wxPython wxListCtrl selected row color

Question

I want to have certain rows selected color be red instead of the standard color (blue on windows) so that I can indicate status. Anyone know if this is possible in wxPython?

Answer 1

In order to do what you want, i.e. have a different selection color when certain items are selected, you will need to drop into win32. Fortunately, it is not too hard to do that in python. It does however make your code platform dependent. I tried it out today in a small program. If the Genre is not "Rock" I make the selection orange. Here are some screenshots.

Rock Items Selected

Mixed Items Selected. Notice the RnB and Blues are selected with Orange alt text http://img258.imageshack.us/img258/1307/soshot2.jpg

Here is the code. It looks scary at first but if you know any win32, its not that bad. I make use of the pywin32 package and the std ctypes libraries. I had to define some of the SDK constants as they were not available in the win32con module.

import sys
import wx
import wx.lib.mixins.listctrl  as  listmix

import win32api
import win32gui
import win32con
import win32gui_struct
import commctrl
import ctypes
from ctypes.wintypes import BOOL, HWND, RECT, UINT, DWORD, HDC, DWORD, LPARAM, COLORREF

LVM_FIRST = 0x1000
LVM_GETSUBITEMRECT=(LVM_FIRST + 56)
LVIR_BOUNDS             =0
LVIR_ICON               =1
LVIR_LABEL              =2
LVIR_SELECTBOUNDS       =3
DEFAULT_GUI_FONT    =17

#LPNMHDR
class NMHDR(ctypes.Structure):
    pass
INT = ctypes.c_int
NMHDR._fields_ = [('hwndFrom', HWND), ('idFrom', UINT), ('code', INT)]
LPNMHDR = ctypes.POINTER(NMHDR)

#LPNMCUSTOMDRAW
class NMCUSTOMDRAW(ctypes.Structure):
    pass
NMCUSTOMDRAW._fields_ = [('hdr', NMHDR), ('dwDrawStage', DWORD), ('hdc', ctypes.c_int), 
                         ('rc', RECT), ('dwItemSpec', DWORD), ('uItemState', UINT),
                         ('lItemlParam', LPARAM)]
LPNMCUSTOMDRAW = ctypes.POINTER(NMCUSTOMDRAW)

#LPNMLVCUSTOMDRAW
class NMLVCUSTOMDRAW(ctypes.Structure):
    pass
NMLVCUSTOMDRAW._fields_ = [('nmcd', NMCUSTOMDRAW), 
                           ('clrText', COLORREF),
                           ('clrTextBk', COLORREF),
                           ('iSubItem', ctypes.c_int),
                           ('dwItemType', DWORD),
                           ('clrFace', COLORREF),
                           ('iIconEffect', ctypes.c_int),
                           ('iIconPhase', ctypes.c_int),
                           ('iPartId', ctypes.c_int),
                           ('iStateId', ctypes.c_int),                           
                           ('rcText', RECT),
                           ('uAlign', UINT)
                           ]
LPNMLVCUSTOMDRAW = ctypes.POINTER(NMLVCUSTOMDRAW)


musicdata = {
1 : ("Bad English", "The Price Of Love", "Rock"),
2 : ("DNA featuring Suzanne Vega", "Tom's Diner", "Rock"),
3 : ("George Michael", "Praying For Time", "Rock"),
4 : ("Gloria Estefan", "Here We Are", "Rock"),
5 : ("Linda Ronstadt", "Don't Know Much", "Rock"),
6 : ("Michael Bolton", "How Am I Supposed To Live Without You", "Blues"),
7 : ("Paul Young", "Oh Girl", "Rock"),
8 : ("Paula Abdul", "Opposites Attract", "Rock"),
9 : ("Richard Marx", "Should've Known Better", "Rock"),
10 : ("Bobby Brown", "My Prerogative", "RnB"),
}




class MyListCtrl(wx.ListCtrl, listmix.ListCtrlAutoWidthMixin):
    def __init__(self, parent, ID, pos=wx.DefaultPosition,
                 size=wx.DefaultSize, style=0):
        wx.ListCtrl.__init__(self, parent, ID, pos, size, style)
        listmix.ListCtrlAutoWidthMixin.__init__(self)

    def ShouldCustomDraw(self, row):
        if self.IsSelected(row):
            listitem = self.GetItem(row, 2)
            genre = listitem.GetText()

            return genre != "Rock"


    def CustomDraw(self, lpcd):        
        if lpcd.contents.nmcd.dwDrawStage == commctrl.CDDS_PREPAINT:
            return (True, commctrl.CDRF_NOTIFYITEMDRAW)

        if lpcd.contents.nmcd.dwDrawStage == commctrl.CDDS_ITEMPREPAINT:                
            if self.ShouldCustomDraw(lpcd.contents.nmcd.dwItemSpec):
                #do custom drawing for non Rock selected rows
                #paint the selection background
                color = win32api.RGB(255, 127, 0) #orange
                brush = win32gui.CreateSolidBrush(color)   
                r = lpcd.contents.nmcd.rc
                win32gui.FillRect(int(lpcd.contents.nmcd.hdc),  (r.left+4, r.top, r.right, r.bottom), brush)                
                win32gui.DeleteObject(brush)
                return (True, commctrl.CDRF_NOTIFYSUBITEMDRAW)                    

        if lpcd.contents.nmcd.dwDrawStage == commctrl.CDDS_ITEMPREPAINT|commctrl.CDDS_SUBITEM:                
            row = lpcd.contents.nmcd.dwItemSpec
            col = lpcd.contents.iSubItem
            item = self.GetItem(row, col)
            text = item.GetText()
            #paint the text
            rc = RECT()
            rc.top = col
            if col > 0:
                rc.left = LVIR_BOUNDS
            else:
                rc.left = LVIR_LABEL
            success = win32api.SendMessage(self.Handle, LVM_GETSUBITEMRECT, row, ctypes.addressof(rc))
            if col > 0:
                rc.left += 5
            else:
                rc.left += 2
            rc.top += 2

            if success:                
                oldColor = win32gui.SetTextColor(lpcd.contents.nmcd.hdc, win32gui.GetSysColor(win32con.COLOR_HIGHLIGHTTEXT))                
                win32gui.DrawText(lpcd.contents.nmcd.hdc, text, len(text), (rc.left, rc.top, rc.right, rc.bottom), win32con.DT_LEFT|win32con.DT_VCENTER)
                win32gui.SetTextColor(lpcd.contents.nmcd.hdc, oldColor)                                

            return (True, commctrl.CDRF_SKIPDEFAULT)


        # don't need custom drawing
        return (True, commctrl.CDRF_DODEFAULT)


class MyFrame(wx.Frame):
    def __init__(self, *args, **kwds):
        wx.Frame.__init__(self, *args, **kwds)
        self._sizer = wx.BoxSizer(wx.VERTICAL)
        tID = wx.NewId()
        self._ctl = MyListCtrl(self, tID,
                                 style=wx.LC_REPORT 
                                 #| wx.BORDER_SUNKEN
                                 | wx.BORDER_NONE
                                 | wx.LC_EDIT_LABELS
                                 | wx.LC_SORT_ASCENDING
                                 #| wx.LC_NO_HEADER
                                 #| wx.LC_VRULES
                                 #| wx.LC_HRULES
                                 #| wx.LC_SINGLE_SEL
                                 )
        self._sizer.Add(self._ctl, 1, wx.EXPAND, 3)
        self.PopulateList()

        self.oldWndProc = win32gui.SetWindowLong(self.GetHandle(), win32con.GWL_WNDPROC, self.MyWndProc)


    def MyWndProc(self, hWnd, msg, wParam, lParam):

        if msg == win32con.WM_NOTIFY:
            hwndFrom, idFrom, code = win32gui_struct.UnpackWMNOTIFY(lParam)
            if code == commctrl.NM_CUSTOMDRAW and hwndFrom == self._ctl.Handle:                
                lpcd = ctypes.cast(lParam, LPNMLVCUSTOMDRAW)
                retProc, retCode = self._ctl.CustomDraw(lpcd)

                if retProc:
                    return retCode


        # Restore the old WndProc.  Notice the use of wxin32api
        # instead of win32gui here.  This is to avoid an error due to
        # not passing a callable object.
        if msg == win32con.WM_DESTROY:
            win32api.SetWindowLong(self.GetHandle(),
                              win32con.GWL_WNDPROC,
                              self.oldWndProc)

        # Pass all messages (in this case, yours may be different) on
        # to the original WndProc
        return win32gui.CallWindowProc(self.oldWndProc,
                                  hWnd, msg, wParam, lParam)

    def PopulateList(self):
        self._ctl.InsertColumn(0, "Artist")
        self._ctl.InsertColumn(1, "Title")
        self._ctl.InsertColumn(2, "Genre")

        items = musicdata.items()

        for key, data in items:            
            index = self._ctl.InsertStringItem(sys.maxint, data[0])
            self._ctl.SetStringItem(index, 1, data[1])
            self._ctl.SetStringItem(index, 2, data[2])
            self._ctl.SetItemData(index, key)


        self._ctl.SetColumnWidth(0, wx.LIST_AUTOSIZE)
        self._ctl.SetColumnWidth(1, wx.LIST_AUTOSIZE)
        self._ctl.SetColumnWidth(2, 100)

        self.currentItem = 0

class MyApp(wx.App):
    def OnInit(self):
        frame = MyFrame(None, -1, 'wxListCtrl StackOverflow')
        frame.Show()
        self.SetTopWindow(frame)
        return 1

if __name__ == "__main__":
    app = MyApp(0)
    app.MainLoop()

Answer 2

In your class that you derive from wx.ListCtrl, take a look at overriding

def OnGetItemAttr(self, item):
    return self.normalAttr[item % 2]
#

Where the item attributes are initialized ahead of time using:

    self.normalAttr = []
    self.normalAttr.append(wx.ListItemAttr())
    grayAttr = wx.ListItemAttr()
    grayAttr.SetBackgroundColour(lightGray)
    self.normalAttr.append(grayAttr)

So in this case, I'm alternating background colors between the default, and a light Gray attribute.

This function is called for each row as its painted, so you can use it to indicate all sorts of status. If row is selected should be an easy case.