Adding a new label where clicked SWIFT - swift

Question

I would like to write a simple swift code for a MacOS app which add a new label wherever the user perform a mouse click in a window.
This code compiles but make the app crash:
#IBOutlet var here2 = [NSTextField]()
var count: Int = 0
func getCoordinates(){
NSEvent.addLocalMonitorForEvents(matching: [.leftMouseDown]) {
if self.location.x < 700 && self.location.y<750 {
self.here2.append(NSTextField.init())
self.here2[self.count].frame.origin = CGPoint(x: self.location.x, y: self.location.y)
self.here2[self.count].stringValue = String(self.count)
print("count is: " + String(self.here2.count))
self.count+=1
}
return $0
}

Answer 1

Here is a programmatic approach which may be run in Terminal. Note that window.acceptsMouseMovedEvents is set to true.
//May be run in Terminal with:
//swiftc label.swift -framework Cocoa -o label && ./label
import Cocoa
class AppDelegate: NSObject, NSApplicationDelegate {
var window : NSWindow!
var here2 = [NSTextField]()
var count: Int = 0
let _wndW : CGFloat = 700
let _wndH : CGFloat = 750
let _labelW : CGFloat = 24
let _labelH : CGFloat = 24
#objc func getCoordinates(_ sender:AnyObject ) {
NSEvent.addLocalMonitorForEvents(matching: [.leftMouseDown]) {
var pt: NSPoint? { self.window.mouseLocationOutsideOfEventStream }
if let location = pt {
let msPt:NSPoint = self.window.contentView!.convert(location, from: nil)
print("x = \(msPt.x) : y = \(msPt.y)")
if msPt.x < (self._wndW - self._labelW) && msPt.y < (self._wndH - self._labelH ) {
self.here2.append(NSTextField.init())
self.here2[self.count].frame = NSMakeRect(msPt.x, msPt.y, self._labelW, self._labelH)
print(self.here2[self.count].frame)
self.window.contentView!.addSubview (self.here2[self.count])
self.here2[self.count].backgroundColor = NSColor.white
self.here2[self.count].isSelectable = false
self.here2[self.count].stringValue = String(self.count)
print("count is: " + String(self.here2.count))
self.count+=1
}
}
return $0
}
}
func buildMenu() {
let mainMenu = NSMenu()
NSApp.mainMenu = mainMenu
// **** App menu **** //
let appMenuItem = NSMenuItem()
mainMenu.addItem(appMenuItem)
let appMenu = NSMenu()
appMenuItem.submenu = appMenu
appMenu.addItem(withTitle: "Quit", action:#selector(NSApplication.terminate), keyEquivalent: "q")
}
func buildWnd() {
window = NSWindow(contentRect:NSMakeRect(0,0,_wndW,_wndH),styleMask:[.titled, .closable, .miniaturizable, .resizable], backing:.buffered, defer:false)
window.center()
window.title = "Swift Test Window"
window.makeKeyAndOrderFront(window)
window.acceptsMouseMovedEvents = true
// **** Button **** //
let myBtn = NSButton (frame:NSMakeRect( _wndW - 180, 15, 135, 24 ))
myBtn.bezelStyle = .rounded
myBtn.autoresizingMask = [.maxXMargin,.minYMargin]
myBtn.title = "Start Label Maker"
myBtn.action = #selector(self.getCoordinates(_:))
window.contentView!.addSubview (myBtn)
// **** Quit btn **** //
let quitBtn = NSButton (frame:NSMakeRect( _wndW - 50, 10, 40, 40 ))
quitBtn.bezelStyle = .circular
quitBtn.autoresizingMask = [.minXMargin,.maxYMargin]
quitBtn.title = "Q"
quitBtn.action = #selector(NSApplication.terminate)
window.contentView!.addSubview(quitBtn)
}
func applicationDidFinishLaunching(_ notification: Notification) {
buildMenu()
buildWnd()
}
func applicationShouldTerminateAfterLastWindowClosed(_ sender: NSApplication) -> Bool {
return true
}
}
let appDelegate = AppDelegate()
// **** main.swift **** //
let app = NSApplication.shared
app.delegate = appDelegate
app.setActivationPolicy(.regular)
app.activate(ignoringOtherApps:true)
app.run()

Answer 2

You cannot call copy on NSTextView, that causes the error message.
You implement all the required methods by subclassing the view, but I'd suggest you allocate new text views programmatically and set their style in code instead of Interface builder.
Here's another thread dealing with copying objects: "[something copyWithZone:]: unrecognized selector sent to instance" when using Bindings / Core Data

Answer 3

You can't connect and array of NSTextField in a storyboard. In my opinion it's a bug in Xcode, IB shouldn't make the connection. It's also a bug in AppKit, I tried this and got this weird error:
Failed to set (contentViewController) user defined inspected property on (NSWindow): [<__NSTimeZone 0x6040000a2280> valueForUndefinedKey:]: this class is not key value coding-compliant for the key identifier.
Solution: remove the connection in IB and change
#IBOutlet var here2 = [NSTextField]()
to
var here2 = [NSTextField]()
#IBOutlet weak var here2TextField: NSTextField!
Connect here2TextField in IB and append here2TextField to here2 in viewDidLoad().

Answer 4

#Marco: The code which I posted is a template (aka boilerplate) example of the programmatic approach to creating applications. All that I did was copy/paste your function into the AppDelegate class of the template and connect it to a button. From there I revised your code until the desired result was obtained. Instead of using a XIB or storyboard the technique requires that source code be written by the author (or use templates). The good news is that you have control of your application and nothing is done behind your back; what you see is what you get. The downside is that the technique is cumbersome for really large projects; for this I rely on Xcode with XIBs. The autocompletion feature of Xcode is also very helpful, while with the programmatic approach you have to rely on Xcode/Help/DeveloperDocumentation as well as internet searches, especially StackOverflow (usually someone else has had the same problem that you are experiencing). In lieu of using the CommandLine from Terminal for every compile I automated the process with a very simple editor which was written in Swift using Xcode (with XIB). However, the posted code may also be run in Xcode by doing the following:
1) Create a new macOS App using Swift (User Interface is XIB but it won’t be needed for the demo)
2) Use File/New/File to add a Swift file and name it ‘main.swift’
3) In the new main.swift file change ‘import Foundation’ to ‘import Cocoa’
4) Copy/paste the last five lines of the demo (labelled main.swift) into this file
5) Go into the AppDelegate file that Apple provided and delete everything there except for ‘import Cocoa’
6) Copy/paste the entire AppDelegate class of the posted code (down to the main.swift section which you have already used)
7) Hit the ‘Run’ button, and it should compile without error.
Hope it helps and good luck with your project. Thanks for posting.