Hello I am a beginner at SWIFT and I have an issue with my project : I have a picker View on one of my View controller and I think that I have connected all outlets but when I execute the code and test my app on the emulator it comes an error when I click on the button (on the previous View) that has to open the view in which my picker View is set. When I get rid of my the picker View from the View controller, there is no more error.
The fact is that I have watched every tutorials on PickerView and did all they shew ...
I don't know where comes from my mistake.
I let some screen shots to be clearer
The first problem is that you don't store the created picker view instance. You instantiate it inside of a function, assign the delegate and dataSource and then you don't store it in your class. So the ARC (Automatic Reference Counting) releases it, because it thinks the instance is not longer needed. Just create a variable in your PickerController and store as long as the view controller is alive.
The second problem is that you actually want to see the picker view, so you need to add it to the view controller's view. You might need to position it right or use layout constraints (Search for Auto Layout).
var pickerView: UIPickerView!
func createPickerView() {
pickerView = UIPickerView()
pickerView.delegate = self
pickerView.dataSource = self
view.addSubview(pickerView)
}
Related
An UITableViewController pretty much takes up the entire view. I need a way to limit its height, width and add some shadows etc. For a clear explanation, I won't show the UITableViewController's contents.
Without the use of a storyboard, I subviewed the UITableViewController:
// In another UIViewController
let otherController = OtherController() // A subclass of UITableViewController
let otherControllerView = otherController.view
someView.addSubView(otherControllerView)
[...] // bunch of constraints
Notes:
In AppDelegate, if I set the rootController as OtherController(), everything works as it should. If I change it back to SomeView(), I see my modified tableView. If I should click it, it disappears.
This was the only thing that came close to my issue but sadly, I could not understand the answers provided as nothing made any sense to me.
I need to understand, why it disappears when touched etc.
view.bringSubviewToFront(...) proved futile. I'm gessing that a tableView should be rendered in its own controller and not in another view?
So just to answer this question, indeed you got two options. One is the best way, as suggested by Rakesha. Just use UITableView. Add it as a subview. Done.
And in the future, if you really want any controller to be added onto any UIView, remember you need to add that controller as a child. For example, in your case:
The controller of the view that will hold your UITableViewController will add such UITableViewController as a child.
self.addChild(yourUITableViewController)
self.whatEverViewContainer.addSubview(yourUITableViewController.view)
// Take note of the view of your tableViewController above^.
// Then setup the constraints of your yourUITableViewController.view below.
I hope this helps!
You must add the instance of UITableViewController's subclass as child view controller of the other view controller. You need to ensure few points in order to make it work. The points are as listed below:
Create the instance of your TableViewController
Add it as a child view controller of the other view controller
Add its view as a subview of the desired view (you may do these steps in viewDidLaod since they need to be done only once)
Keeping in mind the view cycle of a view controller. You must keep a weak reference of the child view controller aka TableViewController to adjust its view frame after the parent view controller has laid its subviews.
Code here:
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
let vc = TableViewController()
addChildViewController(vc)
view.addSubview(vc.view)
vc.didMove(toParentViewController: self)
childVC = vc
}
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
childVC?.view.frame = view.frame
}
I'm trying to add a sliding photo gallery functionality to the top portion of a view.
To give context, a user taps on a button or row or something. Then i load a scrollview with a uistackview in it. organized vertically, i had an image, and then another stack view with some text in it. Now, i want that image to become part of a larger "gallery". My research told me to implement UIPageviewcontroller and add the other images to a childVC.
i used this as a tutorial (the first example): http://www.raywenderlich.com/76436/use-uiscrollview-scroll-zoom-content-swift
the only relevant deviation from the tutorial my app has is that it creates things programmatically.
With my proof of concept for the gallery functionality, i wanted to integrate it with the previously mentioned stack view. my plan was to first add the pageviewcontroller stuff into the overall stack view with the original image view right below it and then simply remove the original image view to leave me the final product.
i was able to add the pageviewcontroller.view to the stackview, but the gallery doesn't show. taking a look at the UI Inspector, i can see that the gallery is kinda loaded, but it's messed up.
it's as if the uiview has a frame of 0 height and so the other stack view items don't respect the images that the pageviewcontroller is trying to show.
I think it could be that stack views can only handle specific views, not stuff as complicated as pageviewcontrollers.
also note: my implementation is all programmatic, no storyboards, and so for no xibs. so maybe i missed something here.
here is some code, if it helps:
note the constrain functions you see are from the "cartography" pod
this adds the "gallery" to the stack view, it's a delegate function from my view
func addZoomStuff(sender: UIStackView) {
let zoomer = PageBaseViewController()
addChildViewController(zoomer)
zoomer.view.translatesAutoresizingMaskIntoConstraints = false
zoomer.view.tag = 5
sender.addArrangedSubview(zoomer.view)
zoomer.didMoveToParentViewController(self)
}
this is what creates the scrollview, image view, etc for the gallery items:
override func viewDidLoad() {
super.viewDidLoad()
//MARK: - Zoom View Elements
// prep
scrollView = UIScrollView(frame: self.view.frame)
scrollView.delegate = self
self.view.addSubview(scrollView)
constrain(scrollView, view) { view, view2 in
view.edges == view2.edges
}
self.view.setNeedsUpdateConstraints()
// 1
let image = UIImage(named: imageName)!
imageView = UIImageView(image: image)
// 2
scrollView.addSubview(imageView)
constrain(imageView){ view in
view.edges == view.superview!.edges
}
scrollView.contentSize = image.size
i tried adding the constraints like this but there was no effect
func addZoomStuff(sender: UIStackView) {
let zoomer = PageBaseViewController()
addChildViewController(zoomer)
view.addSubview(zoomer.view)
constrain(zoomer.view, view) { view, view2 in
view.width == view2.width
view.height == view2.height * 2 / 3
view.leading == view2.leading
view.top == view2.top
}
zoomer.view.setNeedsUpdateConstraints()
zoomer.view.removeFromSuperview()
zoomer.view.translatesAutoresizingMaskIntoConstraints = false
zoomer.view.tag = 5
print("sender.subviews: \(sender.subviews)")
sender.addArrangedSubview(zoomer.view)
zoomer.didMoveToParentViewController(self)
print("sender.subviews: \(sender.subviews)")
}
if this method isn't going to work, can i do a nested horizontal stack view instead of the pageviewcontroller and somehow get that same scrolling/snap effect to see on image view at a time?
TLDR;
Create a subclass of UIPageViewController, make it it's own delegate.
Initialize the subclass with a plain UIViewController, only set a backgroundcolor.
In the pageviewcontroller subclass, implement the two delegate callbacks for a next and previous viewcontroller: create a plain viewcontrolller, with some random backgroundcolor.
If this works, replace the plain viewcontroller by your actual contentviewcontroller.
Long version:
Have you seen this: Maybe this link will help: https://developer.apple.com/library/ios/documentation/WindowsViews/Conceptual/ViewControllerCatalog/Chapters/PageViewControllers.html
It might help, as it explains the details of UIPageViewController. Basically, you need to create a viewController (not a view!), that shows one page of the gallery. So this VC has a stackview, and manages the content of it. The pageviewcontroller is initialized with your first contentviewController. If you create a subclass of the uipageviewcontroller, you can set self of that subclass as the delegate of it. Implement the delegate callbacks that return the next or previous viewController and thats it. For this last part, it is convenient to have a property on the contentviewcontroller from which the subclasses of the pageviewcontroller can figure out what data to set on the next or previousviewcontroller.
Your title seeks to hint at some confusion: its not possible to add a viewcontroller to a view. You can only add other views to a (stack)view. A viewcontroller owns and manages a viewhierarchy. A pageviewcontroller has no content, but manages the insertion and removal of viewcontrollers. as the pageviewcontroller is a containerviewcontroller, it will als take the contentViewcontrollers' views and place them in the viewhierarchy. But this is not something your code has to do when you subclass UIPageViewControlller and implement it's delegates on itself (and don't forget to assign self to be the delegate).
I want to replace the default keyboard of a UITextField with a custom keyboard. So I created a new subclass of a UIViewController with a xib-file (the other way like creating both files seperately and setting the File's Owner doesn't work either).
Then I added a button to the KeyboardView and connected it to an IBAction. After that I set the textfields inputView to the new view like this:
override func viewDidLoad() {
let keyboardVC = KeyboardViewController()
textField.inputView = keyboardVC.view
keyboardVC.view.autoresizingMask = .FlexibleHeight
keyboardVC.delegate = textField
}
It's working and the custom keyboard shows up, but if I touch the button, the IBAction is not called. What's the problem in my setup? (I checked some examples and they all do it the same way).
UPDATE:
I now removed the ViewController and subclassed the UIView. Now the actions are working. Why isn't it working with a ViewController?
Since no one holds the UIViewController- there is no reference to it after the viewDidLoad() ended, it is released from the memory.
When the button is pressed, the view controller that should response to the action is not exist -> you are holding only the view of the view controller as the textField.inputView.
The headline seems lengthy but what I'm trying to do is quite simple.
I have a couple of identical buttons lined in a row and set their tags to 0...n. Clicking on any of them (the 2nd for example) would bring up a popover view in which there are several buttons representing different options (A, B, C, D). What I want to do is to turn the 2nd Button's title to B if we click on option B.
The problem is that the popover view does not know which Button presented it, since all popoverViews are instances of the same UIViewController class. So I am thinking of distinguishing the n buttons by setting their tags to different values. However, I don't know how to get the UIButton's tag from a button inside the popover this UIButton presented.
Many thanks in advance!
This is how I will solve this in swift. I will declare a delegate in the popoverViewController and have a method e.g
protocol popOverViewControllerDelegate: class {
func popOverViewController(controller: PopOverViewController,
didSelectItem buttonTitle: String)
}
then I will add a target action to the UIButton in the popOver
button.addTarget(self, action: "selected:",forControlEvents:.TouchUpInside)
the select method will have sender passed to it
func selected(sender:UIButton){
delegate?.popOverViewController(self, didSelectItem: sender.currentTitle)
//dismiss viewcontroller
}
remember to declare
weak var delegate: popOverViewControllerDelegate!
now have the viewcontroller that called the popOver, subclass to this delegate and implement it's method. Whenever a button in the popOver is selected, this method will be called and the currentTitle of the method will be passed. You can now use that to set the currentTitle of the button that called the popOver.
In case you need further help with the last part, please ask.
I've fixed the problem by adding a property tagNumberso that after instantiating the popoverViewController's class, I set the instance's tagNumber to the sender's tag. Then I send the tagNumber back together with sender.currentTitle. This way, the presenter of the popover could know both the title and tag number of the UIButton.
I have an app where I want, by tapping a static UITableViewCell within a UITableViewController, a UIDatePicker to pop up on the bottom of the screen, that lets me pick the time(e.g. the hour, minute, and AM/PM).
Obviously, it would have to be created completely programmatically because
I want to hide it(when a button on the picker is pressed or
somewhere outside the picker is tapped)
I can't add it to the View Controller. Any ideas?
Apple implements similar functionality in their DateCell example, as * Islam Q.* mentioned in a comment on your original question. However, for this answer, I'll assume you'd rather do what you described.
Your goal can actually be achieved with very little code.
First, drag a UIDatePicker out onto a view controller in your
Storyboard.
Then, connect that date picker to an IBOutlet in the
implementation of your view controller subclass.
#IBOutlet weak var datePicker: UIDatePicker!
In that same view controller's viewDidLoad() (or viewDidAppear(:), if that's more appropriate), move the date picker below the bottom edge of the screen by changing its frame. Don't animate the frame change. Nothing's onscreen anyway.
override func viewDidLoad() {
super.viewDidLoad()
self.datePicker.frame = self.offscreenFrame
// ...
}
Next, in tableView(_:didSelectRowAtIndexPath:), animate datePicker back onto the screen. Right before you perform the animation, make sure to set the date picker's date to the current date.
self.datePicker.date = UIDate()
// now do the animation
Finally, make sure to animate the dismissal of the date picker when appropriate (in tableView(_:didDeselectRowAtIndexPath:), for example).
UIView.animateWithDuration(0.2) { () -> Void in
self.datePicker.frame = self.onscreenFrame
}
Note that the actual implementation of each of these bullet points can differ depending on your situation. Also, offscreenFrame and onscreenFrame are "imaginary" variables that I used to simplify the code snippets.