实际上我有一个带有4种方法的视图控制器。 3个方法用于显示UIAlertController没有操作按钮，例如＆＃34; ok＆＃34;或＆＃34;取消＆＃34;。标题和消息。解雇那些UIAlertController的最终方法。我的一个警报是在异步调用请求时显示。当我们得到结果时，它将被解雇并隐藏。
问题是当我的第一个警报显示并且突然连接丢失时，另一个警报将显示关于＆＃34; Internet Lost＆＃34;由于该警告，消息无法显示。
2015-06-17 13:49:04.787 myauction[2404:40506] Warning: Attempt to present <UIAlertController: 0x7f8d136bafa0> on <myauction.AuctionLatestViewController: 0x7f8d13771180> while a presentation is in progress!
这意味着我无法成功解除第一个警报。有什么帮助吗？
这是myAlertController
import UIKit
class MyAlertViewController:UIViewController{
var myAlertController : UIAlertController!
func displayLoadingAlert(viewController: UIViewController?) -> UIAlertController {
var controllerToPresent = viewController
if controllerToPresent == nil {
controllerToPresent = self
}
//create an alert controller
myAlertController = UIAlertController(title: "Loading...", message: "We are getting the data,Please Wait", preferredStyle: .Alert)
let indicator = UIActivityIndicatorView()
indicator.color = UIColor.redColor()
indicator.setTranslatesAutoresizingMaskIntoConstraints(false)
myAlertController.view.addSubview(indicator)
let views = ["pending" : myAlertController.view, "indicator" : indicator]
var constraints = NSLayoutConstraint.constraintsWithVisualFormat("V:[indicator]-(7)-|", options: nil, metrics: nil, views: views)
constraints += NSLayoutConstraint.constraintsWithVisualFormat("H:|[indicator]|", options: nil, metrics: nil, views: views)
myAlertController.view.addConstraints(constraints)
indicator.userInteractionEnabled = false
indicator.startAnimating()
controllerToPresent!.presentViewController(myAlertController, animated: true, completion: nil)
return myAlertController
}
func connectionErrorAlert(viewController: UIViewController?) -> UIAlertController {
var controllerToPresent = viewController
if controllerToPresent == nil {
controllerToPresent = self
}
//create an alert controller
myAlertController = UIAlertController(title: "Not Connected", message: "No Internet Connection", preferredStyle: .Alert)
let defaultAction = UIAlertAction(title: "OK", style: .Default,handler:nil)
myAlertController.addAction(defaultAction)
controllerToPresent!.presentViewController(myAlertController, animated: true, completion: nil)
return myAlertController
}
func requestTimeOutErrorAlert(viewController: UIViewController?) -> UIAlertController {
var controllerToPresent = viewController
if controllerToPresent == nil {
controllerToPresent = self
}
//create an alert controller
myAlertController = UIAlertController(title: "Request Time Out", message: "Please Tap Retry to Get The Data", preferredStyle: .Alert)
let defaultAction = UIAlertAction(title: "OK", style: .Default,handler:nil)
myAlertController.addAction(defaultAction)
controllerToPresent!.presentViewController(myAlertController, animated: true, completion: nil)
return colayAlertController
}
func dismissLoadingAlert(){
myAlertController.dismissViewControllerAnimated(true, completion: nil)
}
}
这是我的viewcontroller（注意我不会显示myAlertViewController的初始化）
func getResults{
api.searchCar()
//This is where i start to load my first alert every time it call
self.myAlertViewController = displayLoadingAlert(self)
}
func didReceiveAPIResults(results: NSDictionary,headers:JSON) {
dispatch_async(dispatch_get_main_queue(), {
//do about showing the results....
//Then i dismiss my first loading alert
self.myAlertController.dismissViewControllerAnimated(true){}
})
}
func didNotReceiveAPIResults(results: Bool,error:NSError){
dispatch_async(dispatch_get_main_queue(), {
//I did dismiss the first alert before i gonna show another one
self.myAlertController.dismissViewControllerAnimated(true){
if (results) {
if error.localizedDescription == "The Internet connection appears to be offline."{
self.myAlertViewController = connectionErrorAlert(self)
self.carTableView.hidden=true
self.retryButton?.hidden=false
self.retryButton?.enabled=true
}
if error.localizedDescription == "Request Time Out."{
self.myAlertViewController = requestTimeOutErrorAlert(self)
self.carTableView.hidden=true
self.retryButton?.hidden=false
self.retryButton?.enabled=true
}
}else{
//self.myAlertController.displayLoadingAlert(self)
self.retryButton?.hidden=true
self.retryButton?.enabled=false
self.carTableView.hidden=false
self.carTableView.reloadData()
}
}
})
}
答案 0 :(得分：2)
您应该在completion方法的dismissViewControllerAnimated块中插入代码，然后再以模态方式呈现另一个ViewController。
查看我已更新的代码：
func didNotReceiveAPIResults(results: Bool,error:NSError){
dispatch_async(dispatch_get_main_queue(), {
//
// I'm calling your error message in the completion block of the
// dismissViewControllerAnimated Method
//
self.myAlertController.dismissViewControllerAnimated(true) {
if (results) {
if error.localizedDescription == "The Internet connection appears to be offline."{
self.myAlertController.connectionErrorAlert(self)
}
if error.localizedDescription == "Request Time Out."{
self.myAlertController.requestTimeOutErrorAlert(self)
}
//
// Moved this code out of your if-statements since they are called
// no matter which case is true
//
self.carTableView.hidden=true
self.retryButton?.hidden=false
self.retryButton?.enabled=true
} else {
//self.myAlertController.displayLoadingAlert(self)
self.retryButton?.hidden=true
self.retryButton?.enabled=false
self.carTableView.hidden=false
self.carTableView.reloadData()
}
}
})
}
答案 1 :(得分：0)
首先，我犯了一个错误，因为我正在创建新的viewcontroller而不是定义extension.So，如果有些初学者正在搜索结果，请不要像上面的代码那样。所以这就是答案。< / p>
如果您想添加自定义提醒，请使用此类扩展程序。
import UIKit
extension UIAlertController {
class func displayLoadingAlert() -> UIAlertController {
//create an alert controller
let myAlertController = UIAlertController(title: "Loading...", message: "We are getting the data,Please Wait...", preferredStyle: .Alert)
let indicator = UIActivityIndicatorView()
indicator.color = UIColor.redColor()
indicator.setTranslatesAutoresizingMaskIntoConstraints(false)
myAlertController.view.addSubview(indicator)
let views = ["pending" : myAlertController.view, "indicator" : indicator]
var constraints = NSLayoutConstraint.constraintsWithVisualFormat("V:[indicator]-(7)-|", options: nil, metrics: nil, views: views)
constraints += NSLayoutConstraint.constraintsWithVisualFormat("H:|[indicator]|", options: nil, metrics: nil, views: views)
myAlertController.view.addConstraints(constraints)
indicator.userInteractionEnabled = false
indicator.startAnimating()
return myAlertController
}
class func connectionErrorAlert() -> UIAlertController {
let myAlertController = UIAlertController(title: "Not Connected", message: "No Internet Connection", preferredStyle: .Alert)
let defaultAction = UIAlertAction(title: "OK", style: .Default,handler:nil)
myAlertController.addAction(defaultAction)
return myAlertController
}
class func requestTimeOutErrorAlert() -> UIAlertController {
// same as above
}
}
然后如何从其他视图控制器中使用它（用于显示和解除）
class ViewController : UIViewController{
var myAlert : UIAlertController!
//For displaying the one of the alert
func getResults(){
myAlert = UIAlertController.displayLoadingAlert()
self.presentViewController(myAlert, animated: true, completion: nil)
}
//For dismissing the alert,please add the code in the completion that will do after dismiss
func afterGettingResults(){
self.myAlert.dismissViewControllerAnimated(true){
//do your job after dismiss is done
}
}
}
希望每个人都能得到这个帮助。感谢@ezCoding试图帮助我摆脱我的这个黑暗错误并向我展示成功之光。