Here is what I'm trying to do.
class UserProfileHeader: UICollectionViewCell {
lazy var button: UIButton = {
let button = UIButton(type: .system)
//...
button.addTarget(self, action: #selector(handleButtonTapped), for: touchUpInside)
return button
}()
func handleButtonTapped() {
print("action working now")
// How to push another vc here?
}
// ...
}
I want to call a navigationController to push(show) another ViewController here in the collectionViewCell. How can I access there? I tried, not worked. Is it because of MVC pattern? Cell can't talk with others? Or is there any ways to make it? like using Delegate/Protocol? I don't know much about those things.
Create one custom delegate and set to its viewcontroller and then when you tap on collectionview cell button called that delegate method and it will invoke inside your viewcontroller there you can push the view controller
func handleButtonTapped() {
//Your delegate method showuld be invoked here
delegate?.buttontappFromCollectionViewCell()
}
//Now inside your view controller
func buttontappFromCollectionViewCell() {
let vc = UIStoryboard(name: "storyboardName", bundle: nil).instantiateViewController(withIdentifier: "yourViewControllerIdentifier")
let navigationController = UINavigationController(rootViewController: vc)
navigationController.pushViewController(vc, animated: true)
}
Related
why with this code, outlets in second view controller are unwrapped as the were nil crashing the app? they even are not appearing. issue happens if I try to access the outlets, but not if I change the view's background.
in view controller 1 button:
let vc = SecondViewController.self.createAcertainCustomAppearenceOfVC()
vc.modalPresentationStyle = .overCurrentContext
vc.modalTransitionStyle = .crossDissolve
present(vc, animated: true, completion: nil)
in second view controller
final class func createAcertainCustomAppearenceOfVC() -> SecondViewController {
let VC = SecondViewController()
VC.view.backgroundColor = .systemRed
// VC.tappedSecondOut.setTitle("push", for: .normal)
VC.tappedSecondOut.backgroundColor = .black
return VC
}
You're trying to instantiate a view controller that has outlets in a storyboard, you need to instantiate the controller from both the storyboard name and the view controller's identifier that is set in Interface Builder.
final class func createAcertainCustomAppearenceOfVC() -> SecondViewController? {
let storyboard = UIStoryboard.init(name: "Main", bundle: nil)
return storyboard.instantiateViewController(withIdentifier: "secondViewControllerIdentifier") as? SecondViewController
}
I have a customerViewController that has a simple a form. When the user presses submit, a segue is triggered and another view appears. The problem occurs when the user goes back to the customerViewController and finds all of the old information still there. I could simply reset the form fields, but what I'd really like is to find a way to reset the entire VC. From what I've learned so far, the way to reset a vc that hasn't been pushed is to remove it and then add it back.
customerViewController is the initial view controller in a navigation controller which is embedded in a tab bar controller. I have a tabBarController class that is a UITabBarControllerDelegate. This is where I call:
override func tabBar(_ tabBar: UITabBar, didSelect item: UITabBarItem) {
if item.tag == 2 { //This is the tab with my navigation controller
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier: "CustomerVCID")
var viewcontrollers = self.navigationController?.viewControllers
viewcontrollers?.removeFirst()
viewControllers?.insert(vc, at: 0)
self.navigationController?.setViewControllers(viewcontrollers!, animated: true)
}
The problem with my code is that navigationController?.viewControllers is nil in the code above. I can reference viewControllers which gives me a list of tab bar viewControllers, but I'm not sure how to get from there to the navigation controller.
I guess my question is, assuming that I'm on the right track, how do I reference the view controllers in my navigation controller?
You can reset your form values in vc inside the viewWillAppear(_:),
class ViewController: UIViewController {
override func viewWillAppear(_ animated: Bool) {
//clear the textfields, textviews values etc. here.
}
}
It turns out, I was over-complicating things by trying to access navigationController.viewControllers or tabBarController.viewControllers. All I needed was viewControllers which is a property of UITabBarController that contains an array of the controllers associated with each tab:
override func tabBar(_ tabBar: UITabBar, didSelect item: UITabBarItem) {
if item.tag == 2 { //tab with navigation controller
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vcon = storyboard.instantiateViewController(withIdentifier: "CustomerVCID")
for viewcontroller in viewControllers! {
if let vc = viewcontroller as? UINavigationController {
vc.viewControllers.removeFirst()
vc.viewControllers.insert(vcon, at: 0)
vc.setViewControllers(vc.viewControllers, animated: true)
}
}
}
I am presenting a UICollectionViewController but it just ends up as a controller with no back buttons to get back to the last controller or the home controller, how would i add a back button? or what other options do i have?
class UserProfileController: UICollectionViewController, UICollectionViewDelegateFlowLayout, UserProfileHeaderDelegate, ProfileHeaderClosedDelegate {
func presentFRC() {
let PE = FriendsRequestsController(collectionViewLayout:
UICollectionViewFlowLayout())
let NPE = UINavigationController(rootViewController: PE)
self.present(NPE, animated: true, completion: nil)
}
}
Add the following code in the view did load of the view controller you are presenting.
override func viewDidLoad() {
super.viewDidLoad()
var backbutton = UIButton(type: .Custom)
backbutton.setImage(UIImage(named: "BackButton.png"), forState: .Normal)
backbutton.setTitle("Back", forState: .Normal)
backbutton.setTitleColor(backbutton.tintColor, forState: .Normal) // You can change the TitleColor
backbutton.addTarget(self, action: "backAction", forControlEvents: .TouchUpInside)
self.navigationItem.leftBarButtonItem = UIBarButtonItem(customView: backbutton)
}
func backAction() -> Void {
self.navigationController?.popViewControllerAnimated(true)
}
You have two options:
Embed your view controllers into UINavigationController and use UINavigationBar and segues for navigation. The easiest way to build such a system would be through storyboard though. But you can do that programmatically as well, but it would be a lot more work.
Add your own back button programmatically the way #ZahurafzalMirza has shown you. Since you are not using UINavigationController, your navigationController will be nil. So the action should look like this
func backAction() -> Void {
self.dismiss(animated: true)
}
I am having a bit of an issue with dismissing a modal view presented from a childviewController in a container view. I have a UINavigationController as the rootViewController (MainNavigationController), and present a modal from one of the childViewControllers from the selectedSegmentIndex 1 (secondViewController). The modal is presented fine, but when I dismiss the modal to go back to the secondViewController(a subclass of HomeController) it returns me back to selectedIndex 0, so not the selectedIndex 1 childViewController it was presented from. I would like the modal to dismiss and return the user back to childViewController it was presented from (the secondViewController) and not return back to selectedIndex 0. Thanks in advance!
// NavigationConroller as rootViewController
class MainNavigationController: UINavigationController {
var segmentedController: UISegmentedControl!
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
let vc1 = TravelersFeedVC()
let vc2 = ProfileVC()
if isLoggedIn() {
// assume user is logged in
let homeController = HomeController()
viewControllers = [homeController]
homeController.firstViewController = vc1
homeController.secondViewController = vc2
} else {
perform(#selector(showLoginController), with: nil, afterDelay: 0.01)
}
}
fileprivate func isLoggedIn() -> Bool {
return UserDefaults.standard.isLoggedIn()
}
func showLoginController() {
let loginController = LoginController()
present(loginController, animated: true, completion: {
// perhaps do something here later
})
}
}
// HomeController as parentViewController
class HomeController: UIViewController, FBSDKLoginButtonDelegate {
// child view controllers to put inside content view
var firstViewController: TravelersFeedVC?
var secondViewController: ProfileVC?
private var activeViewController: UIViewController? {
didSet {
removeInactiveViewController(inactiveViewController: oldValue)
updateActiveViewController()
}
}
private func removeInactiveViewController(inactiveViewController: UIViewController?) {
if let inActiveVC = inactiveViewController {
// call before removing child view controller's view from hierarchy
inActiveVC.willMove(toParentViewController: nil)
inActiveVC.view.removeFromSuperview()
// call after removing child view controller's view from hierarchy
inActiveVC.removeFromParentViewController()
}
}
private func updateActiveViewController() {
if let activeVC = activeViewController {
// call before adding child view controller's view as subview
addChildViewController(activeVC)
activeVC.view.frame = contentView.bounds
contentView.addSubview(activeVC.view)
// call before adding child view controller's view as subview
activeVC.didMove(toParentViewController: self)
}
}
// UI elements
lazy var contentView: UIView = {
let tv = UIView()
tv.backgroundColor = UIColor.purple
tv.translatesAutoresizingMaskIntoConstraints = false
tv.layer.masksToBounds = true
return tv
}()
var segmentedController: UISegmentedControl!
override func viewDidLoad() {
super.viewDidLoad()
activeViewController = firstViewController
checkIfUserIsLoggedIn()
view.addSubview(contentView)
setupProfileScreen()
let items = ["Travelers", "Me"]
segmentedController = UISegmentedControl(items: items)
navigationItem.titleView = segmentedController
segmentedController.tintColor = UIColor.black
segmentedController.selectedSegmentIndex = 0
// Add function to handle Value Changed events
segmentedController.addTarget(self, action: #selector(HomeController.segmentedValueChanged(_:)), for: .valueChanged)
navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Sign Out", style: .plain, target: self, action: #selector(handleSignOut))
navigationItem.leftBarButtonItem?.tintColor = UIColor.black
}
// reference to collectionViewController
var travelersFeedVC: TravelersFeedVC!
func segmentedValueChanged(_ sender:UISegmentedControl!)
{
switch segmentedController.selectedSegmentIndex {
case 0:
activeViewController = firstViewController
case 1:
activeViewController = secondViewController
default: // Do nothing
break
}
}
// secondViewcontroller in containerView where modal is presented from
class ProfileVC: UIViewController {
// button to present modal
lazy var placesButton: UIButton = {
let customButton = UIButton(type: .system)
customButton.backgroundColor = UIColor.clear
// customButton.frame = CGRect(x: 150, y: 50, width: 120, height: self.view.frame.height)
customButton.setTitle("## of Places", for: .normal)
customButton.titleLabel?.font = UIFont.boldSystemFont(ofSize: 16)
customButton.setTitleColor(.white, for: .normal)
customButton.addTarget(self, action: #selector(handleShowPlacesVC), for: .touchUpInside)
return customButton
}()
// function to call to present modal
func handleShowPlacesVC() {
let placesVC = PlacesTableVC()
let navigationController = UINavigationController(rootViewController: placesVC)
present(navigationController, animated: true, completion: nil)
}
// modal view to dismiss
override func viewDidLoad() {
super.viewDidLoad()
navigationItem.leftBarButtonItem = UIBarButtonItem(title: "back", style: .plain, target: self, action: #selector(handleCancel))
}
// dismiss modal view to return to secondViewController in childViewController containerView
func handleCancel() {
dismiss(animated: true, completion: nil)
}
When closing the modal dialog the viewDidAppear function in MainNavigationController is called. There you set a new homeController with it's childs. This will trigger a viewDidload in the HomeController with setting of firstViewController. Try to set a breakpoint there and you will see it.
I suggest to avoid content creation in viewDidAppear, use viewDidLoad instead.
Another hint: 'dismiss' is defined as: 'Dismisses the view controller that was presented modally by the view controller.' - If you open for instance an alert above your modal vc it closes the alert, not the modal view (self). A correct implementation has to call dismiss on the presenting controller (same controller that opened it): "presentingViewController?.dismiss()"
It works in your code because apple has implemented a fallback for the case that nothing is presented, but it's a trap that cause some headache sometime.
The chances are that although you're calling present from the child view controller, it isn't in fact handling the presentation. From the Apple docs:
The object on which you call this method may not always be the one that handles the presentation. Each presentation style has different rules governing its behavior. For example, a full-screen presentation must be made by a view controller that itself covers the entire screen. If the current view controller is unable to fulfill a request, it forwards the request up the view controller hierarchy to its nearest parent, which can then handle or forward the request.
Since you're keeping a reference of the active view controller, one solution may be to explicitly set the index upon dismissal.
I am trying to implement a push/show segue from a UITableViewController that is presented modally. I am able to perform a push segue from a row in the tableview, but it is delayed. I know it has something to do with the navigation hierarchy stack, and I have tried many things like resetting the rootViewController but am not having any luck...thanks for any help!
// present place tableViewController ---> modally
func handleShowPlacesVC() {
let vc = PlacesTableVC()
let navigationController = UINavigationController(rootViewController: vc)
present(navigationController, animated: true, completion: nil)
}
// show details tableViewController ---> push segue from tableview
func handleShowCurrentUserPlaceDetailsVC() {
let vc = CurrentUserPlaceDetailsVC()
navigationController?.pushViewController(vc, animated: true)
}