Question

我正在创建一个应用。在某个视图中，有几个文本字段，用户在其中输入数字，然后按下按钮，并被传输到下一个视图控制器。

如果一个人点击按钮，并且一个或多个文本字段为空，segue取消，我该怎么做呢？

到目前为止，这是我的代码：

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if saveButton === sender {
        let name = nameTextField.text ?? ""

        // Set the meal to be passed to MealListTableViewController after the unwind segue.
        meal = Meal(name: name)

    }

   if calcButton === sender {

    if weightInKilos.text == "" && percentOfDehydration.text == "" && ongoingLosses.text == "" && factor.text == "" {

        let alertController = UIAlertController(title: "Fields were left empty.", message:
            "You left some fields blank! Please make sure that all fields are filled in before tapping 'Calculate'.", preferredStyle: UIAlertControllerStyle.Alert)
        alertController.addAction(UIAlertAction(title: "Dismiss", style: UIAlertActionStyle.Default,handler: nil))

        self.presentViewController(alertController, animated: true, completion: nil)

    }

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

        let weightInt: Int? = Int(weightInKilos.text!)
        let dehydrationInt: Int? = Int(percentOfDehydration.text!)
        let lossesInt: Int? = Int(ongoingLosses.text!)
        let factorInt: Int? = Int(factor.text!)

        let lrs24Int = (30 * weightInt! + 70) * factorInt! + weightInt! * dehydrationInt! * 10 + lossesInt!

        let lrsPerHourint = lrs24Int / 24

        DestViewController.lrsHr = "\(lrsPerHourint)"
        DestViewController.lrs24Hrs = "\(lrs24Int)"
    }
    }
}

Answer 1

在调用segue之前，您必须检查所需的一切。

因此，用户编写答案，检查一切是否正常，如果，确定，请执行segue，否则，提醒用户并要求重新输入信息。

知道了吗？

如何在某些条件下取消segue（if / else）？

1 个答案: