Question

我使用Swift和Xcode 6.4，我想使用Segue将变量从一个View Controller传递给另一个。按下按钮时，变量持续时间应该为ViewController2提供值。在ViewController2中，我想再次使用这个变量。

Main.storyboard按钮标识符名为Test1

我该怎么做？你能帮我解决一下我的代码吗？怎么了？

由于

Code ViewController1：

导入UIKit

类ViewController1：UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}

@IBAction func ButtonTapped(sender: AnyObject) {
    var duration = 1.0
    self.performSegueWithIdentifier("Test1", sender: duration)
}


override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
    if (segue.identifier = "Test1") {
        let secondViewController = segue.destinationViewController as ViewController2
        let duration = sender as Double
        secondViewController.duration = duration
    }
}

}

Code ViewController2：

导入UIKit

类ViewController2：UIViewController {

var duration:Double?

var result = duration + 2.0
println(\(result))

override func viewDidLoad() {
    super.viewDidLoad()
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}

}

Answer 1

var duration = Double()  // now "duration" is global

@IBAction func ButtonTapped(sender: AnyObject) {
    duration = 1.0
    self.performSegueWithIdentifier("Test1", sender: duration)
    // VVV Any new variable created in this scope will be deallocated 
}   // HERE

//Then this scope starts...
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
    if (segue.identifier == "Test1") {
        let secondViewController = segue.destinationViewController as ViewController2
       // delete this... duration = sender as Double
        secondViewController.duration = duration
    }
}

使用segue在View Controllers之间保存变量

1 个答案: