Cannot find 'UIAlertController' in scope error in swift? - swift

Why I am getting Cannot find 'UIAlertController' in scope? error if i write alert function in separate swift file or if i use extension its not coming to another viewcontroller why?
code:
func showAlert(title: String, message: String) {
let alertController = UIAlertController(title: title, message:
message, preferredStyle: .alert)
alertController.addAction(UIAlertAction(title: "OK", style: .default, handler: {action in
}))
self.present(alertController, animated: true, completion: nil)
}
error:
Cannot find 'UIAlertController' in scope,
Cannot find 'UIAlertAction' in scope
Cannot find 'self' in scope

Probably you forgot this in your viewController:
import UIKit
so your file has no idea what UIAlertController or UIAlertAction is
if you want to create an alert view controller to be used across multiple UIViewController you can do this:
import UIKit
class CustomAlertController: NSObject {
let message:String?
let title:String?
init(title:String, message:String) {
self.message = message
self.title = title
}
func showAlert()->UIAlertController {
let alertController = UIAlertController(title: self.title, message: self.message, preferredStyle: .alert)
// you can further customize your buttons, buttons' title etc
alertController.addAction(UIAlertAction(title: "OK", style: .default, handler: {action in
}))
return alertController
}
}
then your view controllers
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let alert = CustomAlertController(title: "Hello", message: "My message to the world")
DispatchQueue.main.async {
self.present(alert.showAlert(), animated: true, completion: nil)
}
}
}

Related

Google Nearby Messages API SwiftUI Error "UIAlertView is deprecated and unavailable for UIScene based applications, please use UIAlertController!' [duplicate]

I have been working to create a UIAlertView in Swift, but for some reason I can't get the statement right because I'm getting this error:
Could not find an overload for 'init' that accepts the supplied
arguments
Here is how I have it written:
let button2Alert: UIAlertView = UIAlertView(title: "Title", message: "message",
delegate: self, cancelButtonTitle: "OK", otherButtonTitles: nil)
Then to call it I'm using:
button2Alert.show()
As of right now it is crashing and I just can't seem to get the syntax right.
From the UIAlertView class:
// UIAlertView is deprecated. Use UIAlertController with a
preferredStyle of UIAlertControllerStyleAlert instead
On iOS 8, you can do this:
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)
Now UIAlertController is a single class for creating and interacting with what we knew as UIAlertViews and UIActionSheets on iOS 8.
Edit: To handle actions:
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")
}
}}))
Edit for 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)
Edit for 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)
One Button
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)
}
}
Two Buttons
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)
}
}
Three Buttons
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)
}
}
Handling Button Taps
The handler was nil in the above examples. You can replace nil with a closure to do something when the user taps a button. For example:
alert.addAction(UIAlertAction(title: "Launch the Missile", style: UIAlertAction.Style.destructive, handler: { action in
// do something like...
self.launchMissile()
}))
Notes
Multiple buttons do not necessarily need to use different UIAlertAction.Style types. They could all be .default.
For more than three buttons consider using an Action Sheet. The setup is very similar. Here is an example.
You can create a UIAlert using the standard constructor, but the 'legacy' one seems to not work:
let alert = UIAlertView()
alert.title = "Alert"
alert.message = "Here's a message"
alert.addButtonWithTitle("Understood")
alert.show()
In Swift 4.2 and Xcode 10
Method 1 :
SIMPLE ALERT
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)
})
Method 2 :
ALERT WITH SHARED CLASS
If you want Shared class style(Write once use every where)
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() {
}
}
Now call alert like this in every ware
SharedClass.sharedInstance.alert(view: self, title: "Your title here", message: "Your message here")
Method 3 :
PRESENT ALERT TOP OF ALL WINDOWS
If you want to present alert on top of all views, use this code
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)
})
}
Function calling
SharedClass.sharedInstance.alertWindow(title:"This your title", message:"This is your message")
Method 4 :
Alert with Extension
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)
})
}
}
Now call like this
//Call showAlert function in your class
#IBAction func onClickAlert(_ sender: UIButton) {
showAlert(withTitle:"Your Title Here", withMessage: "YourCustomMessageHere")
}
Method 5 :
ALERT WITH TEXTFIELDS
If you want to add textfields to alert.
//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)
}
Method 6:
Alert in SharedClass with Extension
//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)
}
}
}
Now call directly like this
self.showAlert(title: "Your title here...", msg: "Your message here...")
Method 7:
Alert with out shared class with Extension in separate class for alert.
Create one new Swift class, and import UIKit. Copy and paste below code.
//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)
}
}
Now call alert function like this in all your classes (Single line).
UIAlertController.alert(title:"Title", msg:"Message", target: self)
How is it....
Click of View
#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")
}))
}
Done with two buttons OK & Cancel
If you're targeting iOS 7 and 8, you need something like this to make sure you're using the right method for each version, because UIAlertView is deprecated in iOS 8, but UIAlertController is not available in iOS 7:
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()
}
}
With the protocol extensions of Swift 2, you can make a protocol that provides a default implementation to your view controllers:
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!")
}
}
Show UIAlertView in swift language :-
Protocol UIAlertViewDelegate
let alert = UIAlertView(title: "alertView", message: "This is alertView", delegate:self, cancelButtonTitle:"Cancel", otherButtonTitles: "Done", "Delete")
alert.show()
Show UIAlertViewController in swift language :-
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)
Simply do not provide otherButtonTitles in the constructor.
let alertView = UIAlertView(title: "Oops!", message: "Something
happened...", delegate: nil, cancelButtonTitle: "OK")
alertView.show()
But I do agree with Oscar, this class is deprecated in iOS 8, so there won't be no use of UIAlertView if you're doing an iOS 8 only app. Otherwise the code above will work.
For SWIFT4, I think, extending UIViewController and creating a reusable confirmation control is the most elegant way.
You can extend the UIViewController as below:
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)
}))
}
}
Then you can use it anytime:
AskConfirmation(title: "YOUR MESSAGE TITLE", message: "YOUR MESSAGE") { (result) in
if result { //User has clicked on Ok
} else { //User has clicked on Cancel
}
}
AlertView Swift 5 and above:-
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)
I found this one,
var alertView = UIAlertView();
alertView.addButtonWithTitle("Ok");
alertView.title = "title";
alertView.message = "message";
alertView.show();
not good though, but it works :)
Update:
but I have found on header file as:
extension UIAlertView {
convenience init(title: String, message: String, delegate: UIAlertViewDelegate?, cancelButtonTitle: String?, otherButtonTitles firstButtonTitle: String, _ moreButtonTitles: String...)
}
somebody may can explain this.
For iOS 13 Xcode 11+ Swift 5.X
UIAlertController can now provide Alerts as well as Action Sheets
Alerts
// 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)
Note that it's is a fundamental nature for all action buttons to dismiss the alert view when tapped. The style parameter is just for deciding the color of the text (and some default order in which the buttons should appear which ofc can be changed)
A sample handler function could be
func handler(_ action: UIAlertAction) {
if action.title == 'Title' {
// do stuff
}
}
As a side note, I would say instead of making 3 different handlers you can just make 1 and trace back to the element which provoked it in the manner shown above
We can also check alert.style but that again we can have multiple .default styled actions , I wouldn't recommend that
Action Sheets
The explanation is similar because the main difference here is that an alert interrupts the user whereas an action sheet slides from the bottom in an iPhone and appears as a popover in an iPad
The Purpose of action sheets is to guide the users in deciding his actions based on their current state. So you gotta treat action sheets like crossroads !. There is generally no message and the title is rendered as caption sized text
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)
The above code is going to work for an iPhone but will crash at runtime for an iPad because UIPopoverPresentationController is going to take charge of the alert and it won't be referencing anything at that time. So to avoid that you will have to provide the following chunk of code its mandatory
if let pop = action.popoverPresentationController {
let v = sender as! UIView
pop.sourceView = v
pop.sourceRect = v.bounds
}
Also in case of iPad tapping on anywhere outside the popover will dismiss it and the completion handler of .cancel action button will be called.
Hope that helps :) That being said, comment down below if you have any doubts
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")
}
}
}
}
I have another trick. Suppose you have 5 classes where a logout alert to be applied. Try with swift class extension.
File- New- Swift class- Name it.
Add the following:
public extension UIViewController
{
func makeLogOutAlert()
{
var refreshAlert = UIAlertController(title: "Log Out", message: "Are You Sure to Log Out ? ", preferredStyle: UIAlertControllerStyle.Alert)
refreshAlert.addAction(UIAlertAction(title: "Confirm", style: .Default, handler: { (action: UIAlertAction!) in
self.navigationController?.popToRootViewControllerAnimated(true)
}))
refreshAlert.addAction(UIAlertAction(title: "Cancel", style: .Default, handler: { (action: UIAlertAction!) in
refreshAlert .dismissViewControllerAnimated(true, completion: nil)
}))
presentViewController(refreshAlert, animated: true, completion: nil)
}
}
Implement using : self.makeLogOutAlert(). Hope it helps.
I have made a singleton class to make this convenient to use from anywhere in your app: https://github.com/Swinny1989/Swift-Popups
You can then create a popup with multiple buttons like this:
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
}
}
or popups with a single button like this:
Popups.SharedInstance.ShowPopup("Title goes here", message: "Message goes here.")
Swift 3
The following is a simple example of how to create a simple alert with one button with Swift 3.
let alert = UIAlertController(title: "Title",
message: "Message",
preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "Ok", style: .default))
present(alert, animated: true)
In the above example the handle callback of the action has been omitted because the default behaviour of an alert view with one button is to disappear when the button is clicked.
Here is how to create another action, which could be added to the alert with "alert.addAction(action)". The different styles are .default, .destructive and .cancel.
let action = UIAlertAction(title: "Ok", style: .default) { action in
// Handle when button is clicked
}
I got the following UIAlertView initialization code to compile without errors (I thing the last, varyadic part is tricky perhaps). But I had to make sure the class of self (which I am passing as the delegate) was adopting the UIAlertViewDelegate protocol for the compile errors to go away:
let alertView = UIAlertView(
title: "My Title",
message: "My Message",
delegate: self,
cancelButtonTitle: "Cancel",
otherButtonTitles: "OK"
)
By the way, this is the error I was getting (as of Xcode 6.4):
Cannot find an initializer for type 'UIAlertView' that accepts an
argument list of type '(title: String, message: String, delegate:
MyViewController, cancelButtonTitle: String, otherButtonTitles:
String)'
As others mentioned, you should migrate to UIAlertController if you can target iOS 8.x+. To support iOS 7, use the code above (iOS 6 is not supported by Swift).
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)
}
You can use this simple extension with n number of buttons and associated actions swift4 and above
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)
}
}
you can use it like ,
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])
The reason it doesn't work because some value you passed to the function isn't correct. swift doesn't like Objective-C, you can put nil to arguments which are class type without any restriction(might be). Argument otherButtonTitles is defined as non-optional which its type do not have (?)at its end. so you must pass a concrete value to it.
#IBAction func Alert(sender: UIButton) {
var alertView:UIAlertView = UIAlertView()
alertView.title = "Alert!"
alertView.message = "Message"
alertView.delegate = self
alertView.addButtonWithTitle("OK")
alertView.show()
}
Try this
Use this code to display an alertview
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)
Reference: Swift Show Alert using UIAlertController
in xcode 9
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)
SWIFT 4 : Simply create a extension to UIViewController as follows:
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)
}
}
Now in your ViewController, directly call above function as if they are provided by UIViewController.
yourViewController.showSuccessAlert(withTitle:
"YourTitle", andMessage: "YourCustomTitle")
Or just do this
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)
try This.
Put Bellow Code In Button.
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)
Here is a funny example in Swift:
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)
}
}
Here is a pretty simple function of AlertView in Swift :
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()
}
You have to pass message as a String where you use this function.
The Old Way: 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 {
// ...
}
}
The New Way: 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) {
// ...
}

Is it possible to present an UIAlertController in a SwiftUI class?

I have a class and i try to present an UIAlertController directly in it if there is an error. Is it possible to do that in SwiftUI?
My code (obviously not working) :
import Firebase
import Combine
class TestFirebaseAlertClass: ObservableObject {
var didChange = PassthroughSubject<TestFirebaseAlertClass, Never>()
func resetPassword(email: String, password: String, handler: #escaping AuthDataResultCallback) {
Auth.auth().sendPasswordReset(withEmail: email, completion: { error in
if let error = error {
let alert = UIAlertController(title: "Error", message: error.localizedDescription, preferredStyle: UIAlertController.Style.alert)
alert.addAction(UIAlertAction(title: "OK", style: UIAlertAction.Style.default, handler: nil))
view.present(alert, animated: true, completion: nil)
}
})
}
}

DispatchQueue : Cannot be called with asCopy = NO on non-main thread

I am presenting the UIAlertController on the main thread as :
class HelperMethodClass: NSObject {
class func showAlertMessage(message:String, viewController: UIViewController) {
let alertMessage = UIAlertController(title: "", message: message, preferredStyle: .alert)
let cancelAction = UIAlertAction(title: "Ok", style: .cancel)
alertMessage.addAction(cancelAction)
DispatchQueue.main.async {
viewController.present(alertMessage, animated: true, completion: nil)
}
}
}
And I am calling the method from any UIViewController as:
HelperMethodClass.showAlertMessage(message: "Any Message", viewController: self)
I am getting the output properly.
But in console I am getting below message:
[Assert] Cannot be called with asCopy = NO on non-main thread.
Is there something I have done wrong here or I can ignore this message ?
Edit
Thanks to #NicolasMiari :
Adding below code is not showing any message:
DispatchQueue.main.async {
HelperMethodClass.showAlertMessage(message: "Any Message", viewController: self)
}
What can be the reason that previously it was showing the message in console?
You should call all code from showAlertMessage on main queue:
class func showAlertMessage(message:String, viewController: UIViewController) {
DispatchQueue.main.async {
let alertMessage = UIAlertController(title: "", message: message, preferredStyle: .alert)
let cancelAction = UIAlertAction(title: "Ok", style: .cancel)
alertMessage.addAction(cancelAction)
viewController.present(alertMessage, animated: true, completion: nil)
}
}

use same UIAlertController in different ViewControllers

I have used side navigation menu(SWReveal). I have 4 ViewControllers. How can use same alertAction in different views.
You can create UIViewController extension like below:
extension UIViewController {
func showAlert(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)
}
}
And you can use this alert in UIViewController like below:
showAlert(title: "Your Title", message: "Your custom Message", actionTitles: ["Ok","Cancel"], actions: [{ action1 in
//OK Action
}, { action2 in
// Cancel Action
}
])
Hope will get your solution.
You can also use like this way.
class IOSPublicDefaultAlert: NSObject{
var viewController: UIViewController?
var actionCompletion: ((String) -> ())?
var alertTitle: String?
var alertMessage : String?
var alertType: UIAlertControllerStyle?
var actionTitleAndType: [String: UIAlertActionStyle]?
init(viewController : UIViewController,alertTitle: String?,alertMessage : String?,alertType: UIAlertControllerStyle = .alert,actionTitleAndType: [String: UIAlertActionStyle] ,actionCompletion : ((String)->())?){
super.init()
self.viewController = viewController
self.actionCompletion = actionCompletion
self.alertTitle = alertTitle
self.alertMessage = alertMessage
self.alertType = alertType
self.actionTitleAndType = actionTitleAndType
showAlert()
}
func showAlert(){
let alert = UIAlertController.init(title: alertTitle, message: alertMessage, preferredStyle: self.alertType ?? .alert)
for (actionTitle, actionType) in actionTitleAndType!{
let action = UIAlertAction(title: actionTitle, style: actionType) { (action) in
if let com = self.actionCompletion{
com(actionTitle)
}
}
alert.addAction(action)
}
viewController?.present(alert, animated: true, completion: nil)
}
}
and use add where you like as below sample
_ = IOSPublicDefaultAlert.init(viewController: self, alertTitle: "Warning!!!", alertMessage: alertMessage, actionTitleAndType: ["Ok" : .destructive, "Cancel" : .default], actionCompletion: { [unowned self] (title) in
if title == "Ok"{
}
})
In swift, your project, you can create a new .swift file and in this file create a class:
import UIKit
import Foundation
class yourFileName {
//Create a class function alerview
class func displayAlert(title: String, withMessage msg: String, andbtnTitle btntitle: String, in vc: UIViewController) {
let alert = UIAlertController(title: title, message: msg, preferredStyle: .alert)
alert.addAction(UIAlertAction(title: btntitle, style: UIAlertActionStyle.default, handler: nil))
appDelegate.window?.rootViewController?.present(alert, animated: true, completion: nil)
}
}
//and now your any ViewController.swift file or any other file in your project you can access alert following way.
class viewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
yourfilename.displayAlert(title: "Alert", withMessage msg: "my alert view display", andbtnTitle btntitle: "Ok", in vc: self) // access your alertview
}
}
I hope it's work for you.
Create BaseController with a method that can show alert.
//Copyright © 2017 dip. All rights reserved.
import UIKit
class BaseController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
///This is common method to show alert with same action
func showAlert() {
let alert = UIAlertController(title: "Alert", message: "my msg on alert", preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "OK", style: .default, handler: { (action) in
///This will be common alert ok aciton for all child controllers.
print("Do some userful common work..")
}))
self.present(alert, animated: true, completion: nil)
}
}
Inherit Your 4 controllers from BaseController
// Copyright © 2017 dip. All rights reserved.
//
import UIKit
class ChildVC: BaseController {
override func viewDidLoad() {
super.viewDidLoad()
//call show alert when ever you wish
///This method will call showAlert() method on super class (BaseController)
self.showAlert()
}
}
Call self.showAlert() method from child when you want show alert with common action.
// MARK: - Alertable View
protocol AlertableView {
// Use handler if need catch cancel alert action
typealias CompletionHandler = (() -> Void)
func displayAlert(with title: String, message: String, actions: [UIAlertAction]?)
func displayAlert(with title: String, message: String, style: UIAlertControllerStyle, actions: [UIAlertAction]?, completion: CompletionHandler?)
}
extension AlertableView where Self: UIViewController {
func displayAlert(with title: String, message: String, actions: [UIAlertAction]?) {
self.displayAlert(with: title, message: message, style: .alert, actions: actions, completion: nil)
}
func displayAlert(with title: String, message: String, style: UIAlertControllerStyle, actions: [UIAlertAction]?, completion: CompletionHandler?) {
let alertCancelAction = UIAlertAction(title: "Cancel".localized, style: .cancel) { (action) in
guard let completion = completion else { return }
completion()
}
let alertController = UIAlertController(title: title, message: message, preferredStyle: style)
if let actions = actions {
for action in actions {
alertController.addAction(action)
}
alertController.addAction(alertCancelAction)
} else {
// If not any custom actions, we add OK alert button
let alertOkAction = UIAlertAction(title: "OK".localized, style: .cancel) { (action) in
guard let completion = completion else { return }
completion()
}
alertController.addAction(alertOkAction)
}
self.present(alertController, animated: true, completion: nil)
}
}
Create a common function ,
import UIKit
class AlertClass: NSObject {
func showAlertWithVC(_ VC : UIViewController, andMessage message: String ){
DispatchQueue.main.async {
let alert = UIAlertController(title: "APPLICATION_NAME", message: message , preferredStyle: UIAlertControllerStyle.alert)
alert.addAction(UIAlertAction(title: "Ok", style: UIAlertActionStyle.default, handler: nil))
VC.present(alert, animated: true, completion: nil)
}
}
}
Simply call AlertClass().showAlertWithVC() where you want to show Alert.

Swift expecting declaration but already declared

I am trying to create an alert view that performs a certain action when the button is clicked. I have tried creating a new class for the alert view, but when I try to add an action to the alert view controller, Xcode tells me that it is expecting a declaration, although the variable is declared just two steps above the line where the error occurs. Here's the code
class alerts: UIAlertController {
var alertThenGenerateNewThingController: UIAlertController = UIAlertController()
var generateNewThingOkButton = UIAlertAction (title: "OK", style: UIAlertActionStyle.Default) {
UIAlertAction in
println ("generate new thing action")
}
alertThenGenerateNewThingController.addAction (generateNewThingOkButton) // Here is where Xcode says it expected a declaration
func alertThenGenerateNewThing (alertTitle: String, alertMessage: String) {
alertThenGenerateNewThingController = UIAlertController (title: alertTitle, message: alertMessage, preferredStyle: .Alert)
self.presentViewController (alertThenGenerateNewThingController, animated: true, completion: nil)
}
}
You can't subclass UIAlertController, for one thing. Second of all, you can only interact with object properties inside of methods, functions, or the global scope. Run this code inside of the view controller where you plan on presenting your alert:
class viewController: UIViewController {
var alertThenGenerateNewThingController: UIAlertController = UIAlertController()
var generateNewThingOkButton = UIAlertAction (title: "OK", style: UIAlertActionStyle.Default) {
UIAlertAction in
println ("generate new thing action")
}
override func viewDidLoad() {
alertThenGenerateNewThingController.addAction(generateNewThingOkButton)
}
func alertThenGenerateNewThing (alertTitle: String, alertMessage: String) {
alertThenGenerateNewThingController = UIAlertController (title: alertTitle, message: alertMessage, preferredStyle: .Alert)
self.presentViewController (alertThenGenerateNewThingController, animated: true, completion: nil)
}
}