xcode - 停止 Segue 并显示警报部分不起作用 - Xcode

Question

我之前遇到过停止转场并在文本字段为空时显示警报的问题。这个问题就解决了。我现在想通过一些逻辑测试进一步运行这些文本字段的内容。但是，我的代码似乎没有捕获错误。代码如下:

import Foundation
import UIKit
import Darwin

class View3on3 : UIViewController, UITextFieldDelegate {


@IBOutlet weak var APTeams: UITextField!
@IBOutlet weak var APRounds: UITextField!
@IBOutlet weak var APBreakers: UITextField!


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


func initializeTextFields()
{
    APTeams.delegate = self
    APTeams.keyboardType = UIKeyboardType.NumberPad

    APRounds.delegate = self
    APRounds.keyboardType = UIKeyboardType.NumberPad

    APBreakers.delegate = self
    APBreakers.keyboardType = UIKeyboardType.NumberPad
}


    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

        if (APTeams.text!.isEmpty || APRounds.text!.isEmpty || APBreakers.text!.isEmpty)
        {
            let alertController: UIAlertController = UIAlertController(
                title: "Data missing!",
                message: "Please enter valid data into all 3 fields.",
                preferredStyle: UIAlertControllerStyle.Alert)

            let okAction = UIAlertAction(
                title: "OK",
                style: UIAlertActionStyle.Default,
                handler: nil)

            alertController.addAction(okAction)

            presentViewController(alertController, animated: true, completion: nil)
        }

        else if (Int(String(APTeams.text)) < Int(String(APBreakers.text)))
        {
            let alertController: UIAlertController = UIAlertController(
                title: "Math Error!",
                message: "The number of breaking teams cannot be more than the number of teams.",
                preferredStyle: UIAlertControllerStyle.Alert)

            let okAction = UIAlertAction(
                title: "OK",
                style: UIAlertActionStyle.Default,
                handler: nil)

            alertController.addAction(okAction)

            presentViewController(alertController, animated: true, completion: nil)
        }

        else if (Int(String(APTeams.text)) > 9999)
        {
            let alertController: UIAlertController = UIAlertController(
                title: "Math Error!",
                message: "Please input a number of teams less than 10,000.",
                preferredStyle: UIAlertControllerStyle.Alert)

            let okAction = UIAlertAction(
                title: "OK",
                style: UIAlertActionStyle.Default,
                handler: nil)

            alertController.addAction(okAction)

            presentViewController(alertController, animated: true, completion: nil)
        }

        else
        {
            let DestViewController : View3on3Results = segue.destinationViewController as! View3on3Results

            DestViewController.AP1 = APTeams.text!
            DestViewController.AP2 = APRounds.text!
            DestViewController.AP3 = APBreakers.text!

            //self.performSegueWithIdentifier("segueTest",sender: View3on3Results.self)//
        }



        }

}

有人知道怎么回事吗？对非空字段的第一个测试工作正常，如果 3 个文本字段中的任何一个为空，则会抛出错误。

此外，如果有人知道如何测试以确保条目仅包含整数，我们将不胜感激。这是在测试整数值之前我需要运行的第二个测试。

附录:我正在使用 XCode 7 beta 4，用 Swift 2.0 编写。

编辑:我的代码现在看起来像这样，现在转场就发生了，根本不需要检查。

@derdida 试图遵循你所说的。没有检查任何条件就发生了segue。您能更正我更新的代码吗？

func checkIfPassed() {

    if (APTeams.text!.isEmpty || APRounds.text!.isEmpty || APBreakers.text!.isEmpty)
    {
        let alertController: UIAlertController = UIAlertController(
            title: "Data missing!",
            message: "Please enter valid data into all 3 fields.",
            preferredStyle: UIAlertControllerStyle.Alert)

        let okAction = UIAlertAction(
            title: "OK",
            style: UIAlertActionStyle.Default,
            handler: nil)

        alertController.addAction(okAction)

        presentViewController(alertController, animated: true, completion: nil)
    }


    else if (Int(String(APTeams.text)) < Int(String(APBreakers.text)))
    {
        let alertController: UIAlertController = UIAlertController(
            title: "Math Error!",
            message: "The number of breaking teams cannot be more than the number of teams.",
            preferredStyle: UIAlertControllerStyle.Alert)

        let okAction = UIAlertAction(
            title: "OK",
            style: UIAlertActionStyle.Default,
            handler: nil)

        alertController.addAction(okAction)

        presentViewController(alertController, animated: true, completion: nil)
    }

    else if (Int(String(APTeams.text)) > 9999)
    {
        let alertController: UIAlertController = UIAlertController(
            title: "Math Error!",
            message: "Please input a number of teams less than 10,000.",
            preferredStyle: UIAlertControllerStyle.Alert)

        let okAction = UIAlertAction(
            title: "OK",
            style: UIAlertActionStyle.Default,
            handler: nil)

        alertController.addAction(okAction)

        presentViewController(alertController, animated: true, completion: nil)
    }

    else
    {
        // everything is fine, so manually go to your next ViewController
        self.performSegueWithIdentifier("3on3Segue", sender: nil)
    }


   }


    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

       let DestViewController : View3on3Results = segue.destinationViewController as! View3on3Results

            DestViewController.AP1 = APTeams.text!
            DestViewController.AP2 = APRounds.text!
            DestViewController.AP3 = APBreakers.text!
        }

Answer 1

我会稍微改变一下你的代码。

将 ViewController1 连接到 ViewController2(不是 Button)，这样您就可以手动执行 Segue。我不会进入“prepareForSegue” - 我会编写自己的“检查是否通过”函数，如下所示:

    func checkIfPassed() {

        if (APTeams.text!.isEmpty || APRounds.text!.isEmpty || APBreakers.text!.isEmpty)
        {
           // show your first alert
        } else if(APTeams.text.toInt() != nil && ABreakers.text.toInt() != nil)) {
           // ok, both values are no integers, show your next error

           // show your second alert

        } else if(APTeams.text.toInt() < ABreakers.text.toInt()) { 
           // values are integers, and ABreakers.text is > then APTeams.text
           // show your third alert, and so on

        } else {
           // everything is fine, so manually go to your next ViewController
           self.performSegueWithIdentifier("yourSegueIdentifier", nil)
        }


    }

更新:您现在可以检查字符串是否是带有可选值的整数:(Swift 2.0)

 let text:Int? = Int(textfield.text)