I have an error in my code when trying to return a variable that is in the App delegate to a viewController, it returns a null value and therefore does not assign the delegate
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
var client: SINClient!
.
.
.
}
class ViewController: UIViewController, SINCallClientDelegate {
#IBOutlet weak var destination: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
func client() -> SINClient? {
return (UIApplication.shared.delegate as! AppDelegate).client
}
override func awakeFromNib() {
super.awakeFromNib()
self.client()?.call().delegate = self
}
#IBAction func actionCall(_ sender: UIButton) {
if destination.text != "" && self.client()!.isStarted() {
weak var call = client()!.call().callUserVideo(withId: destination.text)
performSegue(withIdentifier: "callView", sender: call)
}
}
func client(_ client: SINCallClient?, didReceiveIncomingCall call: SINCall?) {
performSegue(withIdentifier: "callView", sender: call)
}
}
Fatal error: Unexpectedly found nil while unwrapping an Optional value
Related
I am using Xcode 10.1 two create a simple single window application. The issue is that I see two windows instantiated when I run it instead of the single one I expect. Here is my code
//AppDelegate
import Cocoa
#NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {
var mainWindowController: WindowController!
func applicationDidFinishLaunching(_ aNotification: Notification) {
// Insert code here to initialize your application
print("loading")
let mainWindowController = WindowController()
mainWindowController.showWindow(self)
self.mainWindowController = mainWindowController
}
func applicationWillTerminate(_ aNotification: Notification) {
// Insert code here to tear down your application
print("closed")
}
}
//WindowController.swift
import Cocoa
class WindowController: NSWindowController, NSSpeechSynthesizerDelegate {
#IBOutlet weak var textField: NSTextField!
#IBOutlet weak var speakButton: NSButton!
#IBOutlet weak var stopButton: NSButton!
override var windowNibName: String {
return "Window"
}
let speechSynth = NSSpeechSynthesizer()
var isStarted: Bool = false {
didSet {
updateButtons()
}
}
override func windowDidLoad() {
super.windowDidLoad()
viewDidLoad()
}
func viewDidLoad() {
// super.viewDidLoad()
updateButtons()
speechSynth.delegate = self
print("view load")
// Do any additional setup after loading the view.
}
#IBAction func speakIt(sender: NSButton) {
let string = textField.stringValue
if string.isEmpty {
print("String is empty")
}
else {
print(string)
speechSynth.startSpeaking(string)
isStarted = true
}
}
#IBAction func stopIt(sender: NSButton) {
speechSynth.stopSpeaking()
isStarted = false
}
func updateButtons() {
if isStarted {
speakButton.isEnabled = false
stopButton.isEnabled = true
} else {
stopButton.isEnabled = false
speakButton.isEnabled = true
}
}
func speechSynthesizer(_ sender: NSSpeechSynthesizer, didFinishSpeaking finishedSpeaking: Bool) {
isStarted = false
}
}
My Xib has the option checked "Visible at launch". If I uncheck it, I see no window.
Basically, I am attempting a program from the book "Cocoa Programming for OSX". However, the book is obsolete. But I am trying to find my way through new Xcode and Swift. Any help?
Also a point worth noting is that only one window is functional, the second window IBOutlets and IBAction are not connected. So nothing happens in the second window.
I can't figure out why is this happening?
I have a task to create an app that checks if a String is a palindrome or not. And also I have instructed to create a file and in that file should be a function. But what I can't figure out is how to make a button run that function that is in the file.
func isPalidrone(phrase: String) -> Bool {
let isPalidrone = true
let reversed = String(phrase.reversed())
if reversed == phrase {
return isPalidrone
} else {
return !isPalidrone
}
}
class ViewController: UIViewController {
#IBOutlet weak var Label: UILabel!
#IBOutlet weak var textFieldOutlet: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func buttonPressed(_ sender: Any) {
}
}
Like this:
#IBAction func buttonPressed(_ sender: Any) {
let pal = isPalidrone(phrase: self.textFieldOutlet.text!)
// now pal is true or false and you can decide what else to do ...
// for example:
self.Label.text = pal ? "It is a palindrome" : "It is not a palindrome"
}
I'm doing a test of a custom keyboard. This is what I need:
It has to have two UITextFields. Cannot be labels.
The keyboard is an embedded UIView.
The default keyboard should be disabled.
It cannot be a keyboard extension.
Not sure why the app is crashing. PS: Not all the keys are on the code yet. Here is an image of what I'm trying to do and the two View Controllers.
Edit: The error is: Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value
First ViewController:
import UIKit
class HomeVC: UIViewController, ButtonTapDelegate {
#IBOutlet var textField1: UITextField!
#IBOutlet var textField2: UITextField!
#IBOutlet var keyboardView: UIView!
var buttonPressed = [String]()
override func viewDidLoad() {
addKeyboard(view: keyboardView)
buttonPressed = [String]()
textField1.inputView = UIView()
textField2.inputView = UIView()
}
func addKeyboard(view: UIView) {
let keyboard = KeyboardVC(nibName: "KeyboardVC", bundle: nil)
view.addSubview(keyboard.view)
addChild(keyboard)
}
func didTapButton(sender: UIButton) {
if sender.tag == 5 {
textField1.text?.append(contentsOf: " ")
} else if sender.tag == 6 {
textField1.text?.removeAll()
buttonPressed = [String]()
} else {
let val = sender.titleLabel?.text
textField1.text?.append(contentsOf: val!)
}
self.textField1.text = buttonPressed.joined(separator: "")
}
}
Here is the second View Controller:
import UIKit
protocol ButtonTapDelegate {
func didTapButton(sender: UIButton)
}
class KeyboardVC: UIViewController {
var delegate: ButtonTapDelegate!
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func buttons(_ sender: UIButton) {
delegate.didTapButton(sender: sender)
print(sender)
}
}
var delegate: ButtonTapDelegate!
An implicitly unwrapped optional is essentially a promise that you're definitely going to give the variable a value before you try to access it. The problem in this case is that you haven't done that. Most likely, you want to do this in your first view controller:
func addKeyboard(view: UIView) {
let keyboard = KeyboardVC(nibName: "KeyboardVC", bundle: nil)
keyboard.delegate = self // Now "delegate" will have a value before the function gets called
view.addSubview(keyboard.view)
addChild(keyboard)
}
This is the error Xcode outputs
Unexpectedly found nil while unwrapping an Optional value
I have a viewcontroller that has a tableview and a few buttons; the buttons allow me to insert or remove data. It seems that when I click on Add (which brings up a new viewcontroller via segue as a sheet) the app crashes with the error above. Clicking on remove doesn't have this affect. So it has to do with something regarding the new viewcontroller as a guess. The console doesn't go further into the error other than printing out (lldb)
Here's my code
override func viewDidLoad() {
super.viewDidLoad()
alarmTableView.dataSource = self //error occurs here
alarmTableView.delegate = self //if i remove the above line if will occur here too.
}
My Viewcontroller which the above viewDidLoad func is embedded lists the protocols I need
class ViewController: NSViewController, NSTableViewDelegate, NSTableViewDataSource {
#IBOutlet weak var addAlarm: NSButton!
#IBOutlet weak var resetDataButton: NSButton!
#IBOutlet var alarmArrayController: NSArrayController!
#IBOutlet weak var alarmTableView: NSTableView!
#IBOutlet weak var deleteAll: NSButton!
#objc let moc: NSManagedObjectContext
required init?(coder: NSCoder) {
self.moc = CoreDataHandler.getContext()
super.init(coder: coder)
}
override func prepare(for segue: NSStoryboardSegue, sender: Any?) {
let destinationController = segue.destinationController as! AddAlarmViewController
//pass data to next controller here
}
#IBAction func deleteAllAction(_ sender: Any) {
if (alarmTableView.selectedRow >= 0) {
if (CoreDataHandler.deleteAllObjectsInEntity(entityName: "Alarm")) {
//remove from nsarray controller
for object in alarmArrayController.arrangedObjects as! [Alarm] {
print(object)
alarmArrayController.removeObject(object)
}
alarmTableView.reloadData()
}
}
else {
printInfo(str: "There are no alarms to delete")
}
}
/* Response to the remove alarm button - It removes a selected alarm object from the table */
#IBAction func resetDataAction(_ sender: Any) {
if (alarmTableView.selectedRow >= 0) {
let selectedAlarm = self.alarmArrayController.selectedObjects.first as! Alarm
alarmArrayController.remove(atArrangedObjectIndex: alarmTableView.selectedRow)
CoreDataHandler.deleteObjectInEntity(entityName: "Alarm", obj: selectedAlarm)
alarmTableView.reloadData()
}
else {
//will need a warning or play a sound.
printInfo(str: "Please select an alarm")
}
}
override func viewDidLoad() {
super.viewDidLoad()
printInfo(str: "viewdidload")
print(alarmTableView)
if (alarmTableView != nil) {
printInfo(str: "AlarmTableView Is initialised")
alarmTableView.dataSource = self
alarmTableView.delegate = self
}
else {
printInfo(str: "AlarmTableView is not initialised")
}
}
override var representedObject: Any? {
didSet {
// Update the view, if already loaded.
}
}
func printInfo(str: String) {
print("ViewController: \(str)")
}
func tableView(_ tableView: NSTableView, heightOfRow row: Int) -> CGFloat {
return 100.0
}
}
class AddAlarmViewController: ViewController {
#IBOutlet weak var closeButton: NSButton!
override func viewDidLoad() {
super.viewDidLoad()
// Do view setup here.
printClassInfo(str: "viewDidLoad")
CoreDataHandler.saveTestData()
}
#IBAction func closeButtonAction(_ sender: Any) {
self.dismissViewController(self)
}
func printClassInfo(str: String) {
print("AddAlarmViewController \(str)")
}
}
If I remove the lines where the error occurs the app run fine. But I want to override the delegate and datasource and use the functions to further customise the table. I'm also using Cocoa Bindings.
Why am I getting this error?
Update
I haven't solved it yet, but i placed a couple of print statements in my viewDidLoad function. It seems that when the app is first loaded, the table view is initialised. But after when I clicked on the Add button, the table view is then set to nil for some odd reason, as if another table view has been initialised. However the data is still visible
Problem:
class AddAlarmViewController: ViewController {
//...
override func viewDidLoad() {
super.viewDidLoad()
//...
}
}
Your AddAlarmViewController is a subclass of ViewController instead of NSViewController.
In AddAlarmViewController's viewDidLoad you call super.viewDidLoad() which basically calls ViewController's viewDidLoad.
But... in this case ViewController is a new instance as the super class of AddAlarmViewController and none of it's properties are initialized.
Whatever it be, it's probably not what you want.
Solution:
class AddAlarmViewController: NSViewController {
//... rest as it is
}
I want to pass a Bool value from on view controller to another without the help of segues. So i referred & got Delegates.
I have applied delegates in my App. But the Delegate method is not being called. I don't know where i am making the mistake.
So Please help me.
MainViewController
class MainViewController: UIViewController, WriteValueBackDelegate {
#IBOutlet weak var LoginButton: UIButton!
var LoggedInL :Bool?
override func viewDidLoad() {
super.viewDidLoad()
}
func writeValueBack(value: Bool) {
println("Delegate Method")
if (value == true){
LoginButton.setTitle("My Profile", forState:UIControlState.Normal)
}
}
Second View Controller
class LoginController: UIViewController {
#IBOutlet weak var LoginLabel: UILabel!
#IBOutlet weak var email: UITextField!
#IBOutlet weak var pwd: UITextField!
var LoggedInL :Bool?
var mydelegate: WriteValueBackDelegate?
override func viewDidLoad() {
super.viewDidLoad() }
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func onSubmit(sender: AnyObject) {
Alamofire.request(.GET, "http://www.jive.com/index.php/capp/user_verification/\(email.text)/\(pwd.text)")
.responseJSON { (_, _, data, _) in
println(data)
let json = JSON(data!)
let name = json["first_name"].stringValue
let status = json["valid_status"].intValue
println(status)
var e = self.email.text
println(e)
self.LoginLabel.text = "Hey \(name)!"
if status == 1{
println("Correect")
self.LoggedInL = true
self.mydelegate?.writeValueBack(true)
}else {
self.LoggedInL = false
println("Error")
}
}
navigationController!.popViewControllerAnimated(true)
}
}
protocol WriteValueBackDelegate {
func writeValueBack(value: Bool)
}
you didn't initialize the delegate, and no need to, delegates are usually for async callbacks. do that instead:
class MainViewController: UIViewController {
static var sharedInstace : MainViewController?;
#IBOutlet weak var LoginButton: UIButton!
var LoggedInL :Bool?
override func viewDidLoad() {
super.viewDidLoad()
MainViewController.sharedInstace = self; //this is better from init function
}
func writeValueBack(value: Bool) {
println("Delegate Method")
if (value == true){
LoginButton.setTitle("My Profile", forState:UIControlState.Normal)
}
}
}
in login view controller
MainViewController.sharedInstance?.writeValueBack(true)
In MainViewControlleryou need a reference of the LoginController instance maybe with an IBOutlet and then set the delegate in viewDidLoad
#IBOutlet weak var loginController : LoginController!
override func viewDidLoad() {
super.viewDidLoad()
loginController.mydelegate = self
}