Swift 2，无法识别的选择器发送到 UIAlertController 的实例

Question

点击搜索后点击 TableView 时出现如下错误。

以下错误 2016-06-03 11:20:31.578 ContactPLUS[1724:678512] 警告：尝试在 已经呈现（空） 圣>> 2016-06-03 11:20:32.001 ContactPLUS[1724:678512]-[_UIAlertControllerAlertPresentationController AdaptivePresentationController]： 无法识别的选择器发送到实例 0x1616570d0

2016-06-03 11:20:32.001 ContactPLUS[1724:678512] *** 由于未捕获的异常“NSInvalidArgumentException”而终止应用程序， 原因：'-[_UIAlertControllerAlertPresentationController AdaptivePresentationController]：无法识别的选择器发送到实例 0x1616570d0'

*** 首先抛出调用堆栈： (0x182876e38 0x181edbf80 0x18287dccc 0x18287ac74 0x182778d1c 0x18836433c 0x1880117f8 0x187d20740 0x187c72fd8 0x187c80990 0x1879b24a4 0x18282c7b0 0x18282a554 0x18282a984 0x182754d10 0x18403c088 0x187a29f70 0x1000f8070 0x1822f28b8) libc++abi.dylib：以 NSException 类型的未捕获异常终止

下面是我的代码

进入函数

dispatch_async(dispatch_get_main_queue()) {
                                   self.searchActivityLoader.stopAnimating()
                                   self.searchActivityLoader.hidden = true
                                    self.showError(self.noDataFound)
                                }

显示警报控制器的逻辑：

func showError(errorStr: String){

    dispatch_async(dispatch_get_main_queue(), {

        if(!errorStr.isEmpty){
            let alertController =  self.controllerUtil!.customOkAlert("Fail",buttonTitle:"OK" , alertMessage: errorStr)
            self.presentViewController(alertController, animated: true, completion: nil) 
            //**Error comes after executing  above two lines**
        }
        self.genericArr = []

        self.contactsTableView.dataSource = self
        self.contactsTableView.reloadData()
        self.searchActivityLoader.stopAnimating()
        self.searchActivityLoader.hidden = true
    })

}

///CustomeOkAlert

//警报控制器使用默认操作和自定义消息进行管理

func customOkAlert(alertPageTitle: String,buttonTitle: String, alertMessage: String) -> UIAlertController
{
    let customeAlert = UIAlertController(title: alertPageTitle, message: alertMessage, preferredStyle: UIAlertControllerStyle.Alert)

    customeAlert.view.layer.cornerRadius = 10
    customeAlert.view.backgroundColor = utility.uicolorFromHex(0xEBEBED)
    customeAlert.view.tintColor = utility.uicolorFromHex(0x70B420)
    let cancelAction: UIAlertAction = UIAlertAction(title: buttonTitle, style: .Default){action in
        //do nothing
    }
    customeAlert.addAction(cancelAction)


    return customeAlert
}

Answer 1

Attempt to present <UIAlertController which is already presenting的原因是经常报错，需要添加检查是否已经出现报错信息。 以下代码帮助我重现了您的问题。在handleError 方法中评论检查将开始问题再现：

class ViewController: UIViewController {

    var alertController: UIAlertController!

    override func viewDidLoad() {
        super.viewDidLoad()

        handleError()
        handleError()
    }

    func handleError() {

        dispatch_async(dispatch_get_main_queue(), {

            //commenting this check will start issue reproduction
            if self.alertController != nil {
                print("alert is already presented")
                return
            }
            self.alertController =  self.customOkAlert("Fail",buttonTitle:"OK" , alertMessage: "qweqwe")
            self.presentViewController(self.alertController, animated: true, completion: nil)
        })
    }

    func customOkAlert(alertPageTitle: String,buttonTitle: String, alertMessage: String) -> UIAlertController
    {
        let customeAlert = UIAlertController(title: alertPageTitle, message: alertMessage, preferredStyle: UIAlertControllerStyle.Alert)

        customeAlert.view.layer.cornerRadius = 10

        let cancelAction: UIAlertAction = UIAlertAction(title: buttonTitle, style: .Default){action in

            self.alertController = nil
        }
        customeAlert.addAction(cancelAction)


        return customeAlert
    }
}