Update(3)
I have the following code:
This works if I wait in the debugger:
And if I dont:
A view can only be associated with at most one view controller at a
time!
#IBAction func openTestViewController(_ sender: Any) {
let b = Bundle(identifier: "com.test")
let m = MultipleListViewController(nibName: "MultipleListViewController", bundle: b)
self.present(m, animated: true, completion: nil)
}
This does not work; error: `
A view can only be associated with at most one view controller at a
time!
#IBAction func openTestViewController(_ sender: Any) {
DispatchQueue.main.async {
let b = Bundle(identifier: "com.test")
let m = MultipleListViewController(nibName: "MultipleListViewController", bundle: b)
self.present(m, animated: true, completion: nil)
}
}
Note: The reason I do Bundle(identifier: "com.test") is because I have it in a framework.
This only works if:
1. I set a breakpoint
2. And wait for it to load - and make sure that I can see it with the little preview eye when debugging.
How can I/should i wait for it in code?
Related
I'm creating an app that uses the Facebook SDK to authenticate users. I'm trying to consolidate the facebook logic in a separate class. Here is the code (stripped for simplicity):
import Foundation
class FBManager {
class func fbSessionStateChane(fbSession:FBSession!, fbSessionState:FBSessionState, error:NSError?){
//... handling all session states
FBRequestConnection.startForMeWithCompletionHandler { (conn: FBRequestConnection!, result: AnyObject!, error: NSError!) -> Void in
println("Logged in user: \n\(result)");
let storyboard = UIStoryboard(name: "Main", bundle: NSBundle.mainBundle())
let loggedInView: UserViewController = storyboard.instantiateViewControllerWithIdentifier("loggedInView") as UserViewController
loggedInView.result = result;
//todo: segue to the next view???
}
}
}
I'm using the above class method to check session state changes, and it works fine.
Q: Once I have the user's data, how can I segue to the next view from within this custom class?
Just to be clear, I have a segue with identifier on the storyboard, and I'm trying to find a way to perform a segue from a class which is not the view controller
If your segue exists in the storyboard with a segue identifier between your two views, you can just call it programmatically using:
performSegue(withIdentifier: "mySegueID", sender: nil)
For older versions:
performSegueWithIdentifier("mySegueID", sender: nil)
You could also do:
presentViewController(nextViewController, animated: true, completion: nil)
Or if you are in a Navigation controller:
self.navigationController?.pushViewController(nextViewController, animated: true)
If your segue exists in the storyboard with a segue identifier between your two views, you can just call it programmatically using
self.performSegueWithIdentifier("yourIdentifierInStoryboard", sender: self)
If you are in Navigation controller
let viewController = YourViewController(nibName: "YourViewController", bundle: nil)
self.navigationController?.pushViewController(viewController, animated: true)
I will recommend you for second approach using navigation controller.
You can use NSNotification
Add a post method in your custom class:
NSNotificationCenter.defaultCenter().postNotificationName("NotificationIdentifier", object: nil)
Add an observer in your ViewController:
NSNotificationCenter.defaultCenter().addObserver(self, selector: "methodOFReceivedNotication:", name:"NotificationIdentifier", object: nil)
Add function in you ViewController:
func methodOFReceivedNotication(notification: NSNotification){
self.performSegueWithIdentifier("yourIdentifierInStoryboard", sender: self)
}
You can use segue like this:
self.performSegueWithIdentifier("push", sender: self)
override func prepareForSegue(segue: UIStoryboardSegue!, sender: AnyObject!) {
if segue.identifier == "push" {
}
}
Swift 3 - Also works with SpriteKit
You can use NSNotification.
Example:
1.) Create a segue in the storyboard and name the identifier "segue"
2.) Create a function in the ViewController you are segueing from.
func goToDifferentView() {
self.performSegue(withIdentifier: "segue", sender: self)
}
3.) In the ViewDidLoad() of your ViewController you are segueing from create the observer.
NotificationCenter.default.addObserver(self, selector: #selector(goToDifferentView), name: "segue" as NSNotification.Name, object: nil)
Update -
Last time I used this I had to change the .addObserver call to the following code to silence the errors.
NotificationCenter.default.addObserver(self, selector: #selector(goToDifferentView), name: NSNotification.Name(rawValue: "segue"), object: nil)
4.) In the ViewController or Scene you are segueing to, add the Post Method wherever you want the segue to be triggered.
NotificationCenter.default.post(name: "segue" as NSNotification.Name, object: nil)
Update -
Last time I used this I had to change the .post call to the following code to silence the errors.
NotificationCenter.default.post(NSNotification(name: NSNotification.Name(rawValue: "segue"), object: nil) as Notification)
There are already great answers above, i'd like to put little focus on preparation before performing segue.
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.destination is YourDestinationVC {
let vc = segue.destination as? YourDestinationVC
// "label" and "friends" are part of destinationVC
vc?.label = "someText"
vc?.friends = ["John","Mike","Garry"]
}
Once your are done with data that you want to pass on to your destinationVC then perform your segue at an appropriate place.
You can set "IdentifierOfDestinationVC" in StoryBoard Identity inspector in StoryBoard ID field
performSegue(withIdentifier: "IdentifierOfDestinationVC", sender: nil)
What you want to do is really important for unit testing. Basically you need to create a small local function in the view controller. Name the function anything, just include the performSegueWithIndentifier.
func localFunc() {
println("we asked you to do it")
performSegueWithIdentifier("doIt", sender: self)
}
Next change your utility class FBManager to include an initializer that takes an argument of a function and a variable to hold the ViewController's function that performs the segue.
public class UtilClass {
var yourFunction : () -> ()
init (someFunction: () -> ()) {
self.yourFunction = someFunction
println("initialized UtilClass")
}
public convenience init() {
func dummyLog () -> () {
println("no action passed")
}
self.init(dummyLog)
}
public func doThatThing() -> () {
// the facebook login function
println("now execute passed function")
self.yourFunction()
println("did that thing")
}
}
(The convenience init allows you to use this in unit testing without executing the segue.)
Finally, where you have //todo: segue to the next view???, put something along the lines of:
self.yourFunction()
In your unit tests, you can simply invoke it as:
let f = UtilClass()
f.doThatThing()
where doThatThing is your fbsessionstatechange and UtilClass is FBManager.
For your actual code, just pass localFunc (no parenthesis) to the FBManager class.
This worked for me.
First of all give the view controller in your storyboard a Storyboard ID inside the identity inspector. Then use the following example code (ensuring the class, storyboard name and story board ID match those that you are using):
let viewController:
UIViewController = UIStoryboard(
name: "Main", bundle: nil
).instantiateViewControllerWithIdentifier("ViewController") as UIViewController
// .instantiatViewControllerWithIdentifier() returns AnyObject!
// this must be downcast to utilize it
self.presentViewController(viewController, animated: false, completion: nil)
For more details see http://sketchytech.blogspot.com/2012/11/instantiate-view-controller-using.html
best wishes
Another option is to use modal segue
STEP 1: Go to the storyboard, and give the View Controller a Storyboard ID. You can find where to change the storyboard ID in the Identity Inspector on the right.
Lets call the storyboard ID ModalViewController
STEP 2: Open up the 'sender' view controller (let's call it ViewController) and add this code to it
public class ViewController {
override func viewDidLoad() {
showModalView()
}
func showModalView() {
if let mvc = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ModalViewController") as? ModalViewController {
self.present(mvc, animated: true, completion: nil)
}
}
}
Note that the View Controller we want to open is also called ModalViewController
STEP 3: To close ModalViewController, add this to it
public class ModalViewController {
#IBAction func closeThisViewController(_ sender: Any?) {
self.presentingViewController?.dismiss(animated: true, completion: nil)
}
}
You can do this thing using performSegueWithIdentifier function.
Syntax :
func performSegueWithIdentifier(identifier: String, sender: AnyObject?)
Example :
performSegueWithIdentifier("homeScreenVC", sender: nil)
This worked for me:
//Button method example
#IBAction func LogOutPressed(_ sender: UIBarButtonItem) {
do {
try Auth.auth().signOut()
navigationController?.popToRootViewController(animated: true)
} catch let signOutError as NSError {
print ("Error signing out: %#", signOutError)
}
}
The problem here is that I'm presenting EditCommentVC modally, over the current context of the CommentVC because I want to set the background of the UIView to semi-transparent. Now, on the EditCommentVC I have a UITextView that allows the user to edit their comment, along with 2 buttons - cancel (dismisses the EditCommentVC) and update that updates the new comment and push it to the database.
In term of code, everything is working, except that once the new comment is being pushed and EditCommentVC is being dismissed, the UITableView on CommentsVC with all the comments is not being reloaded to show the updated comments. Tried calling it from viewWillAppear() but it doesn't work.
How can I reload the data in the UITableView in this case?
#IBAction func updateTapped(_ sender: UIButton) {
guard let id = commentId else { return }
Api.Comment.updateComment(forCommentId: id, updatedComment: editTextView.text!, onSuccess: {
DispatchQueue.main.async {
let commentVC = CommentVC()
commentVC.tableView.reloadData()
self.dismiss(animated: true, completion: nil)
}
}, onError: { error in
SVProgressHUD.showError(withStatus: error)
})
}
The code in the CommentVC where it transitions (and passes the id of the comment). CommentVC conforms to a CommentActionProtocol that passes the id of that comment:
extension CommentVC: CommentActionProtocol {
func presentActionSheet(for commentId: String) {
let actionSheet = UIAlertController(title: nil, message: nil, preferredStyle: .actionSheet)
let editAction = UIAlertAction(title: "Edit", style: .default) { _ in
self.performSegue(withIdentifier: "CommentVCToEditComment", sender: commentId)
}
actionSheet.addAction(editAction)
present(actionSheet, animated: true, completion: nil)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "CommentVCToEditComment" {
let editCommentVC = segue.destination as! EditCommentVC
let commentId = sender as! String
editCommentVC.commentId = commentId
}
}
}
I see atleast 2 problems here:
You are creating a new CommentVC which you should not do if you want to update the tableView in the existing view controller.
Since you have mentioned that Api.Comment.updateComment is a an asynchronous call, you need to write the UI code to run on the main thread.
So first you need to have the instance of the commentVC in a variable inside this viewController. You can store the instance of the view controller from where you are presenting this view controller.
class EditCommentVC {
var commentVCdelegate: CommentVC!
// Rest of your code
}
Now you need to pass the reference commentVC in this variable when you are presenting the edit view controller.
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "CommentVCToEditComment" {
let editCommentVC = segue.destination as! EditCommentVC
let commentId = sender as! String
editCommentVC.commentId = commentId
editCommentVC.commentVCdelegate = self
}
}
Now you need to use this reference to reload your tableView.
Api.Comment.updateComment(forCommentId: id, updatedComment: editTextView.text!, onSuccess: {
DispatchQueue.main.async {
commentVCdelegate.tableView.reloadData() // - this commentVC must be an instance that you store of the your commentVC that you created the first time
self.dismiss(animated: true, completion: nil)
}
}, onError: { error in
SVProgressHUD.showError(withStatus: error)
})
Well, i had this problem too, and the solution i found was to use Protocol. I would recommend you to search how to send data back to previous ViewController. That way, when you dismiss the EditCommentVC, you then send back a value(in my case i send true) to the previous ViewController(in your case, CommentVC), and then you'll have a function in CommentVC checking if the value is true and if it is, reload the TableView.
Here, let me show you an example of how i used (those are the names of my ViewControllers, functions and protocols, you can use whatever you want and send whatever data you want back):
In your CommentVC, you'll have something like this:
protocol esconderBlurProtocol {
func isEsconder(value: Bool)
}
class PalestranteVC: UIViewController,esconderBlurProtocol {
func isEsconder(value: Bool) {
if(value){
//here is where you can call your api again if you want and reload the data
tableView.reloadData()
}
}
}
Also, dont forget that you have to set the delegate of EditCommentVC, so do it when you're presenting EditCommentVC, like this:
let viewController = (self.storyboard?.instantiateViewController(withIdentifier: "DetalhePalestranteVC")) as! DetalhePalestranteVC
viewController.modalPresentationStyle = .overFullScreen
viewController.delegate = self
self.present(viewController, animated: true, completion: nil)
//replace **DetalhePalestranteVC** with your **EditCommentVC**
And in your EditCommentVC you'll have something like this:
class DetalhePalestranteVC: UIViewController {
var delegate: esconderBlurProtocol?
override func viewWillDisappear(_ animated: Bool) {
delegate?.isEsconder(value: true)
}
}
That way, everything you dismiss EditCommentVC, you'll send back True and reload the tableView.
I am trying to building a app using the master details template.
in the Master view controller I added a button called Catalogue : this button showing a tabbar controller called Catalogue.
I don't use Segue to show the catalogue, I use the code below to show the tab controller
From Master form I called the Tabbar controller :
#IBAction func Btn_Catalogue(_ sender: Any) {
let AddCatalogueVC = self.storyboard?.instantiateViewController(withIdentifier: "CatalogueVC") as! CatalogueVC
present(AddCatalogueVC, animated: true, completion: nil)
}
From CategorieVC I use the code below to show
#IBAction func Btn_AddCategorie(_ sender: Any) {
self.Mode = "New"
let AddCategorieViewController = self.storyboard?.instantiateViewController(withIdentifier: "AddCategorieVC") as! AddCategorieVC
present(AddCategorieViewController, animated: true, completion: nil)
}
I dismiss the AddCategorieVC using the code below
#IBAction func Btn_Save(_ sender: Any)
{
if self.Txt_CategorieName.text != ""{
self.Mysave = true
self.MyCategorieName = self.Txt_CategorieName.text!
self.dismiss(animated: true, completion: nil)
}
}
I have unwind SEGUE from Save button to a function in categorieVC
#IBAction func FctSaveCategories(_ sender: UIStoryboardSegue) {
let sendervc = sender.source as! AddCategorieVC
if self.Mode == "New" && sendervc.Mysave == true { // Mode insert
let MyCategories = TblCategorie(context: Mycontext)
MyCategories.categorie_Name = sendervc.MyCategorieName
do {
try Mycontext.save()
} catch {
debugPrint ("there is an error \(error.localizedDescription)")
}
}
}
The problem is when I hit the save button in categorieVC the catalogueVC is also dismissing at the same time returning me to the master control.
I am almost sure that the problem came from the Unwind segue but I don't know why.
Update: I activate the Cancel button in AddCategorieVC with the code below
self.dismiss(animated: true, completion: nil)
and when I clicked on it only the AddCategorieVC is being dismissed and I go back to CatalogueVC. The difference between the save button and the Cancel Button is only the UNWIND segue on the Save Button.
And when I add UnWIND segue to the cancel Button (just to test the behavior) it took me back to the master form instead CatalogueVC.
How can I solve that?
And yesss I found it
It look like that unwind segue automaticly handled dismiss contrôle
So all I need to do is remove the dismiss code from the save button this way the unwind segue will took me back to catalogueVC.
.
When I dismiss an instance of MFMailComposeViewController or MFMessageComposeViewController that is presented modally from the third viewController in a navigation stack, the navigation stack is reset, and the root VC is reloaded. How can I prevent this behavior and remain on the original presenting viewController (third VC in the stack)? I get the same behavior whether I call dismiss from the presenting VC, the presented VC, or the navigationController.
This has been asked before, but I have not seen a solution.
App Structure looks like this:
TabBarController
Tab 1 - TripsNavController
-> Trips IntroductionVC (root VC) segue to:
-> TripsTableViewController segue to:
-> TripEditorContainerVC
- TripEditorVC (child of ContainerVC)
- HelpVC (child of ContainerVC)
Tab 2...
Tab 3...
Tab 4...
In the TripEditorVC I present the MFMailComposeViewController. The functions below are declared in an extension to UIViewController that adopts the MFMailComposeViewControllerDelegate protocol
func shareWithEmail(message: NSAttributedString) {
guard MFMailComposeViewController.canSendMail() else {
showServiceError(message: "Email Services are not available")
return
}
let composeVC = MFMailComposeViewController()
composeVC.setSubject("My Trip Plan")
composeVC.setMessageBody(getHTMLforAttributedString(attrStr: message), isHTML: true)
composeVC.mailComposeDelegate = self
present(composeVC, animated: true, completion: nil)
}
Then in the delegate method I dismiss the MFMailComposeVC:
public func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
switch result {
case .sent:
print("Mail sent")
case .saved:
print("Mail saved")
case .cancelled:
print("Mail cancelled")
case .failed:
print("Send mail failed")
}
if error != nil {
showServiceError(message: "Error: \(error!.localizedDescription)")
}
dismiss(animated: true, completion: nil)
}
I have tried the following to present and dismiss and get the same behavior, i.e.: the TripsNavController clears the nav stack and reloads the TripsIntroductionVC as its root VC:
self.present(composeVC, animated: true, completion: nil)
self.parent?.present(composeVC, animated: true, completion: nil)
self.parent?.navigationController?.present(composeVC, animated: true, completion: nil)
self.navigationController?.present(composeVC, animated: true, completion: nil)
You can also check with presentingViewController?.dismiss method to get the solution.
I have tried with following navigation stack.
I am able to send email successfully from Container VC's Send Email button using your code only.
Can you please check and verify navigation flow?
Please let me know if you still face any issue.
dismiss(animated: true, completion: nil)
to
self.dismiss(animated: true, completion: nil)
Try this
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let secondViewController = storyboard.instantiateViewControllerWithIdentifier("secondViewControllerId") as! SecondViewController
self.presentViewController(secondViewController, animated: true, completion: nil)
or
https://stackoverflow.com/a/37740006/8196100
Just Use Unwind Segue its Pretty simple and perfect in your case
I have used many times..
just look at this Unwind segue's example
. If u still don't able to find answer or not able to understand the Unwind segue then just reply to me.
Hope this will solve your problem.
I found the problem with my navigation stack today. I built a simple
project that duplicated the tabBarController/NavigationControler architecture of my problem project, component by component, until dismissing a MFMailComposeViewController caused my navigation stack to reset as described in my original post.
That immediately pointed to the source of the bug. In my subclassed UINavigationCotroller I was instantiating the root viewController in code so that I could skip an introductory view if the user had set a switch in the apps settings. In order to pick up changes in that switch setting I was calling my instantiation code in viewDidAppear of the navigationController. That worked fine EXCEPT when dismissing the mailComposeVC. The fix was to add a guard statement in viewDidAppear to return if the navControllers viewController collection was not empty, and send and respond to an NSNotification when the switch was changed.
class TopNavigationController: UINavigationController {
var sectionType: SectionType?
var defaults = UserDefaults.standard
var showIntroFlag: Bool = true
override func viewDidLoad() {
super.viewDidLoad()
// Handle initial load of the tab bar controller where we are not sent a sectionType
if sectionType == nil {
sectionType = .groups
}
setShowIntroFlag()
NotificationCenter.default.addObserver(self, selector: #selector(resetControllers), name: NSNotification.Name(rawValue: "kUserDidChangeShowIntros"), object: nil)
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(true)
guard self.viewControllers.isEmpty else {
return
}
loadControllers()
}
func setShowIntroFlag() {
showIntroFlag = true
// Check NSUserDefaults to see if we should hide the Intro Views for all sections
if defaults.bool(forKey: "SHOW_SECTION_INTROS") == false {
showIntroFlag = false
}
}
func loadControllers() {
if showIntroFlag == true {
showIntro()
} else {
skipIntro()
}
}
func resetControllers() {
setShowIntroFlag()
loadControllers()
}
I created a custom alert in a viewcontroller, following the guidelines of the most voted answer of that question:
https://stackoverflow.com/a/37275840/6196609
I use this to display the alert, it is used as a "loading".
let pending = UIAlertController()
override func viewDidLoad() {
super.viewDidLoad()
[…]
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let pending = storyboard.instantiateViewControllerWithIdentifier("alertaLoad")
pending.modalPresentationStyle = UIModalPresentationStyle.OverCurrentContext
pending.modalTransitionStyle = UIModalTransitionStyle.CrossDissolve
[…]
}
to show:
self.presentViewController(self.pending, animated: true, completion: nil)
I succeeded in showing it, but I need to terminate it by the viewcontroller that invoked it after the end of my process, not by itself as was done in the example I quoted.
I've tried this but nothing happens.
self.pending.dismissViewControllerAnimated(false, completion: { (vetor) -> Void in
[…]
})
How could I do this correctly?
Call dismisson the presenting UIViewController, not on the presented one:
self.dismiss(animated: true) {
// go on
}