I got simple UIViewController + UIAlert extension:
extension UIViewController {
func alert(title: String = "", message: String){
let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
alert.addAction(UIAlertAction(title: Localized.ok(), style: .default, handler: nil))
present(alert, animated: true, completion: nil)
}
}
Within the ViewController I got a method:
func findUser() {
userService.findUser { (userinfo, error) in
if error != nil {
if let errText = error?.localizedDescription {
self.alert(message: errText)
}
self.doAuth()
return
}
}
}
this doAuth() method should redirect to loginViewController using:
navigationController?.pushViewController(loginViewController, animated: false)
The problem is, that in this scenario, this push doesn't work (nothing appears) (I click OK button on the alert, alert dissapears but loginViewController is not pushed)
I refactored extension a little bit:
extension UIViewController {
func alert(title: String = "", message: String, action completion: (() -> Void)? = nil){
let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
alert.addAction(UIAlertAction(title: Localized.ok(), style: .default, handler: { _ in
completion?()
}))
present(alert, animated: true, completion: nil)
}
}
so findUser() method is calling doAuth() in differently:
func findUser() {
userService.findUser { (userinfo, error) in
if error != nil {
if let errText = error?.localizedDescription {
self.alert(message: errText){ [weak self] in
self?.doAuth()
}
}
return
}
}
}
and it works!
Problem is I have no idea why. And what could have happened in the first scenario?
I feel it should be some simple explanation, but I can't figure it out.
Edit
The explanation is simple and was printed in the console:
pushViewController:animated: called on <UINavigationController 0x7f86050b4400>
while an existing transition or presentation is occurring; the navigation stack
will not be updated.
So doAuth() (with pushing VC method) was called while alert was visible/presented, so alert took the focus and VC couldn't be pushed.
cc: #Paulw11 # cookednick
Problem is navigating and presenting in same if statement
If error != nil , means it only show the alert not try to doAuth().
But you are calling doAuth() in same if block then it is trying to present alert as well as to navigate
func findUser() {
userService.findUser { (userinfo, error) in
if error != nil {
if let errText = error?.localizedDescription {
self.alert(message: errText)
}
return
}
//Out side if block
self.doAuth()
}
}
in the simple language: can we create that alert Box as a reusable method
i want to made 1 Alert box in to the function.
like this.
// this code has separate file
import UIKit
struct AlertView {
public func showAlertBox(title: String, message: String) -> UIAlertController {
let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "OK", style: .cancel, handler: { _ in
}))
return alert
}
}
and here is my caller ViewController file code.
#IBAction func submitPressed(_ sender: Any) {
let alertView = AlertView()
let alert = alertView.showAlertBox(title: "Hours Added", message: "Hours have been updated")
alert.present(alert, animated: true) {
self?.dismiss(animated: true, completion: nil)
self?.timeSubmitted = true
self?.performSegue(withIdentifier: "unwindToMyHours", sender: nil)
}
}
You need alert action to performing ok action.
You can modify your code by this
Here are the helper functions.
struct AlertView {
public static func showAlertBox(title: String, message: String, handler: ((UIAlertAction)->Void)?) -> UIAlertController {
let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "OK", style: .cancel, handler: handler))
return alert
}
}
extension UIAlertController {
func present(on viewController: UIViewController, completion: (() -> Void)? = nil) {
viewController.present(self, animated: true, completion: completion)
}
}
Usage
class ViewController: UIViewController {
#IBAction func submitPressed(_ sender: Any) {
AlertView.showAlertBox(title: "Hours Added", message: "Hours have been updated") { [weak self] action in
// Okay action code
}.present(on: self) { [weak self] in
self?.dismiss(animated: true, completion: nil)
self?.timeSubmitted = true
self?.performSegue(withIdentifier: "unwindToMyHours", sender: nil)
}
}
}
Note: self is dismissing so might be your alert is not presenting. You can present your alert on top most view controller. see this
Yes, you can create a shared alert controller. I would suggest making it a static method of your struct, or even a global function. It's silly to create an instance of your struct only to invoke a method that doesn't need any instance variables:
public static func alertBox(title: String, message: String) -> UIAlertController {
let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "OK", style: .cancel, handler: { _ in
}))
return alert
}
}
And then you'd invoke it by saying
let alert = AlertView.alertBox(title: "title",message: "message" )
(Your function doesn't show the alert, it just creates it. I would therefore suggest naming it alertBox, not 'showAlertBox`.
Yes, you can use a shared alert controller. What I would suggest is making the AlertView struct, a singleton. You can change the struct as follows
struct AlertView {
// Shared instance
static let shared: AlertView = AlertView()
// Private initializer to prevent creating of new instances
private init() {}
public func showAlertBox(title: String, message: String) -> UIAlertController {
let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "OK", style: .cancel, handler: { _ in
}))
return alert
}
}
By doing so, you will be able to create just one instance of AlertView and you have to use that single instance in your program. That way you won't have to create new instances of AlertView every time you need to display an alert. You can invoke it using,
let alert = AlertView.shared.showAlertBox(title: "Hours Added", message: "Hours have been updated")
Edit - You can refer this medium article to understand the singleton design patter
The best way is to perform simple encapsulation through extension, and complex encapsulation just loses applicability
example:
let alertVC = UIAlertController(title: "title", message: "message", preferredStyle: .alert)
.addActionTitles(titles) { (alertVC, action) in
let actionIdx = alertVC.actions.firstIndex(of: action)
DDLog(actionIdx)
}
self.present(alertVC, animated: true, completion:{})
code:
public let kTitleSure = "Yes"
public let kTitleCancell = "No"
/// contentViewController
public let kAlertContentViewController = "contentViewController"
#objc public extension UIAlertController{
///add UIAlertAction
#discardableResult
func addActionTitles(_ titles: [String]? = [kTitleCancell, kTitleSure], handler: ((UIAlertController, UIAlertAction) -> Void)? = nil) -> Self {
titles?.forEach({ (string) in
let style: UIAlertAction.Style = string == kTitleCancell ? .cancel : .default
self.addAction(UIAlertAction(title: string, style: style, handler: { (action) in
handler?(self, action)
}))
})
return self
}
///add textField
#discardableResult
func addTextFieldPlaceholders(_ placeholders: [String]?, handler: ((UITextField) -> Void)? = nil) -> Self {
if self.preferredStyle != .alert {
return self
}
placeholders?.forEach({ (string) in
self.addTextField { (textField: UITextField) in
textField.placeholder = string
handler?(textField)
}
})
return self
}
#discardableResult
func setContent(vc: UIViewController, height: CGFloat) -> Self {
setValue(vc, forKey: kAlertContentViewController)
vc.preferredContentSize.height = height
preferredContentSize.height = height
return self
}
}
github
I'm trying to create uialertcontroller in Config.swift file as follow.
static func showAlertMessage(titleStr:String, messageStr:String) -> Void {
let window : UIWindow?
let alert = UIAlertController(title: titleStr, message: messageStr, preferredStyle: UIAlertControllerStyle.Alert);
self.window!.presentViewController(alert, animated: true, completion: nil)
}
problem is I've found problem in self.window!.
Type 'Config' has no member 'window'
Please let me know how to solve that issue.
swift
Here's what I used, this is the same as #penatheboss answered, just add the ability of adding actions and handlers.
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)
}
}
Just make sure actionTitles and actions array the same count. Pass nil if you don't need any action handler closure.
self.popupAlert(title: "Title", message: " Oops, xxxx ", actionTitles: ["Option1","Option2","Option3"], actions:[{action1 in
},{action2 in
}, nil])
Objective C:
Add the category for UIViewController
UIViewController+PopAlert.h
#import <UIKit/UIKit.h>
#interface UIViewController (UIViewControllerCategory)
- (void) popAlertWithTitle: (NSString*) title message: (NSString*) message actionTitles:(NSArray *) actionTitles actions:(NSArray*)actions;
#end
UIViewController+PopAlert.m
#import "UIViewController+PopAlert.h"
#implementation UIViewController (UIViewControllerCategory)
- (void) popAlertWithTitle: (NSString*) title message: (NSString*) message actionTitles:(NSArray *) actionTitles actions:(NSArray*)actions {
UIAlertController *alert = [UIAlertController alertControllerWithTitle:title message:message preferredStyle:UIAlertControllerStyleAlert];
[actionTitles enumerateObjectsUsingBlock:^(id _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
UIAlertAction *action = [UIAlertAction actionWithTitle:obj style:UIAlertActionStyleDefault handler:actions[idx]];
[alert addAction:action];
}];
[self presentViewController:alert animated:YES completion:nil];
}
#end
Usage:
#import UIViewController+PopAlert.h
...
[super viewDidDisappear:animated];
NSArray *actions = #[^(){NSLog(#"I am action1");}, ^(){NSLog(#"I am action2");}];
[self popAlertWithTitle:#"I am title" message:#"good" actionTitles:#[#"good1", #"good2"] actions:actions];
self.window would mean that there's a window object in this class, and it's not the case.
You would need to use your let window : UIWindow? with window?.presentViewController(alert, animated: true, completion: nil), but this won't help, since this window does not actually represent any existing window, and it's not a view controller anyway.
So I suggest you pass the actual view controller you'll be using to the method:
static func showAlertMessage(vc: UIViewController, titleStr:String, messageStr:String) -> Void {
let alert = UIAlertController(title: titleStr, message: messageStr, preferredStyle: UIAlertControllerStyle.Alert);
vc.presentViewController(alert, animated: true, completion: nil)
}
and you call it from a class where a UIViewController object is available.
Details
Swift 5.1, Xcode 11.3.1
Global UIAlertController With UIViewController Extension
extension UIViewController{
// Global Alert
// Define Your number of buttons, styles and completion
public func openAlert(title: String,
message: String,
alertStyle:UIAlertController.Style,
actionTitles:[String],
actionStyles:[UIAlertAction.Style],
actions: [((UIAlertAction) -> Void)]){
let alertController = UIAlertController(title: title, message: message, preferredStyle: alertStyle)
for(index, indexTitle) in actionTitles.enumerated(){
let action = UIAlertAction(title: indexTitle, style: actionStyles[index], handler: actions[index])
alertController.addAction(action)
}
self.present(alertController, animated: true)
}
}
Usage
Alert
self.openAlert(title: "alert",
message: "add your message",
alertStyle: .alert,
actionTitles: ["Okay", "Cancel"],
actionStyles: [.default, .cancel],
actions: [
{_ in
print("okay click")
},
{_ in
print("cancel click")
}
])
ActionSheet
self.openAlert(title: "actionsheet",
message: "add your message",
alertStyle: .actionSheet,
actionTitles: ["Okay", "Cancel"],
actionStyles: [.default, .cancel],
actions: [
{_ in
print("okay click")
},
{_ in
print("cancel click")
}
])
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)
}
}
You can try this, please add below code in AppDelegate.swift file.
static func showAlertView(vc : UIViewController, titleString : String , messageString: String) ->()
{
let alertView = UIAlertController(title: titleString, message: messageString, preferredStyle: .alert)
let alertAction = UIAlertAction(title: "ok", style: .cancel) { (alert) in
vc.dismiss(animated: true, completion: nil)
}
alertView.addAction(alertAction)
vc.present(alertView, animated: true, completion: nil)
}
and call showAlertView method from any viewcontroller
AppDelegate.showAlertView(vc: self, titleString: "testTitle", messageString: "test msg")
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.
I created a alerMessage class .I can call any where in my application
//Common Alert Message Class
class AlertMessage {
internal static var alertMessageController:UIAlertController!
internal static func disPlayAlertMessage(titleMessage:String, alertMsg:String){
AlertMessage.alertMessageController = UIAlertController(title: titleMessage, message:
alertMsg, preferredStyle: UIAlertControllerStyle.Alert)
AlertMessage.alertMessageController.addAction(UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default,handler: nil))
if let controller = UIApplication.sharedApplication().keyWindow?.rootViewController?.presentedViewController {
controller.presentViewController(AlertMessage.alertMessageController, animated: true, completion: nil)
}
else{
UIApplication.sharedApplication().delegate?.window!!.rootViewController?.presentViewController(AlertMessage.alertMessageController, animated: true, completion: nil)
}
return
}
}
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)
}
}
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)
}
Single function gives Alert by default and can optionally be used for ActionSheet.
Arrays buttonTexts, buttonStyles and handlers can be of unequal sizes as per requirement.
Actions can be styled.
Animated can be specified.
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)
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
If you want to present from AppDelegate windows you can use like this
UIApplication.sharedApplication().delegate?.window.rootViewController?.presentViewController(vc, animated: true, completion: nil)
This is also the way you can present on top of the View Controller available.
UIApplication.topViewController()?.present(alertViewController!, animated: true, completion: nil)
This is my current code:
import UIKit
class classViewController: UIViewController {
// The function i want to call in other view controllers..
func alertView(title: String, message: String) {
var alert:UIAlertController = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default, handler: { (action) -> Void in
self.dismissViewControllerAnimated(true, completion: nil)
}))
self.presentViewController(alert, animated: true, completion: nil)
}
}
In the other view controller, where I've made an IBAction to perform this alertView, I have done this:
#IBAction func button(sender: AnyObject) {
classViewController().alertView("title", message: "message")
}
When I run the app, after tapping the button I get this error, but no alertView:
Warning: Attempt to present on
whose view is not in the
window hierarchy!
Right. If you want to make a global class that displays alerts, you need to pass in a reference to the current view controller, and use that instead of "self" in calls like presentViewController.
Your class should probably not be a subclass of UIViewController, since it looks like you're never displaying it to the screen.
I created a Utils class that is a subclass of NSObject.
It has a method showAlertOnVC that looks like this:
class func showAlertOnVC(targetVC: UIViewController?, var title: String, var message: String)
{
title = NSLocalizedString(title, comment: "")
message = NSLocalizedString(message, comment: "")
if let targetVC = targetVC
{
let alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.Alert)
let okButton = UIAlertAction(
title:"OK",
style: UIAlertActionStyle.Default,
handler:
{
(alert: UIAlertAction!) in
})
alert.addAction(okButton)
targetVC.presentViewController(alert, animated: true, completion: nil)
}
else
{
println("attempting to display alert to nil view controller.")
println("Alert title = \(title)")
println("Alert message = \(message)")
}
}
I am trying to use one single alert controller which include multiple alert showing functions and one dismiss function.But I am having this warning in my console and my other alert don't show.I wonder why?and the solution for that.
Here is my alert controller
import UIKit
class MyAlertViewController: UIViewController {
var myAlertController : UIAlertController!
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func displayLoadingAlert(viewController: UIViewController?) -> UIAlertController {
var controllerToPresent = viewController
if controllerToPresent == nil {
controllerToPresent = self
}
//create an alert controller
myAlertController = UIAlertController(title: "Loading...", message: “We are receiving data,please wait“, preferredStyle: .ActionSheet)
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 Click Retry”, preferredStyle: .Alert)
let defaultAction = UIAlertAction(title: "OK", style: .Default,handler:nil)
myAlertController.addAction(defaultAction)
controllerToPresent!.presentViewController(myAlertController, animated: true, completion: nil)
return myAlertController
}
func dismissLoadingAlert(){
myAlertController.dismissViewControllerAnimated(true, completion: nil)
}
}
I use to do dismissLoadingAlert() when I get the results from API.But,when I don't get the results from API.i used to do this delegate method from my protocol.
func didNotReceiveAPIResults(results: Bool,error:NSError){
dispatch_async(dispatch_get_main_queue(), {
// This condition will be enter if we dont get the results and show user with alert.
if (results) {
// I have done dismiss first data receiving alert,what do i doing wrong?
self.myAlertController.dismissLoadingAlert()
if error.localizedDescription == "The Internet connection appears to be offline."{
self.myAlertController.connectionErrorAlert(self)
self.carTableView.hidden=true
self.retryButton?.hidden=false
self.retryButton?.enabled=true
}
if error.localizedDescription == "Request Time Out."{
self.myAlertController.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()
}
})
}
You are on the wrong track. You should not subclass this controller.
The UIAlertController class is intended to be used as-is and does not support subclassing. The view hierarchy for this class is private and must not be modified.
If you need a convenience class, refactor using a NSObject subclass that presents dynamic UIAlertController instances.