Trying to setup validation for a few text fields in a new (and very small) Swift Mac app. Following various other topics here on SO and a few other examples, I can still not get controlTextDidChange to propagate (to my ViewController).
E.g: How to live check a NSTextField - Swift OS X
I have read at least a dozen variations of basically that same concept. Since none of the accepted answers seem to work I am just getting more and more confused by something which is generally a fairly simple task on most platforms.
I have controlTextDidChange implemented to just call NSLog to let me know if I get anything.
AppDelegate should be part of the responder chain and should eventually handle controlTextDidChange but I see nothing there either.
Using the current Xcode I start a new project. Cocoa app, Swift, Storyboard and nothing else.
From what I can gather the below isolated example should work. In my actual app I have tried some ways of inserting the ViewController into the responder chain. Some answers I found suggested it was not always there. I also tried manually adding the ViewController as the delegate in code theTextField.delegate = self
Nothing I have done seems to get text changed to trigger any events.
Any ideas why I have so much trouble setting up this delegation?
My single textfield example app
Storyboard is about as simple as it gets:
AppDelegate
import Cocoa
#NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate, NSTextFieldDelegate, NSTextDelegate {
func applicationDidFinishLaunching(_ aNotification: Notification) {
// Insert code here to initialize your application
}
func applicationWillTerminate(_ aNotification: Notification) {
// Insert code here to tear down your application
}
func controlTextDidChange(notification: NSNotification) {
let object = notification.object as! NSTextField
NSLog("AppDelegate::controlTextDidChange")
NSLog("field contains: \(object.stringValue)")
}
}
ViewController
import Cocoa
class ViewController: NSViewController, NSTextFieldDelegate, NSTextDelegate {
#IBOutlet var theTextField: NSTextField!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override var representedObject: Any? {
didSet {
// Update the view, if already loaded.
}
}
func controlTextDidChange(notification: NSNotification) {
let object = notification.object as! NSTextField
NSLog("ViewController::controlTextDidChange")
NSLog("field contains: \(object.stringValue)")
}
}
I think the samples you're following are a bit out-of-date.
Try...
override func controlTextDidChange(_ notification: Notification) {
...as the function definition for your method in your NSTextFieldDelegate.
Related
I created an outlet in ViewController class and I'd like to modify it.
In the ViewController.swift file I have
import Cocoa
class ViewController: NSViewController {
#IBOutlet var LabelText: NSTextFieldCell?
override func viewDidLoad() {
super.viewDidLoad()
}
//other things
}
I'd like to change the background color of the label. How can I do that from AppDelegate?
At first I thought I could solve this problem using a function in ViewController and calling it in AppDelegate
func changeBackground() {
LabelText.textColor = NSColor.red
}
But soon I realised that it wasn't possible unless I used a static function. Then I tried to modify the code in ViewController like that
static func changeBackground() {
LabelText.textColor = NSColor.red
}
and call this function in AppDelegate like that
ViewController.changeBackground()
In this way I can access to changeBackground() function from AppDelegate, but in ViewController it gives me an error: Instance member 'LabelText' cannot be used on type 'ViewController'
I understood that this cannot be possible because somehow I'm calling "LabelText" before it's initialised (or something like that).
I don't know much about Swift and I'm trying to understand how it works. I've been searching for the answer to my question for hours, but still I don't know how to solve this.
Solution
As Rob suggested, the solution is to use NotificationCenter.
A useful link to understand how it works: https://www.appypie.com/notification-center-how-to-swift
Anyway, here how I modified the code.
In ViewController:
class ViewController: NSViewController {
#IBOutlet var label: NSTextFieldCell!
let didReceiveData = Notification.Name("didReceiveData")
override func viewDidLoad() {
NotificationCenter.default.addObserver(self, selector: #selector(onDidReceiveData(_:)), name: didReceiveData, object: nil)
super.viewDidLoad()
}
#objc func onDidReceiveData(_ notification: Notification) {
label.textColor = NSColor.red
}
}
And then, in AppDelegate:
let didReceiveData = Notification.Name("didReceiveData")
NotificationCenter.default.post(name: didReceiveData, object: nil)
I am a Swift/MacOS newbie working on a MacOS application does some setup involving keychain access and API calls in the viewDidLoad() methods in the main ViewController.
I am working on unit tests for my models, so I don't need and in fact do not want the code in viewDidLoad() to run. However, from what I can tell, the app gets loaded and those methods run before the test case setup() method, so I don't know how I could do any mocking or other actions.
I am using Xcode 11.5 and Swift 5.
One way to do it would be to have an separate NSApplicationMain for when unit tests are run vs one for "normal" runs.
First remove the #NSApplicationMain annotation from your current AppDelegate class. It should end up looking something like this:
AppDelegate.swift
import AppKit
class AppDelegate: NSObject, NSApplicationDelegate {
func applicationDidFinishLaunching(_ aNotification: Notification) {
print("Debug/Production run")
// Insert code here to initialize your application
}
func applicationWillTerminate(_ aNotification: Notification) {
// Insert code here to tear down your application
}
}
Now create a new file called AppDelegateUnitTesting.swift and it's source should look like this:
AppDelegateUnitTesting.swift
import Foundation
import Cocoa
class AppDelegateTesting: NSObject, NSApplicationDelegate {
func applicationDidFinishLaunching(_ aNotification: Notification) {
print("Unit Testing Run")
// Insert code here to initialize your application
}
func applicationWillTerminate(_ aNotification: Notification) {
// Insert code here to tear down your application
}
}
Now add a new file called main.swift this file will determine in which environment our app is running, the source should be something like this:
main.swift
import Foundation
import Cocoa
let isRunningTests = NSClassFromString("XCTestCase") != nil &&
ProcessInfo.processInfo.arguments.contains("-XCUnitTests")
fileprivate var delegate: NSApplicationDelegate?
if !isRunningTests {
delegate = AppDelegate()
NSApplication.shared.delegate = delegate
// See this Answer to initialize the Windows programmatically
// https://stackoverflow.com/a/44604229/496351
} else {
delegate = AppDelegateTesting()
NSApplication.shared.delegate = delegate
}
NSApplication.shared.run()
To determine whether it's running in a Unit Test environment it checks if it can load the XCTestClass (which is only injected when testing) and it checks for the presence of the -XCUnitTest command line argument, we have to set this argument ourselves as part of the Scheme's Test action as shown in the image below
After doing all of this, you should see the message "Debug/Production run" printed when you press the play button and you should see the message "Unit Testing Run" printed whenever you run your unit tests.
You'll most likely have to add code to load the initial window programmatically this other answer shows how to do it:
how to Load initial window controller from storyboard?
I've tried, without success, respond to events such as windowWillClose() and windowShouldClose() inside NSWindowController (yes conforming to NSWindowDelegate).
Later, to my surprise, I was able to receive those events if I make my contentViewController (NSViewController) conform to NSWindowDelegate.
Unfortunately, later on, found out that view.window?.windowController is nil inside windowWillClose() or windowShouldClose(), code:
override func viewDidAppear() {
super.viewDidAppear()
self.view.window?.delegate = self
self.view.window?.windowController // not nil!
}
func windowWillClose(_ notification: Notification) {
self.view.window?.windowController // nil!!
}
func windowShouldClose(_ sender: NSWindow) -> Bool {
self.view.window?.windowController // nil!!
return true
}
After realizing that view.window?.windowController is not nil inside viewDidAppear() the next thing I thought was that Swift garbage collected the controller, so I changed viewDidAppear() in a way that creates another reference of windowController thus preventing garbage collection on said object, code:
var windowController: NSWindowController?
override func viewDidAppear() {
super.viewDidAppear()
self.view.window?.delegate = self
windowController = view.window?.windowController
}
func windowWillClose(_ notification: Notification) {
self.view.window?.windowController // NOT nil
}
func windowShouldClose(_ sender: NSWindow) -> Bool {
self.view.window?.windowController // NOT nil
return true
}
My hypothesis turned out to be correct (I think).
Is this the same issue that is preventing me from receiving those events inside NSWindowController?
Is there another way I can achieve the same thing without creating more object references?
In order to post code, I use the Answer option even though it is more of a comment.
I added in NSViewController:
override func viewDidAppear() {
super.viewDidAppear()
parentWindowController = self.view.window!.windowController
self.view.window!.delegate = self.view.window!.windowController as! S1W2WC. // The NSWC class, which conforms to NSWindowDelegate
print(#function, "windowController", self.view.window!, self.view.window!.windowController)
}
I get print log:
viewDidAppear() windowController Optional()
and notification is passed.
But if I change to
override func viewDidAppear() {
super.viewDidAppear()
// parentWindowController = self.view.window!.windowController
self.view.window!.delegate = self.view.window!.windowController as! S1W2WC
print(#function, "windowController", self.view.window!, self.view.window!.windowController)
}
by commenting out parentWindowController, notification don't go anymore to the WindowController…
Edited: I declared in ViewController:
var parentWindowController: NSWindowController? // Helps keep a reference to the controller
The proposed solutions are, in my opinion, hacks that can cause serious problems with memory management by creating circular references. You definitely can make instances of NSWindowController work as the window’s delegate. The proper way is to wire it up correctly in either code or in Interface Builder in Xcode. An example of how to do it properly is offered here.
If the delegate methods are not called is because the wiring up is not done correctly.
Another thing that must be done in Swift is when you add the name of the NSWindowController subclass in Interface Builder in Xcode is to check the checkbox of Inherits from Module. If you fail to do this, none of your subclass methods will be called.
I'm working through a cocoa application tutorial from the Big Nerd Ranch's Cocoa Programming 5th edition book (I'm in the beginning chapters). On their blog website for discussing the book, a user mentions that passing in 'self' isn't necessary and that it's covered in chapter 18. I'm very curious now though as to how this could be refactored without having to pass in 'self'. Is it possible?
This code is basically creating an instance of a custom ViewController which will need to load from the AppDelegate.
import Cocoa
#NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {
var mainWindowController: MainWindowController?
func applicationDidFinishLaunching(_ aNotification: Notification) {
// Insert code here to initialize your application
let mainWindowController = MainWindowController()
//put the window of the window controller on the screen
mainWindowController.showWindow(self)
//set the property to point to the window controller
self.mainWindowController = mainWindowController
}
func applicationWillTerminate(_ aNotification: Notification) {
// Insert code here to tear down your application
}
}
MainWindowController class if you need to see the functionality. It's very basic, its not doing much:
import Cocoa
class MainWindowController: NSWindowController {
#IBOutlet weak var textField: NSTextField!
override var windowNibName: NSNib.Name {
return NSNib.Name.init("MainWindowController")
}
override func windowDidLoad() {
super.windowDidLoad()
// Implement this method to handle any initialization after your window controller's window has been loaded from its nib file.
}
#IBAction func generatePassword(_ sender: AnyObject) {
//Get a random string of length 8
let length = 8
let password = generateRandomString(length: length)
//tell the text field to display the string
textField.stringValue = password
}
}
I want a function to fire every time the user makes a change to my NSTextView. I got this to work in an iOS app and am now trying to make it work in an OS X app. I created an outlet for my NSTextView and wrote the following Swift code:
import Cocoa
class ViewController: NSViewController, NSTextViewDelegate {
#IBOutlet var textViewOutlet: NSTextView!
func textViewDidChange(textView: NSTextView) {
print("Text view changed!")
}
}
I don't get any errors but my statement doesn't print.
It should be textDidChange(notification:). Try like this:
func textDidChange(_ notification: Notification) {
guard let textView = notification.object as? NSTextView else { return }
print(textView.string)
}
This should be why there is no delegate assignment.
TextViewOutlet.delegate = self;
And the method actually looks like this. Notice the parameters
func textDidChange(_ notification: Notification) {
}