App stays in Activity Monitor after it has been quit

Question

I am creating an macOS application with a NSTimer instance in the background using this class:

class RepeatingTimer {
    private var timer: Timer?

    init(timeInterval: TimeInterval, eventHandler: @escaping ((Timer) -> Void)) {
        timer = Timer.scheduledTimer(withTimeInterval: timeInterval, repeats: true, block: eventHandler)
    }

    deinit {
        cancel()
    }

    func cancel() {
        timer?.invalidate()
    }
}

Except when I terminate my app (CMD+Q) or just regularly quit my app, there is still a process of my app in Activity Monitor, event though I terminate the NSTimer in AppDelegate:

    func applicationWillTerminate(_ aNotification: Notification) {
        MainVC.repeatingTimer?.cancel()
    }

I setup my timer in the main viewDidLoad() method of my application like this:

MainVC.repeatingTimer = RepeatingTimer(timeInterval: TimeInterval(1), eventHandler: onTimerUpdate(timer:))

I also tried to delegate my main ViewController with NSWindowDelegate, and use this to try to get rid of the process, but that did also not work:

    override func viewDidAppear() {
        self.view.window?.delegate = self
    }

    func windowWillClose(_ notification: Notification) {
        MainVC.repeatingTimer?.cancel()
    }

Can you attach to the process after you've quit it and see what's still running in it? — user1118321
I can attach to the process after I quit it, in fact, XCode still recognizes it as "running" after I quit the application and never disconnects - but the NSTimer is not running when I quit the application. — Devxln
@user1118321 XCode says AppDelegate is still running, and there seems to be an com.apple.NSEventThread running, plus another Thread with 0 0x00000000 as instruction. — Devxln
That's really odd! Does your applicationWillTerminate() actually get called? If you break in there, does the debugger stop? — user1118321
@user1118321 thank you for referencing to that! The issue was laying on Core Data, I don't use Core Data but somehow in my appdelegate there was a lot of junk with CoreData trying to save data before quit. Removed all of them. — Devxln

Devxln Devxln · Accepted Answer · 2019-09-26T18:33:46

This fixed it:

    func applicationShouldTerminateAfterLastWindowClosed(_ sender: NSApplication) -> Bool {
        return true
    }

Also make sure Core Date is either disabled, or Core Data is saving things correctly (if not, it will not 'actually' quit the application)

App stays in Activity Monitor after it has been quit

1 Answers