view controller that's named MYviewController.
In - (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender; I would like to substitute the view controller that I'm segueing to, by one of its child, for example: MYviewControllerChild1 OR MYviewControllerChild2. The child that's segued to depends on the sender parameter.
These view controllers have the same scene (in the storyboard). Only their behaviour is slightly different.
I have a tableView that shows the user the settings of the application. When he clicks a cell, it segues to a viewController where he can modify the value of some setting. Some of theses are alphanumeric, others are numeric. Depending on which cell is clicked, I'd like the input viewController to format the value accordingly (if it's a decimal value I'll use a NSNumberFormatter for example).
Is that possible?
As mentioned in comments to your OP, I believe you should handle this kind of scenario in one viewcontroller.
However, if you insist on using separate controllers, maybe because you think the functionality will be expanded later down the line and therefore add more diversity, you need to handle this by creating multiple storyboard scenes - one for each child controller.
The destination view controller in prepareForSegue is imposed by the viewcontroller at the end of the segue in the storyboard. I don't think there is any way to override that.
As described, your problem isn't really a good candidate for a storyboard. If you use a storyboard you will have to create and sync multiple scenes. Several possible solutions::
Create multiple storyboard scenes and invoke them manually via performSegueWithIdentifier.
Use a nib file instead of a storyboard for this scene. You can use a single nib file since the view controller is created outside the storyboard with [[VCClass alloc] initWithNibFile: bundle: You can create the appropriate view controller class and pass the same nib file to all instances.
Use a single storyboard scene and view controller and pass in typing information in your prepareForSegue.
I am new to iOS development, with a couple of years of Android experience. I started directly with XCode 5 and the Storyboard paradigm. I like the visual approach to sketching out the flow of an app, but IMHO, it does not really force component reuse, or maybe I do not know how to do it.
I have an actual problem, which is the following: Instead of the typical master-detail approach, I have a situation, in which clicking on a TableView cell forces a push to another TableView, which looks the same and behaves the same way. There are two specific types of a TableViewCell that I want to reuse across the whole application, so I can't just duplicate the first TableViewController several times. I need changes in one type of TableViewCell to be affected everywhere, same for the look and behaviour of the Tableview. Sort of like reusing a component, you get the picture I hope.
I tried creating a custom TableView and TableViewCell in a separate xib file, connecting it to a custom controller class. Yet, when I want to reuse that controller class in the storyboard, I can't make a segue from the cell to the next one, because only view controllers are displayed, but no views inside.
Maybe, I am doing it all wrong. Perhaps, I should make a single controller, and force it to seque to itself if possible, no idea.
What would you do?
You can do programatic Segue from the didselected.....
#import "someVC.h"
Then when you want to Segue to the new VC
// Create a VC and remember to set the Storyboard ID of someVC (example someVCID)
someVC *newView = [self.storyboard instantiateViewControllerWithIdentifier:#"someVCID"];
// Can't remember how this works but you can change the Transition method
// newView.modalTransitionStyle = UIModalTransition;
// If you want to pass data, setup someArray in the someVC .h with #property (nonatomic, strong) NSArray *someArray;
newView.someArray = MyLocalArray;
// Animated or not
[self presentViewController:newView animated:NO completion:nil];
If what you're trying to do is performing a segue on the same UITableView you can check this answer by Rob
I'll report what it contains for completeness:
If you're using dynamic cell prototypes, you obviously can do a segue
from the table view cell to the controller without any problem.
When you make your segue, you end up with:
But let's imagine for a second that there's some reason that doesn't
work for you, e.g. you could not have a segue from the cell (for
example, you need to invoke segue from didSelectRowAtIndexPath, not
upon selecting the cell). In this case, you couldn't use that previous
technique.
There are a couple of options in this case:
As pointed out by Chris, if only supporting iOS 6 and above, use the above technique, but (a) make sure your
didSelectRowAtIndexPath uses self for the sender and then have
shouldPerformSegueWithIdentifier only allow the segue if the sender
== self (thus when the sender is the table view cell, it will be canceled);
Perhaps even easier, just don't define a segue at all and have your didSelectRowAtIndexPath manually
instantiateViewControllerWithIdentifier and then push/present
that view controller as appropriate; or
You can use the following, kludgy work-around: In short, add a button to your view controller (drag it down to the bar at the
bottom), where it won't show up on the view, but you can use its
segues. So first, drag the rounded button to the controller's bar at
the bottom of the scene:
Now you can make a segue from that button to your view controller:
And thus, you end up with the self-referential segue again:
You must give that segue an identifier, so you can invoke it
programmatically via performSegueWithIdentifier, but it works. Not
the most elegant of solutions, but I think it's better than having an
extra scene on your storyboard.
None of these are ideal, but you have lots of options.
well.. in iOs think about it differently, if i were you i would create multiple ViewController, even if they're almost the same, and create a custom cell class, and make this cell take a configuration block.
Now for each ViewController (( or TableViewController )), you reuse your same custom UITableViewCell and just pass it what's slightly different for each case, and moreover you can also create a BaseTableViewController that will have the general configuration, and in each ViewController pass the custom changes you need.
Think about it, when you look at your storyboard you'll be able to see all your workflow, and when something goes wrong you'll be able to debug, if you have are gonna use what you suggested, debugging will be a real pain i imagine.
Anyway, try it out, and ask more if you need further clarification.
I have a storyboard with a navigation controller that leads to an UIVIewController that I want to reuse. That UIVIewController has a ParentUIViewController that has all the basic functionalities for all the UIVIewControllers that I am reusing.
Currently I am copying and pasting (meh) and then I change the class of the UIViewController to the ChildUIVIewController that I want to use (ChildUIViewController extends ParentUIViewController).
But this sounds like a bad solution. Everytime I want to change the ParentViewController visually I need to update, manually, all other ChildViewControllers.
I have tried to create a xib for the ParentViewController but the xib isn't loaded because I need a xib with the name of the ChildViewController. I have created it and then said the class is the ParentViewController but it crashes in the segue.
EDIT
I have created an example of the status of my problem
https://github.com/tiagoalmeida/storyboardexample
Note that the ParentViewController has a set of logic way more complicated that is not illustrated there. Also note that I am also using a TableView. I hope that this can illustrate the problem.
Keep the logic on the parentViewController and the UI Part on the child UIViewControllers. If you need to create a new UIViewController, you will create a child that will have a corresponding XIB (or get rid of XIBs and create the interface by hand).
Have you considered looping back into the same UIViewController via a "phantom button"?
Have a look at this: UIStoryboard Power Drill, Batteries included
Essentially you can drag a Bar Button Item into the little black bar under the View Controller in Storyboard (the 1 with View Controller, First Responder, and Exit icons; sorry, I don't recall what this is called exactly), then you can control+drag from that button back into the UIViewController for a Push segue. This should create a loop segue in your Storyboard. All you need to do next is give that segue an identifier, programmatically call it from your code using [self performSegueWithIdentifier:], then implement -(void)prepareForSegue: and use [segue destinationViewController] to conditionally set the title and perhaps some flags so you can identify when to use different kinds of fetches (or other code variations) in the same Class code.
I have a view controller which as one of its views a container view (in IB storyboard) which embeds a table view controller, which in turn has a container view that embeds yet another view controller. In this last view controller I set up a delegate protocol with a weak synthesized delegate property as an IBOutlet. The very first view controller is what I want to receive the delegate methods from the last and I added the protocol <...> to it.
The problem is that I have not figured out a way while in storyboard (or otherwise) to link the IBOutlet delegate of the last view controller to the first view controller which follows the protocol so the last can send the first messages. I thought I could just drag and drop (with the control key) but all I find is segue options on the destination. It seems even though the delegate appears in the outlet connections window, it will not connect to ANY view controller in my project.
Can't ANY view controller be a delegate of another's protocol? And can be linked in IB? If I cannot do it with IB, I don't know how to make another VC a delegate upstream.
Any advice would be appreciated. Thanks.
You cannot connect IBOutlets between view controllers. You need to do it in code. You'll have to go through the chain of childViewController to get from the first controller to the last -- if I understand your structure properly, from the first view controller:
LastController *last = ((UIViewController *)self.childViewControllers[0]).childViewControllers[0];
last.delegate = self;
I asked a similar question Interface Builder won't allow connections to custom UIView class? I ultimately opened a bug with Apple. After a few follow up queries from Apple, I haven't heard any kind of resolution.