Question

我目前在其中一个应用中有以下代码行。这是一个简单的UIAlertView。但是，从iOS 8开始，现在不推荐使用它：

let alertView = UIAlertView(title: "Oops!", message: "This feature isn't available right now", delegate: self, cancelButtonTitle: "OK")

如何更新此功能以使用iOS 8+？我相信我必须改变一些东西UIAlertCotroller，虽然我不太清楚是什么。

Answer 1

您需要使用UIAlertController代替。对于class documentation来说非常简单，甚至在文档的开头包含清单1中的用法示例（确定它在ObjC中而不是在Swift中，但它非常相似）。

因此，对于您的用例，以下是它的转换方式（添加了注释）：

let alert = UIAlertController(title: "Oops!", message:"This feature isn't available right now", preferredStyle: .alert)
let action = UIAlertAction(title: "OK", style: .default) { _ in
  // Put here any code that you would like to execute when
  // the user taps that OK button (may be empty in your case if that's just
  // an informative alert)
}
alert.addAction(action)
self.presentViewController(alert, animated: true){}

因此紧凑的代码看起来像：

let alert = UIAlertController(title: "Oops!", message:"This feature isn't available right now", preferredStyle: .Alert)
alert.addAction(UIAlertAction(title: "OK", style: .Default) { _ in })
self.present(alert, animated: true){}

此处self应该是UIViewController。

其他提示：如果您需要调用在UIViewController的上下文之外显示提醒的代码，（其中self不是UIViewController），您可以随时使用您应用的根VC：

let rootVC = UIApplication.sharedApplication().keyWindow?.rootViewController
rootVC?.presentViewController(alert, animated: true){}

（但一般情况下，当你拥有一个已知的UIViewController时，最好使用已知的public class SubjectQuestion { public int Id { get; set; } public int SubjectId { get; set; } public int QuestionId { get; set; } public virtual Question.Question Question { get; set; } //Change one to one } list = _db.QuestionSubjects.Where(i => i.SubjectId == subjectId).ToList().Select(x => x.Questions.ToModel()).ToList(); - 而且你通常会提出来自UIViewControllers的警报 - 或者尝试获取最合适的警报，具体取决于你的上下文而不是依赖于这个提示）

Answer 2

对于那些想知道如何在Objective-C中执行此操作的人：

    //Step 1: Create a UIAlertController
    UIAlertController *myAlertController = [UIAlertController alertControllerWithTitle:@"MyTitle"
                                                              message: @"MyMessage"
                                                              preferredStyle:UIAlertControllerStyleAlert                   ];

    //Step 2: Create a UIAlertAction that can be added to the alert
    UIAlertAction* ok = [UIAlertAction
                         actionWithTitle:@"OK"
                         style:UIAlertActionStyleDefault
                         handler:^(UIAlertAction * action)
                         {
                             //Do some thing here, eg dismiss the alertwindow
                             [myAlertController dismissViewControllerAnimated:YES completion:nil];

                         }];

    //Step 3: Add the UIAlertAction ok that we just created to our AlertController
    [myAlertController addAction: ok];

    //Step 4: Present the alert to the user
    [self presentViewController:myAlertController animated:YES completion:nil];

这将弹出一个如下所示的警告：

Answer 3

let alertView = UIAlertView(title: "Oops!", message: "This feature isn't available right now", delegate: self, cancelButtonTitle: "OK")

变为

let alertController = UIAlertController(title: "Oops!", message: "This feature isn't available right now", preferredStyle: .Alert)
let OKAction = UIAlertAction(title: "OK", style: .Default) { (action) in }
alertController.addAction(OKAction)
self.presentViewController(alertController, animated: true) { }

Answer 4

我认为这是为旧iOS SDK提供向后兼容性以及在使用较新SDK时使用新API的方法。此外，使用已弃用的类在代码中弃用也没有警告。

    if ([UIAlertController class]) {
        // Use new API to create alert controller, add action button and display it
        UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"CityBoard" message:error.errorDescription preferredStyle:UIAlertControllerStyleAlert];
        UIAlertAction* ok = [UIAlertAction actionWithTitle: @"OK" style:UIAlertActionStyleDefault handler:^(UIAlertAction * action) {
            [alertController dismissViewControllerAnimated:YES completion:nil];
        }];
        [alertController addAction: ok];
        [self presentViewController:alertController animated:YES completion:nil];
    } else {
        // We are running on old SDK as the new class is not available
        // Hide the compiler errors about deprecation and use the class available on older SDK
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"CityBoard"
                                                        message:error.errorDescription
                                                       delegate:self
                                              cancelButtonTitle:@"OK"
                                              otherButtonTitles:nil];
        [alert show];
#pragma clang diagnostic pop

Answer 5

Swift 2.0：

使用AlertController。

操作表示例：

  let mediaActionSheet: UIAlertController = UIAlertController(title: "Media Action Sheet", message: "Choose an option!", preferredStyle: .ActionSheet)

  //Create and add the Cancel action
  let cancelAction: UIAlertAction = UIAlertAction(title: "Cancel", style: .Cancel) { action -> Void in

   //Just dismiss the action sheet

  }
  mediaActionSheet.addAction(cancelAction)
  //Create and add first option action
  let takePictureAction: UIAlertAction = UIAlertAction(title: "Take Picture", style: .Default) { action -> Void in

   //Code for launching the camera goes here

  }

  mediaActionSheet.addAction(takePictureAction)

  //Create and add a second option action
  let choosePictureAction: UIAlertAction = UIAlertAction(title: "Choose From Gallery", style: .Default) { action -> Void in

   //Code for picking from gallery goes here

  }

  mediaActionSheet.addAction(choosePictureAction)

  //Present the AlertController
  self.presentViewController(mediaActionSheet, animated: true, completion: nil)

警报示例：

1）

let simpleAlert = UIAlertController(title: "Simple Alert", message: "It is just awesome", preferredStyle: UIAlertControllerStyle.Alert);

  //show it
  showViewController(simpleAlert, sender: self);

2）警告使用TextField。

  let inputTextFieldAlert:UIAlertController = UIAlertController(title: " Input TextField Alert ", message: " Enter on the below TextField ", preferredStyle: UIAlertControllerStyle.Alert);

  //default input textField (no configuration...)
  inputTextFieldAlert.addTextFieldWithConfigurationHandler(nil);

  //no event handler (just close dialog box)
  inputTextFieldAlert.addAction(UIAlertAction(title: "No", style: UIAlertActionStyle.Cancel, handler: nil));

  //event handler with closure
  inputTextFieldAlert.addAction(UIAlertAction(title: "Yes", style: UIAlertActionStyle.Default, handler: {(action:UIAlertAction) in

   let fields = inputTextFieldAlert.textFields!;
   print("Output: "+fields[0].text!);
  }));

  presentViewController(inputTextFieldAlert, animated: true, completion: nil);

3）

var alert = UIAlertController(title: "TextField Alert", message: "Enter on the below TextField", preferredStyle: UIAlertControllerStyle.Alert);

  //configured input textField
  var field:UITextField?;

  alert.addTextFieldWithConfigurationHandler({(input:UITextField)in
   input.placeholder="Empty Dtaa ;-)";
   input.clearButtonMode=UITextFieldViewMode.WhileEditing;

   field=input;
  });

  //YES Handler
  func yesHandler(actionTarget: UIAlertAction){

   print(field!.text!);
  }
  //event handler with predefined function
  alert.addAction(UIAlertAction(title: "Yes", style: UIAlertActionStyle.Default, handler: yesHandler));

  presentViewController(alert, animated: true, completion: nil);

Answer 6

上面的例子对我没什么帮助。我的解决方案适用于XCode 6.4。，Swift 1.2，您可以将此代码复制并粘贴到测试项目中，以了解它是如何工作的：

解决方案1 - Swift 1.2：

import UIKit

let ALERT_TITLE   = "Got you working, right?"
let ALERT_MESSAGE = "Well maybe..."

class ViewController: UIViewController
{
    private var alert: UIAlertController!

    private var presentAlertButton: UIButton!

    override func viewDidAppear(animated: Bool)
    {
        /*
        // QUICK TEST - 1
        self.presentViewController(alert, animated: true, completion: nil)
        */


        // QUCIK TEST - 2
        /*
        let rootVC = UIApplication.sharedApplication().keyWindow?.rootViewController
        rootVC?.presentViewController(alert, animated: true, completion: nil)
        */
    }

    override func viewDidLoad()
    {
        super.viewDidLoad()

        createAndAddAlertV()

        createAndAddAlertButton()
    }

    private func createAndAddAlertV()
    {
        alert = UIAlertController(title:ALERT_TITLE, message:ALERT_MESSAGE, preferredStyle: .Alert)
        let alertAction = UIAlertAction(title: "OK", style: .Default, handler: nil)
        alert.addAction(alertAction)
    }

    private func createAndAddAlertButton()
    {
        presentAlertButton = UIButton(frame: CGRectMake(
            view.frame.size.width / 2,
            view.frame.size.height / 2,
            200,
            100))

        presentAlertButton.layer.anchorPoint = CGPointMake(1.0, 1.0)
        presentAlertButton.backgroundColor = UIColor.redColor()
        presentAlertButton.setTitle("Click For Alert", forState: .Normal)
        presentAlertButton.addTarget(self, action: "showAlertV", forControlEvents: .TouchUpInside)
        self.view.addSubview(presentAlertButton)
    }

    @IBAction func showAlertV()
    {
        println(" Showing... ")
        self.presentViewController(alert, animated: true, completion: nil)
    }

}

我在Xcode 7.0中检查了这个解决方案。有效。 Xcode做了一个改变。我再次在Xcode 6.4中重新编译它，它工作。如果存在的话，Swift 2.0的更改应该是次要的。

希望这会有所帮助;）

Answer 7

您可以将此代码用于警报视图：

 UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"Title" message:@"Message" preferredStyle:UIAlertControllerStyleAlert];

        UIAlertAction* ok = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:nil];
        [alertController addAction:ok];

        [self presentViewController:alertController animated:YES completion:nil];

对于多个按钮，您可以使用：

 UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"Title" message:@"Message" preferredStyle:UIAlertControllerStyleAlert];

        [alertController addAction:[UIAlertAction actionWithTitle:@"Button 1" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
            [self loadGooglrDrive];
        }]];

        [alertController addAction:[UIAlertAction actionWithTitle:@"Button 2" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
            [self loadDropBox];
        }]];

        [alertController addAction:[UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
            [self closeAlertview];
        }]];

        dispatch_async(dispatch_get_main_queue(), ^ {
            [self presentViewController:alertController animated:YES completion:nil];
        });

-(void)closeAlertview
{

    [self dismissViewControllerAnimated:YES completion:nil];
}

Answer 8

https://github.com/nagibazad/UIAlertControllerWrapper

此包装器提供了一种将UIAlertView轻松转换为UIAlertController的方法。 UIAlertView不推荐使用iOS 9.0。将您的UIAlertView的旧项目转换为UIAlertController，使用此UIAlertControllerWrapper使您的委托实现保持相同，并摆脱所有与UIAlertView相关的warnings。

如何从UIAlertView迁移（在iOS8中已弃用）

8 个答案: