我会尽量说清楚，尽管这在我的脑海里有点混乱。
我有一个 PyQt 应用程序已经工作了大约一年。更新到 PyQt 4.5.1（从 4.3.3）后，我的图标都不再出现在 QTableView 中（此更新与从 2.5.1 到 python 2.6.5 的更新同时进行）。恢复到较旧的 python 和 PyQt，一切都按预期工作。
细分是这样的：
我正在使用模型视图方法。我的模型，当通过 data() 方法中的 Qt.DecorationRole 请求时，将返回一个自定义对象 (ColorSwatch)，它是 QIcon 类的子类。这一直有效（需要注意的是，由于我不明白的原因，我必须先将其重铸为 QVariant）。更新到 PyQt 4.5.1 后，它似乎可以正常运行（即我没有收到任何错误），但图标没有绘制（尽管绘制它的空间是“保留的”，即文本已向右移动为这个不可见的图标让路）。
以下是我尝试过的一些事情：
我已经验证了 ColorSwatch 类仍然有效。同一个类用于将图标绘制到上下文菜单中 - 并且它们显示正确。
我已经验证了 data() 方法实际上被调用并返回了这个 ColorSwatch 对象（重铸成 QVariant <- 尽管我也测试过没有这个重铸）。
将蛇血倒在我的键盘上并点燃它。
到目前为止，还没有给我任何关于我应该做什么的线索。任何提示将不胜感激。谢谢。
下面是一些（可能）相关的代码（注意 paramObj.get_icon() 返回一个 ColorSwatch 对象）：
#---------------------------------------------------------------------------
def data(self, index, role=QtCore.Qt.DisplayRole):
"""
Returns the text or formatting for a particular cell, depending on the
role supplied.
"""
blah
blah
blah
elif role == QtCore.Qt.DecorationRole:
if platform.system()=='Darwin':
return QtGui.QIcon(paramObj.get_icon())
else:
return QtCore.QVariant(paramObj.get_icon())
和
import os
import tempfile
import sys
import colorsys
import copy
import fnmatch
import time
from PyQt4 import QtGui
from PyQt4 import QtCore
################################################################################
class ColorSwatch(QtGui.QIcon):
"""
A subclass of QIcon, this class draws a colored paint chip with a border
The color and size are determined at construction time, and cannot
be changed later.
"""
#---------------------------------------------------------------------------
def __init__(self, r=1, g=1, b=1, br = 0, bg = 0, bb = 0, w=20, h=20):
"""
Constructor for the ColorSwatch class. Takes the passed arguments and
creates a square icon filled with the given color and with a border
color determined by br, bg, bb. All colors should be in floating point
format.
"""
QtGui.QIcon.__init__(self)
#normalize the color
r8, g8, b8 = self.normalize_color((r, g, b))
#convert the r, g, b values to 8 bit colors
r8, g8, b8 = self.fp_to_8b_color((r8, g8, b8))
#Create the pixmap and painter objects
paintChip = QtGui.QPixmap(w, h)
painter = QtGui.QPainter()
painter.begin(paintChip)
#fill the swatch
baseColor = QtGui.QColor(r8, g8, b8)
painter.fillRect(0, 0, w, h, baseColor)
#if any of the values were super brights (>1), draw a smaller, white
#box inset to make sure the user knows
if r > 1 or g > 1 or b > 1:
painter.fillRect(5, 5, w-10, h-10, QtGui.QColor(255, 255, 255))
#if all values are 0, put a faint x through the icon
# # # brush = QtGui.QBrush()
# # # brush.setColor(QtGui.QColor(30, 30, 30))
painter.setPen(QtGui.QColor(200, 200, 200))
if r ==0 and g == 0 and b == 0:
painter.drawLine(0, 0, w, h)
painter.drawLine(w-1, 0, -1, h)
# # #
# # # #normalize the color
# # # r8, g8, b8 = self.normalize_color((r8, g8, b8))
#now draw the border(s)
#convert the r, g, b values to 8 bit colors
r8, g8, b8 = self.fp_to_8b_color((br, bg, bb))
#draw the border
painter.setPen(QtGui.QColor(r8, g8, b8))
painter.drawRect(0,0,w-1,h-1)
#if any of the values were super brights (>1), draw a border around the
#inset box as well.
if r > 1 or g > 1 or b > 1:
painter.drawRect(5,5,w-11,h-11)
#done drawing
painter.end()
#add it (both to the normal and the selected modes)
self.addPixmap(paintChip, QtGui.QIcon.Normal)
self.addPixmap(paintChip, QtGui.QIcon.Selected)
#---------------------------------------------------------------------------
def fp_to_8b_color(self, color):
"""
Convert a floating point color value (passed in the form of a three
element tuple) to a regular 8-bit 0-255 value. Returns a 3 item tuple.
"""
r = max(min(int(color[0]*255),255),0)
g = max(min(int(color[1]*255),255),0)
b = max(min(int(color[2]*255),255),0)
return (r,g,b)
#---------------------------------------------------------------------------
def normalize_color(self, color):
"""
"normalizes" a color value so that if there are any super-whites, it
balances all the other floating point values so that we end up with a
"real" color. Negative values will result in undefined behavior.
Mainly used to make the color chip "look right" when using super whites.
"""
maxValue = max(color)
if maxValue > 1:
return (color[0]/maxValue, color[1]/maxValue, color[2]/maxValue)
else:
return color