一个按钮

Question

我一直在努力在Swift中创建一个UIAlertView，但由于某些原因我无法得到正确的声明，因为我收到了这个错误：

找不到接受提供的'init'的重载参数

以下是我写的方式：

let button2Alert: UIAlertView = UIAlertView(title: "Title", message: "message",
                     delegate: self, cancelButtonTitle: "OK", otherButtonTitles: nil)

然后打电话给我我正在使用：

button2Alert.show()

截至目前它正在崩溃，我似乎无法正确使用语法。

Answer 1

来自UIAlertView班级：

//不推荐使用UIAlertView。使用 UIAlertController 而不是UIAlertControllerStyleAlert的preferredStyle

在iOS 8上，您可以这样做：

let alert = UIAlertController(title: "Alert", message: "Message", preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "Click", style: UIAlertActionStyle.Default, handler: nil))
self.presentViewController(alert, animated: true, completion: nil)

现在UIAlertController是一个单独的类，用于在iOS 8上创建和我们所知的UIAlertView和UIActionSheet s。

编辑：要处理操作：

alert.addAction(UIAlertAction(title: "OK", style: .Default, handler: { action in
    switch action.style{
    case .Default:
        print("default")

    case .Cancel:
        print("cancel")

    case .Destructive:
        print("destructive")
    }
}}))

编辑Swift 3：

let alert = UIAlertController(title: "Alert", message: "Message", preferredStyle: UIAlertControllerStyle.alert)
alert.addAction(UIAlertAction(title: "Click", style: UIAlertActionStyle.default, handler: nil))
self.present(alert, animated: true, completion: nil)

编辑Swift 4.x：

let alert = UIAlertController(title: "Alert", message: "Message", preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "OK", style: .default, handler: { action in
      switch action.style{
      case .default:
            print("default")

      case .cancel:
            print("cancel")

      case .destructive:
            print("destructive")


}}))
self.present(alert, animated: true, completion: nil)

Answer 2

一个按钮

class ViewController: UIViewController {

    @IBAction func showAlertButtonTapped(_ sender: UIButton) {

        // create the alert
        let alert = UIAlertController(title: "My Title", message: "This is my message.", preferredStyle: UIAlertController.Style.alert)

        // add an action (button)
        alert.addAction(UIAlertAction(title: "OK", style: UIAlertAction.Style.default, handler: nil))

        // show the alert
        self.present(alert, animated: true, completion: nil)
    }
}

两个按钮

class ViewController: UIViewController {

    @IBAction func showAlertButtonTapped(_ sender: UIButton) {

        // create the alert
        let alert = UIAlertController(title: "UIAlertController", message: "Would you like to continue learning how to use iOS alerts?", preferredStyle: UIAlertController.Style.alert)

        // add the actions (buttons)
        alert.addAction(UIAlertAction(title: "Continue", style: UIAlertAction.Style.default, handler: nil))
        alert.addAction(UIAlertAction(title: "Cancel", style: UIAlertAction.Style.cancel, handler: nil))

        // show the alert
        self.present(alert, animated: true, completion: nil)
    }
}

三个按钮

class ViewController: UIViewController {

    @IBAction func showAlertButtonTapped(_ sender: UIButton) {

        // create the alert
        let alert = UIAlertController(title: "Notice", message: "Lauching this missile will destroy the entire universe. Is this what you intended to do?", preferredStyle: UIAlertController.Style.alert)

        // add the actions (buttons)
        alert.addAction(UIAlertAction(title: "Remind Me Tomorrow", style: UIAlertAction.Style.default, handler: nil))
        alert.addAction(UIAlertAction(title: "Cancel", style: UIAlertAction.Style.cancel, handler: nil))
        alert.addAction(UIAlertAction(title: "Launch the Missile", style: UIAlertAction.Style.destructive, handler: nil))

        // show the alert
        self.present(alert, animated: true, completion: nil)
    }
}

处理按钮点击

以上示例中的handler为nil。当用户点按按钮时，您可以将nil替换为closure来执行某些操作。例如：

alert.addAction(UIAlertAction(title: "Launch the Missile", style: UIAlertAction.Style.destructive, handler: { action in

    // do something like...
    self.launchMissile()

}))

注释

多个按钮不一定需要使用不同的UIAlertAction.Style类型。它们都可以是.default。
对于三个以上的按钮，请考虑使用操作表。设置非常相似。 Here is an example.

Answer 3

您可以使用标准构造函数创建UIAlert，但“遗留”似乎不起作用：

let alert = UIAlertView()
alert.title = "Alert"
alert.message = "Here's a message"
alert.addButtonWithTitle("Understood")
alert.show()

Answer 4

在Swift 4.2和Xcode 10中

方法1：

简单提醒

let alert = UIAlertController(title: "Your title", message: "Your message", preferredStyle: .alert)

     let ok = UIAlertAction(title: "OK", style: .default, handler: { action in
     })
     alert.addAction(ok)
     let cancel = UIAlertAction(title: "Cancel", style: .default, handler: { action in
     })
     alert.addAction(cancel)
     DispatchQueue.main.async(execute: {
        self.present(alert, animated: true)
})

方法2：

具有共享类的ALERT

如果您要使用共享类样式（在每个位置写入一次）

import UIKit
class SharedClass: NSObject {//This is shared class
static let sharedInstance = SharedClass()

    //Show alert
    func alert(view: UIViewController, title: String, message: String) {
        let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
        let defaultAction = UIAlertAction(title: "OK", style: .default, handler: { action in
        })
        alert.addAction(defaultAction)
        DispatchQueue.main.async(execute: {
            view.present(alert, animated: true)
        })
    }

    private override init() {
    }
}

现在在每个商品中都这样的呼叫提醒

SharedClass.SharedInstance.alert(view: self, title: "Your title here", message: "Your message here")

方法3：

所有窗口的当前警报顶部

如果要在所有视图顶部显示警报，请使用此代码

func alertWindow(title: String, message: String) {
    DispatchQueue.main.async(execute: {
        let alertWindow = UIWindow(frame: UIScreen.main.bounds)
        alertWindow.rootViewController = UIViewController()
        alertWindow.windowLevel = UIWindowLevelAlert + 1

        let alert2 = UIAlertController(title: title, message: message, preferredStyle: .alert)
        let defaultAction2 = UIAlertAction(title: "OK", style: .default, handler: { action in
        })
        alert2.addAction(defaultAction2)

        alertWindow.makeKeyAndVisible()

        alertWindow.rootViewController?.present(alert2, animated: true, completion: nil)
    })
}

函数调用

SharedClass.sharedInstance.alertWindow(title:"This your title", message:"This is your message")

方法4：

扩展通知

extension  UIViewController {

    func showAlert(withTitle title: String, withMessage message:String) {
        let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
        let ok = UIAlertAction(title: "OK", style: .default, handler: { action in
        })
        let cancel = UIAlertAction(title: "Cancel", style: .default, handler: { action in
        })
        alert.addAction(ok)
        alert.addAction(cancel)
        DispatchQueue.main.async(execute: {
            self.present(alert, animated: true)
        })
    }
}

现在这样通话

//Call showAlert function in your class
@IBAction func onClickAlert(_ sender: UIButton) {
    showAlert(withTitle:"Your Title Here", withMessage: "YourCustomMessageHere")
}

方法5：

带有文本字段的ALERT

如果您想添加文本字段来提醒。

//Global variables
var name:String?
var login:String?

//Call this function like this:  alertWithTF() 
//Add textfields to alert 
func alertWithTF() {

    let alert = UIAlertController(title: "Login", message: "Enter username&password", preferredStyle: .alert)
    // Login button
    let loginAction = UIAlertAction(title: "Login", style: .default, handler: { (action) -> Void in
        // Get TextFields text
        let usernameTxt = alert.textFields![0]
        let passwordTxt = alert.textFields![1]
        //Asign textfileds text to our global varibles
        self.name = usernameTxt.text
        self.login = passwordTxt.text

        print("USERNAME: \(self.name!)\nPASSWORD: \(self.login!)")
    })

    // Cancel button
    let cancel = UIAlertAction(title: "Cancel", style: .destructive, handler: { (action) -> Void in })

    //1 textField for username
    alert.addTextField { (textField: UITextField) in
        textField.placeholder = "Enter username"
        //If required mention keyboard type, delegates, text sixe and font etc...
        //EX:
        textField.keyboardType = .default
    }

    //2nd textField for password
    alert.addTextField { (textField: UITextField) in
        textField.placeholder = "Enter password"
        textField.isSecureTextEntry = true
    }

    // Add actions
    alert.addAction(loginAction)
    alert.addAction(cancel)
    self.present(alert, animated: true, completion: nil)

}

方法6：

带有扩展名的SharedClass的警报

//This is your shared class
import UIKit

 class SharedClass: NSObject {

 static let sharedInstance = SharedClass()

 //Here write your code....

 private override init() {
 }
}

//Alert function in shared class
extension UIViewController {
    func showAlert(title: String, msg: String) {
        DispatchQueue.main.async {
            let alert = UIAlertController(title: title, message: msg, preferredStyle: .alert)
            alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
            self.present(alert, animated: true, completion: nil)
        }
    }
}

现在直接像这样呼叫

self.showAlert(title: "Your title here...", msg: "Your message here...")

方法7：

与扩展程序在单独的类中没有共享类的警报。

创建一个新的Swift类，然后import UIKit。复制并粘贴以下代码。

//This is your Swift new class file
import UIKit
import Foundation

extension UIAlertController {
    class func alert(title:String, msg:String, target: UIViewController) {
        let alert = UIAlertController(title: title, message: msg, preferredStyle: UIAlertControllerStyle.alert)
        alert.addAction(UIAlertAction(title: "Ok", style: UIAlertActionStyle.default) {
        (result: UIAlertAction) -> Void in
        })
        target.present(alert, animated: true, completion: nil)
    }
}

现在在您所有的类中（单行）都具有这样的呼叫提醒功能。

UIAlertController.alert(title:"Title", msg:"Message", target: self)

怎么样......

Answer 5

点击查看

@IBAction func testClick(sender: UIButton) {

  var uiAlert = UIAlertController(title: "Title", message: "Message", preferredStyle: UIAlertControllerStyle.Alert)
  self.presentViewController(uiAlert, animated: true, completion: nil)

  uiAlert.addAction(UIAlertAction(title: "Ok", style: .Default, handler: { action in
   println("Click of default button")
  }))

  uiAlert.addAction(UIAlertAction(title: "Cancel", style: .Cancel, handler: { action in
   println("Click of cancel button")
  }))

}

用两个按钮完成OK＆amp;取消

Answer 6

如果你的目标是iOS 7 和 8，那么你需要这样的东西，以确保你为每个版本使用正确的方法，因为在iOS 8中不推荐使用UIAlertView ，但在iOS 7中无法使用UIAlertController：

func alert(title: String, message: String) {
    if let getModernAlert: AnyClass = NSClassFromString("UIAlertController") { // iOS 8
        let myAlert: UIAlertController = UIAlertController(title: title, message: message, preferredStyle: .Alert)
        myAlert.addAction(UIAlertAction(title: "OK", style: .Default, handler: nil))
        self.presentViewController(myAlert, animated: true, completion: nil)
    } else { // iOS 7
        let alert: UIAlertView = UIAlertView()
        alert.delegate = self

        alert.title = title
        alert.message = message
        alert.addButtonWithTitle("OK")

        alert.show()
    }
}

Answer 7

用快速语言显示UIAlertView： -

协议UIAlertViewDelegate

let alert = UIAlertView(title: "alertView", message: "This is alertView", delegate:self, cancelButtonTitle:"Cancel", otherButtonTitles: "Done", "Delete")
alert.show()

用快速语言显示UIAlertViewController： -

let alert = UIAlertController(title: "Error", message: "Enter data in Text fields", preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler: nil))
self.presentViewController(alert, animated: true, completion: nil)

Answer 8

只是不要在构造函数中提供otherButtonTitles。

let alertView = UIAlertView(title: "Oops!", message: "Something
happened...", delegate: nil, cancelButtonTitle: "OK")

alertView.show()

但我确实同意奥斯卡，这个类在iOS 8中已被弃用，因此如果您只使用iOS 8应用，则不会使用UIAlertView。否则上面的代码将起作用。

Answer 9

使用Swift 2的协议扩展，您可以创建一个为视图控制器提供默认实现的协议：

ShowsAlert.swift

import UIKit

protocol ShowsAlert {}

extension ShowsAlert where Self: UIViewController {
    func showAlert(title: String = "Error", message: String) {
        let alertController = UIAlertController(title: title, message: message, preferredStyle: .Alert)
        alertController.addAction(UIAlertAction(title: "Ok", style: .Default, handler: nil))
        presentViewController(alertController, animated: true, completion: nil)
    }
}

ViewController.swift

class ViewController: UIViewController, ShowsAlert {
    override func viewDidLoad() {
        super.viewDidLoad()
        showAlert(message: "Hey there, I am an error message!")
    }
}

Answer 10

我找到了这个，

var alertView = UIAlertView();
alertView.addButtonWithTitle("Ok");
alertView.title = "title";
alertView.message = "message";
alertView.show();

虽然不好，但确实有效：）

更新

但我在头文件中找到了：

extension UIAlertView {
    convenience init(title: String, message: String, delegate: UIAlertViewDelegate?, cancelButtonTitle: String?, otherButtonTitles firstButtonTitle: String, _ moreButtonTitles: String...)
}

有人可以解释一下。

Answer 11

对于 SWIFT4 ，我认为，扩展UIViewController并创建可重复使用的确认控件是最优雅的方式。

您可以扩展UIViewController，如下所示：

extension UIViewController {

func AskConfirmation (title:String, message:String, completion:@escaping (_ result:Bool) -> Void) {
    let alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.alert)
    self.present(alert, animated: true, completion: nil)

    alert.addAction(UIAlertAction(title: "Ok", style: .default, handler: { action in
        completion(true)
    }))

    alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: { action in
        completion(false)
    }))
  }
}

然后你可以随时使用它：

 AskConfirmation(title: "YOUR MESSAGE TITLE", message: "YOUR MESSAGE") { (result) in
        if result { //User has clicked on Ok

        } else { //User has clicked on Cancel

        }
    }

Answer 12

Swift 3

以下是如何使用Swift 3的一个按钮创建简单警报的简单示例。

let alert = UIAlertController(title: "Title",
                              message: "Message",
                              preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "Ok", style: .default))
present(alert, animated: true)

在上面的示例中，操作的句柄回调已被省略，因为单击按钮时，带有一个按钮的警报视图的默认行为将消失。

以下是如何创建另一个操作，可以使用“alert.addAction（action）”将其添加到警报中。不同的样式是.default，.destructive和.cancel。

let action = UIAlertAction(title: "Ok", style: .default) { action in
    // Handle when button is clicked    
}

Answer 13

我制作了一个单身人士课程，方便您在应用中的任何位置使用：https://github.com/Swinny1989/Swift-Popups

然后，您可以创建一个包含多个按钮的弹出窗口，如下所示：

Popups.SharedInstance.ShowAlert(self, title: "Title goes here", message: "Messages goes here", buttons: ["button one" , "button two"]) { (buttonPressed) -> Void in
    if buttonPressed == "button one" { 
      //Code here
    } else if buttonPressed == "button two" {
        // Code here
    }
}

或弹出一个按钮，如下所示：

Popups.SharedInstance.ShowPopup("Title goes here", message: "Message goes here.")

Answer 14

    class Preview: UIViewController , UIAlertViewDelegate
    {
        @IBAction func MoreBtnClicked(sender: AnyObject)
        {
            var moreAlert=UIAlertView(title: "Photo", message: "", delegate: self, cancelButtonTitle: "No Thanks!", otherButtonTitles: "Save Image", "Email", "Facebook", "Whatsapp" )
            moreAlert.show()
            moreAlert.tag=111;
        }

        func alertView(alertView: UIAlertView, didDismissWithButtonIndex buttonIndex: Int)
        {
            if alertView.tag==111
            {
                if buttonIndex==0
                {
                    println("No Thanks!")
                }
                else if buttonIndex==1
                {
                    println("Save Image")
                }
                else if buttonIndex == 2
                {
                    println("Email")
                }
                else if buttonIndex == 3
                {
                    println("Facebook")
                }
                else if buttonIndex == 4
                {
                    println("Whatsapp")
                }
            }
        }
    }

Answer 15

我有另一招。假设您有5个类，其中要应用注销警报。尝试使用swift类扩展。

File- New- Swift类 - 命名它。

添加以下内容：

#include <fstream>
#include <sstream>

#include "DDImage/Knobs.h"
#include "DDImage/DDMath.h"
#include "DDImage/ViewerContext.h"
#include "DDImage/Iop.h"
#include "DDImage/PixelIop.h"
#include "DDImage/Row.h"

using namespace DD::Image;

////////////////////////////////////////////////////////////////
/// GPU File Shader Op.

class GPUFileShader : public DD::Image::PixelIop
{

    const char* shaderFile_;
    std::string currShaderFile_;
    std::string shader_;
    int version_;
    int currVersion_;

    const char* gpuEngine_body() const
    {
        return shader_.c_str();
    }

    void pixel_engine(const Row& in, int y, int x, int r, ChannelMask channels, Row& out)
    {
        foreach(z, channels) {
            const float* inptr = in[z] + x;
            const float* END = inptr + (r - x);
            float* outptr = out.writable(z) + x;
            while (inptr < END)
                *outptr++ = *inptr++;
        }
    }

    void in_channels(int, DD::Image::ChannelSet& c) const { } // return c unchanged

public:
    GPUFileShader(Node* node)
        : PixelIop(node)
        , shaderFile_(0)
        , version_(0)
        , currVersion_(0)
    { }

    void knobs(Knob_Callback f)
    {
        File_knob(f, &shaderFile_, "shader_file", "OpenGL Shading Language file");
    }

    void _validate(bool)
    {
        if (!shaderFile_)
            return;

        if (version_ != currVersion_ || currShaderFile_ != std::string(shaderFile_)) {
            std::ifstream ifs(shaderFile_);
            if (!ifs) {
                Iop::error("Error reading shader file.");
                return;
            }
            std::stringstream str;
            std::copy(std::istreambuf_iterator<char>(ifs), std::istreambuf_iterator<char>(), std::ostreambuf_iterator<char>(str));
            shader_ = str.str();
            currVersion_ = version_;
            currShaderFile_.assign(shaderFile_);
        }

        copy_info(0);
    }

    static const DD::Image::Op::Description d;
    const char* Class() const { return d.name; }
    const char* node_help() const { return "GPU Op which gets initialised from a file. Customise for proprietary formats. Default assumes OpenGL shading language code."; }

};

static Op* GPUFileShader_c(Node* node) { return new GPUFileShader(node); }
const Op::Description GPUFileShader::d("GPUFileShader", GPUFileShader_c);

使用：self.makeLogOutAlert（）实现。希望它有所帮助。

Answer 16

我得到了以下UIAlertView初始化代码来编译而没有错误（我最后一点，变量部分也许很棘手）。但是我必须确保self的类（我作为委托传递）正在采用UIAlertViewDelegate协议来消除编译错误：

let alertView = UIAlertView(
                  title: "My Title",
                  message: "My Message",
                  delegate: self,
                  cancelButtonTitle: "Cancel",
                  otherButtonTitles: "OK"
                )

顺便说一句，这是我得到的错误（从Xcode 6.4开始）：

找不到接受的“UIAlertView”类型的初始值设定项类型'的参数列表（标题：字符串，消息：字符串，委托： MyViewController，cancelButtonTitle：String，otherButtonTitles：字符串）'

正如其他人提到的，如果你可以定位iOS 8.x +，你应该迁移到UIAlertController。要支持iOS 7，请使用上面的代码（Swift不支持iOS 6）。

Answer 17

 let alertController = UIAlertController(title: "Select Photo", message: "Select atleast one photo", preferredStyle: .alert)
    let action1 = UIAlertAction(title: "From Photo", style: .default) { (action) in
        print("Default is pressed.....")
    }
    let action2 = UIAlertAction(title: "Cancel", style: .cancel) { (action) in
        print("Cancel is pressed......")
    }
    let action3 = UIAlertAction(title: "Click new", style: .default) { (action) in
        print("Destructive is pressed....")

    }
    alertController.addAction(action1)
    alertController.addAction(action2)
    alertController.addAction(action3)
    self.present(alertController, animated: true, completion: nil)

}

Answer 18

使用此代码显示警报视图

  let alertController = UIAlertController(title: "Hello  Coders", message: "your alert message", preferredStyle: .Alert)
        let defaultAction = UIAlertAction(title: "Close Alert", style: .Default, handler: nil)
        alertController.addAction(defaultAction)

        presentViewController(alertController, animated: true, completion: nil)

参考：Swift Show Alert using UIAlertController

Answer 19

xcode 9中的

let alert = UIAlertController(title: "Alert", message: "message", preferredStyle: UIAlertControllerStyle.alert)
alert.addAction(UIAlertAction(title: "Ok", style: UIAlertActionStyle.default, handler: nil))
self.present(alert, animated: true, completion: nil)

Answer 20

@IBAction func Alert(sender: UIButton) {

    var alertView:UIAlertView = UIAlertView()
    alertView.title = "Alert!"
    alertView.message = "Message"
    alertView.delegate = self
    alertView.addButtonWithTitle("OK")

    alertView.show()

}

试试这个

Answer 21

它不起作用的原因是因为传递给函数的某些值不正确。 swift不喜欢Objective-C，你可以将nil设置为没有任何限制的类类型的参数（可能是）。参数otherButtonTitles定义为非可选的，其类型在其末尾没有（？）。所以你必须传递一个具体的值。

Answer 22

SWIFT 4：只需创建UIViewController的扩展，如下所示：

extension  UIViewController {        
    func showSuccessAlert(withTitle title: String, andMessage message:String) {
        let alert = UIAlertController(title: title, message: message,
                                  preferredStyle: UIAlertController.Style.alert)
        alert.addAction(UIAlertAction(title: "OK".localized, style:
        UIAlertAction.Style.default, handler: nil))
        self.present(alert, animated: true, completion: nil)
    }
}

现在在你的ViewController中，直接调用上面的函数，好像它们是由UIViewController提供的。

    yourViewController.showSuccessAlert(withTitle: 
      "YourTitle", andMessage: "YourCustomTitle")

Answer 23

试试这个。把Bellow代码放在按钮中。

let alert = UIAlertController(title: "Your_Title_Text", message: "Your_MSG", preferredStyle: UIAlertControllerStyle.alert)
alert.addAction(UIAlertAction(title: "Your_Text", style: UIAlertActionStyle.default, handler: nil))
self.present(alert, animated:true, completion: nil)

Answer 24

SWIFT 4.X

    let alert = UIAlertController(title: "user entered title", message: "user entered message", preferredStyle: .alert)
    alert.addAction(UIAlertAction(title: "OK", style: .default, handler: { action in
        print("Okay'd")
    }))
    alert.addAction(UIAlertAction(title: "Cancel", style: .default, handler: { action in
        print("cancelled")
    }))
    self.present(alert, animated: true, completion: nil)

Answer 25

或者只是这样做

        let alert = UIAlertController(title: "Alert", message: "Saved Successfully", preferredStyle: UIAlertController.Style.alert)
        alert.addAction(UIAlertAction(title: "Ok", style: UIAlertAction.Style.default, handler: nil))
        self.present(alert, animated: true, completion: nil)

Answer 26

AlertView Swift 5及更高版本：-

let alert = UIAlertController(title: LocalizedStringConstant.alert, message: message, preferredStyle: UIAlertController.Style.alert) alert.addAction(UIAlertAction(title: "Retry", style: .cancel, handler: { (_) in })) self.present(alert, animated: true, completion: nil)

Answer 27

对于iOS 13 Xcode 11+ Swift 5.X

UIAlertController现在可以提供警报以及操作表

警报

// First instantiate the UIAlertController

let alert = UIAlertController(title: "Title",
                              message: "Message ?",
                              preferredStyle: .alert)


 // Add action buttons to it and attach handler functions if you want to 

 alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
 alert.addAction(UIAlertAction(title: "Just Do It!", style: .destructive, handler: nil))
 alert.addAction(UIAlertAction(title: "Maybe", style: .default, handler: nil))

// Show the alert by presenting it

self.present(alert, animated: true)

请注意，这是所有操作按钮在被点击时关闭警报视图的基本特征。 style参数仅用于确定文本的颜色（以及一些默认的显示按钮顺序，按钮的显示顺序可以更改）

示例处理程序函数可能是

func handler(_ action: UIAlertAction) { 

   if action.title == 'Title' {
       // do stuff
   }

}

作为一个补充说明，我可以说不用制作3个不同的处理程序，而只需制作1个并追溯到以上述方式激发它的元素即可。我们也可以检查alert.style，但同样可以有多个.default样式的动作，我不建议

操作表

解释类似，因为此处的主要区别在于 警报会打断用户，而操作表会从iPhone的底部滑动 ，并在其中弹出iPad

操作表的目的是指导用户根据其当前状态决定其操作。因此，您必须像十字路口一样对待操作单！通常没有消息，标题显示为字幕大小的文本

let action = UIAlertController(title: "What do you want to do with the message",
                               message: nil,
                               preferredStyle: .actionSheet)

action.addAction(UIAlertAction(title: "Cancel", style: .cancel)) 

for act in ["Save", "Post", "Discard"] {  
          action.addAction(UIAlertAction(title: act, style: .default, handler: nil))
}

self.present(action, animated: true)

上面的代码将在iPhone上运行，但 在iPad上将在运行时崩溃 ，因为UIPopoverPresentationController将负责警报，那时它不会引用任何东西。因此，为避免这种情况，您必须提供以下代码段其必填项

if let pop = action.popoverPresentationController {

     let v = sender as! UIView 
     pop.sourceView = v 
     pop.sourceRect = v.bounds
 }

如果iPad在弹窗之外的任何地方点击都会将其关闭，并调用.cancel动作按钮的完成处理程序。

希望有帮助:)话虽如此，如果您有任何疑问，请在下面写下来

Answer 28

下面是警报视图和操作表的可重用代码，只需编写一行即可在应用程序中的任何地方显示警报

pic = QLabel(self)
pic.setPixmap(QtGui.QPixmap('escudo.gif'))
pic.setFixedWidth(250)
pic.setFixedHeight(250)

用法：

pic.setMaximumWidth(250)
pic.setMaximumHeight(250)

Answer 29

{'Coca Cola': [1.5, 'drinks'], 'Sprite': [1.5, 'drinks'], 'Apple Juice': [2.5, 'drinks'], 'Orange juice': [2.5, 'drinks'], 'Grape Juice': [2.5, 'drinks']}

Answer 30

// UIAlertView的通用类

//MARK:- MODULES
import Foundation
import UIKit

//MARK:- CLASS
class Alert  : NSObject{

static let shared = Alert()

var okAction : AlertSuccess?
typealias AlertSuccess = (()->())?
var alert: UIAlertController?

/** show */
public func show(title : String?, message : String?, viewController : UIViewController?, okAction : AlertSuccess = nil) {

    let version : NSString = UIDevice.current.systemVersion as NSString
    if  version.doubleValue >= 8 {
        alert = UIAlertController(title: title, message: message, preferredStyle:.alert)
        alert?.addAction(UIAlertAction(title: "OK", style: .default, handler: { (action: UIAlertAction) in

            if let okAction = okAction {
                okAction()
            }
        }))
        viewController?.present(alert ?? UIAlertController(), animated:true, completion:nil);
    }
}

/** showWithCancelAndOk */
public func showWithCancelAndOk(title : String, okTitle : String, cancelTitle : String, message : String, viewController : UIViewController?, okAction : AlertSuccess = nil, cancelAction : AlertSuccess = nil) {
    let version:NSString = UIDevice.current.systemVersion as NSString;

    if  version.doubleValue >= 8 {
        alert = UIAlertController(title: title, message: message, preferredStyle:.alert)

        alert?.addAction(UIAlertAction(title: cancelTitle, style: .default, handler: { (action: UIAlertAction) in

            if let cancelAction = cancelAction {
                cancelAction()
            }
        }))
        alert?.addAction(UIAlertAction(title: okTitle, style: .default, handler: { (action: UIAlertAction) in

            if let okAction = okAction {
                okAction()
            }
        }))
        viewController?.present(alert!, animated:true, completion:nil);
    }
}

/** showWithTimer */
public func showWithTimer(message : String?, viewController : UIViewController?) {

    let version : NSString = UIDevice.current.systemVersion as NSString
    if  version.doubleValue >= 8 {
        alert = UIAlertController(title: "", message: message, preferredStyle:.alert)
        viewController?.present(alert ?? UIAlertController(), animated:true, completion:nil)
        let when = DispatchTime.now() + 1
        DispatchQueue.main.asyncAfter(deadline: when){
            self.alert?.dismiss(animated: true, completion: nil)
        }
    }
}
}

使用： -

Alert.shared.show(title: "No Internet Connection", message: "The internet connection appers to be offline.", viewController: self) //without ok action

Alert.shared.show(title: "No Internet Connection", message: "The internet connection appers to be offline.", viewController: self, okAction: {
                            //ok action
                        }) // with ok action

Alert.shared.show(title: "No Internet Connection", message: "The internet connection appers to be offline.", viewController: self, okAction: {
                            //ok action 
}, cancelAction: {
 //cancel action
}) //with cancel and ok action

Alert.shared.showWithTimer(message : "This is an alert with timer", viewController : self) //with timer

Answer 31

在IOS 9上

，你可以这样做

let alert = UIAlertController(title: "Alert", message: "Message", preferredStyle: UIAlertControllerStyle.alert)
alert.addAction(UIAlertAction(title: "Click", style: UIAlertActionStyle.default, handler: nil))
self.present(alert, animated: true, completion: nil)

Answer 32

这是Swift中一个有趣的例子：

private func presentRandomJoke() {
  if let randomJoke: String = jokesController.randomJoke() {
    let alertController: UIAlertController = UIAlertController(title:nil, message:randomJoke, preferredStyle: UIAlertControllerStyle.Alert)
    alertController.addAction(UIAlertAction(title:"Done", style:UIAlertActionStyle.Default, handler:nil))
    presentViewController(alertController, animated:true, completion:nil)
  }
}

Answer 33

旧方式：UIAlertView

let alertView = UIAlertView(title: "Default Style", message: "A standard alert.", delegate: self, cancelButtonTitle: "Cancel", otherButtonTitles: "OK")
alertView.alertViewStyle = .Default
alertView.show()

// MARK: UIAlertViewDelegate

 func alertView(alertView: UIAlertView, clickedButtonAtIndex buttonIndex: Int) {
 switch buttonIndex {

    // ...
   }
  }

新方式：UIAlertController

let alertController = UIAlertController(title: "Default Style", message: "A standard alert.", preferredStyle: .Alert)

let cancelAction = UIAlertAction(title: "Cancel", style: .Cancel) { (action) in
// ...
 }
 alertController.addAction(cancelAction)

 let OKAction = UIAlertAction(title: "OK", style: .Default) { (action) in
// ...
 }
 alertController.addAction(OKAction)
 self.presentViewController(alertController, animated: true) {
 // ...
}

Answer 34

以下是Swift中AlertView的一个非常简单的功能：

class func globalAlertYesNo(msg: String) {
        let alertView = UNAlertView(title: "Title", message: msg)

        alertView.messageAlignment = NSTextAlignment.Center
        alertView.buttonAlignment  = UNButtonAlignment.Horizontal

        alertView.addButton("Yes", action: {

            print("Yes action")

        })

        alertView.addButton("No", action: {

            print("No action")

        })

        alertView.show()

    }

您必须将消息作为字符串传递给您使用此功能。

Answer 35

您可以将此简单扩展程序与 n个数字按钮以及相关的动作swift4及以上

一起使用

extension UIViewController {
    func popupAlert(title: String?, message: String?, actionTitles:[String?], actions:[((UIAlertAction) -> Void)?]) {
        let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
        for (index, title) in actionTitles.enumerated() {
            let action = UIAlertAction(title: title, style: .default, handler: actions[index])
            alert.addAction(action)
        }
        self.present(alert, animated: true, completion: nil)
    }
}

您可以像使用它，

self.popupAlert(title: "Message", message: "your message", actionTitles: ["first","second","third"], actions:[
            {action1 in
                //action for first btn click
            },
            {action2 in
                //action for second btn click
            },
            {action3 in
                //action for third btn click
            }, nil])

Answer 36

在Swift 5.x和Xcode 11.x上

SwiftUI

import SwiftUI

struct ContentView: View {

    @State private var isShowingAlert = false

    var body: some View {
        VStack {
            Button("A Button") {

                self.isShowingAlert.toggle()
            }
            .alert(isPresented: $isShowingAlert) { () -> Alert in
                Alert(
                    title: Text("Alert"),
                    message: Text("This is an alert"),
                    dismissButton:
                        .default(
                            Text("OK"),
                            action: {
                                print("Dismissing alert")
                            }
                        )
                )
            }

        }
        .padding()
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

我如何在Swift中创建UIAlertView？

36 个答案:

一个按钮

两个按钮

三个按钮

处理按钮点击

注释