Question

我试图通过segue将var projectNumber从ViewController传递给Project1ViewController，并将其保存为var projectNum。然后使用projectNum更新Project1ViewController中的标签。 segue和action / outlet都已设置完毕。该应用程序运行流畅（没有错误），但是，Project1ViewController中的projectNum未获取projectNumber值并使其成为projectNum。

如何将projectNumber值从ViewController传递给Project1ViewController并将其保存在projectNum中？我已经看到了描述通过代表执行的类似操作的教程，但我不确定代表是否适用于我的问题。任何反馈都有帮助。

的ViewController

import UIKit

class ViewController: UIViewController{

var projectNumber:String = "" 
@IBOutlet var projectButton1 : UIButton!
@IBOutlet var projectButton2 : UIButton!
@IBOutlet var projectButton3 : UIButton!
@IBOutlet var projectButton4 : UIButton!

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.
}

@IBAction func updateLabels(sender: UIButton!) {

    projectNumber = String(sender.tag)
    println(projectNumber)
    sender.setTitle(String(projectNumber), forState: UIControlState.Normal)

    func prepareForSegue(segue: UIStoryboardSegue!, sender: AnyObject!) {
            //if user presses Project 3921 button
        if segue.identifier == "Project3921Segue"
        {
            if var destinationVC = segue.destinationViewController as? Project1ViewController{
                destinationVC.projectNum = projectNumber
            }
        }
            //if user presses Project 3922 button
        else if segue.identifier == "Project3922Segue"
        {
            if var destinationVC = segue.destinationViewController as? Project1ViewController{
                destinationVC.projectNum = projectNumber
            }
        }
            //if user presses Project 3923 button
        else if segue.identifier == "Project3923Segue"
        {
            if var destinationVC = segue.destinationViewController as? Project1ViewController{
                destinationVC.projectNum = projectNumber
            }
        }
            //otherwise user presses Project 3924 button
        else if segue.identifier == "Project3924Segue"
        {
            if var destinationVC = segue.destinationViewController as? Project1ViewController{
                destinationVC.projectNum = projectNumber
            }
        }   
    }        
}
}

Project1ViewController

import UIKit

class Project1ViewController: UIViewController {

var projectNum:String!
@IBOutlet var projectNumLabel: UILabel!
@IBOutlet var projectNumTitle: UINavigationItem!

override func viewDidLoad() {
    super.viewDidLoad()

    projectNumLabel.text = projectNum
    projectNumTitle.title = projectNum
    println(projectNum)

    // Do any additional setup after loading the view.
}

override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}
}

谢谢！

Answer 1

您正在里面定义按钮动作功能中的prepareForSegue 。它是一个被覆盖的ViewController函数。您的解决方案可以更简单：

class ViewController: UIViewController{ 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 prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) { if var destinationVC = segue.destinationViewController as? Project1ViewController{ destinationVC.projectNum = segue.identifier } } }

请注意，您不需要按钮插座，因为您只需在故事板中使用正确的segue标识符对其进行配置。除非您需要按钮触发其他一些自定义操作。

和

class Project1ViewController: UIViewController { var projectNum:String! @IBOutlet var projectNumLabel: UILabel! override func viewDidLoad() { super.viewDidLoad() projectNumLabel.text = projectNum self.title = projectNum println(projectNum) } }

注意我只是设置了title的{{1}}属性，以便在导航控制器中显示Project1ViewController作为标题。我假设您的控制器嵌入在导航控制器中，projectNum的按钮ViewController已经移位到show。

通过segue在2个视图控制器和更新标签之间传递数据

1 个答案: