I have 2 Controllers: MainVC and SideMenuVC.
I wanted to modify MainVC using SideMenuVC, so created delegate of SideMenuVC ( as well, there's Emdebed segue "name..." to "Side Menu View Controller" on storyboard because MainViewController has subView, which contains ContainerView - this container is our SideMenuVC. And this delegate works as he should.
However, due to logic in the app, I also need to send data from MAINVC to SIDEMENUVC.
So i did the same - created another delegate of second VC... But I turned out, MainViewControllerDelegate is not responding in SideMenuViewController. And i'm absolutely clueless...
Yes, i do implement necessary protocols in both classes, in extension!
Code of both VCs below, screens of storyboard in the attachment
MainViewController + MainViewControllerDelegate
protocol MainViewControllerDelegate{
func isImageLoaded(_ isLoaded:Bool)
}
class MainViewController: UIViewController {
/* ... */
var delegate: MainViewControllerDelegate?
var sideMenuViewController: SideMenuViewController?
private var isSideMenuPresented:Bool = false
private var isImageLoaded:Bool = false
override func viewDidLoad() {
super.viewDidLoad()
self.isImageLoaded = false
self.setupUI()
self.delegate?.isImageLoaded(false)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if (segue.identifier == "MainVC_SideMenuVC_Segue")
{
if let controller = segue.destination as? SideMenuViewController
{
self.sideMenuViewController = controller
self.sideMenuViewController?.delegate = self
}
}
}
/* ... */
//I'm using PHPicker, and when new image is selected, i want to send "true" via delegate
func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
dismiss(animated: true)
if let itemProvider = results.first?.itemProvider, itemProvider.canLoadObject(ofClass: UIImage.self){
let previousImage = self.presentedImage.image
itemProvider.loadObject(ofClass: UIImage.self){ [weak self] image, error in
DispatchQueue.main.async {
guard let self = self, let image = image as? UIImage, self.presentedImage.image == previousImage else {
return
}
self.presentedImage.image = image
self.isImageLoaded = true;
self.delegate?.isImageLoaded(true)
}
}
}
}
SideMenuViewController + SideMenuViewControllerDelegate
protocol SideMenuViewControllerDelegate{
func hideSideMenu()
func performAction(_ type:OperationType)
}
class SideMenuViewController: UIViewController {
/*...*/
var delegate: SideMenuViewControllerDelegate?
var mainViewController: MainViewController?
private var menuData: [ExpandingCellModel] = []
private var isImageLoaded: Bool = false
override func viewDidLoad() {
super.viewDidLoad()
// self.mainViewController?.delegate = self
menuData = setupData()
setupUI()
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let controller = segue.destination as? MainViewController {
controller.delegate = self
}
}
}
/* ... */
Here is what I think is happening.
There is segue happening from MainVC to SideMenuVC but there is no segue actually happening between SideMenuVC to MainVC in my opinion.
Happening is keyword because there is an EmbedSegue from MainVC to SideMenuVC but where is the segue from SideMenuVC to MainVC ? You did some connection in storyboard but nothing is happening in my opinion.
That is why in override func prepare is being called as planned in MainViewControllerDelegate and the delegate is getting set but it is not getting set in SideMenuViewController since override func prepare doesn't get called as no segue happens.
What you can do instead which might work is set both the delegates inside prepare in MainViewControllerDelegate
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if (segue.identifier == "MainVC_SideMenuVC_Segue")
{
if let sideMenuVC = segue.destination as? SideMenuViewController
{
sideMenuVC.delegate = self
// assign MainViewControllerDelegate here
self.delegate = sideMenuVC
}
}
}
Check now if data is sent back to main view controller also.
If your issue is still not yet solved, please have a look and try this small example I set for you in github to show passing data between mainVC and embeddedVC and it might give you some hints.
You can see the result of this in action here: https://youtu.be/J7C7SEC04_E
Related
I made a drawer with two sections.. therefore I implemented a delegate pattern to access a embedded tableView inside of my container.
class Drawer: UIViewController, DrawerTableViewDelegate {
var drawerVC : DrawerTableView?
override func viewDidLoad() {
super.viewDidLoad()
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "tableViewSegue" {
self.drawerVC = (segue.destination as! DrawerTableView
self.drawerVC!.delegate = self
}
}
In my DrawerTableView class is the delegate implemented and also some code to access the rows in the tableView:
class MenuTableViewController: UITableViewController {
var delegate : MenuTableViewControllerDelegate?
//tableview delegate
The drawer gets called in two scenes in the same way:
#objc func didTapRowInDrawer(_ sender: UIBarButtonItem) {
guard let drawerVC = storyboard?.instantiateViewController(withIdentifier: "DrawerCtrl") as? Drawer else { return }
drawerVC.modalPresentationStyle = .overCurrentContext
drawerVC.transitioningDelegate = self
present(drawerVC, animated: true)
}
Can I determine the calling ViewController of my drawer?
I thought of something like
if segue.source is VC {
//do something
} else if segue.source is VC2 {
// do something else
}
in Drawer::prepare
From the code, it looks like the Drawer was presented as a Modal. The viewController which presented a Modal is stored in presentingViewController variable. You can use the below code in the DrawerViewController to determine which ViewController had presented the Drawer.
if let presentingVC = self.presentingViewController {
if presentingVC.isKind(of: VC1.self) {
//do something
} else if presentingVC.isKind(of: VC2.self) {
// do something else
}
}
I have a NewCartViewController that's embedded in a UINavigationController
In my ContainerViewController:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "goToCart" {
self.cartVC = segue.destination as? NewCartViewController
self.cartVC?.delegate = self
print("cartVC Delegate", cartVC?.delegate) // value is NOT nil here
let pendingCart = PendingCart(color: .blue)
self.cartVC?.setupPaintOrder(cart: pendingCart)
}
}
In my NewCartViewController
protocol NewCartViewControllerDelegate: class {
func vcDidFinishWithCancel(_ newCartViewController: NewCartViewController)
}
class NewCartViewController: UIViewController {
weak var delegate: NewCartViewControllerDelegate?
....
#objc func dismissVC() { // called from the leftBarButtonItem
print(delegate) // nil
}
I've looked at other answers that are related but I'm not sure what's going on here. Any help would be appreciated. Thanks!
Edit - more detail on how the VC is instantiated:
My BuyButtonVC calls a delegate method back to AddToCartContainerVC:
extension AddToCartContainerViewController: BuyButtonViewControllerDelegate {
func buyButtonVCDidPressButton(_ vc: BuyButtonViewController) {
performSegue(withIdentifier: "goToCart", sender: self)
}
}
Which then fires the prepare(for segue:) function from the first code block above where the we look at the the segue.destination and set the delegate.
I have a print on the didSet on the delegate in my NewCartViewController and I see that the delegate is set.
The user goes to the screen, the didSet is never called again as if it was getting set to nil. But then when I try to call the delegate method in the second code block, the delegate is nil
I have tried with the following code and seems to work fine.
Few times we get this unknown behavior and is frustrating when stuck. Try to clean build and quit Xcode clear derived data and do it again.
class ContainerViewController: UIViewController, NewViewControllerDelegate {
weak var cartVC: NewViewController?
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "goToCart" {
self.cartVC = segue.destination as? NewViewController
self.cartVC?.delegate = self
print("cartVC Delegate", cartVC?.delegate) // value is NOT nil here
// let pendingCart = PendingCart(color: .blue)
// self.cartVC?.setupPaintOrder(cart: pendingCart)
}
}
func vcDidFinishWithCancel(_ newViewController: NewViewController) {
print(newViewController.delegate)
self.navigationController?.popViewController(animated: true)
}
}
protocol NewViewControllerDelegate: class {
func vcDidFinishWithCancel(_ newViewController: NewViewController)
}
class NewViewController: UIViewController {
weak var delegate: NewViewControllerDelegate?
#IBOutlet weak var leftBarButtonItem: UIBarButtonItem!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Cancel", style: .plain, target: self, action: #selector(dismissVC))
}
#objc func dismissVC() { // called from the leftBarButtonItem
print(delegate) // nil
delegate?.vcDidFinishWithCancel(self)
}
}
Output: when leftbarbuttonitem clicked
cartVC Delegate Optional(<NetworkExtensionTest.ViewController: 0x7f84c6d07670>)
Optional(<NetworkExtensionTest.ViewController: 0x7f84c6d07670>)
Optional(<NetworkExtensionTest.ViewController: 0x7f84c6d07670>)
I cannot get my delegate protocol to work. I used this stack overflow questions as a guide dispatch event to parent ViewController in swift . I don't know if things have changed in Swift 3 since this post, but my function in my parentViewController is never getting called. Here is my setup.
//PROTOCOL
protocol PDPPropDetailsDelegate {
func buttonPressed(PropDetailsVC: propertyDetailsVC)
}
// CHILD VIEW CONTROLLER
class propertyDetailsVC: UIViewController {
var delegate: PDPPropDetailsDelegate?
#IBAction func emailButton(_ sender: AnyObject) {
self.delegate?.buttonPressed(PropDetailsVC: self)
}
}
The Button is getting called in Child View Controller.
// PARENT VIEW CONTROLLER
class ImageDetailsVC: UIViewController, PDPPropDetailsDelegate {
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "container"{
container = segue.destination as! ContainerViewController
}
}
#IBAction func segmentControlAct(_ sender: Any) {
switch segmentControllerView.selectedIndex {
case 0: print("case 1")
container!.segueIdentifierReceivedFromParent("first")
case 1: print("case 2")
container!.segueIdentifierReceivedFromParent("second")
PropertyDetailsVC.delegate = self // **WHERE I SET DELEGATE**
setUpPropertyDetailsUI(property: filterImages)
default: print("default")
}
}
func buttonPressed(PropDetailsVC: propertyDetailsVC) {
print("BUTTON PRESSED")
}
}
Button Pressed is never called. I assume it has to do with the delegate not getting set properly. Not exactly sure why that would be the case though. My setUpPropertyDetailsUI(property: filterImages) takes the Outlets from that VC and sets that works just fine. I did a breakpoint and it is called when I segment over to the PropertyDetailsVC. Any advice or suggestions?
import UIKit
open class ContainerViewController: UIViewController {
//Manipulating container views
fileprivate weak var viewController : UIViewController!
//Keeping track of containerViews
fileprivate var containerViewObjects = Dictionary<String,UIViewController>()
/** Specifies which ever container view is on the front */
open var currentViewController : UIViewController{
get {
return self.viewController
}
}
fileprivate var segueIdentifier : String!
/*Identifier For First Container SubView*/
#IBInspectable internal var firstLinkedSubView : String!
override open func viewDidLoad() {
super.viewDidLoad()
}
open override func viewDidAppear(_ animated: Bool) {
if let identifier = firstLinkedSubView{
segueIdentifierReceivedFromParent(identifier)
}
}
override open func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func segueIdentifierReceivedFromParent(_ identifier: String){
self.segueIdentifier = identifier
self.performSegue(withIdentifier: self.segueIdentifier, sender: nil)
}
override open func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == segueIdentifier{
//Remove Container View
if viewController != nil{
viewController.view.removeFromSuperview()
viewController = nil
}
//Add to dictionary if isn't already there
if ((self.containerViewObjects[self.segueIdentifier] == nil)){
viewController = segue.destination
self.containerViewObjects[self.segueIdentifier] = viewController
}else{
for (key, value) in self.containerViewObjects{
if key == self.segueIdentifier{
viewController = value
}
}
}
self.addChildViewController(viewController)
viewController.view.frame = CGRect(x: 0,y: 0, width: self.view.frame.width,height: self.view.frame.height)
self.view.addSubview(viewController.view)
viewController.didMove(toParentViewController: self)
}
}
}
import UIKit
class EmptySegue: UIStoryboardSegue{
override func perform() {
}
/*
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
// Get the new view controller using segue.destinationViewController.
// Pass the selected object to the new view controller.
}
*/
}
You seem to be a little confused at the flow of the app. Here's an answer I wrote for someone else's question about this same topic:
https://stackoverflow.com/a/45312362/3832646
Your protocol and Child view controller look great, but there are quite a few things amiss with the rest of your code here:
your prepare(for segue:_, sender:_) is typically where you would set the delegate for the destination (child) view controller.
PropertyDetailsVC.delegate = self won't do anything - you need an instance of the view controller to set its delegate.
It looks like you're using some sort of container global variable that I'm not sure what it would be for.
Take a look at the answer I posted and have another go. It's in Swift 3.
I am trying to pass data back from the second viewController.
I can do that without NavigationController. But now I need to use NavigationController. Then my code does work as before. The data wont pass.
Here is the simple code:
In first viewController
class ViewController: UIViewController, backfromSecond {
#IBOutlet weak var text: UILabel!
var string : String?
override func viewDidLoad() {
super.viewDidLoad()
self.string = "Start here"
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(true)
self.text.text = self.string
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let destinationViewController = segue.destination as? secondViewController{
destinationViewController.delegate = self
}
}
func back(text: String) {
self.string = text
print(text)
}
}
And Second viewController:
protocol backfromSecond {
func back(text: String)
}
class secondViewController: UIViewController {
var string : String = "nothing here"
var delegate : backfromSecond?
override func viewDidLoad() {
super.viewDidLoad()
delegate?.back(text: string)
// Do any additional setup after loading the view.
}
}
What is wrong here?
Suppose A & B are two controllers and you first navigated from A to B with some data. And now you want to POP from B to A with some data.
Unwind Segues is the best and recommended way to do this.
Here are the steps.
Open A.m
define following method
#IBAction func unwindSegueFromBtoA(segue: UIStoryNoardSegue) {
}
open storyboard
Select B ViewController and click on ViewController outlet. press control key and drag to 'Exit' outlet and leave mouse here. In below image, selected icon is ViewController outlet and the last one with Exit sign is Exit Outlet.
You will see 'unwindSegueFromBtoA' method in a popup . Select this method .
Now you will see a segue in your view controler hierarchy in left side. You will see your created segue near StoryBoard Entry Piont in following Image.
Select this and set an identifier to it. (suggest to set the same name as method - unwindSegueFromBtoA)
Open B.m . Now, wherever you want to pop to A. use
self.performSegueWithIdentifier("unwindSegueFromBtoA", sender: dataToSend)
Now when you will pop to 'A', 'unwindSegueFromBtoA' method will be called. In unwindSegueFromBtoA of 'A' you can access any object of 'B'.
That's it..!
I think your problem is in the prepare for segue method. If the view controller is on a navigation stack i think your code should be something like
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let destinationViewController = segue.destination as? UINavigationController).topViewController as! secondViewController{
destinationViewController.delegate = self
}
}
You can use unwind segues to pass data back.
Here's a tutorial
https://spin.atomicobject.com/2014/10/25/ios-unwind-segues/
This works me well.
1st VC
class ViewController: UIViewController, backfromSecond {
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func Passingfrom1stVCTo2ndVC(_ sender: AnyObject) {
if let vc = self.storyboard?.instantiateViewController(withIdentifier: "ViewController3") as? ViewController3{
vc.dataFrom1StVC = "message send from 1st VC"
vc.delegate = self
self.navigationController?.pushViewController(vc, animated: true)
}
}
func back(text: String) {
print("data\(text)")
}
}
2nd VC.
protocol backfromSecond: class {
func back(text: String)
}
class ViewController3: UIViewController {
var dataFrom1StVC : String? = nil
week var delegate : backfromSecond?
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func DataSendFrom2ndVCTo1stVC(_ sender: AnyObject) {
self.delegate?.back(text: "Message Send From 2nd vc to 1st VC")
self.navigationController?.popViewController(animated: true)
}
}
I hope it will work you. If any problem then ask me i will help you.
How can I pass data back from a PopoverViewController to the main view controller on an iPhone?
I know I'm doing something terribly wrong but I cannot figure it out.
Here is the code:
PopoverViewController.swift
protocol PopoverViewControllerDelegate {
func messageData(data: AnyObject)
}
class PopoverViewController: UIViewController {
#IBOutlet weak var inputMessage: UITextField!
var delegate: PopoverViewControllerDelegate?
#IBAction func sendData(sender: AnyObject) {
if inputMessage.text != ""{
self.presentingViewController!.dismissViewControllerAnimated(true, completion: nil)
self.delegate?.messageData(inputMessage.text!)
}
}
}
Main ViewController.swift:
class ViewController: UIViewController, UIPopoverPresentationControllerDelegate, PopoverViewControllerDelegate {
#IBOutlet weak var showData: UILabel!
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
// popover segue
if segue.identifier == "popoverSegue" {
let popoverViewController = segue.destinationViewController
popoverViewController.popoverPresentationController!.delegate = self
}
// code to comunicate with data in popoverViewController
let pvc = storyboard?.instantiateViewControllerWithIdentifier("popoverViewController") as! PopoverViewController
pvc.delegate = self
self.presentViewController(pvc, animated:false, completion:nil)
}
func adaptivePresentationStyleForPresentationController(controller: UIPresentationController) -> UIModalPresentationStyle {
return UIModalPresentationStyle.None
}
func messageData(data: AnyObject) {
self.showData.text = "\(data)"
}
}
With the code above I can pass data back to the main view controller without a problem, the issue is that the popover doesn't work, it just acts like a regular ViewController occupying the whole screen.
The funny thing is that if I comment the following line of code the popover works but I can no longer pass data back, I can see the popover but the passing data stops working.
// if I comment this line
self.presentViewController(pvc, animated:false, completion:nil)
I don't get any errors, one just stops working.
Any suggestions?
Thanks a lot
In prepareForSegue, the destinationViewController is your PopoverViewController. You need to cast it to that and set the delegate on that so that you can pass back data, and you need to set the popoverPesentationController?.delegate as well. You don't need the rest of the code in prepareForSegue:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
// popover segue
if segue.identifier == "popoverSegue" {
let popoverViewController = segue.destinationViewController as! PopoverViewController
popoverViewController.delegate = self
popoverViewController.popoverPresentationController?.delegate = self
}
}