How to create uialertcontroller in global swift

Question

I\'m trying to create uialertcontroller in Config.swift file as follow.

static func showAlertMessage(titleStr:String, messageStr:St         


        

Answer 1

This is also the way you can present on top of the View Controller available.

UIApplication.topViewController()?.present(alertViewController!, animated: true, completion: nil)

Answer 2

I am suggest you write this code, but if you really need, try this:

static func showAlertMessage(titleStr:String, messageStr:String) -> Void {
    let alert = UIAlertController(title: titleStr, message: messageStr, preferredStyle: UIAlertControllerStyle.Alert);
    if let viewController = UIApplication.sharedApplication().windows.first?.rootViewController as UIViewController? {
        viewController.presentViewController(alert, animated: true, completion: nil)
    }
}

At least it won't break down.

@Eric D better answer.

Answer 3

You can use my Utility class created for Show Alert in Swift4. Its super easy to use just by writing single line of code:

Show Simple Alert

@IBAction func showDefaultAlert(_ sender: Any) {

  Alert.showAlert(title:"Alert", message:"Default Alert")

}

Demo code link: https://github.com/smindia1988/EasyAlertInSwift4

Answer 4

Please refer the below GIT Example

https://github.com/amilaim/CommonAlertView

//  ViewController.swift
//  CommonAlertView
//
//  Created by Amila Munasinghe on 4/25/17.
//  Copyright © 2017 Developer Insight. All rights reserved.
//
import UIKit

class ViewController: UIViewController,AlertViewControllerDelegate {

@IBOutlet weak var AlertViewResultTextOutlet: UITextField!

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
}

@IBAction func ShowAlertAction(_ sender: Any) {

    let alert = AlertViewController.sharedInstance
    alert.delegate = self
    alert.SubmitAlertView(viewController: self,title: "Developer Insight", message: "Please enter any text value")

}


override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


func SubmitAlertViewResult(textValue : String) {

    AlertViewResultTextOutlet.text = textValue

 } 
}

Common UIAlertViewController Implementation

import UIKit

protocol AlertViewControllerDelegate {
func SubmitAlertViewResult(textValue : String)
 }

class AlertViewController {

static let sharedInstance = AlertViewController()

private init(){}

var delegate : AlertViewControllerDelegate?

func SubmitAlertView(viewController : UIViewController,title : String, message : String){

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

    // Submit button
    let submitAction = UIAlertAction(title: "Submit", style: .default, handler: { (action) -> Void in
        // Get 1st TextField's text
        let textField = alert.textFields![0]

        if(textField.text != "")
        {
            self.delegate?.SubmitAlertViewResult(textValue: textField.text!)
        }

    })

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


    // Add 1 textField and cutomize it
    alert.addTextField { (textField: UITextField) in
        textField.keyboardAppearance = .dark
        textField.keyboardType = .default
        textField.autocorrectionType = .default
        textField.placeholder = "enter any text value"
        textField.clearButtonMode = .whileEditing

    }

    // Add action buttons and present the Alert
    alert.addAction(submitAction)
    alert.addAction(cancel)
    viewController.present(alert, animated: true, completion: nil)

 }

}

Answer 5

I suggest creating an extension:

extension UIViewController {
    func showAlertMessage(titleStr:String, messageStr:String) {
        let alert = UIAlertController(title: titleStr, message: messageStr, preferredStyle: UIAlertControllerStyle.Alert)
       self.presentViewController(alert, animated: true, completion: nil)
    }
}

Answer 6

What I'm using based on the solution by @William Hu:

func popup(caller:UIViewController, style:UIAlertControllerStyle? = UIAlertControllerStyle.alert,
        title:String, message:String, buttonTexts:[String], buttonStyles:([UIAlertActionStyle?])? = nil,
        handlers:[((UIAlertAction) -> Void)?], animated:Bool? = nil, completion: (() -> Void)? = nil) {
    let alert = UIAlertController(title: title, message: message, preferredStyle: style!)
    for i in 0..<buttonTexts.count {
        alert.addAction(UIAlertAction(title: buttonTexts[i],
            style: (buttonStyles == nil || i >= buttonStyles!.count || buttonStyles![i] == nil ?
                UIAlertActionStyle.default : buttonStyles![i]!),
            handler: (i >= handlers.count || handlers[i] == nil ? nil : handlers[i]!)))
    }
    caller.present(alert, animated: animated != nil ? animated! : true, completion: completion)
}

1. Single function gives Alert by default and can optionally be used for ActionSheet.
2. Arrays buttonTexts, buttonStyles and handlers can be of unequal sizes as per requirement.
3. Actions can be styled.
4. Animated can be specified.
5. Optional block can be specified to be executed when presentation finishes.

Usage:

popup(caller: self, style: UIAlertControllerStyle.alert,
        title: "Title", message: "Message",
        buttonTexts: ["Destructive", "Cancel", "OK"],
        buttonStyles: [UIAlertActionStyle.destructive, UIAlertActionStyle.cancel],
        handlers: [nil], animated: false)