Closed. This question needs debugging details. It is not currently accepting answers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 6 years ago.
Improve this question
My iOS app requires a customized group of alerts with similar functionality. Can I pack those in a class, so I don't have to copy paste in every UIViewController?
func displayAlert(msg:String, handler: (UIAlertAction) -> Void）{...}
func successMsg (msg: String){...}
func failMsg(msg: String){...}
I was trying to pack them into a subclass(AlertViewController) of UIViewController, but then there was runtime error:"Attempt to present <...UIAlertController...> on <...UIAlertController...> whose view is not in the window hierachy!"
code in myViewController:
#IBAction func leave() {
let date = getDate()
let datePresent = dateForPresent()
if stID == nil || name == nil {
return
} else {
alert.displayAlert("\(datePresent)"){action in
self.request.getResult(self.request.leavePara(self.stID!, date: date, name: self.name!) ){ (result) in
dispatch_async(dispatch_get_main_queue(), {
let flag = result["result","out_Flag"].int
print(result)
let msg = result["result","out_nszRtn"].string!
if flag == 0 {
self.alert.successMsg(msg){ action in
self.performSegueWithIdentifier("personUnwind", sender: self)
}
}else {
self.alert.failMsg(msg)
}
})
}
}
}
}
Please use this code.
func displayAlertWithMessage(title: String, message: string){
let ac = UIAlertController(title: title, message: message, preferredStype: .Alert)
ac.addAction(UIAlertAction(title:"OK", style: .Default, handler: nil))
let rootVC = UIApplication.sharedApplication().keyWindow?.rootViewController
rootVC?.presentViewController(ac, animated: true){}
}
If you want to display alert for specific view controller you can use this function.
func displayAlertWithMessage(viewController: UIViewController, title: String, message: string){
let ac = UIAlertController(title: title, message: message, preferredStype: .Alert)
ac.addAction(UIAlertAction(title:"OK", style: .Default, handler: nil))
viewController.presentViewController(ac, animated: true){}
}
And you can call it function with this code.
displayAlertWithMessage(self, animated: true, completion: nil)
I'm not sure what the error you were getting was about, but if you want to avoid a subclass you could implement a UIAlertViewController initializer that returns an object customized to your needs.
For example, the following could be written at a global level:
extension UIAlertController {
enum AlertMessageID {
case SaveFailed
}
convenience init(messageID: AlertMessageID) {
switch messageID {
case .SaveFailed:
self.init(title: "Oops", message: "The save failed.", preferredStyle: .Alert)
}
let okayButton = UIAlertAction(title: "Okay", style: .Default, handler: nil)
self.addAction(okayButton)
}
}
Related
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 extremely new to iOS. I'm trying to show a dialog to the user to get some input, but the actions are never triggered. I've been searching on the net for hours and no answer seem to work for me.
Here's the function I'm trying to use to show the dialog:
private func showAmountDialog(type: String, onComplete: #escaping (Double) -> Void) {
let alert = UIAlertController(title: "Enter an amount", message: nil, preferredStyle: .alert)
alert.addAction(UIAlertAction(title: LzStrings.Common_Cancel, style: .cancel, handler: nil))
alert.addTextField(configurationHandler: { textField in
textField.placeholder = "0.00 \(type)"
textField.keyboardType = .decimalPad
})
alert.addAction(UIAlertAction(title: LzStrings.Common_OK, style: .default) { (UIAlertAction) in
if let input = alert.textFields?.first?.text, let amount = Double(input) {
print("Your amount: \(amount)")
}
})
self.present(alert, animated: true)
}
self here is my ViewController which has a parent of UIViewController type and several other protocols.
What I might be doing wrong?
EDIT: The way I knew it isn't executing is using break-points and not by relying on print("...")
Also, since I added the TextField right before adding the action, the nullability check is useless and the textFields.first is never nil, so in both cases, a break-point should be triggered or the print("...") should be executed, which neither of them is happening.
EDIT 2: Since the if statement can do a little distraction, I edited my code this way and tested again:
alert.addAction(UIAlertAction(title: LzStrings.Common_OK, style: .default) { (UIAlertAction) in
if let input = alert.textFields?.first {
if let amount = Double(input.text ?? "") {
print("Your amount: \(amount)")
} else {
print("Can't cast this string to double")
}
} else {
print("Text field is null")
}
})
Still, no feedback from the dialog.
PS: Even the Cancel button doesn't work.
EDIT 3: My dismiss function is overridden in the super class, but it passes completion closure normally:
override open func dismiss(animated flag: Bool, completion: (() -> Void)? = nil) {
if let navigationController = self.navigationController as? NavigationController {
navigationController.dismiss(animated: flag, completion: completion)
} else {
super.dismiss(animated: flag, completion: completion)
}
}
After having a conversation with one of my colleagues, we found out that to show standard UIAlertController we must use this:
self.view.window!.rootViewController?.present(alert, animated: true, completion: nil)
Instead of this
self.present(alert, animated: true, completion: nil)
It fixed my issue. I hope someone will find this helpful.
Another option is to use an extention for ViewController:
extension UIViewController {
//Show a basic alert
func showAlert(alertText : String, alertMessage : String) {
let alert = UIAlertController(title: alertText, message: alertMessage, preferredStyle: UIAlertControllerStyle.alert)
alert.addAction(UIAlertAction(title: "Got it", style: UIAlertActionStyle.default, handler: nil))
//Add more actions as you see fit
self.present(alert, animated: true, completion: nil)
}
}
I want to have a base UIAlertController and I want to use it in different classes by just passing the buttons and their closures. To achieve this, I created an extension from UIAlertController like below:
extension UIAlertController {
func showAlert(buttons: [ButtonsAction]?) -> UIAlertController {
let alert = self
guard let alertButtons = buttons else {
return alert
}
for button in alertButtons {
let alertAction = UIAlertAction(title: button.title, style: button.style, handler: {action in
button.handler()
})
alert.addAction(alertAction)
}
return alert
}
}
for my buttons I have a struct:
struct ButtonsAction {
let title: String!
let style: UIAlertAction.Style
let handler: () -> Void
}
In one of my viewControllers I have a function which shows the alert. In that function I have a title and a message then I want to have 1 button to dismiss the alert. The function is something like this:
func fetchFaild(title: String, message: String) {
let buttons = ButtonsAction.init(title: "cancel", style: .cancel, handler: {action in
//here I want to dissmiss the alert I dont know how
})
let alert = UIAlertController(title: title, message: message, preferredStyle: .alert).showAlert(buttons: buttons)
alert.show(self, sender: nil)
}
I have problem adding buttons to the Alert and I don't know how to add actions to the buttons.
I know this is not the best practice here. If any one knows any example or any tutorial that can help me achieve this I really appreciate it.
An extension of UIViewController might be a more reasonable solution and the ButtonsAction struct seems to be redundant.
extension UIViewController {
func showAlert(title: String, message: String, actions: [UIAlertAction], completion: (() -> Void)? = nil) {
let alertController = UIAlertController(title: title, message: message, preferredStyle: .alert)
actions.forEach{alertController.addAction($0)}
self.present(alertController, animated: true, completion: completion)
}
}
class MyController : UIViewController {
func fetchFailed(title: String, message: String) {
let actions = [UIAlertAction(title: "Cancel", style: .cancel, handler: { (action) in
print("Cancel tapped")
})]
showAlert(title: title, message: message, actions: actions)
}
}
I came across a scenario where i had to call a function inside enum's function in swift 3.
The scenario is as follows:
class SomeViewController: UIViewController {
enum Address {
case primary
case secondary
func getAddress() {
let closure = { (text: String) in
showAlert(for: "")
}
}
}
func showAlert(for text: String) {
let alertController = UIAlertController(title: text, message: nil, preferredStyle: .alert)
alertController.addAction(UIAlertAction(title:NSLocalizedString("OK", comment:"OK button title"), style: .cancel, handler: nil))
present(alertController, animated: true, completion: nil)
}
}
As you can see from the above code I get an error on line 10 (showAlert(for: ""))
The error is:
instance member showAlert cannot be used on type SomeViewController; did you mean to use a value of this type instead?
How can I call a function from enum's function then?
Alternative approach:
You can use a static method of SomeViewController to present the alert.
Example:
static func showAlert(for text: String)
{
let alertController = UIAlertController(title: text, message: nil, preferredStyle: .alert)
alertController.addAction(UIAlertAction(title:NSLocalizedString("OK", comment:"OK button title"), style: .cancel, handler: nil))
UIApplication.shared.keyWindow?.rootViewController?.present(alertController, animated: true, completion: nil)
}
Using it:
enum Address
{
case primary
case secondary
func getAddress()
{
let closure = { (text: String) in
SomeViewController.showAlert(for: "")
}
closure("hello")
}
}
override func viewDidLoad()
{
super.viewDidLoad()
let addr = Address.primary
addr.getAddress()
}
The enum does not know the instance and thus can not access its members. One approach to deal with this situation would be to inform the client of the enum that something went wrong.
class SomeViewController: UIViewController {
enum Address {
case primary
case secondary
func getAddress() -> String? {
//allGood == whatever your logic is to consider a valid address
if allGood {
return "theAddress"
} else {
return nil;
}
}
}
func funcThatUsesAddress() {
let address = Address.primary
guard let addressString = address.getAddress() else {
showAlert(for: "")
return
}
// use your valid addressString here
print(addressString)
}
func showAlert(for text: String) {
let alertController = UIAlertController(title: text, message: nil, preferredStyle: .alert)
alertController.addAction(UIAlertAction(title:NSLocalizedString("OK", comment:"OK button title"), style: .cancel, handler: nil))
present(alertController, animated: true, completion: nil)
}
}
I want to make a function in NSObject class for UIAlertCotroller. So that I can access this function in any class. I have tried with that following code:
open class func showActionSheet(_ delegate: UIViewController, message: String, strtittle: String, handler: ((UIAlertController) -> Void)! = nil)
{
let actionSheetController: UIAlertController = UIAlertController(title: strtittle, message: message, preferredStyle: UIAlertControllerStyle.actionSheet)
if handler == nil{
actionSheetController.addAction(UIAlertAction(title: "Default(Off)" , style: .default , handler:{ (UIAlertAction)in
}))
}
else{
actionSheetController.addAction(UIAlertAction(title: "Default(Off)" , style: .default , handler:{ (UIAlertAction)in
}))
}
delegate.present(actionSheetController, animated: true, completion: {
print("completion block")
})
}
This is the function that I made, but problem is there can be number of actions in ActionSheet and they also have different tittle and different styles.
Question: How can I make this function? Please Help.
Thanks!
Make extension of UIAlertController
extension UIAlertController{
func AlertWithTextField(_ view:UIViewController) -> UIAlertController{
let actionSheetController: UIAlertController = UIAlertController(title: "Action Sheet", message: message, preferredStyle: UIAlertControllerStyle.actionSheet)
actionSheetController.addAction(UIAlertAction(title: "No" , style: .default , handler:{ (UIAlertAction)in
}))
actionSheetController.addAction(UIAlertAction(title: "Yes" , style: .default , handler:{ (UIAlertAction)in
}))
view.present(actionSheetController, animated: true, completion: {
print("completion block")
})
return actionSheetController
}
}
Call this from your ViewController
let alert = UIAlertController()
alert.AlertWithTextField(self)
I have found solution of my problem by using this Swift - How to present ViewController when tapping button in a custom AlertController
Their are following modification that I have to do to achieve my goal. Here is the code:
In Controller Class:
Alert.showActionSheet(self, message: "Save incoming media for this chat",strtittle: "",actionTittle: ["Default(Off)","Always","Never","Cancel"],
actionStyle: [.default,.default,.default,.cancel] ,
withHandler: [defaultHandler, alwaysHandler, neverHandler, cancelHandler])
func defaultHandler(action: UIAlertAction) {
//Add code of present
print("DefaultHandler")
}
func alwaysHandler(action: UIAlertAction) {
//Add code of present
print("alwaysHandler")
}
func neverHandler(action: UIAlertAction) {
//Add code of present
print("neverHandler")
}
func cancelHandler(action: UIAlertAction) {
//Add code of present
print("cancelHandler")
}
In NSObject Class:
open class func showActionSheet(_ delegate: UIViewController, message: String, strtittle: String, actionTittle: [String], actionStyle: [UIAlertActionStyle], withHandler handler: [((UIAlertAction) -> Void)]?)
{
var actionSheetController: UIAlertController = UIAlertController()
if message != "" || strtittle != ""
{
actionSheetController = UIAlertController(title: strtittle, message: message, preferredStyle: UIAlertControllerStyle.actionSheet)
}
for i in 0..<actionTittle.count
{
actionSheetController.addAction(UIAlertAction(title: actionTittle[i],
style: actionStyle[i],
handler: handler?[i]))
}
delegate.present(actionSheetController, animated: true, completion: nil)
}
Using this I can gave number of actions, their tittle and styles to action sheet. And also I can simply call this method in each class. :)