我有一个我在swift中创建的计算器。我正在尝试添加其他功能，我想将我已经按下的操作历史记录传递到我的TableViewController中。我试图删除数据，但似乎无法得到它。我有几个不同的准备我正在玩的segue方法被注释掉了。到目前为止，这是我的代码：
ViewController.swift
import UIKit
class ViewController: UIViewController {
@IBOutlet weak var displayLabel: UILabel!
@IBOutlet weak var HistoryLabel: UILabel!
var historyArray: [String] = []
var userIsTypingNumbers = false
var firstNumber = 0
var secondNumber = 0
var operation = ""
var result = 0.0
@IBAction private func NumbersEntered(_ sender: UIButton) {
//know what number is being pressed
let number = sender.currentTitle
//if user is typing number, do this.
if userIsTypingNumbers {
//specify what number is being pressed.
//append the number onto the previous number.
displayLabel.text = displayLabel.text! + number!
} else {
displayLabel.text = number
userIsTypingNumbers = true
}
}
var displayValue: Double {
get {
return Double(displayLabel.text!)!
}
set {
displayLabel.text = String(newValue)
}
}
private var calculations = PerformCalculations()
@IBAction func OperationsPressed(_ sender: UIButton) {
userIsTypingNumbers = false
firstNumber = Int(Double(displayLabel.text!)!)
operation = sender.currentTitle!
if operation == "√" {
result = (PerformCalculations().squareroot(a: Double(firstNumber)))
displayLabel.text = String(result)
}
}
@IBAction func Enter(_ sender: UIButton) {
userIsTypingNumbers = false
secondNumber = Int(Double(displayLabel.text!)!)
if operation == "+" {
result = (PerformCalculations().add(a: Double(firstNumber), b: Double(secondNumber)))
} else if operation == "÷" {
result = (PerformCalculations().division(a: Double(firstNumber), b: Double(secondNumber)))
} else if operation == "×" {
result = (PerformCalculations().multiplication(a: Double(firstNumber), b: Double(secondNumber)))
} else if operation == "-" {
result = (PerformCalculations().subtract(a: Double(firstNumber), b: Double(secondNumber)))
}
displayLabel.text = String(result)
historyArray.append("\(firstNumber) \(operation) \(secondNumber) = \(result)")
userIsTypingNumbers = false
//self.performSegue(withIdentifier: "History", sender: self)
}
@IBAction func Clear(_ sender: UIButton) {
//clear display to 0.
displayLabel.text = "0"
}
@IBAction func Delete(_ sender: UIButton) {
//deleting last typed number, if user messed up.
let name: String = self.displayLabel.text!
//count number of characters.
let stringLength = name.characters.count
let substringIndex = stringLength - 1
displayLabel.text = (name as NSString).substring(to: substringIndex)
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
/*override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "History" {
if let destinationVC = segue.destination as? TableTableViewController {
destinationVC.dataString = historyArray.description
}
}
}*/
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let destViewController : TableTableViewController = segue.destination as! TableTableViewController
destViewController.dataString = historyArray.description
}
}
Model.swift
import Foundation
class PerformCalculations {
func add(a: Double, b: Double) -> Double {
let result = a + b
return result
}
func division(a: Double, b: Double) -> Double {
let result = a / b
return result
}
func subtract(a: Double, b: Double) -> Double {
let result = a - b
return result
}
func multiplication(a: Double, b: Double) -> Double {
let result = a * b
return result
}
func squareroot(a: Double) -> Double {
let result = sqrt(a)
return result
}
}
TableTableViewController.swift
import UIKit
class TableTableViewController: UITableViewController {
//var dataString:String!
var historyArray: [String] = []
var i = 0
override func viewDidLoad() {
super.viewDidLoad()
i = 0
while i < historyArray.count{
AddLabel(history: historyArray[i])
i = i+1
}
// Uncomment the following line to preserve selection between presentations
// self.clearsSelectionOnViewWillAppear = false
// Uncomment the following line to display an Edit button in the navigation bar for this view controller.
// self.navigationItem.rightBarButtonItem = self.editButtonItem()
}
func AddLabel(history: String){
let label = UILabel()
label.text = history
let y = i*15
label.frame = CGRect(x:125,y:y,width:200,height:21)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - Table view data source
override func numberOfSections(in tableView: UITableView) -> Int {
// #warning Incomplete implementation, return the number of sections
return 0
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of rows
return 0
}
/*
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "reuseIdentifier", for: indexPath)
// Configure the cell...
return cell
}
*/
/*
// Override to support conditional editing of the table view.
override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
// Return false if you do not want the specified item to be editable.
return true
}
*/
/*
// Override to support editing the table view.
override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete {
// Delete the row from the data source
tableView.deleteRows(at: [indexPath], with: .fade)
} else if editingStyle == .insert {
// Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
}
}
*/
/*
// Override to support rearranging the table view.
override func tableView(_ tableView: UITableView, moveRowAt fromIndexPath: IndexPath, to: IndexPath) {
}
*/
/*
// Override to support conditional rearranging of the table view.
override func tableView(_ tableView: UITableView, canMoveRowAt indexPath: IndexPath) -> Bool {
// Return false if you do not want the item to be re-orderable.
return true
}
*/
/*
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
// Get the new view controller using segue.destinationViewController.
// Pass the selected object to the new view controller.
}
*/
}
非常感谢任何帮助，谢谢！
答案 0 :(得分：0)
在您转入的视图控制器中，您可以使用historyArray访问ViewController个实例的(self.presentingViewController as? ViewController).historyArray。
答案 1 :(得分：0)
为了让segue工作，你必须控制从ViewControllerA到故事板中的ViewControllerB的拖动。选择您已创建的segue，并为其指定标识符＆＃34; History＆＃34;
现在您可以在功能中手动触发segue
self.performSegue(withIdentifier: "History", sender: self)
在为segue做准备时，你必须在你的情况下检查标识符＆＃34;历史＆＃34;
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "History" {
if let destinationVC = segue.destination as? TableTableViewController {
destinationVC.dataString = historyArray.description
}
}
}
注意：如果您的viewControllerB未包装或嵌入在Navigationcontroller中，则此检查有效。如果是，那么你必须首先检查导航控制器然后查看viewController。