This is probably a very simple question but I can't find the answer to it.
I am working on a new project that uses Storyboards for the first time.
I have a number of view controllers that connect the way I want them to.
Each view controller has an info button.
I have one view controller (AboutViewController) that I want to use to display the info for all the view controllers. I am currently calling this via a popover segue from each screen. So I have one destination view controller (AVC) that I am calling from a number of VCs- VC1toAVC, VC2toAVC, VC3toAVC etc. I want two textfields in AVC to change, depending on which VC called it.
So here's the problem- how can I tell which view controller called the popup? It's basically the view that's below the popover. Currently I'm storing it as a variable but that's not ideal. I'm guessing it has something to do with the segue identifiers?
Any and all help much appreciated!
One approach to this is adding a property to your pop up view controller and then define the
prepareForSegue:sender:
method so you set your destination view controller's property to the sender of the segue.
Related
I am trying to programmatically instantiate a new view controller of the same type as my original view controller using this code:
self.navigationController!.pushViewController(self.storyboard!.instantiateViewControllerWithIdentifier(StoryboardKeys.ViewIdentifier), animated: true)
I would like the user to be able to go back to my original view controller, so I was wondering if there is a way to keep the old view controller in memory? Also if I instantiate a view controller this way, do I get to prepareforsegue (in order to programmatically add a back button)? If not, how could I add a back button when pushing this view controller?
I suspect there is a better way to do this, so if there is, please let me know. Thank you very much for any help!
UINavigationController maintain your view controllers as a stack automatically, so don't worry about your view controller's memory management.
Only if you want a custom back button, otherwise you don't have to add a back button by yourself, everything has been done.
Just use self.navigationController!.popViewControllerAnimated(true) somewhere in your second view controller . Navigation controller contains a stack of views that you can retrieve by using self.navigationController!.viewControllers. You can modify this stack as you like.
I am a very new iOS dev and need your help.
I have a simple app, made from:
1 view controller that contains
3 UIContainerView, each one is linked to its own view controller and class
A view (the player)
Here is an image of my storyboard so it will be easier to understant:
=> I need 10 rep to post the image as an image
What I want is that when I click the play button on the cell inside "View Controller Search" it calls a method or function from the parent (main?) view controller including the url of the file to play.
I have already a working action on the play button, I have found how to get the url from it and printed it using NSLog so everything is fine from this part. My only problem is to find a way to communicate with the main view by sending the url.
If hope I am clear enough, thank you for your time.
You've got two options:
The quick and dirty one is to use the parentViewController property of your contained controller, cast it to the type of the parent view controller and call a method on it.
The right way is to define a delegate protocol and property for your search view controller, and make the parent view controller conform to it. Then, in the prepareForSegue: of the parent view controller, set the parent as the search controller's delegate.
prepareForSegue: will be called three times when your parent view controller is loaded, once for each embed segue that you have defined in the storyboard above. Just like when you push on a navigation controller, this is your opportunity to configure the destination view controller. You can give each embed segue in your storyboard an identifier to help with this process.
I got app with 2 view controllers, I'm typing values via NSStrings in Label and TextField in my first view controller and when I by pushing my navigation button go to my second view controller.
When I return to my first view controller, I got entered early values. But when next after that I go to my second view controller - values entered via NSStrings in Label and TextField disappear. How to fix this that the values saved?
I tried to use strong and copy properties but that not helps me.
UPDATE
I use segue and storyboards, segue with modal type, I use 2 navigation controllers: for first view controller and for second. I got code only for modal type. First view controller is root for navigation
UPDATE
I use 2 navigation controllers because I need modal segue from first VC to second and from second to first, when I use one navigation controllers that is not works like I need
Post some code otherwise we are just guessing. One guess is that you are using segues. Segues always create a new instance of the viewController. If you don't hold on to the old viewController somehow, it will get destroyed and any values it contained are also gone.
Just a guess.
I have a basic modal view system.
My app loads the UI base in which there are 2 buttons presenting 2 other views.
In those views, a dismiss button.
Everything works fine.
BUT, in one of the 2 modal views, I have a bunch of UISlider & UISwitch.
I want them to retain their values but the dismiss loses them: as soon as I trigger the button to show the view containing the UI elements, this view is shown with all values for all elements as I put initially in the xib.
should I store all values in variables, then in viewWillAppear I could "recall" them ?
would you advice me another strategy ?
Yes, your proposed approach is exactly the right sort of thing. But be careful; viewWillAppear can be called for many reasons; make sure you're only doing this when the view controller is coming into existence and showing the view for the first time.
NSUserDefaults can be an excellent place to store globally needed info like this. In viewWillDisappear, store the desired state info (values of the sliders and switches) in defaults. Then retrieve them the next time the view is about to appear.
When you create the modal view you are creating a new instance of the modalViewController an the modalView. This new instance knows nothing about any other instance. There are a few ways you can retain the information from previous iterations of these modal view controllers.
How I would do it:
Set up place holders in your main view and pass the values that the user selects back to the main view via a protocol and delegate setup. Then when you segue to the modal view you can load those variables in before displaying the modal view.
So let's say you have a dictionary with all of the values: {slider = YES, someValue=10,...} Create that dictionary in the main view controller, the first one that opens, and place some default values in it.
In your modal view controllers create the same dictionary as a property.
Create a protocol in your modal view controller with a method that is something like
- (void) doneEditing:(NSDictionary *)values
Set up your first view as the delegate for the modal view controller and in the implementation of doneEditing copy the values to the dictionary that is present in the first view before popping the modal view.
When the first view is ready to present the modal view again, copy the values to the dictionary property of the modal view before presenting it.
I hope this gets you headed in the right direction. It's important to remember that each time you segue or create and present a modal view you are creating a brand new instance of that view, it knows nothing about the previous instance at all unless you tell it something about it.
Is it possible to create a storyboard segue from a view controller to itself? I have a bunch of Entities that have Related Entities. I'd like to be able to display a Related Entity using the same view controller that's displaying the Entity. But I can't seem to create a segue that will display a new instance of the origin view controller.
Is it just not allowed? Thanks!
Well here's a solution that isn't quite the same but gets me what I want. I found it as an answer to this question.
The reason I thought I had to use a segue rather than the good old programmatic push of a view controller onto the navigation controller's stack is that I had set up the view controller's IBOutlets in the storyboard. I didn't realize that you could create a copy of the view controller as laid out in the storyboard without using a storyboard segue. You can! To see how to do it, check out that other question and up vote the answerer!
You can ctrl-click-drag (or right-click-drag) from an element (UIButton, etc.) to the containing view controller.
(Did you try this? I'm doing it right now; I have one stock UIViewController that just keeps adding itself indefinitely to the containing UINavigationController stack via a normal push segue.)
Yeah, it's annoying I can't do a 'manual' segue to itself.
What I did was added a UIButton to my view and gave it an action of push to the same view controller, and then made this button hidden. Then I can name the segue and reference it in the code.
Hacky, but works.