I downloaded template for viper module and it has no link on view, how do I use navigation here?
Scene Delegate
let startModule = CardsCollectionRouter.createModule()
let navigationController = UINavigationController(rootViewController: startModule)
window?.rootViewController = navigationController
window?.makeKeyAndVisible()
Router
class CardsCollectionRouter: PresenterToRouterCardsCollectionProtocol {
// MARK: Static methods
static func createModule() -> UIViewController {
let viewController = CardsCollectionViewController()
let presenter: ViewToPresenterCardsCollectionProtocol & InteractorToPresenterCardsCollectionProtocol = CardsCollectionPresenter()
let networkService = NetworkService()
viewController.presenter = presenter
viewController.presenter?.router = CardsCollectionRouter()
viewController.presenter?.view = viewController
viewController.presenter?.interactor = CardsCollectionInteractor(networkService: networkService)
viewController.presenter?.interactor?.presenter = presenter
return viewController
}
func showDescription(description: CharacterModel?) {
let descriptionVC = DescripModuleRouter.createModule(description: description)
//How to go on next screen??
let viewController = CardsCollectionViewController()
viewController.navigationController?.pushViewController(descriptionVC, animated: true)
}
}
may be I have an easy way to get a link to the view?
like view.goToAnotherScreen from router and I will have this method on my ViewController
You shouldn't have to create navigation methods outside your router when using this pattern, as navigation is the router's responsibility. You can create router.goToAnotherScreen and call it from your view controller. When creating the router, you should pass the view controller to the router and inside your router you should call viewController.navigationController?.push...
class CardsCollectionRouter: PresenterToRouterCardsCollectionProtocol {
// MARK: Dependencies
private weak var viewController: UIViewController!
// MARK: Initialization
init(viewController: UIViewController) {
self.viewController = viewController
}
// MARK: Static methods
static func createModule() -> UIViewController {
let viewController = CardsCollectionViewController()
let presenter = CardsCollectionPresenter()
let networkService = NetworkService()
viewController.presenter = presenter
viewController.presenter?.router = CardsCollectionRouter(viewController: viewController)
viewController.presenter?.view = viewController
viewController.presenter?.interactor = CardsCollectionInteractor(networkService: networkService)
viewController.presenter?.interactor?.presenter = presenter
return viewController
}
func showDescription(description: CharacterModel?) {
let descriptionVC = DescripModuleRouter.createModule(description: description)
//How to go on next screen: Use your VC instance, which is the one your VIPER scene is controlling
self.viewController.navigationController?.pushViewController(descriptionVC, animated: true)
}
}
Related
Brief :
I have implemented Soroush's Coordinators architecture. Everything works fine except the removing part which is needed to remove previous(child) coordinators.
Scenario :
I have two ViewController named HomeViewController and MyGroupsViewController. Each has its own coordinator named HomeCoordinator and MyGroupsCoordinator respectively.
User taps a button on HomeViewController which triggers gotoMyGroupsTapped function and gets the user to MyGroupsViewController, Then the user taps on another button on MyGroupsViewController which get the user back to HomeViewController by triggering gotoHomePage().
Pretty simple! : HomeVC -> MyGroupsVC -> HomeVC
But the Problem is :
navigationController.transitionCoordinator? is nil in func navigationController(..., didShow viewController: UIViewController...) in both coordinators and I can not remove child coordinators in each transition.
Is it correct to set navigationController.delegate = self in start() func of both coordinators?
Should I use navigationController?.popViewController(animated: false ) in my backToHomePage() func? because Paul Hudson has only used pushViewController.
My Codes [Simplified Versions]:
HomeCoordinator.swift
import Foundation
import UIKit
class HomeCoordinator: NSObject,Coordinator,UINavigationControllerDelegate {
var childCoordinators = [Coordinator]()
var navigationController: UINavigationController
weak var parentCoordinator : Coordinator?
init(navigationController: UINavigationController) {
self.navigationController = navigationController
}
func navigationController(_ navigationController: UINavigationController, didShow viewController: UIViewController, animated: Bool) {
// Transition here is nil
print(" Transition : ",navigationController.transitionCoordinator)
guard let fromViewController = navigationController.transitionCoordinator?.viewController(forKey: .from) else {
print("Unknown fromViewController!")
return
}
// Removing a child coordinator
}
func gotoMyGroups (){
let groupsCoordinator = GroupsCoordinator(navigationController: navigationController)
childCoordinators.append(groupsCoordinator)
groupsCoordinator.parentCoordinator = self
groupsCoordinator.start()
}
func start() {
let vc = HomeViewController.instantiate()
vc.coordinator = self
navigationController.delegate = self
navigationController.pushViewController(vc, animated: false)
navigationController.setNavigationBarHidden(true, animated: false)
}
}
MyGroupsCoordinator.swift
import Foundation
import UIKit
class MyGroupsCoordinator: NSObject,Coordinator,UINavigationControllerDelegate {
var childCoordinators = [Coordinator]()
var navigationController: UINavigationController
weak var parentCoordinator : Coordinator?
init(navigationController: UINavigationController) {
self.navigationController = navigationController
}
func navigationController(_ navigationController: UINavigationController, didShow viewController: UIViewController, animated: Bool) {
// Transition here is nil
print(" Transition : ",navigationController.transitionCoordinator)
guard let fromViewController = navigationController.transitionCoordinator?.viewController(forKey: .from) else {
print("Unknown fromViewController!")
return
}
// Removing a child coordinator
}
func start() {
let vc = MyGroupViewController.instantiate()
vc.coordinator = self
navigationController.delegate = self
navigationController.pushViewController(vc, animated: false)
navigationController.setNavigationBarHidden(true, animated: false)
}
}
MyGroupViewController.magik
class MyGroupViewController : UIViewControllerWithCoordinator,UITextFieldDelegate,Storyboarded{
#IBAction func gotoHomePage(_ sender: Any) {
if let coord = coordinator as? GroupsCoordinator {
coord.parentCoordinator?.start()
}
}
}
HomeViewController.swift
class HomeViewController: UIViewControllerWithCoordinator,Storyboarded {
#IBAction func gotoMyGroupsTapped(_ sender: Any) {
guard let acoordinator = coordinator as? HomeCoordinator else {
return
}
acoordinator.gotoMyGroups()
}
It looks to me there is a confusion around Coordinator pattern usage here.
From your expected flow HomeVC -> MyGroupsVC -> HomeVC, if you mean in the sense level1 -> level2 -> level3, then GroupsCoordinator should create a new HomeCoordinator instance with its own new HomeVC.
So instead of your previous code
class MyGroupViewController ... {
#IBAction func gotoHomePage(_ sender: Any) {
if let coord = coordinator as? GroupsCoordinator {
coord.parentCoordinator?.start()
}
}
}
I would change it to
class MyGroupViewController ... {
#IBAction func gotoHomePage(_ sender: Any) {
if let coord = coordinator as? GroupsCoordinator {
coord.goToHome()
}
}
}
class MyGroupsCoordinator ... {
func goToHome() {
let homeCoordinator = HomeCoordinator(navigationController: navigationController)
childCoordinators.append(homeCoordinator)
groupsCoordinator.parentCoordinator = self
groupsCoordinator.start()
}
}
This will allow you to create a brand new page as you describe there HomeVC -> MyGroupsVC -> HomeVC.
However, if you meant in this approach level1 -> level2 -> (back) level1, then you'll need to terminate MyGroupsCoordinator and remove from the parent while navigating back.
As you noticed, to do so, you'll need to use UINavigationControllerDelegate to be able to be notified when the user navigate back (either pop in code, or with classic back button).
One solution I found is to use a Router to handle all this navigation when a UIViewController is removed from it to also notify via closures the right coordinator to be removed. You can read more about it here.
Hope it helps
In the project shown below there is an InitialViewController that has a single button labeled "Show Popover". When that button is tapped the app is supposed to present the second view controller (PopoverViewController) as a popover. The second view controller just has a label saying "Popover!".
This works fine if the InitialViewController takes care of instantiating PopoverViewController, retrieving the popoverPresentationController and then setting the popoverPresentationController's delegate to itself (to InitialViewController). You can see the result, below:
For maximum reusability, however, it would be great if the InitialViewController did not need to know anything about how the presentation controller is delegated. I think it should be possible for the PopoverViewController to set itself as the popoverPresentationController's delegate. I've tried this in either the viewDidLoad or the viewWillAppear functions of the PopoverViewController. However, the PopoverViewController is presented modally in both cases, as shown below:
All the code is contained in just the InitialViewController and the PopoverViewController. The code used in the failing version of the InitialViewController is shown below:
import UIKit
// MARK: - UIViewController subclass
class InitialViewController: UIViewController {
struct Lets {
static let storyboardName = "Main"
static let popoverStoryboardID = "Popover View Controller"
}
#IBAction func showPopoverButton(_ sender: UIButton) {
// instantiate & present the popover view controller
let storyboard = UIStoryboard(name: Lets.storyboardName,
bundle: nil )
let popoverViewController =
storyboard.instantiateViewController(withIdentifier: Lets.popoverStoryboardID )
popoverViewController.modalPresentationStyle = .popover
guard let popoverPresenter = popoverViewController.popoverPresentationController
else {
fatalError( "could not retrieve a pointer to the 'popoverPresentationController' property of popoverViewController")
}
present(popoverViewController,
animated: true,
completion: nil )
// Retrieve and configure UIPopoverPresentationController
// after presentation (per
// https://developer.apple.com/documentation/uikit/uipopoverpresentationcontroller)
popoverPresenter.permittedArrowDirections = .any
let button = sender
popoverPresenter.sourceView = button
popoverPresenter.sourceRect = button.bounds
}
}
The code in the failing PopoverViewController is shown below:
import UIKit
// MARK: - main UIViewController subclass
class PopoverViewController: UIViewController {
// MARK: API
var factorForMarginsAroundButton: CGFloat = 1.2
// MARK: outlets and actions
#IBOutlet weak var popoverLabel: UILabel!
// MARK: lifecycle
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear( animated )
// set the preferred size for popover presentations
let labelSize =
popoverLabel.systemLayoutSizeFitting( UILayoutFittingCompressedSize )
let labelWithMargins =
CGSize(width: labelSize.width * factorForMarginsAroundButton,
height: labelSize.height * factorForMarginsAroundButton )
preferredContentSize = labelWithMargins
// set the delegate for the popoverPresentationController to self
popoverPresentationController?.delegate = self
}
}
// MARK: - UIPopoverPresentationControllerDelegate
// (inherits from protocol UIAdaptivePresentationControllerDelegate)
extension PopoverViewController: UIPopoverPresentationControllerDelegate
{
func adaptivePresentationStyle(for controller: UIPresentationController,
traitCollection: UITraitCollection)
-> UIModalPresentationStyle{
return .none
}
}
Is it possible for a view controller that is being presented as a popover to be the delegate for its own popoverPresentationController?
I'm using Xcode 8.0, Swift 3.1 and the target is iOS 10.0
It's certainly possible. You're dealing with a timing issue. You need to set the delegate before viewWillAppear. Unfortunately, there is no convenient view lifecycle function to insert the assignment into, so I did this instead.
In your PopoverViewController class, assign the delegate in an overriden getter. You can make the assignment conditional if you'd like. This creates a permanent relationship, so other code code never "override" the delegate by assigning it.
override var popoverPresentationController: UIPopoverPresentationController? {
get {
let ppc = super.popoverPresentationController
ppc?.delegate = self
return ppc
}
}
As #allenh has correctly observed, you need to set the delgate before viewWillAppear, and he has offered a clever solution by setting the delegate by overriding the popoverPresentationController getter.
You could also set the delegate to the popover itself in your showPopover() function between setting modalPresentationStyle and presenting the popover:
let vc = storyboard.instantiateViewController(withIdentifier: Lets.popoverStoryboardID )
vc.modalPresentationStyle = .popover
vc.popoverPresentationController?.delegate = vc
present(vc, animated: true, completion: nil)
I've wrote a label extension which detect links in the label.
It's attributed text with NSLinkAttributeName for links and I'm using
func handleTapOnLabel(_ tapGesture:UITapGestureRecognizer){} to detect where is the tap and which link to choose to open. The problem is that I use the function in extension for UILabel and I want to present an UIAlertController to ask the person - "You are about to open this link in Safari. Would you like to proceed?"... So I can't access viewcontroller to use the function present(UIAlertController... to display the alert. Any suggestions how this can be happened in extension? How to access label's viewcontroller directly from extension ?
Method 1) Present UIAlertController on top most ViewController in ViewController's hierarchy
extension UILabel { //your extension
func openLinkAction() { //your extension custom method
//code
if var topController = UIApplication.sharedApplication().keyWindow?.rootViewController {
while let presentedViewController = topController.presentedViewController {
topController = presentedViewController
}
}
// topController should now be your topmost view controller
// present alert on this controller
}
//and present here with vcInstance
}
}
Method 2) Pass ViewController's object as parameter
extension UILabel { //your extension
func openLink(vc: UIViewController) { //your extension custom method function
// code
// present alert on this vc
}
}
// For getting top most controller you ca use..
extension UIApplication {
class func topViewController(controller: UIViewController? = UIApplication.shared.keyWindow?.rootViewController) -> UIViewController? {
if let navigationController = controller as? UINavigationController {
return topViewController(controller: navigationController.visibleViewController)
}
if let tabController = controller as? UITabBarController {
if let selected = tabController.selectedViewController {
return topViewController(controller: selected)
}
}
if let presented = controller?.presentedViewController {
return topViewController(controller: presented)
}
return controller
}
}
// topController
if let topController = UIApplication.topViewController() {
}
I'm trying to realize the Observer Pattern and I'm experiencing some difficulty as my delegate doesn't seem to be setting properly.
In my Main.storyboard I have a ViewController with a container view. I also have an input box where I'm capturing numbers from a number keypad.
Here's my storyboard:
I'm trying to implement my own Observer Pattern using a protocol that looks like this:
protocol PropertyObserverDelegate {
func willChangePropertyValue(newPropertyValue:Int)
func didChangePropertyValue(oldPropertyValue:Int)
}
My main ViewController.swift
class ViewController: UIViewController {
#IBOutlet weak var numberField: UITextField!
// observer placeholder to be initialized in implementing controller
var observer : PropertyObserverDelegate?
var enteredNumber: Int = 0 {
willSet(newValue) {
print("//Two: willSet \(observer)") // nil !
observer?.willChangePropertyValue(5) // hard coded value for testing
}
didSet {
print("//Three: didSet")
observer?.didChangePropertyValue(5) // hard coded value for testing
}
}
#IBAction func numbersEntered(sender: UITextField) {
guard let inputString = numberField.text else {
return
}
guard let number : Int = Int(inputString) else {
return
}
print("//One: \(number)")
self.enteredNumber = number // fires my property observer
}
}
My ObservingViewController:
class ObservingViewController: UIViewController, PropertyObserverDelegate {
// never fires!
func willChangePropertyValue(newPropertyValue: Int) {
print("//four")
print(newPropertyValue)
}
// never fires!
func didChangePropertyValue(oldPropertyValue: Int) {
print("//five")
print(oldPropertyValue)
}
override func viewDidLoad() {
super.viewDidLoad()
print("view loads")
// attempting to set my delegate
let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let pvc = mainStoryboard.instantiateViewControllerWithIdentifier("ViewController") as! ViewController
print("//six \(pvc)")
pvc.observer = self
}
}
Here's what my console prints:
What's happening
As you can see when my willSet fires, my observer is nil which indicates that I have failed to set my delegate in my ObservingViewController. I thought I set my delegate using these lines:
let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let pvc = mainStoryboard.instantiateViewControllerWithIdentifier("ViewController") as! ViewController
print("//six \(pvc)")
pvc.observer = self
However, I must be setting my delegate incorrectly if it's coming back nil.
Question
How do I properly set my delegate?
You are calling into the storyboard to instantiate a view controller and setting it as the observer, however that instantiates a new instance of that view controller, it doesn't mean that it is referencing the one single "view controller" that is in the storyboard. ObservingViewController needs another way to reference the ViewController that has already been created.
So #Chris did reenforce my suspicions which helped me to figure out a solution for assigning my delegate to my view controller properly.
In my ObservingViewController I just need to replace the code in my viewDidLoad with the following:
override func viewDidLoad() {
let app = UIApplication.sharedApplication().delegate as! AppDelegate
let vc = app.window?.rootViewController as! ViewController
vc.observer = self
}
Rather than creating a new instance of my view controller, I'm now getting my actual view controller.
I want to implement a separate ErrorHandler class, which displays error messages on certain events. The behavior of this class should be called from different other classes.
When an error occurs, it will have an UIAlertView as output.
The display of this AlertView should ALWAYS be on top. So no matter from where the Error gets thrown, the topmost viewController should display the AlertMessage (e.g. when an asynchronous background process fails, I want an error message, no matter what View is displayed in the foreground).
I have found several gists which seem to solve my problem (see the code below).
But calling UIApplication.sharedApplication().keyWindow?.visibleViewController() does return a nil-value.
Extension from gist
extension UIWindow {
func visibleViewController() -> UIViewController? {
if let rootViewController: UIViewController = self.rootViewController {
return UIWindow.getVisibleViewControllerFrom(rootViewController)
}
return nil
}
class func getVisibleViewControllerFrom(vc:UIViewController) -> UIViewController {
if vc.isKindOfClass(UINavigationController.self) {
let navigationController = vc as! UINavigationController
return UIWindow.getVisibleViewControllerFrom( navigationController.visibleViewController)
} else if vc.isKindOfClass(UITabBarController.self) {
let tabBarController = vc as! UITabBarController
return UIWindow.getVisibleViewControllerFrom(tabBarController.selectedViewController!)
} else {
if let presentedViewController = vc.presentedViewController {
return UIWindow.getVisibleViewControllerFrom(presentedViewController.presentedViewController!)
} else {
return vc;
}
}
}
}
Amit89 brought a way to a solution up. You have to call the .windowproperty of the AppDelegate.
So I changed the Swift code from the link below to work as intended to find the topmost ViewController. Make sure, that the view is already in the view hierarchy. So this method cannot be called from a .viewDidLoad
Extension to find the topmost ViewController*
extension UIApplication {
class func topViewController(base: UIViewController? = (UIApplication.sharedApplication().delegate as! AppDelegate).window?.rootViewController) -> UIViewController? {
if let nav = base as? UINavigationController {
return topViewController(base: nav.visibleViewController)
}
if let tab = base as? UITabBarController {
if let selected = tab.selectedViewController {
return topViewController(base: selected)
}
}
if let presented = base?.presentedViewController {
return topViewController(base: presented)
}
return base
}
}
This code originated from GitHub user Yonat in a comment to an objectiveC equivalent. I only changed the bits of code to get it to work without the .keyWindow property
Did you try this from the same link?
let appDelegate = UIApplication.sharedApplication().delegate as! MYAppDelegate//Your app delegate class name.
extension UIApplication {
class func topViewController(base: UIViewController? = appDelegate.window!.rootViewController) -> UIViewController? {
if let nav = base as? UINavigationController {
return topViewController(base: nav.visibleViewController)
}
if let tab = base as? UITabBarController {
if let selected = tab.selectedViewController {
return topViewController(base: selected)
}
}
if let presented = base?.presentedViewController {
return topViewController(base: presented)
}
return base
}
}