PyQt QTreeWidget 自定义委托问题

Question

我正在尝试写一个简单的属性编辑器。我有一个自动生成的pyqt类（下面代码中的WorkZone），我需要用PropertyEditor来查看和编辑它的一些属性，使用的代理是PropertyEditorDelegate，它会用到一些自定义编辑器，比如ColorEditor、LineEditor等。

主要的想法是，WorkZone知道哪些属性需要被编辑以及如何编辑，而PropertyEditor会解析WorkZone，寻找这些属性，并把它们的值填充到QTreeWidget中。

但是有个问题：代理在双击、按'Enter'键或者其他操作时并没有开始编辑。它确实被添加到了正确的行，并且能够绘制项目，但就这些了。此外，当我把Propertyeditor容器的类型改成QTableWidget时，代理的工作表现得更好（但编辑器却是在屏幕的角落里，而不是在表格中）！

另外还有一个问题：有没有办法在不需要把代理实例存储在其他地方（比如脚本中的self._delegates）的情况下，给行添加一些代理，这样做看起来太丑陋了。setItemDelegate方法接受一个指向代理的指针，在C++中它会拥有这个代理，但在PyQT中并不是这样……而且，使用setItem时就没有这个问题。

以下脚本说明了这个问题：

# -*- coding: utf-8 -*-
#!/usr/bin/env python

from PyQt4 import QtCore, QtGui
import inspect


class LineEditor(QtGui.QLineEdit):


    def __init__(self, name = None, parent = None, slot = None):
        QtGui.QLineEdit.__init__(self, parent)
        self.textChanged.connect(slot)
        self.name = name

    @staticmethod
    def paintForDelegate(delegate, painter, option, index):
        QtGui.QItemDelegate.paint(delegate, painter, option, index)

    def get(self):
        return str(self.text())

    def set(self, val):
        self.setText(QtCore.QString.fromUtf8(val))

class ColorEditor(QtGui.QComboBox):


    def _populateList(self):
        for name in QtGui.QColor.colorNames():
            self.addItem(name)
            index = self.findText(name)
            self.setItemData(index, QtGui.QColor(name), QtCore.Qt.DecorationRole)

    def __init__(self, name = None, parent = None, slot = None):
        QtGui.QComboBox.__init__(self, parent)
        self._populateList()
        self.currentIndexChanged.connect(slot)
        self.name = QtCore.QString.fromUtf8(name)

    @staticmethod
    def paintForDelegate(delegate, painter, option, index):
        QtGui.QItemDelegate.paint(delegate, painter, option, index)

    def get(self):
        qColor = QtGui.QColor(self.itemData(self.currentIndex(), QtCore.Qt.DecorationRole))        
        color = ((qColor.blue() | (qColor.green() << 8)) | (qColor.red() << 16))
        return color

    def set(self, val):
        blue = (val & 255)
        green = ((val & 65280) >> 8)
        red = ((val & 16711680) >> 16)
        color = QtGui.QColor(red, green, blue)
        index = self.findData(color, QtCore.Qt.DecorationRole)
        self.setCurrentIndex(index) 

class PropertyEditorDelegate(QtGui.QItemDelegate):


    def __init__(self, object, propName, parent = None):
        QtGui.QItemDelegate.__init__(self, parent)
        self._object = object
        self._propName = propName

    def paint(self, painter, option, index):
        self._object.paintForDelegate(self._propName, self, painter, option, index)

    def createEditor(self, parent, option, index):
        return self._object.createEditor(self._propName)

    def setEditorData(self, editor, index):
        value = index.model().data(index, QtCore.Qt.EditRole)
        editor.set(value)

    def setModelData(self, editor, model, index):
        if index.column() == 0:
            model.setData(index, editor.name, QtCore.Qt.EditRole)
        else:
            model.setData(index, editor.get(), QtCore.Qt.EditRole)

    def updateEditorGeometry(self, editor, option, index):
        editor.setGeometry(option.rect)

class PropertyEditor(QtGui.QWidget):

    def __init__(self, parent = None):
        QtGui.QWidget.__init__(self, parent)
        self._object = None
        self._delegates = []
        self._mainLayout = QtGui.QVBoxLayout()
        self._mainLayout.setContentsMargins(2, 2, 2, 2)
        self._mainLayout.setSpacing(2)
        self.setLayout(self._mainLayout)
        self._contents = QtGui.QTreeWidget()
        self._contents.setColumnCount(2)
        self._contents.currentItemChanged.connect(self.printCurrent)
        self._mainLayout.addWidget(self._contents)

    def printCurrent(self, curr, prev):
        print self._contents.currentIndex().row()
        print self._contents.currentIndex().column()
        print self._contents.itemDelegate(self._contents.currentIndex())._propName
        print self._contents.itemDelegate(self._contents.currentIndex())

    def object(self):
        return self._object

    def setObject(self, value):       
        self._object = value

        def isProperty(p):
            return isinstance(p, property)

        for (name, value) in inspect.getmembers(type(self._object), isProperty):
            if self._object.isEditable(name):
                item = QtGui.QTreeWidgetItem()
                item.setData(0, QtCore.Qt.EditRole, QtCore.QString.fromUtf8(self._object.getPropertyName(name)))
                item.setData(1, QtCore.Qt.EditRole, self._object.get(name))
                self._contents.addTopLevelItem(item)

                self._delegates.append(PropertyEditorDelegate(self._object, name, self._contents))
                index = self._contents.indexOfTopLevelItem(item)    
                self._contents.setItemDelegateForRow(index, self._delegates[index])

class WorkZone(object):


    def __init__(self):

        self._name = ''
        self.currentEditor = None
        self.red = 100
        self.green = 100
        self.blue = 100
        self._width = 1

    def _getColor(self):
        color = ((self.blue | (self.green << 8)) | (self.red << 16))
        return color

    def _setColor(self, color):
        self.blue = (color & 255)
        self.green = ((color & 65280) >> 8)
        self.red = ((color & 16711680) >> 16)

    color = property(_getColor, _setColor)

    def currentColorChanged(self, index):
        if self.currentEditor is not None:
            self.color = self.currentEditor.get()
        print self.color

    def currentNameChanged(self, newName):
        if self.currentEditor is not None:
            self.name = self.currentEditor.get()
        print self.name

    def createEditor(self, prop):
        if prop == 'color':
            self.currentEditor = ColorEditor('Color', None, self.currentColorChanged)
            self.currentEditor.set(self.color) 
            return self.currentEditor
        elif prop == 'name':
            self.currentEditor = LineEditor('Name', None, self.currentNameChanged) 
            self.currentEditor.set(self.name)
            return self.currentEditor
        else:
            return None

    def releaseEditor(self):
        self.currentEditor = None

    def isEditable(self, prop):
        if prop == 'color':
            return True
        elif prop == 'name':
            return True
        else:
            return False

    def set(self, prop, val):
        if prop == 'color':
            self.color = val
        elif prop == 'name':
            self.name = val

    def get(self, prop):
        if prop == 'color':
            return self.color
        elif prop == 'name':
            return self.name

    def getPropertyName(self, prop):
        if prop == 'color':
            return 'Color'
        elif prop == 'name':
            return 'Name'

    def paintForDelegate(self, prop, delegate, painter, option, index):
        if prop == 'color':
            ColorEditor.paintForDelegate(delegate, painter, option, index)
        elif prop == 'name':
            LineEditor.paintForDelegate(delegate, painter, option, index)

    def _setWidth(self, Width):
        self._width = Width

    def _getWidth(self):
        return self._width

    width = property(_getWidth, _setWidth)

    def _getName(self):
        return self._name

    def _setName(self, val):
        self._name = val

    name = property(_getName, _setName)



if __name__ == '__main__':

    import sys

    app = QtGui.QApplication(sys.argv)
    zone = WorkZone()
    zone.color = 0
    zone.width = 1
    propertyEditor = PropertyEditor()
    propertyEditor.setObject(zone)


    propertyEditor.show()
    sys.exit(app.exec_())

Answer 1

答案很简单，和往常一样.. %) 默认情况下，QTreeWidgetItem的标志里并不包括QtCore.Qt.ItemIsEditable这个选项。

Answer 2

在PS上。

来自PyQt的文档

QAbstractItemView.setItemDelegate（self, QAbstractItemDelegate）

这个方法是用来为视图和它的模型设置一个项目代理的。如果你想完全控制项目的编辑和显示，这个方法就很有用。

如果之前有代理的话，会被移除，但不会被删除。QAbstractItemView 并不拥有这个代理。

注意：你不应该在多个视图之间共享同一个代理实例。这样做可能会导致编辑行为不正确或者让人困惑，因为每个连接到同一个代理的视图可能会收到closeEditor()信号，并试图访问、修改或者关闭一个已经关闭的编辑器。

Answer 3

我最后处理了双击事件，让项目变成可编辑的状态，使用editItem()强制进入编辑模式，然后再把它设置回去。这个委托本身负责所有的显示和编辑工作。

# In __init__:
    self.tree.itemActivated.connect(self.onDoubleClick)


def onDoubleClick(self, item, index):
    """ 
    The logic will happen in the editor delegate. This is needed to let
    the delegate run by making this editable
    """        
    item.setFlags(QtCore.Qt.ItemIsSelectable |
                  QtCore.Qt.ItemIsEnabled |
                  QtCore.Qt.ItemIsEditable)            

    # Force the item in to edit mode so the delegate picks it up
    self.tree.editItem(item, index)

    # Set the item back to not editable. The delegate will still do its
    #    job, but the read-only state will already be set when done!
    item.setFlags(QtCore.Qt.ItemIsSelectable |
                  QtCore.Qt.ItemIsEnabled)

第一次设置标志可能只需要ItemIsEditable就可以工作，但这样做感觉更合适。