Question

 import UIKit
 import Foundation

class First: UIViewController {

@IBOutlet var firstTitle: UILabel!
@IBOutlet var firstTxtField: UITextField!

@IBAction func goTo2nd(sender: AnyObject) {
    var second: Second?
         second?.secondTitle.text = firstTxtField.text
}

}

import Foundation
import UIKit

class Second: UIViewController {

@IBOutlet var secondTitle: UILabel!

@IBOutlet var secondTextField: UITextField!

@IBAction func goToFirstVC(sender: AnyObject) {

    var first: First?
    first?.firstTitle.text  = secondTextField.text
}



}

为什么我无法将文本字段值分配给出口标签，我在故事板中创建了2个viewControllers，并为每个分配了这个（First.swift，Second.swift）类

Answer 1

import UIKit
import Foundation

class First: UIViewController {

//下面这个var用作我们将通过在其他swift类中创建该类的对象来访问的属性

var firstTit:String?

@IBOutlet var firstTitle: UILabel!
@IBOutlet var firstTxtField: UITextField!

@IBAction func goTo2nd(sender: AnyObject) {

}
override func viewDidLoad() {
    super.viewDidLoad()
    firstTitle.text = firstTit
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}
override func prepareForSegue(segue: (UIStoryboardSegue!), sender: AnyObject!) {
    if (segue.identifier == "goto2from1")
    {
        var svc = segue!.destinationViewController as Second;
        svc.secondTit = firstTxtField.text
    }
}
}

import Foundation
import UIKit

class Second: UIViewController {
var secondTit: String?

@IBOutlet var secondTitle: UILabel!
@IBOutlet var secondTextField: UITextField!

@IBAction func goToFirstVC(sender: AnyObject) {
}
@IBAction func goToThirdVC(sender: AnyObject) {
}
override func viewDidLoad() {
    super.viewDidLoad()
   secondTitle.text = secondTit

}
override func prepareForSegue(segue: (UIStoryboardSegue!), sender: AnyObject!) {
    if (segue.identifier == "goto1from2")
    {
        var svc = segue!.destinationViewController as First;
        svc.firstTit = secondTextField.text
    }
    else if(segue.identifier == "goto3from2")
    {
        var svc = segue!.destinationViewController as Third;
        svc.thirdTit = secondTextField.text
    }
}   
}


import Foundation
import UIKit

class Third: UIViewController {

var thirdTit:String?

@IBOutlet var thirdTitle: UILabel!
@IBOutlet var thirdTextField: UITextField!

override func viewDidLoad()
{
    super.viewDidLoad()
    thirdTitle.text = thirdTit
}
@IBAction func goTofirstFromThird(sender: AnyObject) {
}
override func prepareForSegue(segue: (UIStoryboardSegue!), sender: AnyObject!) {
    if (segue.identifier == "goto1from3")
    {
        var svc = segue!.destinationViewController as First;
        svc.firstTit = thirdTextField.text
    }
}
}

另一种方式，如果你不想通过第二个ViewController传递数据，但想直接发送到第三个，使用结构

import UIKit
import Foundation

class First: UIViewController {

var firstTit:String?
@IBOutlet var firstTitle: UILabel!
@IBOutlet var firstTxtField: UITextField!
@IBAction func goTo2nd(sender: AnyObject)
{
    Third.thirdGlobalVars.thirdTit = firstTxtField.text  //this line sends field data to third class' preperty (in fact a struct)
    //if u r going through 2nd vc to 3rd, to move from 1st vc to 2nd + if u want to do progammatic initialization use the following line as well
    var storyboard = UIStoryboard(name: "Main", bundle: nil)
    var vc = storyboard.instantiateViewControllerWithIdentifier("secondVC") as Second
    self.presentViewController(vc, animated: true, completion: nil)
}
override func viewDidLoad() {
    super.viewDidLoad()
    firstTitle.text = firstTit
}
override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}
}

class Third: UIViewController {

struct thirdGlobalVars {
static var thirdTit: String?
}
@IBOutlet var thirdTitle: UILabel!
@IBOutlet var thirdTextField: UITextField!

override func viewDidLoad()
{
    super.viewDidLoad()
    thirdTitle.text = thirdGlobalVars.thirdTit
}

分配后，标签值赋值为零

1 个答案: