小编hid*_*ame的帖子

我有一个tableview,当加载时,每个单元格可能会返回一个NSError,我已经选择在UIAlertController中显示它.问题是如果返回多个错误,我会在控制台中收到此错误.

警告:尝试在MessagesMasterVC上呈现UIAlertController:0x14e64cb00:0x14e53d800已经呈现(null)

理想情况下,我希望在我的UIAlertController扩展方法中处理这个问题.

class func simpleAlertWithMessage(message: String!) -> UIAlertController {

    let alertController = UIAlertController(title: nil, message: message, preferredStyle: UIAlertControllerStyle.Alert)
    let cancel = UIAlertAction(title: "Ok", style: .Cancel, handler: nil)

    alertController.addAction(cancel)
    return alertController
}

基于matt的答案,我将扩展名更改为UIViewController扩展,更加清晰,并节省了大量的presentViewController代码.

    func showSimpleAlertWithMessage(message: String!) {

    let alertController = UIAlertController(title: nil, message: message, preferredStyle: UIAlertControllerStyle.Alert)
    let cancel = UIAlertAction(title: "Ok", style: .Cancel, handler: nil)

    alertController.addAction(cancel)

    if self.presentedViewController == nil {
        self.presentViewController(alertController, animated: true, completion: nil)
    }
}