Unable to use wx.NotificationMessage properly with wxPython

Question

I recently upgraded to the development release of wxPython (wxPython 2.9.2.4) since I needed the functionality of wx.NotificationMessage within my application. I have been trying unsuccessfully to create notification bubbles on certain user events due to something I think might be a possible bug. Before submitting such bug, I wanted to go ahead and ask the people of the mailing list what they think might be the problem and hopefully find a solution from within my code.

Here is the code I have used:

import wx, sys

app = wx.PySimpleApp()

class TestTaskBarIcon(wx.TaskBarIcon):

    def __init__(self):
        wx.TaskBarIcon.__init__(self)
        # create a test icon
        bmp = wx.EmptyBitmap(16, 16)
        dc = wx.MemoryDC(bmp)
        dc.SetBrush(wx.RED_BRUSH)
        dc.Clear()
        dc.SelectObject(wx.NullBitmap)

        testicon = wx.EmptyIcon()
        testicon.CopyFromBitmap(bmp)

        self.SetIcon(testicon)
        self.Bind(wx.EVT_TASKBAR_LEFT_UP, lambda e: (self.RemoveIcon(),sys.exit()))

        wx.NotificationMessage("", "Hello world!").Show()

icon = TestTaskBarIcon()
app.MainLoop()

On my Windows 7 computer, the code creates a small white task bar icon and creates a popup with the phrase "Hello World!". The problem? The message is not on my icon. Another icon is being created and the message is being placed there. See this image: http://www.pasteall.org/pic/18068">

What I thought was that this is probably due to the fact that I have passed no parent parameter on line 22:

wx.NotificationMessage("", "Hello world!").Show()

Here is what I changed it to:

wx.NotificationMessage("", "Hello world!", self).Show()

Where 'self' refers to the task bar icon. When I do that, I get an error:

Traceback (most recent call last):
  File "C:\Python27\testnotificationmessage.py", line 24, in <module>
    icon = TestTaskBarIcon()
  File "C:\Python27\testnotificationmessage.py", line 22, in __init__
    wx.NotificationMessage("", "Hello world!", self).Show()
  File "C:\Python27\lib\site-packages\wx-2.9.2-msw\wx\_misc.py", line 1213, in __init__
    _misc_.NotificationMessage_swiginit(self,_misc_.new_NotificationMessage(*args))
TypeError: in method 'new_NotificationMessage', expected argument 3 of type 'wxWindow *'

What's going on? If I remove that argument, I don't get my result, if I add the argument, I get an error! How am I supposed to use wx.NotificationMessage with a wx.TaskBarIcon!

Please help! I hope I've provided enough details. Please comment if you need more!

Answer 1

I would not recommend using 2.9 just yet. I have encountered some strange bugs when trying it out.

You can have the same functionality in 2.8. I am using somewhat modified code that I have found some time ago.

import wx, sys

try:
    import win32gui #, win32con
    WIN32 = True
except:
    WIN32 = False

class BalloonTaskBarIcon(wx.TaskBarIcon):
    """
    Base Taskbar Icon Class
    """
    def __init__(self):
        wx.TaskBarIcon.__init__(self)
        self.icon = None
        self.tooltip = ""

    def ShowBalloon(self, title, text, msec = 0, flags = 0):
        """
        Show Balloon tooltip
         @param title - Title for balloon tooltip
         @param msg   - Balloon tooltip text
         @param msec  - Timeout for balloon tooltip, in milliseconds
         @param flags -  one of wx.ICON_INFORMATION, wx.ICON_WARNING, wx.ICON_ERROR
        """
        if WIN32 and self.IsIconInstalled():
            try:
                self.__SetBalloonTip(self.icon.GetHandle(), title, text, msec, flags)
            except Exception:
                pass # print(e) Silent error

    def __SetBalloonTip(self, hicon, title, msg, msec, flags):

        # translate flags
        infoFlags = 0

        if flags & wx.ICON_INFORMATION:
            infoFlags |= win32gui.NIIF_INFO
        elif flags & wx.ICON_WARNING:
            infoFlags |= win32gui.NIIF_WARNING
        elif flags & wx.ICON_ERROR:
            infoFlags |= win32gui.NIIF_ERROR

        # Show balloon
        lpdata = (self.__GetIconHandle(),   # hWnd
                  99,                       # ID
                  win32gui.NIF_MESSAGE|win32gui.NIF_INFO|win32gui.NIF_ICON, # flags: Combination of NIF_* flags
                  0,                        # CallbackMessage: Message id to be pass to hWnd when processing messages
                  hicon,                    # hIcon: Handle to the icon to be displayed
                  '',                       # Tip: Tooltip text
                  msg,                      # Info: Balloon tooltip text
                  msec,                     # Timeout: Timeout for balloon tooltip, in milliseconds
                  title,                    # InfoTitle: Title for balloon tooltip
                  infoFlags                 # InfoFlags: Combination of NIIF_* flags
                  )
        win32gui.Shell_NotifyIcon(win32gui.NIM_MODIFY, lpdata)

        self.SetIcon(self.icon, self.tooltip)   # Hack: because we have no access to the real CallbackMessage value

    def __GetIconHandle(self):
        """
        Find the icon window.
        This is ugly but for now there is no way to find this window directly from wx
        """
        if not hasattr(self, "_chwnd"):
            try:
                for handle in wx.GetTopLevelWindows():
                    if handle.GetWindowStyle():
                        continue
                    handle = handle.GetHandle()
                    if len(win32gui.GetWindowText(handle)) == 0:
                        self._chwnd = handle
                        break
                if not hasattr(self, "_chwnd"):
                    raise Exception
            except:
                raise Exception, "Icon window not found"
        return self._chwnd

    def SetIcon(self, icon, tooltip = ""):
        self.icon = icon
        self.tooltip = tooltip
        wx.TaskBarIcon.SetIcon(self, icon, tooltip)

    def RemoveIcon(self):
        self.icon = None
        self.tooltip = ""
        wx.TaskBarIcon.RemoveIcon(self)

# ===================================================================
app = wx.PySimpleApp()

class TestTaskBarIcon(BalloonTaskBarIcon):

    def __init__(self):
        wx.TaskBarIcon.__init__(self)
        # create a test icon
        bmp = wx.EmptyBitmap(16, 16)
        dc = wx.MemoryDC(bmp)
        dc.SetBrush(wx.RED_BRUSH)
        dc.Clear()
        dc.SelectObject(wx.NullBitmap)

        testicon = wx.EmptyIcon()
        testicon.CopyFromBitmap(bmp)

        self.SetIcon(testicon)
        self.Bind(wx.EVT_TASKBAR_LEFT_UP, lambda e: (self.RemoveIcon(),sys.exit()))

        self.ShowBalloon("", "Hello world!")

icon = TestTaskBarIcon()
app.MainLoop()

Answer 2

There is an undocumented hidden method in TaskBarIcon called ShowBalloon which is only implemented for Windows.

From the source:

def ShowBalloon(*args, **kwargs):
    """
    ShowBalloon(self, String title, String text, unsigned int msec=0, int flags=0) -> bool

    Show a balloon notification (the icon must have been already
    initialized using SetIcon).  Only implemented for Windows.

    title and text are limited to 63 and 255 characters respectively, msec
    is the timeout, in milliseconds, before the balloon disappears (will
    be clamped down to the allowed 10-30s range by Windows if it's outside
    it) and flags can include wxICON_ERROR/INFO/WARNING to show a
    corresponding icon

    Returns True if balloon was shown, False on error (incorrect parameters
    or function unsupported by OS)

    """
    return _windows_.TaskBarIcon_ShowBalloon(*args, **kwargs)

I tested it on Windows with wxPython 2.9.4.0 and it works well.