How can I create a status bar item with Cocoa and Python (PyObjC)?

Question

I have created a brand new project in XCode and have the following in my AppDelegate.py file:

from Foundation import *
from AppKit import *

class MyApplicationAppDelegate(NSObject):
    def applicationDidFinishLaunching_(self, sender):
        NSLog("Application did finish launching.")

        statusItem = NSStatusBar.systemStatusBar().statusItemWithLength_(NSVariableStatusItemLength)
        statusItem.setTitle_(u"12%")
        statusItem.setHighlightMode_(TRUE)
        statusItem.setEnabled_(TRUE)

However, when I launch the application no status bar item shows up. All the other code in main.py and main.m is default.

Answer 1

The above usage of .retain() is required because the statusItem is being destroyed upon return from the applicationDidFinishLaunching() method. Bind that variable as a field in instances of MyApplicationAppDelegate using self.statusItem instead.

Here is a modified example that does not require a .xib / etc...

from Foundation import *
from AppKit import *
from PyObjCTools import AppHelper

start_time = NSDate.date()


class MyApplicationAppDelegate(NSObject):

    state = 'idle'

    def applicationDidFinishLaunching_(self, sender):
        NSLog("Application did finish launching.")

        self.statusItem = NSStatusBar.systemStatusBar().statusItemWithLength_(NSVariableStatusItemLength)
        self.statusItem.setTitle_(u"Hello World")
        self.statusItem.setHighlightMode_(TRUE)
        self.statusItem.setEnabled_(TRUE)

        # Get the timer going
        self.timer = NSTimer.alloc().initWithFireDate_interval_target_selector_userInfo_repeats_(start_time, 5.0, self, 'tick:', None, True)
        NSRunLoop.currentRunLoop().addTimer_forMode_(self.timer, NSDefaultRunLoopMode)
        self.timer.fire()

    def sync_(self, notification):
        print "sync"

    def tick_(self, notification):
        print self.state


if __name__ == "__main__":
    app = NSApplication.sharedApplication()
    delegate = MyApplicationAppDelegate.alloc().init()
    app.setDelegate_(delegate)
    AppHelper.runEventLoop()

Answer 2

I had to do this to make it work:

1. Open MainMenu.xib. Make sure the class of the app delegate is MyApplicationAppDelegate. I'm not sure if you will have to do this, but I did. It was wrong and so the app delegate never got called in the first place.

2. Add statusItem.retain() because it gets autoreleased right away.