Swift编程地将数据从一个ViewController传递到另一个ViewController

Question

我只想在两个ViewController之间传输一些数据，还写了一些代码。但是，如果我更新tableView，则用户给定的数据不会显示在tableView中。有人能帮我吗？

import UIKit

导入CoreData

类AddNewRecipeViewController:UIViewController，UITableViewDelegate，UITableView DataSource｛

private let reuseIdentifer = "IngredientCell"
let pressGesture = UILongPressGestureRecognizer()
let titleLabel = UILabel()
let tf_one = UITextField()
let tf_two = UITextField()
let tableView = UITableView()
let submitButton = UIButton()
let newButton = UIButton()
var name_array = [String]()
var unit_array = [String]()
var quantity_array = [String]()
let recipeId = Int.random(in: 0...5000)
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .white
createViewControllerItems()
}
@objc func refresh(){
print(name_array)
self.tableView.reloadData()
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
self.view.endEditing(true)
}
@objc func dismissKeyboard() {
view.endEditing(true)
}
func createViewControllerItems() {
// - MARK: Titel
titleLabel.text = "Neues Rezept"
titleLabel.textColor = .black
titleLabel.textAlignment = .center
titleLabel.font = UIFont(name: "Bradley Hand", size: 24)

view.addSubview(titleLabel)
titleLabel.translatesAutoresizingMaskIntoConstraints = false
titleLabel.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
titleLabel.topAnchor.constraint(equalTo: view.topAnchor, constant: 30).isActive = true
titleLabel.widthAnchor.constraint(equalToConstant: 200).isActive = true
titleLabel.heightAnchor.constraint(equalToConstant: 40).isActive = true

newButton.setTitle("test", for: UIControl.State.normal)
newButton.setTitleColor(.black, for: UIControl.State.normal)
newButton.addTarget(self, action: #selector(refresh), for: .touchUpInside)
view.addSubview(newButton)
newButton.translatesAutoresizingMaskIntoConstraints = false
newButton.leftAnchor.constraint(equalTo: view.leftAnchor, constant: 30).isActive = true
newButton.topAnchor.constraint(equalTo: view.topAnchor, constant: 30).isActive = true
newButton.widthAnchor.constraint(equalToConstant: 40).isActive = true
newButton.heightAnchor.constraint(equalToConstant: 40).isActive = true

// - MARK: Überschrift

tf_one.placeholder = "Name"
tf_one.borderStyle = .roundedRect
tf_one.keyboardType = .default
tf_one.spellCheckingType = .yes
tf_one.smartInsertDeleteType = .yes
tf_one.autocorrectionType = .yes
tf_one.autocapitalizationType = .sentences

view.addSubview(tf_one)
tf_one.translatesAutoresizingMaskIntoConstraints = false
tf_one.leftAnchor.constraint(equalTo: view.leftAnchor, constant: 15).isActive = true
tf_one.topAnchor.constraint(equalTo: view.topAnchor, constant: 100).isActive = true
tf_one.widthAnchor.constraint(equalToConstant: 270).isActive = true
tf_one.heightAnchor.constraint(equalToConstant: 34).isActive = true

// - MARK: Anzahl Portionen

tf_two.placeholder = "Anzahl"
tf_two.borderStyle = .roundedRect
tf_two.keyboardType = .decimalPad

view.addSubview(tf_two)
tf_two.translatesAutoresizingMaskIntoConstraints = false
tf_two.topAnchor.constraint(equalTo: view.topAnchor, constant: 100).isActive = true
tf_two.leftAnchor.constraint(equalTo: tf_one.rightAnchor, constant: 3).isActive = true
tf_two.widthAnchor.constraint(equalToConstant: 70).isActive = true
tf_two.heightAnchor.constraint(equalToConstant: 34).isActive = true

// - MARK: Table View
tableView.delegate = self
tableView.dataSource = self
tableView.register(IngredientCell.self, forCellReuseIdentifier: reuseIdentifer)
tableView.rowHeight = 55

view.addSubview(tableView)
tableView.translatesAutoresizingMaskIntoConstraints = false
tableView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
tableView.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
tableView.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: -100).isActive = true
tableView.topAnchor.constraint(equalTo: tf_one.bottomAnchor, constant: 10).isActive = true


// - MARK: Bestätigen
submitButton.layer.cornerRadius = 20
submitButton.clipsToBounds = true
submitButton.backgroundColor = .lightGray
submitButton.setTitle("ok", for: UIControl.State.normal)
submitButton.setTitleColor(.white, for: UIControl.State.normal)
submitButton.titleLabel?.font = UIFont(name: "Chalkduster", size: 24)
submitButton.addTarget(self, action: #selector(save), for: .touchUpInside)

view.addSubview(submitButton)
submitButton.translatesAutoresizingMaskIntoConstraints = false
submitButton.rightAnchor.constraint(equalTo: view.rightAnchor, constant: -30).isActive = true
submitButton.topAnchor.constraint(equalTo: view.topAnchor, constant: 30).isActive = true
submitButton.widthAnchor.constraint(equalToConstant: 40).isActive = true
submitButton.heightAnchor.constraint(equalToConstant: 40).isActive = true

// - MARK: Add Gesture
pressGesture.addTarget(self, action: #selector(pressAction))

view.addGestureRecognizer(pressGesture)
}
@objc func pressAction() {
let generator = UIImpactFeedbackGenerator(style: .heavy)
generator.impactOccurred()
let vc: AddNewIngredientViewController!
vc = AddNewIngredientViewController()
vc.modalPresentationStyle = .automatic
self.present(vc, animated: true)
}
@objc func save() {
//save befor dismiss
dismiss(animated: true, completion: nil)
/*
guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else {
return
}
let context = appDelegate.persistentContainer.viewContext
let entityName = "Recipes"
guard let newEntity = NSEntityDescription.entity(forEntityName: entityName, in: context) else {
return
}
let newRecipe = NSManagedObject(entity: newEntity, insertInto: context)
let name = tf_one.text
let id = recipeId
let category = 1
let persons = 2
newRecipe.setValue(name, forKey: "name")
newRecipe.setValue(id, forKey: "id")
newRecipe.setValue(category, forKey: "category")
newRecipe.setValue(persons, forKey: "persons")
do {
try context.save()
print("Gespeichert!")
let vc: ViewController!
vc = ViewController()
vc.modalPresentationStyle = .fullScreen
self.present(vc, animated: false)
} catch {
print(error)
}*/
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
print(name_array.count)
return name_array.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: reuseIdentifer, for: indexPath) as! IngredientCell
cell.nameLabel.text = name_array[indexPath.row]
cell.descriptionLabel.text = "text"
cell.personsLabel.text = "text"
return cell
}
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete {
guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else {
return
}
let context = appDelegate.persistentContainer.viewContext
let entityName = "/ENTRY/"

let request = NSFetchRequest<NSFetchRequestResult>(entityName: entityName)
do {
let results = try context.fetch(request)

guard results.count > 0 else {
return
}
if let deleteEntity = results[indexPath.row] as? NSManagedObject {
context.delete(deleteEntity) //Das Entity ist hier nur markiert als gelöscht, für evt arbeiten am Item
if context.hasChanges {
do {
try context.save()
print("Datensatz gelöscht!")
let vc: ViewController!
vc = ViewController()
vc.modalPresentationStyle = .fullScreen
self.present(vc, animated: false)
} catch {
print(error)
}
}
}
} catch {
print(error)
}
}
}

}

导入UIKit导入CoreData

类AddNewIngredientViewController:UIViewController｛

let viewExample = UIView()
let titleLabel = UILabel()
let tf_one = UITextField()
let unitTicker = UISegmentedControl()
let unitLabel = UILabel()
let slider = UISlider()
let submitButton = UIButton()
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = UIColor.white.withAlphaComponent(0)
createViewControllerItems()
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
self.view.endEditing(true)
}
@objc func dismissKeyboard() {
view.endEditing(true)
}
func createViewControllerItems() {
// - MARK: View
viewExample.backgroundColor = .white
viewExample.layer.cornerRadius = 15
viewExample.clipsToBounds = true
view.addSubview(viewExample)
viewExample.translatesAutoresizingMaskIntoConstraints = false
viewExample.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: -200).isActive = true
viewExample.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
viewExample.widthAnchor.constraint(equalToConstant: 330).isActive = true
viewExample.heightAnchor.constraint(equalToConstant: 350).isActive = true

// - MARK: Titel
titleLabel.text = "Zutat hinzufügen"
titleLabel.textColor = .black
titleLabel.textAlignment = .center
titleLabel.font = UIFont(name: "Chalkduster", size: 24)

view.addSubview(titleLabel)
titleLabel.translatesAutoresizingMaskIntoConstraints = false
titleLabel.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
titleLabel.topAnchor.constraint(equalTo: view.topAnchor, constant: 50).isActive = true
titleLabel.widthAnchor.constraint(equalToConstant: 250).isActive = true
titleLabel.heightAnchor.constraint(equalToConstant: 40).isActive = true

// - MARK: Überschrift

tf_one.placeholder = "Name"
tf_one.borderStyle = .roundedRect
tf_one.keyboardType = .default
tf_one.spellCheckingType = .yes
tf_one.smartInsertDeleteType = .yes
tf_one.autocorrectionType = .yes
tf_one.autocapitalizationType = .sentences

view.addSubview(tf_one)
tf_one.translatesAutoresizingMaskIntoConstraints = false
tf_one.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
tf_one.topAnchor.constraint(equalTo: view.topAnchor, constant: 100).isActive = true
tf_one.widthAnchor.constraint(equalToConstant: 310).isActive = true
tf_one.heightAnchor.constraint(equalToConstant: 34).isActive = true

// - MARK: Unit Ticker
unitTicker.insertSegment(withTitle: "ml", at: 0, animated: true)
unitTicker.insertSegment(withTitle: "mg", at: 1, animated: true)
unitTicker.insertSegment(withTitle: "unit", at: 2, animated: true)
unitTicker.addTarget(self, action: #selector(updateLabel), for: UIControl.Event.allEvents)
view.addSubview(unitTicker)
unitTicker.translatesAutoresizingMaskIntoConstraints = false
unitTicker.topAnchor.constraint(equalTo: view.topAnchor, constant: 150).isActive = true
unitTicker.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
// - MARK: Slider
slider.maximumValue = 10
slider.addTarget(self, action: #selector(updateLabel), for: UIControl.Event.allEvents)
view.addSubview(slider)
slider.translatesAutoresizingMaskIntoConstraints = false
slider.topAnchor.constraint(equalTo: view.topAnchor, constant: 200).isActive = true
slider.widthAnchor.constraint(equalToConstant: 310).isActive = true
slider.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true

// - MARK: Bestätigen
submitButton.layer.cornerRadius = 20
submitButton.clipsToBounds = true
submitButton.backgroundColor = .lightGray
submitButton.setTitle("ok", for: UIControl.State.normal)
submitButton.titleLabel?.font = UIFont(name: "Chalkduster", size: 24)
submitButton.addTarget(self, action: #selector(save), for: .touchUpInside)

view.addSubview(submitButton)
submitButton.translatesAutoresizingMaskIntoConstraints = false
submitButton.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: 100).isActive = true
submitButton.topAnchor.constraint(equalTo: slider.bottomAnchor, constant: 50).isActive = true
submitButton.widthAnchor.constraint(equalToConstant: 40).isActive = true
submitButton.heightAnchor.constraint(equalToConstant: 40).isActive = true
}
@objc func updateLabel() {
unitLabel.textAlignment = .center
if unitTicker.selectedSegmentIndex == 0{
unitLabel.text = "(Int(slider.value)) ml"
slider.maximumValue = 1000
}else if unitTicker.selectedSegmentIndex == 1{
unitLabel.text = "(Int(slider.value)) mg"
slider.maximumValue = 1000
}else if unitTicker.selectedSegmentIndex == 2{
unitLabel.text = "(Int(slider.value)) unit"
slider.maximumValue = 10
}
view.addSubview(unitLabel)
unitLabel.translatesAutoresizingMaskIntoConstraints = false
unitLabel.topAnchor.constraint(equalTo: view.topAnchor, constant: 230).isActive = true
unitLabel.widthAnchor.constraint(equalToConstant: 310).isActive = true
unitLabel.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
}
@objc func save() {
let viewController = AddNewRecipeViewController()
viewController.name_array.append(tf_one.text!)
print(viewController.name_array)
dismiss(animated: true, completion: nil)
}

}

谢谢！Tom

Answer 1

您可以使用委托方法或NSNotificationon在两个viewController之间传递数据。有关更多信息，请访问NSNotification：https://developer.apple.com/documentation/foundation/nsnotification

对于委托方法，您可以检查https://medium.com/@jamesrochabrun/implementing-delegates-in-swifts-step-by-stepd3211cbac3ef