EDIT: Not sure if this may be the root of my issue, but would this piece of code in the app delegate be a reason why this is not working?
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
// Override point for customization after application launch.
let navigationController = self.window!.rootViewController as! UINavigationController
let controller = navigationController.topViewController as! HomeViewController
controller.managedObjectContext = self.managedObjectContext
return true
}
I am trying to add survey functionality to an app with integration of ResearchKit. I have worked through the setup guide and some other tutorials from Ray Wenderlich. However when I transitioned into an app I would like to develop I got a bit stuck.
I am getting thrown an error: Cannot assign value of type 'HomeviewController to type 'ORKTaskViewControllerDelegate?'
This is the code I am working with:
class HomeViewController: UIViewController {
var managedObjectContext: NSManagedObjectContext?
#IBAction func surveyTapped(sender: AnyObject) {
let taskViewController = ORKTaskViewController(task: SurveyTask, taskRunUUID: nil)
taskViewController.delegate = self
presentViewController(taskViewController, animated: true, completion: nil)
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.destinationViewController.isKindOfClass(NewRideViewController) {
if let newRideViewController = segue.destinationViewController as? NewRideViewController {
newRideViewController.managedObjectContext = managedObjectContext
}
}
}
}
Based on similar questions with this error syntax, users have added another controller class, but which one is beyond me. Your help is greatly appreciated, thank you StackExchange!
Looks like you have not extended you view controller to implement delegate of ORKTaskViewController which is ORKTaskViewControllerDelegate and your VC code should be as follow -
import ResearchKit
class HomeVC: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
#IBAction func surveyTapped(sender: AnyObject) {
let taskViewController = ORKTaskViewController(task: SurveyTask, taskRunUUID: nil)
taskViewController.delegate = self
presentViewController(taskViewController, animated: true, completion: nil)
}
}
extension HomeVC: ORKTaskViewControllerDelegate {
func taskViewController(taskViewController: ORKTaskViewController, didFinishWithReason reason: ORKTaskViewControllerFinishReason, error: NSError?) {
}
}
Related
I'm applying for a junior developer position and I've got a very specific task, that already took me 3 days to complete. Sounds easy - pass data to rootViewController.
That's what I've done:
1)
private func userDefaultsToRootController() {
let input = textField.text!
defaults.set(input, forKey: "SavedLabel")
navigationController?.popViewController(animated: true)
}
private func segueToRootViewController() {
let destinationVC = MainScreen1()
let input = textField.text!
if input == "" { self.navigationController?.popToRootViewController(animated: true) }
destinationVC.input = input
navigationController?.pushViewController(destinationVC, animated: true)
}
private func popToNavigationController() {
let input = textField.text!
if let rootVC = navigationController?.viewControllers.first as? MainScreen1 {
rootVC.input = input
}
navigationController?.popToRootViewController(animated: true)
}
I've used CoreData
But here is the difficult part - I've got an email, that all these methods are not good enough and I need to use delegate and closure. I've done delegation and closures before, but when I popToRootViewController delegate method passes nil. Could you at least point where to find info about this?
** ADDED **
There are 2 View Controllers: Initial and Second one.
That's what I have in the Initial View Controller:
var secondVC = MainScreen2()
override func viewDidLoad() {
super.viewDidLoad()
secondVC.delegate = self
}
That's how I push SecondViewController
#objc private func buttonTapped(_ sender: CustomButton) {
let nextViewController = MainScreen2()
navigationController?.pushViewController(nextViewController, animated: true)
}
In SecondViewController I've got this protocol
protocol PassData {
func transferData(text: String)
}
Also a delegate:
var delegate: PassData?
This is how I go back to initial view controller
#objc private func buttonTapped(_ sender: CustomButton) {
if let input = textField.text {
print(input)
self.delegate?.transferData(text: input)
self.navigationController?.popToRootViewController(animated: true)
}
}
Back to the Initial view controller where I've implemented delegate method
extension MainScreen1: PassData {
func transferData(text: String) {
print("delegate called")
label.text = text
}
}
Delegate doesn't get called.
BASED ON YOUR EDIT:
You must set the delegate in buttonTapped
#objc private func buttonTapped(_ sender: CustomButton) {
let nextViewController = MainScreen2()
nextViewController.delegate = self // HERE WHERE YOU SET THE DELEGATE
navigationController?.pushViewController(nextViewController, animated: true)
}
You can delete the second instance and your code in viewDidLoad. That's not the instance you push.
This should point you in the right direction to use delegation and completion handler.
protocol YourDelegateName {
func passData(data:YourDataType)
}
class SecondViewController: UIViewController {
var delegate: YourDelegateName?
func passDataFromSecondViewController(){
YourCoreDataClass.shared.getCoreData { (yourStringsArray) in
self.delegate?.passData(data: yourStringsArray)
self.navigationController?.popToRootViewController(animated: true)
}
}
class InitialViewController: UIViewController, YourDelegateName {
override func viewDidLoad() {
super.viewDidLoad()
// or whenever you instantiate your SecondViewController
let secondViewController = SecondViewController()
secondViewController.delegate = self //VERY IMPORTANT, MANY MISS THIS
self.navigationController?.pushViewController(createVC, animated: true)
}
func passData(data:YourDataType){
//user your data
}
}
class YourCoreDataClass: NSObject {
static let shared = YourCoreDataClass()
func getCoreData (completion: ([String]) -> ()){
........... your code
let yourStringsArray = [String]() // let's use as example an array of strings
//when you got the data your want to pass
completion(yourStringsArray)
}
}
Main issue is checking if user has a child in the Firebase database so that I know if he is signing up or logging in.
Part 1: Part 1 (Child Database (this works) and making that a user default (I'm not sure how to check it that worked)
Part 2: in different .Swift file (Check if the User Default (aka Education Child) exists. I have pretty much nothing, except I know it must go into viewDidAppear
Part 1
#IBAction func SubmitPressed(_ sender: Any) {
let databaseRef = Database.database().reference()
let uid = Auth.auth().currentUser!.uid
databaseRef.child("Education").child(uid).setValue(self.Education.text!)
UserDefaults.standard.set("Education", forKey: "Education")
Part 2
func viewDidAppear(_ animated: String) {
??????
}
No error for part 1, though not sure if it created the user default. For part 2, I have tried a bunch of stuff, but hasn't worked.
Here is the updated code after first answer:
import Foundation
import UIKit
import SwiftKeychainWrapper
import Firebase
import CoreFoundation
import AVFoundation
import FirebaseDatabase
var educationCache : String {
get {
return (UserDefaults.standard.string(forKey: "Education")!)
} set {
UserDefaults.standard.set(newValue, forKey: "Education")
}
}
relavant part of education/personal info enter page
#IBAction func SubmitPressed(_ sender: Any) {
let databaseRef = Database.database().reference()
let uid = Auth.auth().currentUser!.uid
databaseRef.child("Education").child(uid).setValue(self.Education.text!)
// The following line will save it in userDefault itself. And you dont have to call the whole UserDefault Everywhere
educationCache = "Education"
self.performSegue(withIdentifier: "tohome", sender: nil)
}
homepage
import Foundation
import UIKit
import SwiftKeychainWrapper
import Firebase
import CoreFoundation
import AVFoundation
import FirebaseDatabase
class homepage:UITableViewController {
override func viewDidAppear(_ animated: Bool) {
super.viewWillAppear(animated)
if educationCache.count < 0 {
self.performSegue(withIdentifier: "toFeed", sender: nil)
}
}
override func viewDidLoad() {
navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Sign Out", style: .plain, target: self, action: #selector(signOut))
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#objc func signOut (_sender: AnyObject) {
KeychainWrapper.standard.removeObject(forKey: "uid")
do {
try Auth.auth().signOut()
} catch let signOutError as NSError {
print ("Error signing out: %#", signOutError)
}
dismiss(animated: true, completion: nil)
}
}
You dont want to check the condition is the viewController where you are performing specific actions. Also checking the userDefaults everytime is just putting extra views in heirarchy. Firebase provides .addStateDidChangeListener function to keep a check of it. Add the following code to your delegate. It will automatically switch between the users if there are any or not.
AppDelegate.swift
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
FirebaseApp.configure()
observeUser()
return true
}
func observeUser(){
Auth.auth().addStateDidChangeListener { (auth, user) in
if (user != nil) {
// If the user is not nil. Perform this block
self.showInitController(with identifier: "<add_your_storyboard_reusableID_for_homepage>", animated: false)
// The storyboard Id belongs to the HOMEPAGE/FEED, the view where user goes on signIn
} else {
//If there is no user. This block will perform
self.showInitController(with identifier: "<add_your_storyboard_reusableID_for_loginpage>", animated: false)
// The storyboard Id belongs to the SIGNUP PAGE, the view where user goes on signIn
}
}
}
func showInitController(with identifier: String, animated: Bool = false) {
DispatchQueue.main.async {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier: identifier)
var topRootViewController: UIViewController = (UIApplication.shared.keyWindow?.rootViewController)!
while((topRootViewController.presentedViewController) != nil){
topRootViewController = topRootViewController.presentedViewController!
}
topRootViewController.present(vc, animated: animated, completion: nil)
}
}
In your swift file one. do the following and never look back. You can automatically redirect to view if you applied the other functions.
#IBAction func SubmitPressed(_ sender: Any) {
let databaseRef = Database.database().reference()
let uid = Auth.auth().currentUser!.uid
databaseRef.child("Education").child(uid).setValue(self.Education.text!)
self.performSegue(withIdentifier: "tohome", sender: nil)
}
In the second view dont bother to do anything anywhere. Just leave it, if nothing in that view is required again.
I am having issues trying to pass the data back to the ViewController (from BarCodeScannerViewController to TableViewController)
SecondVC (BarCodeScannerViewController.swift):
#objc func SendDataBack(_ button:UIBarButtonItem!) {
if let presenter = self.presentingViewController as? TableViewController {
presenter.BarCode = "Test"
}
self.dismiss(animated: true, completion: nil)
}
FirstVC (TableViewController.swift):
// The result is (BarCode - )
var BarCode: String = ""
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
print("BarCode - \(BarCode)")
}
Each time ViewWillAppear is running the value is not set, what could be causing this issue?
You should use the delegate pattern. I doubt in your code above that self.presentingViewController is actually set.
An example of using the delegate pattern for this:
// BarCodeScannerViewController.swift
protocol BarcodeScanningDelegate {
func didScan(barcode: String)
}
class BarCodeScannerViewController: UIViewController {
delegate: BarcodeScanningDelegate?
#objc func SendDataBack(_ button:UIBarButtonItem!) {
delegate?.didScan(barcode: "Test")
}
}
// TableViewController
#IBAction func scanBarcode() {
let vc = BarCodeScannerViewController()
vc.delegate = self
self.present(vc, animated: true)
}
extension TableViewController: BarcodeScanningDelegate {
func didScan(barcode: String) {
print("[DEBUG] - Barcode scanned: \(barcode)")
}
}
I am using a third party pod KGFloatingDrawer which is great because it achieves this:
and is a reimplementation of JVFloatingDrawer. I used their sample code and the sliding drawers are working great!
BUT
When I first run my app I call one centreViewController with no drawers (Login). Then after login I call a new centreViewController with
appDelegate.centerViewController = appDelegate.navigationBarController()
which only works if I restart the app. Am I missing something?
The logout seems fine though
appDelegate.centerViewController = appDelegate.drawerSettingsViewController()
which puzzles me a bit because then I think I'm on the right track?
Am I supposed to only use normal segues and such first and then only call the drawerViewController?
Here is the other code when setting up the floating drawers :
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
window = UIWindow(frame: UIScreen.mainScreen().bounds)
window?.rootViewController = drawerViewController
window?.makeKeyAndVisible()
return true
}
private var _drawerViewController: KGDrawerViewController?
var drawerViewController: KGDrawerViewController {
get {
if let viewController = _drawerViewController {
return viewController
}
return prepareDrawerViewController()
}
}
func prepareDrawerViewController() -> KGDrawerViewController {
let drawerViewController = KGDrawerViewController()
drawerViewController.centerViewController = drawerSettingsViewController()
drawerViewController.leftViewController = leftViewController()
drawerViewController.rightViewController = rightViewController()
drawerViewController.backgroundImage = UIImage(named: "sky3")
_drawerViewController = drawerViewController
return drawerViewController
}
private func drawerStoryboard() -> UIStoryboard {
let storyboard = UIStoryboard(name: StoryboardIDs.MainStoryBoardID , bundle: nil)
return storyboard
}
private func viewControllerForStoryboardId(storyboardId: String) -> UIViewController {
let viewController: UIViewController = drawerStoryboard().instantiateViewControllerWithIdentifier(storyboardId)
return viewController
}
func drawerSettingsViewController() -> UIViewController {
let viewController = viewControllerForStoryboardId(StoryboardIDs.LoginViewConSid)
return viewController
}
func sourcePageViewController() -> UIViewController {
let viewController = viewControllerForStoryboardId(StoryboardIDs.SettingsViewConID)
return viewController
}
func navigationBarController() -> UIViewController{
let viewController = viewControllerForStoryboardId(StoryboardIDs.NavConSid)
return viewController
}
private func leftViewController() -> UIViewController {
let viewController = viewControllerForStoryboardId(StoryboardIDs.LeftViewConID)
return viewController
}
private func rightViewController() -> UIViewController {
let viewController = viewControllerForStoryboardId(StoryboardIDs.RightViewConID)
return viewController
}
func toggleLeftDrawer(sender:AnyObject, animated:Bool) {
_drawerViewController?.toggleDrawer(.Left, animated: animated, complete: { (finished) -> Void in
// do nothing
})
}
func toggleRightDrawer(sender:AnyObject, animated:Bool) {
_drawerViewController?.toggleDrawer(.Right, animated: animated, complete: { (finished) -> Void in
// do nothing
})
}
func closeDrawer(sender:AnyObject, animated:Bool){
_drawerViewController?.closeDrawer(.Left, animated: animated, complete: { (finished) -> Void in
})
}
private var _centerViewController: UIViewController?
var centerViewController: UIViewController {
get {
if let viewController = _centerViewController {
return viewController
}
return drawerSettingsViewController()
}
set {
if let drawerViewController = _drawerViewController {
drawerViewController.closeDrawer(drawerViewController.currentlyOpenedSide, animated: true) { finished in }
if drawerViewController.centerViewController != newValue {
drawerViewController.centerViewController = newValue
}
}
_centerViewController = newValue
}
}
Any help/suggestions would be appreciated :D
Just gonna put this here in case anyone has similar problems.
After a week long struggle to find the problem. I eventually found that whenever I changed the centreViewController with
appDelegate.centerViewController = appDelegate.navigationBarController()
OR
appDelegate.centerViewController = appDelegate.logoutController()
that the methods
deinit {
print("deinit called")
notifCentre.removeObserver(self)
}
were not being called in any of the viewControllers.
So I added the line
self.dismissViewControllerAnimated(false, completion: {})
every time that I change the centreViewController.
Apparently Swift normally deinits automagically but when the using the third party methods there is some confusion with the memory handler and we need to step in. Good to know though as it could be a general swift issue as well.
I have two View Controllers: "DiscoverViewController" and "LocationRequestModalViewController".
The first time a user opens the "DiscoverViewController", I overlay "LocationRequestModalViewController" which contains a little blurb about accessing the users location data and how it can help them.
On the "LocationRequestModalViewController" there are two buttons: "No thanks" and "Use location". I need to send the response from the user back to the "DiscoverViewController"
I have done some research and found that delegates/protocols are the best way to do it, so I followed a guide to get that working, but I'm left with 2 errors and can't figure them out.
The errors are:
On DiscoverViewController
'DiscoverViewController' is not convertible to 'LocationRequestModalViewController'
On LocationRequestModalViewController
'LocationRequestModalViewController' does not have a member name 'sendBackUserLocationDataChoice'
I've marked where the errors are happen in the following files:
DiscoverViewController.swift
class DiscoverViewController: UIViewController, UITextFieldDelegate, CLLocationManagerDelegate, LocationRequestModalViewControllerDelegate {
func showLocationRequestModal() {
var storyboard = UIStoryboard(name: "Main", bundle: nil)
var locationRequestVC: AnyObject! = storyboard.instantiateViewControllerWithIdentifier("locationRequestVC")
self.presentingViewController?.modalPresentationStyle = UIModalPresentationStyle.CurrentContext
self.tabBarController?.presentViewController(locationRequestVC as UIViewController, animated: true, completion: nil)
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
let vc = segue.destinationViewController as LocationRequestModalViewController
vc.delegate = self //This is where error 1 happens
}
func sendBackUserLocationDataChoice(controller: LocationRequestModalViewController, useData: Bool) {
var enableData = useData
controller.navigationController?.popViewControllerAnimated(true)
}
override func viewDidLoad() {
super.viewDidLoad()
showLocationRequestModal()
}
}
LocationRequestModalViewController
protocol LocationRequestModalViewControllerDelegate {
func sendBackUserLocationDataChoice(controller:LocationRequestModalViewController,useData:Bool)
}
class LocationRequestModalViewController: UIViewController {
var delegate:LocationRequestModalViewController? = nil
#IBAction func dontUseLocationData(sender: AnyObject) {
self.dismissViewControllerAnimated(true, completion: nil)
}
#IBAction func useLocationData(sender: AnyObject) {
delegate?.sendBackUserLocationDataChoice(self, useData: true) // This is where error #2 happens
}
override func viewDidLoad() {
super.viewDidLoad()
//Modal appearance stuff here...
}
}
The answer is in your question itself. Both errors tells the exact reason.
Issue 1
let vc = segue.destinationViewController as LocationRequestModalViewController
vc.delegate = self //This is where error 1 happens
The self is of type DiscoverViewController
But you declared the delegate as:
var delegate:LocationRequestModalViewController? = nil
You need to change that to:
var delegate:DiscoverViewController? = nil
Issue 2
The same reason, LocationRequestModalViewController does not confirm to the LocationRequestModalViewControllerDelegate, change the delegate declaration.
You have defined your delegate as having type LocationRequestModalViewController which does not conform to LocationRequestModalViewControllerDelegate.