Balloon Taskbar Popup for Windows XP

[Gabriel Genellina]

En Sat, 29 Sep 2007 07:40:21 -0300, makko <elmakko at gmail.com> escribi�:

> I need to create a function that will produce a balloon popup in the
> taskbar when called. Whats the shortest and easiest way to do this?

Mark Hammond's pywin32 extensions support notification icons but not  
balloon popups. The Windows NOTIFYICONDATA structure in newer shell  
versions contains more fields, required to show a balloon tooltip, but it  
is incompatible with earlier versions (there are dumb people in MS too...)
Below there is a demo based on win32gui_taskbar.py, using pywin32, ctypes  
and struct. The bulk of code is just to create the window, setup the menu,  
and such. The balloon is shown on this fragment:

     def show_balloon(self):
         # For this message I can't use the win32gui structure because
         # it doesn't declare the new, required fields
         nid = PyNOTIFYICONDATA()
         nid.hWnd = self.hwnd
         nid.uFlags = NIF_INFO
         # type of balloon and text are random
         from random import choice
         nid.dwInfoFlags = choice([NIIF_INFO, NIIF_WARNING, NIIF_ERROR])
         nid.szInfo = choice(["Balloon text.", "This text is nicer.", "Perl  
rulez! :)"])
         nid.szInfoTitle = "A Title"
         # Call the Windows function, not the wrapped one
         from ctypes import windll
         Shell_NotifyIcon = windll.shell32.Shell_NotifyIconA
         Shell_NotifyIcon(NIM_MODIFY, nid.pack())

For more info see the Shell_NotifyIcon docs at  
<http://msdn2.microsoft.com/en-us/library/ms647738.aspx>

<code>
# Based on win32gui_taskbar demo

 from win32api import *
# Try and use XP features, so we get alpha-blending etc.
try:
     from winxpgui import *
except ImportError:
     from win32gui import *
import win32con
import sys, os
import struct
import timer

class PyNOTIFYICONDATA:
     _struct_format = (
         "I" # DWORD cbSize;
         "I" # HWND hWnd;
         "I" # UINT uID;
         "I" # UINT uFlags;
         "I" # UINT uCallbackMessage;
         "I" # HICON hIcon;
         "128s" #    TCHAR szTip[128];
         "I" # DWORD dwState;
         "I" # DWORD dwStateMask;
         "256s" # TCHAR szInfo[256];
         "I" #     union {
             #    UINT  uTimeout;
             #    UINT  uVersion;
             #} DUMMYUNIONNAME;
         "64s" #    TCHAR szInfoTitle[64];
         "I" #  DWORD dwInfoFlags;
         #       GUID guidItem;
     )
     _struct = struct.Struct(_struct_format)

     hWnd = 0
     uID = 0
     uFlags = 0
     uCallbackMessage = 0
     hIcon = 0
     szTip = ''
     dwState = 0
     dwStateMask = 0
     szInfo = ''
     uTimeoutOrVersion = 0
     szInfoTitle = ''
     dwInfoFlags = 0

     def pack(self):
         return self._struct.pack(
             self._struct.size,
             self.hWnd,
             self.uID,
             self.uFlags,
             self.uCallbackMessage,
             self.hIcon,
             self.szTip,
             self.dwState,
             self.dwStateMask,
             self.szInfo,
             self.uTimeoutOrVersion,
             self.szInfoTitle,
             self.dwInfoFlags)

     def __setattr__(self, name, value):
         # avoid wrong field names
         if not hasattr(self, name):
             raise NameError, name
         self.__dict__[name] = value

class MainWindow:
     def __init__(self):
         message_map = {
                 win32con.WM_DESTROY: self.OnDestroy,
                 win32con.WM_COMMAND: self.OnCommand,
                 win32con.WM_USER+20: self.OnTaskbarNotify,
         }
         # Register the Window class.
         wc = WNDCLASS()
         hinst = wc.hInstance = GetModuleHandle(None)
         wc.lpszClassName = "PythonTaskbarDemo"
         wc.lpfnWndProc = message_map # could also specify a wndproc.
         classAtom = RegisterClass(wc)
         # Create the Window.
         style = win32con.WS_OVERLAPPED | win32con.WS_SYSMENU
         self.hwnd = CreateWindow( classAtom, "Taskbar Demo", style, \
                 0, 0, win32con.CW_USEDEFAULT, win32con.CW_USEDEFAULT, \
                 0, 0, hinst, None)
         UpdateWindow(self.hwnd)
         iconPathName = os.path.abspath(os.path.join( sys.prefix, "pyc.ico"  
))
         icon_flags = win32con.LR_LOADFROMFILE | win32con.LR_DEFAULTSIZE
         try: hicon = LoadImage(hinst, iconPathName, win32con.IMAGE_ICON,  
0, 0, icon_flags)
         except: hicon = LoadIcon(0, win32con.IDI_APPLICATION)
         flags = NIF_ICON | NIF_MESSAGE | NIF_TIP
         nid = (self.hwnd, 0, flags, win32con.WM_USER+20, hicon, "Balloon  
tooltip demo")
         Shell_NotifyIcon(NIM_ADD, nid)
         print "Ready. Click on the Python icon."

     def OnTaskbarNotify(self, hwnd, msg, wparam, lparam):
         if lparam==win32con.WM_LBUTTONUP or lparam==win32con.WM_RBUTTONUP:
             print "Click."
             menu = CreatePopupMenu()
             AppendMenu( menu, win32con.MF_STRING, 1024, "Generate balloon")
             AppendMenu( menu, win32con.MF_STRING, 1025, "Exit")
             pos = GetCursorPos()
             SetForegroundWindow(self.hwnd)
             TrackPopupMenu(menu, win32con.TPM_LEFTALIGN, pos[0], pos[1],  
0, self.hwnd, None)
             PostMessage(self.hwnd, win32con.WM_NULL, 0, 0)
             return 1

     def enqueue_balloon(self):
         timer.set_timer(3000, self.show_balloon)
         print "A balloon will appear in 3 sec"

     def show_balloon(self, id, time):
         timer.kill_timer(id) # one-shot timer!

         # For this message I can't use the win32gui structure because
         # it doesn't declare the new, required fields
         nid = PyNOTIFYICONDATA()
         nid.hWnd = self.hwnd
         nid.uFlags = NIF_INFO
         # type of balloon and text are random
         from random import choice
         nid.dwInfoFlags = choice([NIIF_INFO, NIIF_WARNING, NIIF_ERROR])
         nid.szInfo = choice(["Balloon text.", "This text is nicer.", "Perl  
rulez! :)"])
         nid.szInfoTitle = "A Title"
         # Call the Windows function, not the wrapped one
         from ctypes import windll
         Shell_NotifyIcon = windll.shell32.Shell_NotifyIconA
         Shell_NotifyIcon(NIM_MODIFY, nid.pack())

     def OnCommand(self, hwnd, msg, wparam, lparam):
         id = LOWORD(wparam)
         if id == 1024:
             self.enqueue_balloon()
         elif id == 1025:
             print "Goodbye"
             DestroyWindow(self.hwnd)
         else:
             print "OnCommand for ID", id

     def OnDestroy(self, hwnd, msg, wparam, lparam):
         nid = (self.hwnd, 0)
         Shell_NotifyIcon(NIM_DELETE, nid)
         PostQuitMessage(0) # Terminate the app.

def main():
     w=MainWindow()
     PumpMessages()

if __name__=='__main__':
     main()
</code>

-- 
Gabriel Genellina