swift delegate variable is always nil - swift

I'm a relatively new developer and have used protocols/delegates fairly regularly but I am stuck on getting this one to implement properly. I have a view within my view controller that is assigned a class for a StarRatingView. I need to capture within the viewcontroller class the float value that the StarRatingView generates.
The star rating is working fine. I'm just not able to set the delegate variable for some reason.
here's where I define the protocol and the delegate variable.
protocol StarRatingProtocol {
func receiveStarRating(_ touchedStarRating: Float)
}
#IBDesignable
class StarRatingView: UIView {
var delegate: StarRatingProtocol? //THIS IS ALWAYS NIL NOT GETTING SET
Here's where I call the delegate function
fileprivate func touched(touch: UITouch, moveTouch: Bool) {
guard !moveTouch || lastTouch == nil || lastTouch!.timeIntervalSince(Date()) < -0.1 else { return }
print("processing touch")
guard let hs = self.hstack else { return }
let touchX = touch.location(in: hs).x
let ratingFromTouch = 5*touchX/hs.frame.width
var roundedRatingFromTouch: Float!
switch starRounding {
case .roundToHalfStar, .ceilToHalfStar, .floorToHalfStar:
roundedRatingFromTouch = Float(round(2*ratingFromTouch)/2)
case .roundToFullStar, .ceilToFullStar, .floorToFullStar:
roundedRatingFromTouch = Float(round(ratingFromTouch))
}
self.rating = roundedRatingFromTouch
lastTouch = Date()
guard delegate != nil else {return}
delegate!.receiveStarRating(roundedRatingFromTouch)
}
This is my view controller class where I set the protocol and try to set the delegate value . Should I be setting the delegate value somewhere other than viewdidload?
class LogController: UIViewController, StarRatingProtocol {
#IBOutlet weak var starRatingView: StarRatingView!
#IBOutlet weak var labelStarRating: UILabel!
let starRating = StarRatingView()
var testRating: Float?
override func viewDidLoad() {
super.viewDidLoad()
starRating.delegate = self
}

The problem is that when you say let starRating = StarRatingView(), that is a new and different StarRatingView that you are creating right now. That's not what you want; you want the StarRatingView that already exists in the interface. Presumably, if the outlet is hooked up properly, that would be self.starRatingView. That is the StarRatingView whose delegate you need to set.
Another (unrelated) problem is that the delegate needs to be weak. Otherwise there will be a retain cycle and a memory leak.

Related

Cannot get value of switch from different VC Swift

I want to access switch value with the code below. I get nil value. From the second View controller I get settings value to display content according to the value - englishRef.
SetConViewController is my settings view controller from where I want to get my value.
let languageSettingsRef = SetConvViewController()
var englishRef = ""
// Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value
if languageSettingsRef.swithEnglish.isOn{
englishRef = "yes"
}
In the View Controller below, there are switches for the settings
class SetConvViewController: UIViewController {
var conversationSettingsReference: DatabaseReference!
let userID = Auth.auth().currentUser?.uid
var engS = "engS"
var engGoster = ""
#IBOutlet weak var swithEnglish: UISwitch!
override func viewDidLoad() {
super.viewDidLoad()
if let eng2 = defaults.value(forKey: engS) {
swithEnglish.isOn = eng2 as! Bool
}
}
let defaults = UserDefaults.standard
#IBAction func switchEng(_ sender: UISwitch) {
defaults.set(sender.isOn, forKey: engS)
}
}
I get nil when I want to access value from this class.
First It's nil because you don't load the VC from storyboard or xib
Second this line
let languageSettingsRef = SetConvViewController()
is not the presented one , so use delegate or any other observing technique to get current value of the presented VC
//
class SettingsViewController: UIViewController {
var setVc:SetConvViewController?
}
when you present SettingsViewController with with segue / push , set
settInstance.setVc = self
then ask the var about the switch value
if self.setVc.swithEnglish.isOn{
englishRef = "yes"
}
Making the var as Bool is another better option

Swift OSX - Delegate protocol function returns nil, crashes when unwrapping textfield value

I'm working on an OSX app with Swift which makes use of an NSSplitView which holds two view controllers: "TableViewController" and "EntryViewController". I'm using delegates in order to transmit a custom NSObject ("Entry") on click from TableViewController up to the SplitViewController, then back down to the EntryViewController.
My problem is this: When the Entry object is received in the EntryViewController, any attempt to assign its properties to a text field value result in an unexpectedly found nil type error, never mind that the IBOutlets are properly linked, and that it can both print the Entry.property and the textfield string value (provided it is in a different, unrelated function).
I have tried many arrangements to solve this problem, which is why the current configuration might be a bit over-complicated. A delegate relation straight from Table VC to Entry VC caused the same issues.
Is there some way that the IBOutlets are not connecting, even though the view has loaded before the delegate is called? I've read many many articles on delegation—mostly for iOS—and yet can't seem to find the root of my problems. I'll be the first to admit that my grasp of Swift is a little bit piecemeal, so I am open to the possibility that what I am trying to do is simply bad/hacky coding and that I should try something completely different.
Thanks for your help!
TableViewController:
protocol SplitViewSelectionDelegate: class {
func sendSelection(_ entrySelection: NSObject)
}
class TableViewController: NSViewController {
#IBOutlet weak var searchField: NSSearchField!
#IBOutlet var tableArrayController: NSArrayController!
#IBOutlet weak var tableView: NSTableView!
var sendDelegate: SplitViewSelectionDelegate?
dynamic var dataArray = [Entry]()
// load array from .plist array of dictionaries
func getItems(){
let home = FileManager.default.homeDirectoryForCurrentUser
let path = "Documents/resources.plist"
let urlUse = home.appendingPathComponent(path)
let referenceArray = NSArray(contentsOf: urlUse)
dataArray = [Entry]()
for item in referenceArray! {
let headwordValue = (item as AnyObject).value(forKey: "headword") as! String
let defValue = (item as AnyObject).value(forKey: "definition") as! String
let notesValue = (item as AnyObject).value(forKey: "notes") as! String
dataArray.append(Entry(headword: headwordValue, definition: defValue, notes: notesValue))
}
}
override func viewDidLoad() {
super.viewDidLoad()
self.sendDelegate = SplitViewController()
getItems()
print("TVC loaded")
// Do any additional setup after loading the view.
}
// send selection forward to entryviewcontroller
#IBAction func tableViewSelection(_ sender: Any) {
let index = tableArrayController.selectionIndex
let array = tableArrayController.arrangedObjects as! Array<Any>
let obj: Entry
let arraySize = array.count
if index <= arraySize {
obj = array[index] as! Entry
print(index)
print(obj)
sendDelegate?.sendSelection(obj)
}
else {
print("index unassigned")
}
}
}
SplitViewController:
protocol EntryViewSelectionDelegate: class {
func sendSecondSelection(_ entrySelection: NSObject)
}
class SplitViewController: NSSplitViewController, SplitViewSelectionDelegate {
var delegate: EntryViewSelectionDelegate?
#IBOutlet weak var mySplitView: NSSplitView!
var leftPane: NSViewController?
var contentView: NSViewController?
var entrySelectionObject: NSObject!
override func viewDidLoad() {
super.viewDidLoad()
// assign tableview and entryview as child view controllers
let story = self.storyboard
leftPane = story?.instantiateController(withIdentifier: "TableViewController") as! TableViewController?
contentView = story?.instantiateController(withIdentifier: "EntryViewController") as! EntryViewController?
self.addChildViewController(leftPane!)
self.addChildViewController(contentView!)
print("SVC loaded")
}
func sendSelection(_ entrySelection: NSObject) {
self.delegate = EntryViewController() //if this goes in viewDidLoad, then delegate is never called/assigned
entrySelectionObject = entrySelection
print("SVC:", entrySelectionObject!)
let obj = entrySelectionObject!
delegate?.sendSecondSelection(obj)
}
}
And Finally, EntryViewController:
class EntryViewController: NSViewController, EntryViewSelectionDelegate {
#IBOutlet weak var definitionField: NSTextField!
#IBOutlet weak var notesField: NSTextField!
#IBOutlet weak var entryField: NSTextField!
var entryObject: Entry!
override func viewDidLoad() {
super.viewDidLoad()
print("EVC loaded")
}
func sendSecondSelection(_ entrySelection: NSObject) {
self.entryObject = entrySelection as! Entry
print("EVC:", entryObject)
print(entryObject.headword)
// The Error gets thrown here:
entryField.stringValue = entryObject.headword
}
}
You don't need a delegate / protocol since there is a reference to EntryViewController (contentView) – by the way the instance created with EntryViewController() is not the instantiated instance in viewDidLoad.
Just use the contentView reference:
func sendSelection(_ entrySelection: NSObject) {
contentView?.sendSecondSelection(entrySelection)
}

How to pass value from NSViewController to custom NSView of NSPopover?

By using the delegation protocol I have tried to pass a string (inputFromUser.string) from NSViewController - mainController to custom subclass of NSView of NSPopover - PlasmidMapView, to drawRect function, see code below. But, it didn’t work. I don’t know where a mistake is. Maybe there is another way to pass this string.
Update
File 1.
protocol PlasmidMapDelegate {
func giveDataForPLasmidMap(dna: String)
}
class MainController: NSViewController {
#IBOutlet var inputFromUser: NSTextView!
var delegate: plasmidMapDelegate?
#IBAction func actionPopoverPlasmidMap(sender: AnyObject) {
popoverPlasmidMap.showRelativeToRect(sender.bounds,
ofView: sender as! NSView, preferredEdge: NSRectEdge.MinY)
let dna = inputDnaFromUser.string
delegate?.giveDataForPLasmidMap(dna!)
}
}
File 2
class PlasmidMapView: NSView, PlasmidMapDelegate {
var dnaForMap = String()
func giveDataForPLasmidMap(dna: String) {
dnaForMap = dna
}
override func drawRect(dirtyRect: NSRect) {
let objectOfMainController = MainController()
objectOfMainController.delegate = self
//here I have checked if the string dnaForMap is passed
let lengthOfString = CGFloat(dnaForMap.characters.count / 10)
let pathRect = NSInsetRect(self.bounds, 10, 45)
let path = NSBezierPath(roundedRect: pathRect,
xRadius: 5, yRadius: 5)
path.lineWidth = lengthOfString //the thickness of the line should vary in dependence on the number of typed letter in the NSTextView window - inputDnaFromUser
NSColor.lightGrayColor().setStroke()
path.stroke()
}
}
Ok, there's some architecture mistakes. You don't need delegate method and protocol at all. All you just need is well defined setter method:
I. Place your PlasmidMapView into NSViewController-subclass. This view controller must be set as contentViewController-property of your NSPopover-control. Don't forget to set it the way you need in viewDidLoad-method or another.
class PlasmidMapController : NSViewController {
weak var mapView: PlacmidMapView!
}
II. In your PlacmidMapView don't forget to call needsDisplay-method on dna did set:
class PlasmidMapView: NSView {
//...
var dnaForMap = String() {
didSet {
needsDisplay()
}
//...
}
III. Set dna-string whenever you need from your MainController-class.
#IBAction func actionPopoverPlasmidMap(sender: AnyObject) {
popoverPlasmidMap.showRelativeToRect(sender.bounds,
ofView: sender as! NSView, preferredEdge: NSRectEdge.MinY)
let dna = inputDnaFromUser.string
if let controller = popoverPlasmidMap.contentViewController as? PlasmidMapController {
controller.mapView.dna = dna
} else {
fatalError("Invalid popover content view controller")
}
}
In order to use delegation your class PlasmidMapView needs to have an instance of the MainController (btw name convention is Class, not class) and conform to the PlasmidMapDelegate (once again name convention dictates that it should be PlasmidMapDelegate). With that instance you then can:
mainController.delegate = self
So, after several days I have found a solution without any protocols and delegation as Astoria has mentioned. All what I needed to do was to make #IBOutlet var plasmidMapIBOutlet: PlasmidMapView!for my custom NSView in MainController class and then to use it to set the value for the dnaForMap in #IBAction func actionPopoverPlasmidMap(sender: AnyObject).
class PlasmidMapView: NSView
{
var dnaForMap = String()
}
class MainController: NSViewController
{
#IBOutlet var inputFromUser: NSTextView!
#IBOutlet var plasmidMapIBOutlet: PlasmidMapView!
#IBAction func actionPopoverPlasmidMap(sender: AnyObject)
{
plasmidMapIBOutlet.dnaForMap = inputDnaFromUser.string!
popoverPlasmidMap.showRelativeToRect(sender.bounds,
ofView: sender as! NSView, preferredEdge: NSRectEdge.MinY)
}
}

setting the countdown interval of a WatchKit timer

New to watch development however....
My app gets the user to select a duration for a countdown timer using a slider on one interface controller as shown below:
class game_settings: WKInterfaceController {
#IBOutlet weak var halflength: WKInterfaceSlider!
#IBOutlet weak var halflengthdisplay: WKInterfaceLabel!
#IBOutlet var sethalflengthbutton: WKInterfaceButton!
#IBAction func halfsliderdidchange(value: Float) {
halflengthdisplay.setText("\(value)")
}
override func contextForSegueWithIdentifier(initialhalftogame: String) -> AnyObject? {
// You may want to set the context's identifier in Interface Builder and check it here to make sure you're returning data at the proper times
// Return data to be accessed in ResultsController
return self.halflengthdisplay
}
}
i got this from the following question: Passing data question
then i want the selected interval to be used for the timer on another interface controller as shown below.
class main_game_controller: WKInterfaceController {
#IBOutlet weak var WKTimer: WKInterfaceTimer!//timer that the user will see
var internaltimer : NSTimer?
var ispaused = false
var elapsedTime : NSTimeInterval = 0.0
var StartTime = NSDate()
#IBOutlet var extratime_button: WKInterfaceButton!
#IBOutlet var endgame_button: WKInterfaceButton!
#IBOutlet var sanction_button: WKInterfaceButton!
#IBOutlet var goal_button: WKInterfaceButton!
#IBOutlet var additional_time_timer: WKInterfaceTimer!
#IBOutlet var reset_timer_button: WKInterfaceButton!
#IBOutlet var stop_timer_button: WKInterfaceButton!
#IBOutlet var Start_timer_button: WKInterfaceButton!
override func awakeWithContext(context: AnyObject?) {
super.awakeWithContext(context)
var halflengthinterval : NSTimeInterval// variable was written to, but never read
// Configure interface objects here.
if let halflength: String = context as? String {
halflengthinterval = Double(halflength)!
}
}
override func willActivate() {
super.willActivate()
}
#IBAction func Start_button_pressed() {
internaltimer = NSTimer.scheduledTimerWithTimeInterval(halflengthinterval, target:self, selector: Selector("timerdone"), userInfo: nil, repeats:false) //use of unfesolved identifier"halflengthinterval"
WKTimer.setDate(NSDate(timeIntervalSinceNow: halflengthinterval))
WKTimer.start()//use of unresolved identifier "halflengthinterval"
}
#IBAction func stop_timer_button_pressed() {
if ispaused{
ispaused = false
internaltimer = NSTimer.scheduledTimerWithTimeInterval(halflengthinterval - elapsedTime, target: self, selector: Selector("timerDone"), userInfo: nil, repeats: false)//use of unresolved identifier 'halflengthinterval'
WKTimer.setDate(NSDate(timeIntervalSinceNow: halflengthinterval - elapsedTime))//use of unresolved identifier 'halflengthinterval'
WKTimer.start()
StartTime = NSDate()
stop_timer_button.setTitle("Pause")
}
else{
ispaused = true
//get how much time has passed before they paused it
let paused = NSDate()
elapsedTime += paused.timeIntervalSinceDate(StartTime)
//stop watchkit timer on screen
WKTimer.stop()
//stop internal timer
internaltimer!.invalidate()
//ui modification
stop_timer_button.setTitle("Resume")
}
}
I was following the answer provided in this question: WKInterface implementation
as you can see in the commented lines above, I'm receiving several errors associated with the variable halflengthinterval. I get the feeling that I'm not correctly passing the interval value between the two interface controllers, but for the life of me i have no idea how to do it.
Could someone please help me in showing
how to pass the value for the timer from the first interface
controller to the second interface controller and
how to correctly set the countdown timer for the length of time selected by the slider in the first interface controller.
Thanks very much!
Let's fix first the error regarding to NSInterval, NSInterval is just a typealis for the type Double:
typealias NSTimeInterval = Double
So the problem you're facing is how to convert a String to a Double and the way is using the Double constructor like in this way:
Double(IntValue)
Regarding how to pass data from two WKInterfaceController you're doing in the right way, but you have one mistake to fix. If you want to pass data from one WKInterfaceController to another WKInterfaceController using segues you can use the contextForSegueWithIdentifier, but in your case you are returning a NSInterval type or Double and then you're trying to cast as an String and this fail in this line of code always:
// Configure interface objects here.
if let halflength: String = context as? String {
halflengthinterval = Double(halflength)!
}
You have to change it to this line instead using the guard statement if you like or using optional-binding, it's up to you:
guard
guard let halflength = context as? Double else {
return
}
self.halflengthinterval = Double(halflength)
optional-binding
if let halflength = context as? Double {
self.halflengthinterval = Double(halflength)
}
I hope this help you.

WKInterfaceTable, Row Controllers and Button actions in Swift

I'm having problems with a fairly basic task while experimenting with Apple Watch development in Swift. I recently received what appeared to be a perfect answer to the problem in Obj C but I can't seem to translate it.
I have one Interface controller that contains a table with multiple rows of the same row controller. Each row contains two buttons. When the button is tapped it's background image changes, but another function needs to be called in the interface controller class, and this function will need to access class-level variables in the interface controller class.
The Table is wired to the interface controller. And the buttons are wired to the row controller class. Here is my simplified Swift code. Thanks for having a look!
/// MY INTERFACE CLASS ///
class MainBoard: WKInterfaceController {
#IBOutlet weak var TileGrid: WKInterfaceTable!
let numRows = 3
let imageNames = ["img1","img2","img3"]
override func awakeWithContext(context: AnyObject?) {
super.awakeWithContext(context)
// Configure interface objects here.
initBoard()
}
func initBoard() {
self.TileGrid.setNumberOfRows(self.numRows, withRowType: "Row")
for var i = 0; i < numRows; i++ {
let tmpImageA = UIImage(named: imageNames[0])
let tmpImageB = UIImage(named: imageNames[1])
let rowOfTiles = self.TileGrid.rowControllerAtIndex(i) as Row
rowOfTiles.backImageA = tmpImageA
rowOfTiles.backImageB = tmpImageB
}
}
func doSomething() {
//this function needs to be called whenever a button is pressed
}
}
///////MY ROW CONTROLLER CLASS ////////////////////////
class Row : NSObject {
// At runtime these will be assigned based on the random game board creation
var backImageA = UIImage(named: "default.png")
var backImageB = UIImage(named: "default.png")
#IBOutlet weak var TileA: WKInterfaceButton!
#IBOutlet weak var TileB: WKInterfaceButton!
#IBAction func TapTileA() {
TileA.setBackgroundImage(backImageA)
//NEED TO CALL FUNCTION DO SOMETHING IN INTERFACE CONTROLLER
}
#IBAction func TapTileB() {
TileB.setBackgroundImage(backImageB)
//NEED TO CALL FUNCTION DO SOMETHING IN INTERFACE CONTROLLER
}
}
My best answer would be to create a delegate in your RowController class, then implement this delegate in your InterfaceController
The delegate could have methods buttonOneClickHappened and buttonTwoClickHappened
Then each RowController has the delegate as a property, and when you create the RowControllers call setDelegate: self where self is your InterfaceController
Hope this helps.