simplest-osx-python-app.md

Simplest app can be created via https://gist.github.com/mathiasbynens/674099 e.g.

mkdir -p MyApp.app/Contents/MacOS
printf '#!/bin/bash\nsleep 5' > MyApp.app/Contents/MacOS/MyApp
chmod +x MyApp.app/Contents/MacOS/MyApp
echo "<plist><dict></dict></plist>" > MyApp.app/Contents/Info.plist

But more "appy" app can be done via the followning steps

1. Create app dir structure

   mkdir -p MyApp.app/Contents/MacOS
   mkdir -p MyApp.app/Contents/Resources

2. Create app property list MyApp.app/Contents/Info.plist

   <?xml version="1.0" encoding="UTF-8"?>
   <!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
   <plist version="1.0">
   <dict>
   	<key>CFBundleExecutable</key>
   	<string>MyApp</string>
   	<key>CFBundleGetInfoString</key>
   	<string>MyApp</string>
   	<key>CFBundleIconFile</key>
   	<string>MyApp.icns</string>
   	<key>CFBundleName</key>
   	<string>MyApp</string>
   	<key>CFBundlePackageType</key>
   	<string>APPL</string>
   </dict>
   </plist>

3. Create app executable MyApp.app/Contents/MacOS/MyApp

   #!/bin/bash
   /usr/bin/python $(cd "$(dirname "${BASH_SOURCE[0]}")/../Resources" && pwd)/main.py

4. Create app icon MyApp.app/Contents/Resources/MyApp.icns, e.g. https://gist.github.com/andreif/1691ee0a22458e4a6589

5. Create python app MyApp.app/Contents/Resources/main.py, e.g.

   # coding=utf-8
   # Source: http://www.tkdocs.com/tutorial/firstexample.html
   
   import sys
   py2 = sys.version_info.major == 2
   if py2:
       from Tkinter import *
       import Tkinter as ttk
   else:
       from tkinter import *
       import tkinter as ttk
   
   
   def calculate(*args):
      try:
          value = float(feet.get())
          meters.set((0.3048 * value * 10000.0 + 0.5)/10000.0)
      except ValueError:
          pass
   
   root = Tk()
   root.title("Feet to Meters")
   if py2:
       mainframe = ttk.Frame(root)
   else:
       mainframe = ttk.Frame(root, padding="3 3 12 12")
   mainframe.grid(column=0, row=0, sticky=(N, W, E, S))
   mainframe.columnconfigure(0, weight=1)
   mainframe.rowconfigure(0, weight=1)
   
   feet = StringVar()
   meters = StringVar()
   
   feet_entry = ttk.Entry(mainframe, width=7, textvariable=feet)
   feet_entry.grid(column=2, row=1, sticky=(W, E))
   
   ttk.Label(mainframe, textvariable=meters).grid(column=2, row=2, sticky=(W, E))
   ttk.Button(mainframe, text="Calculate", command=calculate).grid(column=3, row=3, sticky=W)
   
   ttk.Label(mainframe, text="feet").grid(column=3, row=1, sticky=W)
   ttk.Label(mainframe, text="is equivalent to").grid(column=1, row=2, sticky=E)
   ttk.Label(mainframe, text="meters").grid(column=3, row=2, sticky=W)
   
   for child in mainframe.winfo_children():
      child.grid_configure(padx=5, pady=5)
   
   feet_entry.focus()
   root.bind('<Return>', calculate)
   
   root.mainloop()

6. Enjoy the result

   

7. To change app name in the OS X menu bar from Python to e.g. MyApp, use pyobjc, which is pre-installed in the system Python (/System/Library/Frameworks/Python/...):

   from Foundation import NSBundle
   bundle = NSBundle.mainBundle()
   info = bundle.localizedInfoDictionary() or bundle.infoDictionary()
   info['CFBundleName'] = 'MyApp'

8. To prevent multiple instances of the same app:

   try:
       import fcntl
       lockfile = open('/tmp/myapp.lock', 'w')
       fcntl.lockf(lockfile, fcntl.LOCK_EX | fcntl.LOCK_NB)
   except IOError as e:
       exit()

9. To focus on the already running instance is a bit hard atm, so we focus on all Python.app instances, until there is a better solution available/known

   from Foundation import NSWorkspace
   from Cocoa import NSApplicationActivateAllWindows, NSApplicationActivateIgnoringOtherApps
   
   for app in NSWorkspace.sharedWorkspace().runningApplications():
       if app.bundleIdentifier() == 'org.python.python':
           app.activateWithOptions_(NSApplicationActivateAllWindows | NSApplicationActivateIgnoringOtherApps)

10. One could use a pid file as a temporary solution

    from Foundation import NSProcessInfo
    info = NSProcessInfo.processInfo()
    pid = info.processIdentifier()
    with open(PID_FILE, 'w+') as f:
        f.write(str(pid))

    try:
        with open(PID_FILE) as f:
            pid = int(f.read())
    except:
        pid = None
    
    for app in NSWorkspace.sharedWorkspace().runningApplications():
        if app.bundleIdentifier() == 'org.python.python':
            if not pid or pid == app.processIdentifier():
                app.activateWithOptions_(NSApplicationActivateAllWindows | NSApplicationActivateIgnoringOtherApps)