Question

我希望应用程序在达到阵列的最后一个索引后移动到结束屏幕。这就是我所拥有的代码，其中＆＃34; endWorkout＆＃34;是模态segue标识符：

if (index < workouts2.endIndex-1) {
        index++;}

else {
        timerLabel.pause();
        timerLabel.reset();
        performSegueWithIdentifier("endWorkout", sender: self)
        println("Hello")}

应用程序转到End Workout屏幕就好了，但我在xcode控制台中得到了以下错误的不停循环：其视图不在窗口层次结构中！你好

它还不断打印出印刷声明＆＃34;你好＆＃34;应该只打印一次。我读过的其他解决方案表明performSegueWithIdentifier应该在方法＆＃34; viewDidAppear＆＃34;但我需要它在这个特定方法的条件块内，因为屏幕应该出现在整个锻炼程序的末尾。我究竟做错了什么？谢谢！

Answer 1

消息＆＃34;其视图不在窗口层次结构中＆＃34;因为代码仍然在您已经转换到另一个视图时执行。尝试在Public Class Form1 Delegate Function delegateSum(a As Integer, b As Integer) As Integer Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load Dim s As New delegateSum(AddressOf sum1) s += AddressOf sum2 'Here is the error, that is "Expression does not produce a value" End Sub Public Function sum1(x As Integer, y As Integer) As Integer Return x + y End Function Public Function sum2(x As Integer, y As Integer) As Integer Return x + y End Function End Class之后调用return或break来停止循环

Answer 2

尝试在performSegueWithIdentifier（＆＃34; endWorkout＆＃34;，sender：self）之后添加（break;）。

Swift错误：＆＃34; ...其视图不在窗口层次结构中。＆＃34; performseguewithidentifier

2 个答案: