Question

我们有办法阻止for循环吗？

我有一个循环在里面，它向用户询问一个对话框。我想在用户按OK或取消后暂停循环。

有可能吗？

因为当你有很多循环时，循环一个alertController看起来真的很难看。

for request in friendRequests
{
    let alertController = UIAlertController(title: "Friend Request", message: "Would you like to accept this friend request?", preferredStyle: UIAlertControllerStyle.Alert);
    let cancelAction: UIAlertAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.Cancel, handler: nil);
    let confirmAction: UIAlertAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler: nil);

    alertController.addAction(cancelAction);
    alertController.addAction(confirmAction);

    //How do we block or wait until user press a button??  
    self.navigationController.presentViewController(alertController);
}

有什么想法？谢谢

Answer 1

使用递归函数而不是循环

示例

i

Answer 2

不是创建循环，而是实现一个在用户决定后调用自身的逻辑方法。

更改方法实现，如：

func showAlert(var requestIndex : Int)
{
    if (requestIndex < friendRequests.count)
    {
        var request = friendRequests[requestIndex]
        requestIndex++
        let alertController = UIAlertController(title: "Friend Request", message: "Would you like to accept this friend request?", preferredStyle: UIAlertControllerStyle.Alert);
        let cancelAction: UIAlertAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.Cancel, handler:{ action in
            showAlert(requestIndex)
        });
        let confirmAction: UIAlertAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler: { action in
            showAlert(requestIndex)
        });

        alertController.addAction(cancelAction);
        alertController.addAction(confirmAction);

        //How do we block or wait until user press a button??
        self.navigationController.presentViewController(alertController);
    }
}

最初调用方法如：

showAlert(0);

使用UIAlertController阻止循环

2 个答案: