I'm trying to move my fully functioning swipe gesture code into a view model to clean up the view controller but the code uses a lot of self and view references, so I suppose I need to pass along the view or UIView.self as an argument when calling the function. Can't get it to work though. Tried:
vm.swipeCode(myView: self.view)
func swipeCode(myView: UIView) {...
But it crashes. After some research I also tried variations of inout and & but to no avail. Here's the full swipe code (it references back to the view controller but I will move those as well when things start working :) )
var myVC = RecipesViewController()
func swipeCode(myView: UIView) {
//SWIPE RIGHT
let swipingRight = UISwipeGestureRecognizer()
swipingRight.addTarget(self, action: #selector(myVC.swipeRight))
swipingRight.direction = .right
swipingRight.delegate = self as? UIGestureRecognizerDelegate
swipingRight.cancelsTouchesInView = false
myView.isUserInteractionEnabled = true
myView.addGestureRecognizer(swipingRight)
//// ALLOW SWIPE LEFT ////
let swipingLeft = UISwipeGestureRecognizer()
swipingLeft.addTarget(self, action: #selector(myVC.swipeLeft))
swipingLeft.direction = .left
swipingLeft.delegate = self as? UIGestureRecognizerDelegate
swipingLeft.cancelsTouchesInView = false
myView.isUserInteractionEnabled = true
myView.addGestureRecognizer(swipingLeft)
}
The crash is probably because of these two lines:
swipingRight.addTarget(self, action: #selector(myVC.swipeRight))
swipingLeft.addTarget(self, action: #selector(myVC.swipeLeft))
You passed myVC.swipeLeft as the action, but self as the target, so the gesture recogniser will try to find a swipeLeft method in self, which doesn't exist.
You should always ensure that the action is a member of the target:
swipingRight.addTarget(myVC, action: #selector(myVC.swipeRight))
swipingLeft.addTarget(myVC, action: #selector(myVC.swipeLeft))
You should simply make a UIView or UIViewController inherited class instead if your methods use a lot of self then simply make your controllers or views of that class.
class CustomViewController:UIViewController {
func swipeCode(myView: UIView) {
// Your code here
}
// Any other methods your code might need
}
class RecipesViewController:CustomViewController {
// Whatever else your view controller is made from
}
Or if your code swiping works in every view controller you could also extends the UIViewController to add those functionnalities
Related
I created a custom view with a subview where its frame origin x is set to the width of the parent view so that it looks like a tab sticking out of the view. (like a tab folder). The custom view is an IBOutlet in a view controller. My objective is to drag the tab to pull out the custom view like opening a panel. When I add the Pan gesture to the dragging tab, the subview, nothing happens. It works when I add it directly to the parent view. Any help would be awesome.
let pan = UIPanGestureRecognizer(target: self, action: #selector(dragView(pan:)))
pan.minimumNumberOfTouches = 1
pan.delegate = self
notesView.dragView.addGestureRecognizer(pan)
neither the func nor the delegate methods are triggered.
//MARK: - Don't forget to add UIGestureRecognizerDelegate, when you add delegate to gestureRecognizer
class ViewController: UIViewController, UIGestureRecognizerDelegate {
override func viewDidLoad() {
super.viewDidLoad()
//MARK: set panGestureRecognizer
let panGestureRecognizer = UIPanGestureRecognizer(target: self, action: #selector(panGestureRecognizerTapped))
panGestureRecognizer.minimumNumberOfTouches = 1
//MARK: set panGestureRecognizer delegate
panGestureRecognizer.delegate = self
//MARK: Set panGestureRecognizer to view
view.addGestureRecognizer(panGestureRecognizer)
//MARK: - Add user interaction to you custom view or view
view.isUserInteractionEnabled = true
}
//MARK: when tap is happened the below attribute will be executed
#objc func panGestureRecognizerTapped() {
print("Pan Gesture Recognizer Tapped")
}
}
//The resource code is at the below link:
https://github.com/ahmetbostanciklioglu/PanGestureRecognizer.git
I've been trying to correctly implement a ContainerView in my practice app after watching and reading various tutorials. I initially tried creating the child by utilizing the storyboard and dragging the ContainerView onto the ViewController in question, and then utilizing the child ViewController that is then automatically created, but I need to have multiple child ViewControllers and I couldn't quite figure that out. I researched some programatic ways to do it and I successfully have it functioning the way I want. The only hiccup being that when I am viewing the child ViewControllers on my storyboard they are full size and do not correlate in size to my ContainerView. So I have to have a bit of trial and error in getting the objects I place in the child to fit in the ContainerView.
Can anyone give me some pointers on how I fix that? I've used the code below. The function runs when a button on the parent ViewController is touched. There are other associated child ViewControllers: child2, child3 that run depending on which button is pushed. I didn't include that extra code below for the sake of being concise.
private lazy var child1: PersonInfoChildView1Controller = {
let storyboard = UIStoryboard(name: "Main", bundle: Bundle.main)
var viewController = storyboard.instantiateViewController(withIdentifier: "Child1VC") as! PersonInfoChildView1Controller
viewController.person = self.person
addChild(viewController)
return viewController
}()
//MARK: ADD THE CHILD
private func add(asChildViewController viewController: UIViewController) {
containerView.addSubview(viewController.view)
// Configure Child View
viewController.view.frame = containerView.bounds
viewController.view.autoresizingMask = [.flexibleWidth, .flexibleHeight]
// Notify Child View Controller
viewController.didMove(toParent: self)
}
Try to set your child view controller constraints relative to the container view.
Edit your add method like this:
private func add(asChildViewController viewController: UIViewController)
{
viewController.view.translatesAutoresizingMaskIntoConstraints = false
containerView.addSubview(viewController.view)
viewController.view.leftAnchor.constraint(equalTo: containerView.leftAnchor).isActive = true
viewController.view.rightAnchor.constraint(equalTo: containerView.rightAnchor).isActive = true
viewController.view.bottomAnchor.constraint(equalTo: containerView.bottomAnchor).isActive = true
viewController.view.topAnchor.constraint(equalTo: containerView.topAnchor).isActive = true
// Notify Child View Controller
viewController.didMove(toParent: self)
}
Also you can create an extension to UIView class to pin the view to the parent view by just one line code
extension UIView {
func pin(to superview: UIView){
translatesAutoresizingMaskIntoConstraints = false
topAnchor.constraint(equalTo: superview.topAnchor).isActive = true
leadingAnchor.constraint(equalTo: superview.leadingAnchor).isActive = true
trailingAnchor.constraint(equalTo: superview.trailingAnchor).isActive = true
bottomAnchor.constraint(equalTo: superview.bottomAnchor).isActive = true
}
}
put this in a separate swift file with this method you can make the container view same size as the view controller
containerView.addSubview(viewController.view)
viewController.view.pin(containerView)
This will save you a lot of time in the future.
I have a function that creates a button with a selector function as a target. The address of a button gets passed to handleSelectPhoto.
lazy var image1Button = createButton(selector: #selector(handleSelectPhoto))
func createButton(selector: Selector) -> UIButton {
let button = UIButton(type: .system)
button.addTarget(self, action: selector, for: .touchUpInside)
return button
}
#objc func handleSelectPhoto(button: UIButton) {
// Do something with button, this works
}
Now, I am trying to change the class of the above from UIButton to UIImageView like the following,
lazy var image1Button = createButton(selector: #selector(handleSelectPhoto))
func createButton(selector: Selector) -> UIImageView {
let view = UIImageView()
view.addGestureRecognizer(UITapGestureRecognizer(target: self, action: selector))
view.isUserInteractionEnabled = true
return view
}
#objc func handleSelectPhoto(button: UIImageView) {
// HERE, button does not get passed
}
With the above changes, in handleSelectPhoto, button instance is not correct. I can not read it as UIImageView type.
If I add a selector function using addGestureRecognizer, does it behave differently than adding a selector function using addTarget, in terms of how selector function is executed with parameters? Maybe I am not understanding how this selector function works...
Adding a target to something like UIGestureRecognizer or UIButton only passes one parameter to the selected function. This parameter depends on the type you are about to add the target on.
In your case the first code snippet works because you are adding a target to an UIButton, so your selected function gets passed this UIButton instance.
In your second scenario you add the target to an UITapGestureRecognizer, so the passed instance will be exactly this gesture recognizer, which cannot be of type UIImageView.
So the difference from the target parameter perspective between UIGestureRecognizer and UIButton is no difference. They both pass their instances to the selected function.
From the UIView subclass perspective there is the difference that UIGestureRecognizer is not a subclass of UIView, but UIButton is. That's why you can just use the passed UIButton instance in your first snippet. In the second snippet you need use the view property of UIGestureRecognizer.
guard let imageView = gestureRecognizer.view as? UIImageView else { return }
Besides your actual question it seems important to clarify how to write #selectors correctly. You're doing it correct already. No change necessary. Some may say you need to add (_:) or : to your selector like so: #selector(handleSelectPhoto(_:)) but this isn't true. In general, you only need to add these special characters when you are selecting a method which has an overload method with a different amount of parameters, but the same base name.
You should make your tell while setting the selection that your function will accept a parameter by adding : at the end of method name.
lazy var image1Button = createButton(selector: #selector(handleSelectPhoto:))
UIKit will automatically understand that the selector methods parameter will be of type UITapGestureRecognizer. Now rewrite the below method like this and you will be good to go.
#objc func handleSelectPhoto(gesture: UITapGestureRecognizer) {
if let buttonImageView = gesture.view as? UIImageView {
//Here you can make changes in imageview what ever you want.
}
}
I have a 2 classes where I am passing uistackviews from one class to other. I want the controls to be created in same stackview. Hence I am passing the view in all the render function parameters. I also want that view to be passed with action #selector of uibutton
class 1:
class ViewController: UIViewController {
func createbutton(parentview: UIStackView) {
let buttn = UIButton()
buttn.backgroundColor = .gray
buttn.setTitle("testttt", for: .normal)
buttn.frame.size.height = 30
buttn.frame.size.width = 40
buttn.addTarget(self, action: #selector(anotherbutton(parentview:)), for: .touchUpInside)
parentview.addArrangedSubview(buttn)
}
func anotherbutton(parentview: UIStackView) {
//another button here
}
func loadpage() {
print("loadpage")
}
}
Class 2:
class plugin : UIViewController {
let vw = ViewController()
override func viewDidLoad() {
super.viewDidLoad()
let parentview = getparentnode()
vw.createbutton(parentview: parentview)
}
func getparentnode() -> UIStackView {
let parentnode = UIStackView()
parentnode.axis = UILayoutConstraintAxis.vertical
parentnode.distribution = UIStackViewDistribution.equalSpacing
parentnode.alignment = UIStackViewAlignment.center
parentnode.spacing = 16.0
parentnode.tag = 50
parentnode.translatesAutoresizingMaskIntoConstraints = false;
self.view.addSubview(parentnode)
//Constraints
parentnode.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive = true
parentnode.centerYAnchor.constraint(equalTo: self.view.centerYAnchor).isActive = true
return parentnode
}
}
but this throws an error unrecognized selector sent to instance 0x7b25e010'
How to pass the UIView in action selector parameter ? Thank you for any help
You can't. The only things that you can pass through a selector is:
Nothing
The object itself (in this case the button)
These scenarios would look like this:
button.addTarget(self, action: #selector(myFunc), ...) //no parameters
or
button.addTarget(self, action: #selector(myFunc(_:)) //passes itself (the button)
If you want to pass the value of a view to another ViewController I recommend using the prepareForSegue method. That is how you are supposed to pass data from ViewController to ViewController.
In terms of the rest of your code, I believe you are breaking the MVC design pattern by creating an instance of your class in another class (this line: let vw = ViewController()). First of all, this will create an entirely new instance if your ViewController, which isn't the same as the one running on your device. Second of all, this is bad practice. You should be allowing each viewController to manage itself and not have outwards interference from other viewControllers. Using prepareForSegue is an example of using the MVC design pattern effectively.
Hope this helped.
Hi I'm having no cards to used to fixed this. Here we go.
I have this five imageview this is the declaration of first imageview but basically they have same declaration
#IBOutlet weak var first: UIImageView!{
didSet{
first.tag = 1
first.addGestureRecognizer(tapGesture())
}
}
and Then the tapGesture() method is this
private func tapGesture() -> UITapGestureRecognizer {
let tapGesture = UITapGestureRecognizer(target: self, action: Selector("iconTapped:"))
tapGesture.numberOfTapsRequired = 1
tapGesture.numberOfTouchesRequired = 1
return tapGesture
}
the action when the imageview is tapped the iconTapped() method is called, this is the code
func iconTapped(sender:UITapGestureRecognizer){
if let tag = sender.view?.tag{
processGesture(tag)
}
}
I have put all imageview userInteractionEnable to true but still not firing. Could anyone help me?
Some factor may or may not help, inside the viewdidload I update constraints and do some animation to imageview, but I'm not adding any subview programmatically
after trying so many things, I look on my view hierarchy and figure out that the parent view where my UIImageView rest userInteractionEnable is set to false(unchecked) in storyboard.
in this case the parentview is my superview, to fixed that I need to add this in viewDidLoad()
self.view.userInteractionEnabled = true
or
click the parentView in storyboard and in attributes inspector check the User Interaction Enable.
ps. sorry for silly mistake but I'll keep this question posted there might be other encountering same problem.