If I need to perform a method whose multiple parameters' original source are optional, is doing multiple optional binding before performing the method the cleanest way to go about this?
e.g. UIStoryboardSegue's sourceViewController and destionationViewController are both AnyObject? and I need to use source's navigationController to perform something.
override func perform() {
var svc = self.sourceViewController as? UIViewController
var dvc = self.destinationViewController as? UIViewController
if let svc = svc, dvc = dvc {
svc.navigationController?.pushViewController(dvc, animated: true)
}
}
If the view controllers are part of a designed segue in Interface Builder and you actually know that they are not nil, you can unwrap them
override func perform() {
var svc = self.sourceViewController as! UIViewController
var dvc = self.destinationViewController as! UIViewController
svc.navigationController!.pushViewController(dvc, animated: true)
}
otherwise if the source controller could be nil, the push command will only be executed if the controller is not nil, it's like sending a message to nil in Objective-C
override func perform() {
var svc = self.sourceViewController as? UIViewController
var dvc = self.destinationViewController as? UIViewController
svc.navigationController?.pushViewController(dvc, animated: true)
}
It seems unnecessary to create two vars, if you really want to be sure that the optional values are not nil you could use:
override func perform() {
if let svc = self.sourceViewController as? UIViewController,
dvc = self.destinationViewController as? UIViewController {
svc.navigationController?.pushViewController(dvc, animated: true)
}
}
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 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.
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'm quite new with Swift and I'm making this mini game type app that counts the score and updates the label in the view controller. I want to pass that score from a view controller into another external pop up view controller I created.
#IBAction func Button7Tapped(_ sender: AnyObject)
{
if Index == 13 {
game.score += 1
} else {
let scorepopVC = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "finalScorePop") as! finalScoreViewController
self.addChildViewController(scorepopVC)
scorepopVC.view.frame = self.view.frame
self.view.addSubview(scorepopVC.view)
scorepopVC.didMove(toParentViewController: self)
}
updateGame()
}
Above is my code for the external pop up view controller I created, which also has a separated .swift file. How would I go about taking my game.score and passing that into my Popup view controller?
In your finalScoreViewController swift file add a new property.
final class FinalScoreViewController: UIViewController {
var score: Int?
}
And then just assign it when you're instantiating it.
#IBAction func Button7Tapped(_ sender: AnyObject) {
if Index == 13 {
game.score += 1
} else {
let scorepopVC = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "finalScorePop") as! finalScoreViewController
scorepopVC.score = game.score //THIS LINE
self.addChildViewController(scorepopVC)
scorepopVC.view.frame = self.view.frame
self.view.addSubview(scorepopVC.view)
scorepopVC.didMove(toParentViewController: self)
}
updateGame()
}
It is better to use storyboard to open the ViewController. In storyboard, right click and drag from you button to the second view controller (the one that you wish to open).
Choose the segue type that you wish to use. In your case, I think Present Modally will work fine.
You will see a line between the two UIViewControllers in storyboard. That is the segue. Tap on it. In the Attributes inspector give the segue an identifier. For instance "myFirstSegue".
Then in the code of the UIViewController that contains your button override prepare(for:sender:). This method is called when preparing for the segue to happen. I.o.w when you tap on the button. You have access to the destination UIViewController and can therefor access and set the properties on it.
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "myFirstSegue" {
if let vc = segue.destination as? MyViewController {
//here you set your data on the destination view controller
vc.myString = "Hello World"
}
}
}
Note that we check the identifier, because all segues that go from this ViewController to other ViewControllers will call prepare(for:sender:)
It's quite simple, Just add a property in your finalScoreViewController (if you are not already done this) and -for example- call it score:
class finalScoreViewController: UIViewController {
var score: String?
// ...
Add this line to the Button7Tapped action (where you set a value for finalScoreViewController's score):
let scorepopVC = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "finalScorePop") as! finalScoreViewController
// add this line:
scorepopVC.score = "My score"
self.addChildViewController(scorepopVC)
scorepopVC.view.frame = self.view.frame
self.view.addSubview(scorepopVC.view)
scorepopVC.didMove(toParentViewController: self)
Finally, in finalScoreViewController:
override func viewDidLoad() {
super.viewDidLoad()
if let scr = score {
print(scr)
}
}
Hope that helped.
You do not actually have to pass the variable to the next view controller. All you have to do is create a variable outside of the View Controller class, and voila, you can access your variable from anywhere, in any swift file. For example:
var score = 0
class ViewController: UIViewController {
override func viewDidLoad(){
super.viewDidLoad()
}
#IBAction func Button7Tapped(_ sender: AnyObject){
score += 1
}
}
And then in the other View Controller, you would have something like this:
#IBOutlet weak var scoreLabel: UILabel!
class ViewController: UIViewController {
override func viewDidLoad(){
super.viewDidLoad()
var timer1 = Timer.scheduledTimer(timeInterval: 0.1, target: self, selector: #selector(updateScore), userInfo: nil, repeats: true)
}
#objc func updateScore() {
scoreLabel.text = "You have \(score) points!"
}
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.