PyQt QTableView 更新到 PyQt 4.5.1 后不显示图标

Question

我会尽量说得清楚，尽管这在我的脑海里有点混乱。

我有一个 PyQt 应用程序，已经运行了大约一年。更新到 PyQt 4.5.1（从 4.3.3 开始）后，我的图标不再出现在 QTableView 中（此更新与从 2.5.1 到 python 2.6.5 的更新同时进行）。恢复到旧版的 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。当通过 data() 方法中的 Qt.DecorationRole 请求时，我的模型将返回一个自定义对象 (ColorSwatch)，该对象是 QIcon 类的子类。这一直有效（但需要注意的是，由于我不明白的原因，我必须首先将其重新转换为 QVariant）。更新到 PyQt 4.5.1 后，它似乎可以正确运行（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 ColorSwatch 类仍然有效。同样的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 data() 方法实际上被调用并且正在返回此 ColorSwatch 对象（重新转换为 QVariant <- 尽管我也没有进行此重新转换进行了测试）。

将蛇血倒在我的键盘上并点燃它。

到目前为止，我还没有任何线索知道我应该做什么。任何提示将不胜感激。谢谢。

是一些（可能）相关的代码（请注意 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())

以下

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

Answer 1

伊沃在上面回答了我的问题。

实际有效的代码是：

#---------------------------------------------------------------------------
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(QtGui.QIcon(paramObj.get_icon()))
            #Note that it is first cast as a QIcon before
            #being cast as a QVariant.

再次感谢伊沃。