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.
Related
while using a MockTableView this code still not calling reloadData() from the mock,
please i wanna know what is wrong here.
following this book: Test-Driven IOS Development with Swift 4 - Third Edition
page 164, i was as an exercise
full code repo - on github
ItemListViewController.swift
import UIKit
class ItemListViewController: UIViewController, ItemManagerSettable {
#IBOutlet var tableView: UITableView!
#IBOutlet var dataProvider: (UITableViewDataSource & UITableViewDelegate &
ItemManagerSettable)!
var itemManager: ItemManager?
override func viewDidLoad() {
super.viewDidLoad()
itemManager = ItemManager()
dataProvider.itemManager = itemManager
tableView.dataSource = dataProvider
tableView.delegate = dataProvider
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
tableView.reloadData()
}
#IBAction func addItem(_ sender: UIBarButtonItem) {
if let nextViewController =
storyboard?.instantiateViewController(
withIdentifier: "InputViewController")
as? InputViewController {
nextViewController.itemManager = itemManager
present(nextViewController, animated: true, completion: nil)
}
}
}
ItemListViewControllerTest.swift
import XCTest
#testable import ToDo
class ItemListViewControllerTest: XCTestCase {
var sut: ItemListViewController!
var addButton: UIBarButtonItem!
var action: Selector!
override func setUpWithError() throws {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier:
"ItemListViewController")
sut = vc as? ItemListViewController
addButton = sut.navigationItem.rightBarButtonItem
action = addButton.action
UIApplication.shared.keyWindow?.rootViewController = sut
sut.loadViewIfNeeded()
}
override func tearDownWithError() throws {}
func testItemListVC_ReloadTableViewWhenAddNewTodoItem() {
let mockTableView = MocktableView()
sut.tableView = mockTableView
guard let addButton = sut.navigationItem.rightBarButtonItem else{
XCTFail()
return
}
guard let action = addButton.action else{
XCTFail()
return
}
sut.performSelector(onMainThread: action, with: addButton, waitUntilDone: true)
guard let inputViewController = sut.presentedViewController as?
InputViewController else{
XCTFail()
return
}
inputViewController.titleTextField.text = "Test Title"
inputViewController.save()
XCTAssertTrue(mockTableView.calledReloadData)
}
}
extension ItemListViewControllerTest{
class MocktableView: UITableView{
var calledReloadData: Bool = false
override func reloadData() {
calledReloadData = true
super.reloadData()
}
}
}
You inject a MockTableview Then you call loadViewIfNeeded(). But because this view controller is storyboard-based and the table view is an outlet, the actual table view is loaded at this time. This replaces your MockTableview.
One solution is:
Call loadViewIfNeeded() first
Inject the MockTableview to replace the actual table view
Call viewDidLoad() directly. Even though loadViewIfNeeded() already called it, we need to repeat it now that we have a different tableview in place.
Another possible solution:
Avoid MockTableview completely. Continue to use a real table view. You can test whether it reloads data by checking whether the number of rows matches the changed data.
Yet another solution:
Avoid storyboards. You can do this with plain XIBs (but these lack table view prototype cells) or programmatically.
By the way, I see all your tearDownWithError() implementations are empty. Be sure to tear down everything you set up. Otherwise you will end up with multiple instances of your system under test alive at the same time. I explain there here: https://qualitycoding.org/xctestcase-teardown/
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 have simple app which the welcomeVC shows a greeting message with a person's name. In another VC nameVC, users can change the name they want to be called, and it supposes to update the name on the welcomeVC when they click back.
In order to pass the name from nameVC back to welcomeVC, I set up a protocol ChangeNameDelegate in nameVC, and created a variable in my class:
protocol ChangeNameDelegate {
func updateName(name: String)
}
class nameViewController: UIViewController {
#IBOutlet weak var nameTextField: UITextField!
var changeNameDelegate: ChangeNameDelegate!
override func viewDidLoad() {
}
#IBAction func closeNameVC(_ sender: UIButton) {
if let newName = nameTextField.text {
changeNameDelegate.updateName(name: newName)
}
dismiss(animated: true, completion: nil)
}
}
In my welcomeVC, I have made sure that it register the delegate and conforms to the protocol by setting up as follows:
class welcomeViewController: UIViewController, UIViewControllerTransitioningDelegate {
let nameVC = nameViewController()
override func viewDidLoad() {
nameVC.changeNameDelegate = self
}
}
extension welcomeViewController: ChangeNameDelegate {
func updateName(name: String) {
print("The name has been updated!")
nameLabel.text = name
}
}
However when I ran my app, it got a crash because changeNameDelegate appeared to be nil. Does anybody know what could be missed there? Thanks in advance!
It seems that you are instantiating new instance of NameViewController when routing from WelcomeViewController. You should navigate to nameVC which is instantiated before.
I later solved the issue by using notification/observer.
In the parent view:
let userUpdateNotification = Notification.Name(rawValue: "nameNotificationKey")
NotificationCenter.default.addObserver(self, selector: #selector(updateUser), name: userUpdateNotification, object: nil)
}
func updateUser(not: NSNotification) {
if let userInfo = not.userInfo {
if let userName = userInfo["name"] as? String {
nameLabel.text = userName
}
}
}
In the child view:
let name = Notification.Name(rawValue: "nameNotificationKey")
NotificationCenter.default.post(name: name , object: self, userInfo: ["name": nameTextField.text!] )
}
I don't know if delegate/protocol doesn't work between view controllers that are unconnected. Anyone who knows about this is welcomed to comment!
I am developing an application with swift 3.0. Where what I want to do is, from the "MainMapVC" class, which is the view where you have a map with a date slider (see the attached image). I want to move the slider and send that slider position (1,2 or 3) to LeftSideViewController which is the side view (the legend) updating the content depending on the selected date.
View of MainMapVC:
View of MainMapVC with Legend:
Well, and I've come to the point where I have to pass a value between the two view controllers. But problem is that I get the error "fatal error: unexpectedly found nil while unwrapping an optional value". Basically I have a "nil" delegate.
But do not find where the error is, because the definition of the delegate is like "var delegate: MainMapVCDelegate!" And I call it "delegate.moveSliderDates (datePos: Int (roundedValue))" in the "MainMapVC" class.
Does anyone know where I failed in the statement of the delegate?Thanks :)
I attach the code of the two classes so that you see the whole code.
Class MainMapVC (first way):
import UIKit
protocol MainMapVCDelegate: class {
func moveSliderDates(datePos: Int)
}
class MainMapVC: UIViewController, UISearchBarDelegate, CLLocationManagerDelegate, GMSMapViewDelegate {
//MARK: VARIABLES
weak var delegate: MainMapVCDelegate? = nil
let step: Float = 1
#IBAction func moveSliderDates(_ sender: UISlider) {
let roundedValue = round(sender.value / step) * step
sender.value = roundedValue
delegate?.moveSliderDates(datePos: Int(roundedValue))
}
}
The delegate value inside the moveSliderDates function is "nil":
delegate?.moveSliderDates(datePos: Int(roundedValue))
Class LeftSideViewController (first way):
import UIKit
class LeftSideViewController: UIViewController, UITableViewDataSource, UITableViewDelegate, customCellDelegate, MainMapVCDelegate {
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "MainMapVC" {
let secondViewController = segue.destination as! MainMapVC
secondViewController.delegate = self
}
}
func moveSliderDates(datePos: Int){
print(datePos)
print("/////////////")
tableSideLeft.reloadData()
}
not enter inside this function because the delegate of "MainVC" is "nil":
Class MainMapVC (second way):
let step: Float = 1
#IBAction func moveSliderDates(_ sender: UISlider) {
let roundedValue = round(sender.value / step) * step
sender.value = roundedValue
let data:[String: Int] = ["data": Int(roundedValue)]
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "notificationName"), object: nil, userInfo: data)
}
Class LeftSideViewController (second way):
func listnerFunction(_ notification: NSNotification) {
if let data = notification.userInfo?["data"] as? String {
print(data)
}
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(listnerFunction(_:)), name: NSNotification.Name(rawValue: "notificationName"), object: nil)
}
Never goes into the function listnerFunction
You get the error because you defined your delegate as force unwrapped noy-nil version by this code var delegate: LeftSideDelegate!
Instead, you need to change it like this. You should not create strong reference cycle for delegate.
weak var delegate: LeftSideDelegate? = nil
Then for all your delegate calles, do the wrapped version delegate call
delegate?.changeZindexDelivery()
Other than that, change your line protocol LeftSideDelegate { into protocol LeftSideDelegate : class {
Passing data between view controllers using delegate
First, in the class where you want to pass the data to another view controller, declare protocol in this way
protocol SampleDelegate: class {
func delegateFunctionCall(data: String)
}
Then, create delegate variable as optional with type weak var. Call delegate method with you want to pass data or trigger action
class SecondViewController: UIViewController {
weak var delegate: SampleDelegate? = nil
#IBAction func sendTextBackButton(sender: AnyObject) {
delegate?.delegateFunctionCall(data: textField.text!)
}
}
Finally in your view controller that you want to receive action or data, implement the protocol. When you are initiating the second view controller, set it's delegate variable to be the current view controller
class FirstViewController: UIViewController, SampleDelegate {
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "showSecondViewController" {
let secondViewController = segue.destination as! SecondViewController
secondViewController.delegate = self
}
}
func delegateFunctionCall(data: String) {
label.text = data
}
}
Passing data between view controllers using notification
In the destination view controller, register a handler function that is ready to be called. You can add this registration code in view did load
NotificationCenter.default.addObserver(self, selector: #selector(listnerFunction(_:)), name: NSNotification.Name(rawValue: "notificationName"), object: nil)
func listnerFunction(_ notification: NSNotification) {
if let data = notification.userInfo?["data"] as? String {
// do something with your data
}
}
Then in another view controller, if you want to pass data, simply call this
let data:[String: String] = ["data": "YourData"]
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "notificationName"), object: nil, userInfo: data)
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.