I'm new to iOS development and this could be a stupid question for some experienced guys...
When I create a new iOS project in Xcode, I get a ViewController class and a storyboard which sets its Custom Class to this ViewController. It looks like there is a "Storyboard" class holding an instance of ViewController, however, I cannot find where this "Storyboard" class is defined.
Even though I know how to create multiple subclasses of UIViewController to handle different views interaction following some tutorials, I still find it uncomfortable to associate these subclasses to the storyboard by selecting them in the storyboard panel. I would rather see something like a "Storyboard" class holding an array of UIViewController.
So my question is, how these UIViewController interact with the Storyboard under the hood?
Thanks
Roughly, it happens as follows:
App launches.
App loads storryboard.
Depending on app's navigation structure, app instantiates each view controller inside the storyboard as needed.
The storyboard contains detailed information on:
Which custom subclass of UIViewController, UINavigtionController, etc. to use for instantiating each view controller in the storyboard.
How to map (connect) each if its view controllers' subviews to the corresponding custom classes' outlets and actions.
But seriously, read Apple's docs. It's all there.
UIViewController has a property named storyboard which refers to the storyboard file associated with the viewcontroller subclass.
Also the view controller code are interecting with the storyboard with connections symboled with #IBOutlet and #IBAction.
Related
In my project I have two view controllers, and I am having trouble connecting objects such as an UIImageView to the view controller. When I try to create the IBOutlet, it tells me that "Could not insert new outlet collection: could not find any information for the class named UIViewController". I believe this problem stems from the fact that my original declaration of my class is as follows:
class UIViewController: UIViewController {
when in fact the view controller is named mainScene instead. However, when I change the first UIViewController to what I think it should be (mainScene), it doesn't even show me the option of connecting an IBOutlet...
class mainScene: UIViewController {
So, I have two questions.
Do I need to have a whole separate class for the second UIViewController and would that solve my issues?
Is there a better way to link objects to the UIViewController or am I just doing something horribly wrong (the likely scenario)?
Thanks so much
Short answer: 1. Yes, and yes. 2. There's no better way, and you're not doing something horribly wrong. (You probably just missed a step.)
You have two view controllers. Assuming they are different, you would subclass each one from UIViewController with a different name. E.g., mainSceneViewController and otherSceneViewController.
Your mainSceneViewController and otherSceneViewController would each have their own properties and IBOutlets.
Where you're probably stuck, is needing to change the class of your viewController within Interface Builder to match the class name in its .swift file, so IB knows what outlets it can connect for that view controller.
Each scene in your storyboard corresponds to a view controller. When the segue is performed, iOS instantiates your view controller from the storyboard.
While it is possible to only have one view controller subclass, and use the same subclass for different views, it doesn't happen too often.
Update:
Subclassing lets you add properties and methods to a class, and override their superclass.
In your comment, UIViewController is the class, and mainSceneViewController is subclassed from UIViewController. For your second view controller, it would likely be class otherSceneViewController: UIViewController {, as your other scene would likely require a different properties and methods from your main scene view controller.
You can read more about Inheritance in the Swift Programming Language guide.
I am writing a simple app with custom storyboards for iPhone and iPad. I have a generic viewcontroller class from which my custom iPhone and iPad viewcontrollers inherit. Outlets and IBActions in my storyboards are mostly wired up to the generic viewController class and everything works well.
Now for stylistic reasons I decided to make my iPhone's viewcontroller be a UITableViewController and it can no longer inherit from my generic viewcontroller. I've been googling and searching this site and see advice which says I should write a category and use this in my custom classes.
I have never done this, but I looked at the documentation and understand the concept, but once I move my code into a category, how would I be able to link my storyboard's outlets and actions (ctrl-drag from storyboard) to the methods which are now moved out of my custom viewcontroller classes? Usually I would for example ctrl-drag from a switch in the storyboard to an existing IBAction method in my generic viewController, but these methods will now be inherited and not showing my my custom classes to drag to.
I am just a hobbyist and newb, so I apologize if this question is too basic.
You can use UIViewController with UITableView instead of UITableViewController.
1.In storyboard, get a new UIViewController and linking with your custom viewcontroller class.After that,put an UITableView into that UIViewController and linking with that class using (ctrl-drag from storyboard) called mTableView
2.In that class you should implement <UITabBarControllerDelegate,UITableViewDataSource>.
Use mTableView instead of self.tableView just like in UITableViewController.
Currently I'm struggling with creating a subclass of UIViewController or UINavigationController with XIB file as a view.
When I create everything from the Xcode's menu (New File -> Class -> With Nib... etc.) I get a XIB but only with a plain UIView but I want UIViewController instead.
I read somewhere that XIBs are only for a views and you have to handle controller in code, is it true? Because as you can read here it's possible to insert Navigation Controller component into XIB. But I have one problem with the code from this tutorial - I get empty view with empty UINavigationBar. When I do the same with regular View Controller I get info abut this controller being used more than once...
I'm not trying to force Interface Builder to do something unusual but I want to know if this is possible (it would be easier and nicer to modify view controller component insted of a content view)? And if it is, how to achieve this?
I have just checked to confirm whether it is possible and to my surprise it is! You can have UIViewControllers inside Xibs
The test was done in XCode 10.1, Swift 4.2.
I have never used it before, but i thought since it gives you the option from the item library to pick view controllers, it has to be possible. I have added one to my xib, and just like in the storyboards, i have linked it with class, set IBOutlets and IBActions and it all worked perfectly fine.
The key thing is to instantiate it like this:
// Method inside the `UIViewController` you want to present our view controller from xib
// The xib file is `XibViewController.xib` and it has only one item inside - `UIViewController` with custom class set to `XibViewController`
guard let xibViewController = UINib(nibName: "XibViewController", bundle: nil).instantiate(withOwner: self, options: nil).first as? XibViewController else { return }
present(xibViewController, animated: true)
here you can find my test project: https://github.com/stoqn4opm/XibViewController
An XIB file is used for building content that is viewable on a screen. A UIViewController is not viewable. It instead owns a view (which is viewable) created from an XIB or from code.
I think from what you are trying to do is use a storyboard which lets you visually layout your UIViewControllers to define there segue from each other (in your case in a Navigation Controller) which means show the next UIViewControllers view and put it in the UIViewController hierarchy.
I'm attempting to create an application for iOS, using Xamarin and storyboards. Within this, there shall be a button located in a TableViewController which will navigate the user.
To do this, I've used a Container, embedded to a TableViewController. However, my concern is I wish to add an Outlet from the button within the TableViewController to the ViewController header class - Yet it only allows me to try and add one to the 'UITableViewController.h' file.
What is causing this and how am I able to add the Outlet to the 'ViewController.h' file? (Extremely sorry if this makes little sense)
You should not use both the UITableViewController and the UIViewController. UITableViewController is a subclass of UITableViewController so all you need the UITableViewController and you should drag the outlet to it.
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.