I am trying to pass data from a pop-up VC to the parent VC using reusable function to present the pop-up and get the result. I have tried using the closure method with a function variable in the pop-up, I get an error "UIViewController has no member 'onSave' (function variable). Any help would be appreciated. thx
I have used delegates and segues but would like to avoid so one function can be present the pop-up and collect the choices for many instances.
// Parent VC
class a2ExpenseAddViewController: UIViewController {
#IBAction func selectEtype(_ sender: Any) {
popTitle = "Expense Types"//global var
popMessage = "Select type below or add new" // global var
menuPopup(choices: eTypes){ result in guard let result = else{
return
}
self.eType.setTitle(result, for: .normal)
print("popChoice=",result)
}
}
extension UIViewController {
func menuPopup (choices: [String], completion: #escaping (_ choice: String?) -> ()) {
let main = UIStoryboard(name: "Main", bundle: nil)
let goto = main.instantiateViewController(withIdentifier: "popup")
popChoices = choices
// Error below here - UIViewController has no member 'onSave'
goto.onSave = { (data: String) -> () in
choice = data
}
self.present(goto, animated: true, completion: nil)
}
//Popup VC
PopupViewController: UIViewController,.. // storyboard id is 'popup'
var onSave: ((_ data: String) -> ())?
#IBAction func add(_ sender: Any) {
popChoice = choice.text!
onSave?(popChoice)
dismiss(animated: true) }
I expect to assign result via onSave(data) to a button title.
I get an error "UIViewController has no member 'onSave' (function variable).
Cast the ViewController to specific class type after instantiation.
let goto = main.instantiateViewController(withIdentifier: "popup") as? PopupViewController
Then you should be able to do this
goto.onSave = { (data: String) -> () in
choice = data
}
Related
I am trying to test whether the method ReloadData() is called by an instance of UITableView when it's dataSource is updated.
I've created a subclass of UITableView called MockTableView. It has a bool called reloadDataGotCalled which is set to true when the overridden function reloadData() is called. I then try access that property from within my test class to test whether it is true.
However when I try to do so the compiler gives me the message that "Value of type 'UITableView' has no member 'reloadDataGotCalled'"
I'm not sure why it's doing that, because as far as I can see I've set that value to be of the type 'MockTableView' which should have that member?
// A ViewController that contains a tableView outlet that I want to test.
class ItemListViewController: UIViewController {
let itemManager = ItemManager()
#IBOutlet var tableView: UITableView!
#IBOutlet var dataProvider: (UITableViewDataSource & UITableViewDelegate & ItemManagerSettable)!
#IBAction func addItem(_ sender: UIBarButtonItem) {
if let nextViewController = storyboard?.instantiateViewController(identifier: "InputViewController") as? InputViewController {
nextViewController.itemManager = itemManager
present(nextViewController, animated: true, completion: nil)
}
}
override func viewDidLoad() {
super.viewDidLoad()
tableView.dataSource = dataProvider
tableView.delegate = dataProvider
dataProvider.itemManager = itemManager
}
}
// My test class
class ItemListViewControllerTest: XCTestCase {
var sut: ItemListViewController!
override func setUp() {
//Given
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let viewController = storyboard.instantiateViewController(identifier: "ItemListViewController")
sut = (viewController as! ItemListViewController)
//When
sut.loadViewIfNeeded()
}
// The test where I'm trying to assign sut.tableView to mockTableView
func test_TableView_IsReloadedWhenItemAddedToItemManger() {
let mockTableView = MockTableView()
sut.tableView = mockTableView
let item = ToDoItem(title: "Foo")
sut.itemManager.add(item)
sut.beginAppearanceTransition(true, animated: true)
sut.endAppearanceTransition()
XCTAssertTrue(sut.tableView.reloadDataGotCalled) // <- this is where I'm getting the compiler message "Value of type 'UITableView' has no member 'reloadDataGotCalled'"
}
}
// My mockTableView subclass in an extension of the ItemListViewControllerTests
extension ItemListViewControllerTest {
class MockTableView: UITableView {
var reloadDataGotCalled = false
override func reloadData() {
super.reloadData()
reloadDataGotCalled = true
}
}
}
I'm expecting that it should compile, and then the test should fail because I've not written the code to make it pass yet?
You have defined tableView instance in ItemListViewController as UITableView. So, you can't access the MockTableView's property with that instance.
You can only access the parent's properties from the children not the vice versa. If you still want to access the property you can try something like the snippet below.
XCTAssertTrue((sut.tableView as! MockTableView).reloadDataGotCalled)
Hope it helps.
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
I encounter the problem that I cannot present a dynamic UIViewController in my class using "self". It tells me "Value of type '(LoginScreenVC) -> () -> (LoginScreenVC)' has no member 'view'".
It would work using a closure like e.g. if let loginScreen = UIStoryBoard ..., but since the UIViewController to switch to is dynamic, I cannot cast it to a specific UIViewController.
is there any other way to present the ViewController?
This is my code:
SWIFT 4.2 / XCode 10.1
import UIKit
class LoginScreenVC: UIViewController {
let myTokenHandler = TokenHandler()
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func loginButton(_ sender: Any) {
print("Login button pressed")
let usernameInputField = self.view.viewWithTag(6548) as! UITextField
let passwordInputField = self.view.viewWithTag(6549) as! UITextField
userInput = usernameInputField.text!
passInput = passwordInputField.text!
// call completion handler
requestToken(success: handlerBlock)
}
// completion handler step 1: request token and get redirect string to switch screen
func requestToken(success: (String) -> Void) {
let requestResult = myTokenHandler.requestToken(password: passInput, username: userInput)
success(requestResult)
}
// completion handler step 2: use redirect string to switch screen
let handlerBlock: (String) -> Void = { redirect in
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let loginScreen = storyboard.instantiateViewController(withIdentifier: redirect)
self.present(loginScreen, animated: true, completion: nil) //Value of type '(LoginScreenVC) -> () -> (LoginScreenVC)' has no member 'view'
}
}
You are saying:
let handlerBlock: (String) -> Void = { redirect in
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let loginScreen = storyboard.instantiateViewController(withIdentifier: redirect)
self.present(loginScreen, animated: true, completion: nil)
}
The problem is that you are using the term self in a context where there is no self. (Well, there is a self, but it isn't what you think.) present is a UIViewController instance method, so self needs to be a UIViewController instance; and in this context, it isn't.
I can think of half a dozen ways to express the thing you're trying to express, but the simplest would probably be to rewrite that as:
func handlerBlock(_ redirect:String) -> Void {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let loginScreen = storyboard.instantiateViewController(withIdentifier: redirect)
self.present(loginScreen, animated: true, completion: nil)
}
Now handlerBlock is an instance method, and self is meaningful — it is the instance, which is just what you want. The rest of your code is unchanged, because the bare name handlerBlock in the expression requestToken(success: handlerBlock) is a function name, just as before.
I would like to pass data from EditPostViewController to NewsfeedTableViewController using delegates, but func remove(mediaItem:_) is never called in the adopting class NewsfeedTableViewController. What am I doing wrong?
NewsfeedTableViewController: UITableViewController, EditPostViewControllerDelegate {
override func viewDidLoad() {
super.viewDidLoad()
//set ourselves as the delegate
let editPostVC = storyboard?.instantiateViewController(withIdentifier: "EditPostViewController") as! EditPostViewController
editPostVC.delegate = self
}
//remove the row so that we can load a new one with the updated data
func remove(mediaItem: Media) {
print("media is received heeeee")
// it does't print anything
}
}
extension NewsfeedTableViewController {
//when edit button is touched, send the corresponding Media to EditPostViewController
func editPost(cell: MediaTableViewCell) {
let editPostVC = storyboard?.instantiateViewController(withIdentifier: "EditPostViewController") as? EditPostViewController
guard let indexPath = tableView.indexPath(for: cell) else {
print("indexpath was not received")
return}
editPostVC?.currentUser = currentUser
editPostVC?.mediaReceived = cell.mediaObject
self.navigationController?.pushViewController(editPostVC!, animated: true)
}
protocol EditPostViewControllerDelegate: class {
func remove(mediaItem: Media)
}
class EditPostViewController: UITableViewController {
weak var delegate: EditPostViewControllerDelegate?
#IBAction func uploadDidTap(_ sender: Any) {
let mediaReceived = Media()
delegate?.remove(mediaItem: mediaReceived)
}
}
The objects instantiating in viewDidLoad(:) and on edit button click event are not the same objects. Make a variable
var editPostVC: EditPostViewController?
instantiate in in viewDidLoad(:) with delegate
editPostVC = storyboard?.instantiateViewController(withIdentifier: "EditPostViewController") as! EditPostViewController
editPostVC.delegate = self
and then present it on click event
navigationController?.pushViewController(editPostVC, animated: true)
or
present(editPostVC, animated: true, completion: nil)
you can pass data from presenter to presented VC before or after presenting the VC.
editPostVC.data = self.data
I suggest having a property in NewsfeedTableViewController
var editPostViewController: EditPostViewController?
and then assigning to that when you instantiate the EditPostViewController.
The idea is that it stops the class being autoreleased when NewsfeedTableViewController.viewDidLoad returns.
I need to present a modal VC that sets a property in my presenting VC, and then I need to do something with that value back in the presenting VC. I have to be able to pass pointers to different properties to this function, so that it's reusable. I have the code below (KeyPickerTableViewController is the modal VC).
It should work, except not, because the line after present(picker... gets executed immediately after the picker is presented.
How do I get my presenting VC to "wait" until the modal VC is dismissed?
#objc func fromKeyTapped(_ button: UIBarButtonItem) {
print("from tapped")
setKey(for: &sourceKey, presentingFrom: button)
}
#objc func toKeyTapped(_ button: UIBarButtonItem) {
print("from tapped")
setKey(for: &destKey, presentingFrom: button)
}
fileprivate func setKey(for key: inout Key!, presentingFrom buttonItem: UIBarButtonItem) {
let picker = KeyPickerTableViewController()
picker.delegate = self
picker.modalPresentationStyle = .popover
picker.popoverPresentationController?.barButtonItem = buttonItem
present(picker, animated: true, completion: nil)
if let delKey = delegatedKey {
key = delKey
}
}
You could use delegate pattern or closure.
I would do the following
1. I would not use inout pattern, I would first call the popover and then separately update what is needed to be updated
2. In KeyPickerTableViewController define property var actionOnDismiss: (()->())? and setting this action to what we need after initialisation of KeyPickerTableViewController
I could show it in code, but the abstract you've shown is not clear enough to come up with specific amendments. Please refer the illustration below.
import UIKit
class FirstVC: UIViewController {
var key = 0
#IBAction func buttonPressed(_ sender: Any) {
let vc = SecondVC()
vc.action = {
print(self.key)
self.key += 1
print(self.key)
}
present(vc, animated: true, completion: nil)
}
}
class SecondVC: UIViewController {
var action: (()->())?
override func viewDidLoad() {
onDismiss()
}
func onDismiss() {
action?()
}
}
While presenting VC, add dismissing modal VC action in its completion handler, so that Viewcontroller will be presented after dismissal is completed
present(picker, animated: true, completion: { (action) in
//dismissal action
if let delKey = delegatedKey {
key = delKey
}
})