in this case
class ModalManager {
static var parentController: UIViewController?
static weak var initialController: UIViewController?
class func present(_ controller: UIViewController) {
guard let parent = parentController else {
return
}
guard initialController == nil else {
fatalError("initialController not nil")
}
initialController = controller
parent.present(controller, animated: false)
}
}
in some cases, the line initialController = controller gets executed before the guard with fatalError and then the app crashes in the guard initialController == nil .
why would it not be called in order written in some cases?
snippet on how the func is called:
ModalManager.parentController = parentController
ModalManager.present(modalVC)
Related
I want to trigger an action on button tap with my callback. Also I have presenter and coordinator. But nothing happenes. My code is not working in this closure:
startViewController.output = { [weak self] action in
switch action {
case .registrationButtonTapped:
self?.showRegistrationViewController()
case .loginButtonTapped:
self?.showLoginViewController()
}
}
In my ViewController I have enum:
enum StartViewControllerButton {
case registrationButtonTapped
case loginButtonTapped
}
callback:
var output: ((StartViewControllerButton) -> Void)?
and selectors:
#objc func registrationButtonPressed() {
startModulPresenter.openNextScreen()
self.output?(.registrationButtonTapped)
}
#objc func loginButtonPressed() {
startModulPresenter.openNextScreen()
self.output?(.loginButtonTapped)
}
My Presenter
class StartModulPresenter: StartModulPresenterProtocol {
var navigationController: UINavigationController
var coordinator: CoordinatorProtocol?
//Init
init(navigationController: UINavigationController) {
self.navigationController = navigationController
coordinator = AuthorizationCoordinator(navigationController: navigationController)
}
//Functions
func openNextScreen() {
coordinator?.start()
}
}
My Coordinator:
class AuthorizationCoordinator: RegistrationCoordinatorProtocol {
var presenter: PresenterProtocol?
var navigationController: UINavigationController
var childCoordinators: [CoordinatorProtocol] = []
//Init
init(navigationController: UINavigationController) {
self.navigationController = navigationController
}
func start() {
presenter = StartModulPresenter(navigationController: navigationController)
let startViewController = StartViewController(startModulPresenter: presenter as! StartModulPresenter)
startViewController.output = { [weak self] action in
switch action {
case .registrationButtonTapped:
self?.showRegistrationViewController()
case .loginButtonTapped:
self?.showLoginViewController()
}
}
}
private func showRegistrationViewController() {
let registrationViewController = RegistrationViewController()
registrationViewController.view.backgroundColor = .orange
self.navigationController.pushViewController(registrationViewController, animated: true)
}
private func showLoginViewController() {
let loginViewController = LoginViewController()
loginViewController.view.backgroundColor = .orange
self.navigationController.pushViewController(loginViewController, animated: true)
}
}
Could you check if startViewController is pushed/presented or not?
func start() {
presenter = StartModulPresenter(navigationController: navigationController)
let startViewController = StartViewController(startModulPresenter: presenter as! StartModulPresenter)
startViewController.output = { [weak self] action in
switch action {
case .registrationButtonTapped:
self?.showRegistrationViewController()
case .loginButtonTapped:
self?.showLoginViewController()
}
}
}
And, is self.output is nil or not? If it is nil please check your assignment call, it needed to be called before you use this variable.
#objc func loginButtonPressed() {
startModulPresenter.openNextScreen()
self.output?(.loginButtonTapped)
}
Honestly, I don't recommend you to use this design pattern, just a simple thing but the real result is too complicated.
Just use protocol-based MVC. View communicate with Controller via protocol/closure or Reactive-based with Combine (PassthroughSubject/CurrentValueSubject)
I am working on a project with 3 views that are accessed by swiping.
The following code implements the PageViewController I am using to handle the swiping motion:
import UIKit
class PageViewController: UIPageViewController, UIPageViewControllerDelegate, UIPageViewControllerDataSource {
lazy var orderedViewControllers : [UIViewController] = {
return [self.newVC(viewController : "ClimaVC"),
self.newVC(viewController : "WeatherVC"),
self.newVC(viewController : "ClosetVC")]
}()
var myViewControllers = [UIViewController]()
var currentIndex : Int = 0
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
self.dataSource = self
setViewControllers([orderedViewControllers[1]],
direction: .forward, animated: true, completion: nil)
self.delegate = self
}
func newVC(viewController : String) -> UIViewController {
return UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: viewController)
}
func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
guard let viewControllerIndex = orderedViewControllers.index(of: viewController) else {
return nil
}
let previousIndex = viewControllerIndex - 1;
guard previousIndex >= 0 else {
// return orderedViewControllers.last
//Return nil to avoid swiping forever.
return nil
}
guard orderedViewControllers.count > previousIndex else {
return nil
}
currentIndex = previousIndex
return orderedViewControllers[previousIndex]
}
func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
guard let viewControllerIndex = orderedViewControllers.index(of: viewController) else {
return nil
}
let nextIndex = viewControllerIndex + 1;
guard orderedViewControllers.count != nextIndex else {
//return orderedViewControllers.first
//Return nil to avoid swiping forever.
return nil
}
guard orderedViewControllers.count > nextIndex else {
return nil
}
return orderedViewControllers[nextIndex]
}
}
The main View Controller is WeatherVC. In this view, time data is retrieved and stored in an integer variable named timeOfDay.
Depending on the value of timeOfDay, the background displayed will differ. While I was able to use this variable in WeatherVC, I need to pass this variable timeOfDay to the two other view controllers ClimaVC and ClosetVC.
I tried setting up a delegate protocol but failed, explored using the different functions provided by UIPageViewControllerDelegate and it did not get me anywhere.
I would really appreciate some help on this,
Thank you very much!
It's not complicated, just assign the values at the pageviewcontroller datasources.
import UIKit
class ClimaViewController: UIViewController{
var timeOfDayClima: Int = 0
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
print (timeOfDayClima)
}
}
class WeatherViewController: UIViewController{
var timeOfDayClima: Int = 0
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
timeOfDayClima += 1
}
}
class ClosetViewController: UIViewController{
var timeOfDayClima: Int = 0
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
print (timeOfDayClima)
}
}
class PageViewController: UIPageViewController, UIPageViewControllerDelegate, UIPageViewControllerDataSource {
lazy var orderedViewControllers : [UIViewController] = {
return [self.newVC(viewController : "ClimaVC"),
self.newVC(viewController : "WeatherVC"),
self.newVC(viewController : "ClosetVC")]
}()
var myViewControllers = [UIViewController]()
var currentIndex : Int = 0
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
self.dataSource = self
setViewControllers([orderedViewControllers[1]],
direction: .forward, animated: true, completion: nil)
self.delegate = self
}
func newVC(viewController : String) -> UIViewController {
return UIStoryboard(name: "Second", bundle: nil).instantiateViewController(withIdentifier: viewController)
}
func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
//Guard = some kind of if statement.
guard let viewControllerIndex = orderedViewControllers.index(of: viewController) else {
return nil
}
let previousIndex = viewControllerIndex - 1;
guard previousIndex >= 0 else {
// return orderedViewControllers.last
//Return nil to avoid swiping forever.
return nil
}
guard orderedViewControllers.count > previousIndex else {
return nil
}
currentIndex = previousIndex
if(currentIndex == 0) {
(orderedViewControllers.first as! ClimaViewController).timeOfDayClima = (orderedViewControllers[1] as! WeatherViewController).timeOfDayClima
}
return orderedViewControllers[previousIndex]
}
func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
//Guard = some kind of if statement.
guard let viewControllerIndex = orderedViewControllers.index(of: viewController)
else {
return nil
}
let nextIndex = viewControllerIndex + 1;
guard orderedViewControllers.count != nextIndex else {
//return orderedViewControllers.first
//Return nil to avoid swiping forever.
return nil
}
guard orderedViewControllers.count > nextIndex else {
return nil
}
currentIndex = nextIndex
if(currentIndex == orderedViewControllers.count - 1) {
(orderedViewControllers.last as! ClosetViewController).timeOfDayClima = (orderedViewControllers[1] as! WeatherViewController).timeOfDayClima
}
if(nextIndex == 0) {
let secondVC = self.storyboard?.instantiateViewController(withIdentifier: "ClimaVC") as! ClimaViewController
secondVC.timeOfDayClima = 1
}
return orderedViewControllers[nextIndex]
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
Maybe you should try explaining what has failed in setting up your delegate protocol as well because it seems like it is likely the solution you are looking for. I'm writing a protocol here for reference but you have to change it according to your needs.
protocol WeatherVCDelegate {
func changedTime(timeOfDay: Int)
}
Here comes the tricky part. When you declare a delegate in WeatherVC, you need to use the delegate to call the function to relay the timeOfDay to other weatherVC. How this works is that anything that conforms to the delegate protocol will be triggered to use the function.
class WeatherVC {
weak var delegate: WeatherVCDelegate?
func functionName() {
delegate?.changedTime(timeOfDay: value)
}
Now, when you initialize weatherVC in your PageViewController, you need PageViewController to conform to weatherVC delegate.
In PageViewController...
weatherVC.delegate = self
extension PageViewController: WeatherVCDelegate {
...
}
Here is more read up about delegates if my answer is not clear enough
https://medium.com/#jamesrochabrun/implementing-delegates-in-swift-step-by-step-d3211cbac3ef
I have a pageViewController with 3 viewControllers which is embedded in a view of a viewcontroller.
i am setting the view controllers programatically:
lazy var vcArr: [UIViewController] = {
return [self.vcInstance(name: "vc1"),
self.vcInstance(name: "vc2"),
self.vcInstance(name: "vc3"),
]
}()
i am programatically setting the number of pages to 4
let pageController = UIPageControl.appearance()
pageController.numberOfPages = 4
what i want to happen is that if the user tries to swipe right from the 3rd page it will segue to a signup viewController.
I'm currently trying to achieve this in the viewcontroller after function testing for it the next item is greater than or equal to the total count.
public func pageViewController(_ pageViewController: UIPageViewController,
viewControllerAfter viewController: UIViewController) -> UIViewController? {
guard let viewControllerIndex = vcArr.index(of: viewController) else {
return nil
}
let nextIndex = viewControllerIndex + 1
if nextIndex >= vcArr.count {
infoClick()
return nil
} else {
guard nextIndex < vcArr.count else {
return self.vcArr.last
}
guard self.vcArr.count > nextIndex else {
return nil
}
return self.vcArr[nextIndex]
}
}
with this test the way it is sometimes it stops on page 3 and then when swiped right it will segue off with my function infoClick(). however somethings it goes right off when it hits the 3rd page as you would think because its > or = the number of pages which is 3.
when i change this to just > it doesn't display anything on the third page.
I've searched heaps for a way around this but to no avail. does anyone have any ideas how to achieve this?
attaching entire class below:
import UIKit
import Parse
class pageViewController: UIPageViewController, UIPageViewControllerDelegate, UIPageViewControllerDataSource {
#IBOutlet var createAccountBarButton: UIBarButtonItem!
lazy var vcArr: [UIViewController] = {
return [self.vcInstance(name: "vc1"),
self.vcInstance(name: "vc2"),
self.vcInstance(name: "vc3"),
]
}()
override var supportedInterfaceOrientations: UIInterfaceOrientationMask {
return .portrait
}
//---------------------------------------------- autoLogin
/// temporary location, needs to be launched during the loading screen
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(true)
// if (PFUser.current() != nil) {
// let vc = self.storyboard!.instantiateViewController(withIdentifier: "PackViewController")
// self.present(vc, animated: true, completion: nil)
// if (PFUser.current() != nil) {
// let tbc = self.storyboard!.instantiateViewController(withIdentifier: "MyTabController") as! UITabBarController
// tbc.selectedIndex = 1
// self.present(tbc, animated: true, completion: nil)
// }
}
//---------------------------------------------- set the viewcontrollwe instance
private func vcInstance(name: String) -> UIViewController {
return UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: name)
}
//---------------------------------------------- set the direction and first page of the page controller
override func viewDidLoad() {
super.viewDidLoad()
self.tabBarController?.tabBar.isHidden = true
let pageController = UIPageControl.appearance()
pageController.pageIndicatorTintColor = UIColor.lightGray
pageController.currentPageIndicatorTintColor = GeneralFunctions.UIColorFromHEX(hexValue: 0xbb0d2a)
pageController.backgroundColor = UIColor.clear
pageController.bounds = CGRect(x: 0, y: 0, width: 0, height: 0)
pageController.numberOfPages = 4
//GeneralFunctions.commonButtonSettings(buttonName: signUpButton, hexValue: 0x0c1537)
self.dataSource = self
self.dataSource = self
if let firstVC = vcArr.first {
setViewControllers([firstVC], direction: .forward, animated: true, completion: nil)
}
}
//---------------------------------------------- page view controller before settings
public func pageViewController(_ pageViewController: UIPageViewController,
viewControllerBefore viewController: UIViewController) -> UIViewController? {
guard let viewControllerIndex = vcArr.index(of: viewController) else {
return nil
}
let previousIndex = viewControllerIndex - 1
if previousIndex < 0 {
return nil
} else {
guard previousIndex >= 0 else {
return self.vcArr.last
}
guard self.vcArr.count > previousIndex else {
return nil
}
return self.vcArr[previousIndex]
}
}
//---------------------------------------------- page view controller after settings
public func pageViewController(_ pageViewController: UIPageViewController,
viewControllerAfter viewController: UIViewController) -> UIViewController? {
guard let viewControllerIndex = vcArr.index(of: viewController) else {
return nil
}
let nextIndex = viewControllerIndex + 1
if nextIndex >= vcArr.count {
infoClick()
return nil
} else {
guard nextIndex < vcArr.count else {
return self.vcArr.last
}
guard self.vcArr.count > nextIndex else {
return nil
}
return self.vcArr[nextIndex]
}
}
//---------------------------------------------- presentation count
public func presentationCount(for pageViewController: UIPageViewController) -> Int {
return self.vcArr.count
}
//---------------------------------------------- presentation index
public func presentationIndex(for pageViewController: UIPageViewController) -> Int {
guard let firstViewController = viewControllers?.first,
let firstViewControllerIndex = vcArr.index(of: firstViewController) else {
return 0
}
return firstViewControllerIndex
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
//---------------------------------------------- launch the new view controller - still launching before swipped to 4th window sometimes
// not sure if this is the best way to do this need to look at this a bit more
func infoClick() {
let storyboard: UIStoryboard = UIStoryboard (name: "Main", bundle: nil)
let vc: SignupViewController = storyboard.instantiateViewController(withIdentifier: "SignupViewController") as! SignupViewController
let currentController = getCurrentViewController()
currentController?.present(vc, animated: false, completion: nil)
}
func getCurrentViewController() -> UIViewController? {
if let rootController = UIApplication.shared.keyWindow?.rootViewController {
var currentController: UIViewController! = rootController
while( currentController.presentedViewController != nil ) {
currentController = currentController.presentedViewController
}
return currentController
}
return nil
}
}
I created a PageViewController and added three view controllers as a walkthrough for my app, but i want them to be displayed only once, and i can't figure out how.
here is my code for the pageViewController:
import UIKit
class MyPageViewController: UIPageViewController{
override func viewDidLoad() {
super.viewDidLoad()
dataSource = self
// Do any additional setup after loading the view.
if let firstViewController = orderedViewControllers.first {
setViewControllers([firstViewController],
direction: .Forward,
animated: true,
completion: nil)
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
//array for the ordered view controllers
private(set) lazy var orderedViewControllers: [UIViewController] = {
return [self.newColoredViewController("First"),
self.newColoredViewController("Second"),
self.newColoredViewController("Third")]
}()
private func newColoredViewController(color: String) -> UIViewController {
return UIStoryboard(name: "Main", bundle: nil) .
instantiateViewControllerWithIdentifier("\(color)ViewController")
}
}
extension MyPageViewController: UIPageViewControllerDataSource {
//returning index of previous view controller
func pageViewController(pageViewController: UIPageViewController,
viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
guard let viewControllerIndex = orderedViewControllers.indexOf(viewController) else {
return nil
}
let previousIndex = viewControllerIndex - 1
guard previousIndex >= 0 else {
return nil
}
guard orderedViewControllers.count > previousIndex else {
return nil
}
return orderedViewControllers[previousIndex]
}
//returning index of the next view controller
func pageViewController(pageViewController: UIPageViewController,
viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
guard let viewControllerIndex = orderedViewControllers.indexOf(viewController) else {
return nil
}
let nextIndex = viewControllerIndex + 1
let orderedViewControllersCount = orderedViewControllers.count
guard orderedViewControllersCount != nextIndex else {
return nil
}
guard orderedViewControllersCount > nextIndex else {
return nil
}
return orderedViewControllers[nextIndex]
}
}
how do i edit the code to display it only once?
From what you've said I'm guessing that you only want it to show the first time the user opens the app and then not appear again?
Theres a few ways of doing this, the simplest would likely be to set a property on NSUserDefaults, this will remember the setting in between app launches. try something like:
// this should be your initial view controller
let defaults = NSUserDefaults.standardUserDefaults()
override func viewDidLoad() {
super.viewDidLoad()
if !defaults.boolForKey("walkthroughSeen") {
// create page view controller and display
let walkthroughVC = UIStoryboard(name: "Main", bundle: nil).
instantiateViewControllerWithIdentifier("MyPageViewController")
self.presentViewController(walkthroughVC, animated: true)
defaults.setBool(true, forKey: "walkthroughSeen")
}
}
I recently set up a ContainerView with a PageViewController that cycles through views (images) as a sort of banner on top of a TableView that I have. Now, I'm having difficulty hooking that up to an NSTimer (so that it will cycle through the views/images automatically). Everything works, except for the timer piece that I've tried to hook up. I've tried to convert some Objective-C tutorials/SO questions but am still having difficulty.
I have looked at this: Set timer to UIPageViewController, but I can't get that provided code to work for me at all (nor any variation of it).
See below for my code:
class ImageSwapViewController: UIPageViewController {
private(set) lazy var orderedViewControllers: [UIViewController] = {
return [self.newColoredViewController("First"),
self.newColoredViewController("Second"),
self.newColoredViewController("Third")]
}()
private func newColoredViewController(order: String) -> UIViewController {
return UIStoryboard(name: "Main", bundle: nil) .
instantiateViewControllerWithIdentifier("\(order)ViewController")
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
self.dataSource = self
if let firstViewController = orderedViewControllers.first {
setViewControllers([firstViewController],
direction: .Forward,
animated: true,
completion: nil)
}
NSTimer.scheduledTimerWithTimeInterval(2, target: self, selector: #selector(ImageSwapViewController.animation), userInfo: nil, repeats: true)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func animation() {
[NEED HELP WITH WHAT GOES HERE]
}
}
extension ImageSwapViewController : UIPageViewControllerDataSource {
func pageViewController(pageViewController: UIPageViewController,
viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
guard let viewControllerIndex = orderedViewControllers.indexOf(viewController) else {
return nil
}
let previousIndex = viewControllerIndex - 1
guard previousIndex >= 0 else {
return orderedViewControllers.last
}
guard orderedViewControllers.count > previousIndex else {
return nil
}
return orderedViewControllers[previousIndex]
}
func pageViewController(pageViewController: UIPageViewController,
viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
guard let viewControllerIndex = orderedViewControllers.indexOf(viewController) else {
return nil
}
let nextIndex = viewControllerIndex + 1
let orderedViewControllersCount = orderedViewControllers.count
guard orderedViewControllersCount != nextIndex else {
return orderedViewControllers.first
}
guard orderedViewControllersCount > nextIndex else {
return nil
}
return orderedViewControllers[nextIndex]
}
}
Any help is greatly appreciated.
A couple of notes:
1) The general idea is that you need to set up a timer in some reasonable place--viewWillAppear is a common location, and remember to invalidate it when the view is no longer displaying (as in viewWillDisappear). Failing to do so may result in memory growth because the run loop holds a strong reference to the target--in this case, self. I'd recommend moving your NSTimer.scheduledTimer... invocation to viewWillAppear.
2) The animation code above is pretty simple. Basically, you need to get the current "page", find out what the next "page" should be, and then ask your UIPageViewController to display that next "page".
func animation() {
guard let currentViewController = viewControllers?.first else {
return
}
// Use delegate method to retrieve the next view controller
guard let nextViewController = pageViewController(self, viewControllerAfterViewController: currentViewController) else {
return
}
setViewControllers([nextViewController], direction: .Forward, animated: true, completion: nil)
}
You could also simplify your before and after methods slightly:
func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
guard let i = orderedViewControllers.indexOf(viewController) else {
return nil
}
let nextIndex = (i + 1) % AutoAnimatingPageViewController.colors.count
return orderedViewControllers[nextIndex]
}
func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
guard let i = orderedViewControllers.indexOf(viewController) else {
return nil
}
let prevIndex = (i - 1) < 0 ? AutoAnimatingPageViewController.colors.count - 1 : (i - 1)
return orderedViewControllers[prevIndex]
}