Application tried to present modally an active controller
I'm trying to create custom UIAlertController.
Thus from different places will be easier to work with.
but I'm getting this error :
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Application tried to present modally an active controller
class CustomAlert: UIAlertController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
private static var sheet : UIAlertController = UIAlertController()
static let instance = CustomAlert()
func create(title: String, message: String) -> CustomAlert {
CustomAlert.sheet = UIAlertController(title: title, message: message, preferredStyle: .actionSheet)
return self
}
func addlibrary() -> CustomAlert{
let libraryAction = UIAlertAction(title: "library", style: .default, handler: nil)
CustomAlert.sheet.addAction(libraryAction)
return self
}
func show(on vc : UIViewController){
UIApplication.shared.keyWindow?.rootViewController?.present(vc, animated: true, completion: nil)
}
}
Where is the problem?
Thanks
You are trying to present the wrong controller in your show method.
Change:
UIApplication.shared.keyWindow?.rootViewController?.present(vc, animated: true, completion: nil)
to:
vc.present(self, animated: true, completion: nil)
Related
Trying to use MFMailComposeViewController when click alert button. But when I click alert button, controller doesn't pop-up. The code is below. I used extension and I'm trying to call sendmail function when clicking alert button.
extension Alert:MFMailComposeViewControllerDelegate {
func sendmail(){
let mailComposeViewController = configureMailController()
if MFMailComposeViewController.canSendMail() {
let VC = storyboard?.instantiateViewController(withIdentifier: "MainVC")
VC?.present(mailComposeViewController, animated: true, completion: nil)
} else {
showMailError()
}
}
func configureMailController() -> MFMailComposeViewController {
let mailComposerVC = MFMailComposeViewController()
let VC = storyboard?.instantiateViewController(withIdentifier: "MainVC")
mailComposerVC.mailComposeDelegate = VC as? MFMailComposeViewControllerDelegate
mailComposerVC.setToRecipients(["**"])
mailComposerVC.setSubject("**")
mailComposerVC.setMessageBody("\n\n\n\nModel: \nSistem versiyon: )\nuygulamaversiyon:", isHTML: false)
return mailComposerVC
}
func showMailError() {
let sendMailErrorAlert = UIAlertController(title: "Could not send email", message: "Your device could not send email", preferredStyle: .alert)
let dismiss = UIAlertAction(title: "Ok", style: .default, handler: nil)
sendMailErrorAlert.addAction(dismiss)
let VC = storyboard?.instantiateViewController(withIdentifier: "MainVC")
VC?.present(sendMailErrorAlert, animated: true, completion: nil)
}
public func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
controller.dismiss(animated: true, completion: nil)
}
}
Your code tries to present the mail view controller (and also the error alert) on a new view controller which you create with instantiateViewController. Since this new VC itself is not part of your app's VC hierarchy, neither it nor the mail VC will appear on screen.
To make this work, you can either pass a view controller which is part of your app into your sendmail method:
func sendmail(_ root: UIViewController) {
...
root.present(mailComposeViewController, animated: true, completion: nil)
...
Or you can use a globally accessible VC of your app; in a simple app using the root VC should work:
func sendmail() {
...
let root = UIApplication.shared.keyWindow?.rootViewController
root?.present(mailComposeViewController, animated: true, completion: nil)
...
I'd suggest the first approach because it is more flexible (e.g. it allows you to open your mail screen anywhere, even when your VC hierarchy gets more complex).
I have a UIViewController which loads up some json data from the server. If the server is down or the user has data turned off I throw up an alert telling the user such. This is done using a UIAlertController. This works great. So I put this into an extension since it is used by all UIViewControllers which need data. Now the UIAlertController has an action set as well
Alert code
extension UIViewController {
func connectionLost(){
var message = "Your device has lost connection to the server. Check that you have a valid internet connection and then retry."
let alertController = UIAlertController( title: "Connection Lost",
message: message,
preferredStyle: .alert)
let retryAction = UIAlertAction(title:"Retry", style: .default, handler: {
action in
//call function in the viewcontroller that raised this alert to reload the data
})
alertController.addAction(retryAction)
self.present(alertController, animated: true, completion: nil)
}
}
When the user taps the retry button I want to call a function in the uiviewcontroller that raised the alert.
I tried creating a delegate in the extension but struggled with getting it wired up like you do in a class. What sort of approaches are there to call a function from an extension in the viewcontroller that raised the alert?
You should create a BaseViewController and use Inheritance. It could be useful for other implementations too.
class BaseViewController: UIViewController {
func onRetryClick() {
// override to customize or write here the common behaviour
}
}
class FirstViewController: BaseViewController {
override func onRetryClick() {
// do something specific for FirstViewController
}
}
class SecondViewController: BaseViewController {
override func onRetryClick() {
// do something specific for SecondViewController
}
}
class ThirdViewController: BaseViewController {
// if you don't override this method, super class (BaseViewController) implementation will be executed
}
extension BaseViewController {
func connectionLost(){
var message = "Your device has lost connection to the server. Check that you have a valid internet connection and then retry."
let alertController = UIAlertController( title: "Connection Lost",
message: message,
preferredStyle: .alert)
let retryAction = UIAlertAction(title:"Retry", style: .default, handler: { action in
self.onRetryClick()
})
alertController.addAction(retryAction)
self.present(alertController, animated: true, completion: nil)
}
}
Hope this makes sense.
class MyVC: UIViewController {
func retry() {
}
func checkConnection() {
connectionLost { (retry) -> (Void) in
if retry {
self.retry()
}
}
}
}
extension UIViewController {
func connectionLost(completion: #escaping (_ retry: Bool) -> (Void)) {
let message = "Your device has lost connection to the server. Check that you have a valid internet connection and then retry."
let alertController = UIAlertController( title: "Connection Lost",
message: message,
preferredStyle: .alert)
let retryAction = UIAlertAction(title:"Retry", style: .default, handler: {
action in
completion(true)//may be 'false', you decide
})
alertController.addAction(retryAction)
self.present(alertController, animated: true, completion: nil)
}
}
Whenever I press "Cancel" then "Delete Draft", the mail composer won't be dismissed. The error I'm getting is "Thread 1: EXC_BAD_ACCESS (code=1, address=0x40363380)"
In my TableViewController I have:
#IBAction func mailButton(sender: AnyObject) {
let emailComposer = EmailComposer()
if email != "" {
print(email)
if emailComposer.canSendMail() {
emailComposer.setRecipient(email)
let configuredMailComposeViewController = emailComposer.configuredMailComposeViewController()
presentViewController(configuredMailComposeViewController, animated: true, completion: nil)
}
} else {
let alertController = UIAlertController(title: "Sorry!", message: "No email found for this contact", preferredStyle: .Alert)
alertController.addAction(UIAlertAction(title: "OK", style: .Default, handler: { (action) -> Void in
//do nothing
}))
self.presentViewController(alertController, animated: true, completion:nil)
}
}
For those who don't know, EXC_BAD_ACCESS means its trying to access something in memory that is no longer there. I wrongfully created the EmailComposer() object after the button tap so it was going out of scope. So this:
let emailComposer = EmailComposer()
...should have been created here, for example:
class TableViewController: UITableViewController {
let emailComposer = EmailComposer()
I'm trying to make my app able to access and send an email after a button is pressed. This is what I have so far and when I run it, and click the help button the alert pops up and the cancel button works fine but the email part of the alert crashes the app.
When it crashes it highlights the class AppDelegate: UIResponder, UIApplicationDelegate line and says Thread 1: signal SIGABRT.
#IBAction func helpButtonAction(sender: UIButton) {
let alert = UIAlertController(title: "Help", message: "Click 'Email' to email support", preferredStyle: UIAlertControllerStyle.Alert)
alert.addAction(UIAlertAction(title: "Email", style: UIAlertActionStyle.Default, handler: { action in
let emailTitle = "Help Request"
let messageBody = ""
let toRecipents = ["sample#sample.com"]
let mc: MFMailComposeViewController = MFMailComposeViewController()
mc.mailComposeDelegate = self
mc.setSubject(emailTitle)
mc.setMessageBody(messageBody, isHTML: false)
mc.setToRecipients(toRecipents)
self.presentViewController(mc, animated: true, completion: nil)
}))
alert.addAction(UIAlertAction(title: "Cancel", style: UIAlertActionStyle.Cancel, handler: nil))
self.presentViewController(alert, animated: true, completion: nil)
}
func mailComposeController(controller: MFMailComposeViewController, didFinishWithResult result: MFMailComposeResult, error: NSError?) {
self.dismissViewControllerAnimated(false, completion: nil)
}
Heres the console error...
'NSInvalidArgumentException', reason: 'Application tried to present a nil modal view controller on target <app.ViewController: 0x13c64a5f0>.'
*** First throw call stack:
(0x183930f48 0x19847ff80 0x18923def4 0x189240800 0x188fbdea0 0x10004909c 0x1000491d0 0x100048cbc 0x100048d0c 0x1893297d8 0x189329f70 0x189218ba4 0x18921bd9c 0x188ff3668 0x188eff240 0x188efed3c 0x188efebc4 0x1886c5c2c 0x1013d5c68 0x1013db710 0x1838e81f8 0x1838e6060 0x183814ca0 0x18e87c088 0x188f2cffc 0x10004ee78 0x198cc28b8)
libc++abi.dylib: terminating with uncaught exception of type NSException
The problem is how you are instantiating a View Controller.
This code will instantiate the class, but not the view as you want to.
let mc: MFMailComposeViewController = MFMailComposeViewController()
The proper way to do so, can be found in the link above, i will just copy the code here.
You must set an identifier to your view controller, instantiating it by the storyboard, and then, presenting it.
let storyboard = UIStoryboard(name: "MyStoryboardName", bundle: nil)
let vc = storyboard.instantiateViewControllerWithIdentifier("someViewController") as! UIViewController
self.presentViewController(vc, animated: true, completion: nil)
Instantiate and Present a viewController in Swift
I'm trying to create an app with Swift and Parse. I'm using Xcode 7 and Swift 2.
I want to show a alert message when User is login failed, here is my function:
func logInViewController(logInController: PFLogInViewController, didFailToLogInWithError error: NSError?){
let alertLoginFailed = UIAlertController(title: "Login Failed", message: "Your username or password is invalid!", preferredStyle: UIAlertControllerStyle.Alert)
alertLoginFailed.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler: nil))
self.presentViewController(alertLoginFailed, animated: true, completion: nil)
print("Login failed.........!")
}
But I've got this error when run in the emulator:
2015-10-02 11:32:39.988 RedString[2089:886501] Warning: Attempt to present <UIAlertController: 0x7a934400> on <MyProject.ViewController: 0x7b985150> whose view is not in the window hierarchy!
Login failed.........!
I've googled about it, but I didn't found the clear solution.
Here is my whole class:
import UIKit
import Parse
import ParseUI
class ViewController: UIViewController, PFLogInViewControllerDelegate, PFSignUpViewControllerDelegate {
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewDidAppear(animated: Bool) {
self.setupLoginView()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func logInViewController(logInController: PFLogInViewController, didLogInUser user: PFUser){
self.dismissViewControllerAnimated(true, completion: nil)
}
func logInViewController(logInController: PFLogInViewController, didFailToLogInWithError error: NSError?){
let alertLoginFailed = UIAlertController(title: "Login Failed", message: "Your username or password is invalid!", preferredStyle: UIAlertControllerStyle.Alert)
alertLoginFailed.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler: nil))
self.presentViewController(alertLoginFailed, animated: true, completion: nil)
print("Login failed.........!")
}
func signUpViewController(signUpController: PFSignUpViewController, didSignUpUser user: PFUser){
self.dismissViewControllerAnimated(true, completion: nil)
}
func signUpViewController(signUpController: PFSignUpViewController, didFailToSignUpWithError error: NSError?){
print("Sign up failed.........!")
}
func setupLoginView(){
if(PFUser.currentUser() == nil){
let loginViewController = PFLogInViewController()
loginViewController.delegate = self
let signUpViewController = PFSignUpViewController()
signUpViewController.delegate = self
loginViewController.logInView!.logo = UIImageView(image: UIImage(named:"logo.png"))
loginViewController.signUpController = signUpViewController
self.presentViewController(loginViewController, animated: true, completion: nil)
}else{
print("login as: " + PFUser.currentUser()!.username!)
//prepare new view here
}
}
}
when
func logInViewController(logInController: PFLogInViewController, didFailToLogInWithError error: NSError?){
let alertLoginFailed = UIAlertController(title: "Login Failed", message: "Your username or password is invalid!", preferredStyle: UIAlertControllerStyle.Alert)
alertLoginFailed.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler: nil))
self.presentViewController(alertLoginFailed, animated: true, completion: nil)
print("Login failed.........!")
}
is called, your view controller is not on screen. Therefore you could either
dismiss the logInViewController, then display the alert and pass
setUpLogInView as the handler.
or in the above function, try logInController.presentViewController
instead of self.presentViewController
You have to call presentViewController:animated:completion on your login view controller.
Here is a simplified version of your class to show you what I mean:
class ViewController: UIViewController {
weak var loginViewController: UIViewController?
func setupLoginViewController() {
let loginVC = PFLogInViewController()
// setup loginVC
loginViewController = loginVC // store the reference
}
func loginDidFail() {
let alertVC = UIAlertController(...)
// setup alertVC
loginViewController?.presentViewController(...) // present the alert from the login view controller
}
}
I had the same problem in Objective-C, it occurs when the parent window has not yet been drawn to the screen. I solved the problem by calling the code from within viewDidAppear rather than viewDidLoad. See UIAlert error, whose view is not in the window hierarchy