如何在 PySide/PyQt 中撤销对 QStandardItem 的编辑? [英] How to undo edit of QStandardItem in PySide/PyQt?
问题描述
使用 关于 QListWidgets 的相同问题 作为指南，我正在尝试制作一个 QStandardItemModel，我可以在其中撤消对项目的编辑.
Using the identical question asked about QListWidgets as a guide, I am trying to make a QStandardItemModel in which I can undo the edit of an item.
从下面的 SSCCE 中可以看出，我几乎完全复制了这个例子，但有一些因为 currentItemChanged 不适用于 QStandardItemModel，所以稍作调整.为了解决这个问题，我使用 clicked 信号来修复项目的先前文本.
As can be seen in the SSCCE below, I'm pretty much copying the example exactly, but with some minor tweaking because currentItemChanged isn't available for QStandardItemModel. To get around that, I'm using the clicked signal instead to fix the previous text for an item.
奇怪的是，撤消堆栈中显示了正确的描述，但是当我单击 undo 按钮时，它实际上并没有撤消任何内容.
Strangely, the correct description shows up in the undostack, but when I click the undo button it doesn't actually undo anything.
注意目前的问题表面上与这个问题相同.在其他版本中接受的答案与其说是答案，不如说是暗示.这是我试图在此处实施的提示，但尚未奏效.由于这个问题更具体和详细，因此不应算作重复，IMO.
Note the present question is superficially the same as this question. The answer that was accepted at that other version is less an answer, more a hint. It's a hint I am trying to implement here, but it is not working yet. Since this question is more specific and detailed, it shouldn't count as a duplicate, IMO.
SSCCE
from PySide import QtGui, QtCore
import sys
class CommandItemEdit(QtGui.QUndoCommand):
def __init__(self, model, item, textBeforeEdit, description = "Item edited"):
QtGui.QUndoCommand.__init__(self, description)
self.model = model
self.item = item
self.textBeforeEdit = textBeforeEdit
self.textAfterEdit = item.text()
def redo(self):
self.model.blockSignals(True)
self.item.setText(self.textAfterEdit)
self.model.blockSignals(False)
def undo(self):
self.model.blockSignals(True)
self.item.setText(self.textBeforeEdit)
self.model.blockSignals(False)
class UndoableTree(QtGui.QWidget):
def __init__(self, parent = None):
QtGui.QWidget.__init__(self, parent = None)
self.setAttribute(QtCore.Qt.WA_DeleteOnClose)
self.view = QtGui.QTreeView()
self.model = self.createModel()
self.view.setModel(self.model)
self.view.expandAll()
self.undoStack = QtGui.QUndoStack(self)
undoView = QtGui.QUndoView(self.undoStack)
buttonLayout = self.buttonSetup()
mainLayout = QtGui.QHBoxLayout(self)
mainLayout.addWidget(undoView)
mainLayout.addWidget(self.view)
mainLayout.addLayout(buttonLayout)
self.setLayout(mainLayout)
self.makeConnections()
#For undo/redo editing
self.textBeforeEdit = ""
def makeConnections(self):
self.view.clicked.connect(self.itemClicked)
self.model.itemChanged.connect(self.itemChanged)
self.quitButton.clicked.connect(self.close)
self.undoButton.clicked.connect(self.undoStack.undo)
self.redoButton.clicked.connect(self.undoStack.redo)
def itemClicked(self, index):
item = self.model.itemFromIndex(index)
self.textBeforeEdit = item.text()
def itemChanged(self, item):
command = CommandItemEdit(self.model, item, self.textBeforeEdit,
"Renamed '{0}' to '{1}'".format(self.textBeforeEdit, item.text()))
self.undoStack.push(command)
def buttonSetup(self):
self.undoButton = QtGui.QPushButton("Undo")
self.redoButton = QtGui.QPushButton("Redo")
self.quitButton = QtGui.QPushButton("Quit")
buttonLayout = QtGui.QVBoxLayout()
buttonLayout.addStretch()
buttonLayout.addWidget(self.undoButton)
buttonLayout.addWidget(self.redoButton)
buttonLayout.addStretch()
buttonLayout.addWidget(self.quitButton)
return buttonLayout
def createModel(self):
model = QtGui.QStandardItemModel()
model.setHorizontalHeaderLabels(['Titles', 'Summaries'])
rootItem = model.invisibleRootItem()
#First top-level row and children
item0 = [QtGui.QStandardItem('Title0'), QtGui.QStandardItem('Summary0')]
item00 = [QtGui.QStandardItem('Title00'), QtGui.QStandardItem('Summary00')]
item01 = [QtGui.QStandardItem('Title01'), QtGui.QStandardItem('Summary01')]
rootItem.appendRow(item0)
item0[0].appendRow(item00)
item0[0].appendRow(item01)
#Second top-level item and its children
item1 = [QtGui.QStandardItem('Title1'), QtGui.QStandardItem('Summary1')]
item10 = [QtGui.QStandardItem('Title10'), QtGui.QStandardItem('Summary10')]
item11 = [QtGui.QStandardItem('Title11'), QtGui.QStandardItem('Summary11')]
rootItem.appendRow(item1)
item1[0].appendRow(item10)
item1[0].appendRow(item11)
return model
def main():
app = QtGui.QApplication(sys.argv)
newTree = UndoableTree()
newTree.show()
sys.exit(app.exec_())
if __name__ == "__main__":
main()
推荐答案
在一个密切相关的问题中引用另一个答案:
To quote another answer at a closely related question :
点击信号似乎完全是错误的跟踪方式变化.您将如何处理通过键盘所做的更改?那么以编程方式进行的更改呢?对于撤消堆栈正常工作，必须记录每个更改，并在与制作的订单完全相同.
The clicked signal seems to be entirely the wrong way to track changes. How are you going to deal with changes made via the keyboard? And what about changes that are made programmatically? For an undo stack to work correctly, every change has to be recorded, and in exactly the same order that it was made.
同一篇文章继续建议创建一个自定义信号，在数据实际更改时发出旧/新数据.最终，我使用了三个从 SO 无耻地窃取的想法.首先，three_pineapples 的见解需要 disconnect 以避免无限递归.其次，将 QStandardItemModel 子类化以定义一个新的 itemDataChanged 信号，该信号将以前的和新的数据发送到插槽.第三，子类 QStandardItem 并让它在数据更改时发出此信号:这是在 setData() 的重新实现中处理的.
The same post went on to suggest creating a custom signal that emits old/new data when the data are actually changed. Ultimately I used three ideas that I stole shamelessly from SO. First, three_pineapples' insight that disconnect is needed to avoid infinite recursion. Second, subclass QStandardItemModel to define a new itemDataChanged signal that sends both previous and new data to a slot. Third, subclass QStandardItem and have it emit this signal when the data is changed: this is handled in a reimplementation of setData()).
完整代码如下:
# -*- coding: utf-8 -*-
from PySide import QtGui, QtCore
import sys
class CommandTextEdit(QtGui.QUndoCommand):
def __init__(self, tree, item, oldText, newText, description):
QtGui.QUndoCommand.__init__(self, description)
self.item = item
self.tree = tree
self.oldText = oldText
self.newText = newText
def redo(self):
self.item.model().itemDataChanged.disconnect(self.tree.itemDataChangedSlot)
self.item.setText(self.newText)
self.item.model().itemDataChanged.connect(self.tree.itemDataChangedSlot)
def undo(self):
self.item.model().itemDataChanged.disconnect(self.tree.itemDataChangedSlot)
self.item.setText(self.oldText)
self.item.model().itemDataChanged.connect(self.tree.itemDataChangedSlot)
class CommandCheckStateChange(QtGui.QUndoCommand):
def __init__(self, tree, item, oldCheckState, newCheckState, description):
QtGui.QUndoCommand.__init__(self, description)
self.item = item
self.tree = tree
self.oldCheckState = QtCore.Qt.Unchecked if oldCheckState == 0 else QtCore.Qt.Checked
self.newCheckState = QtCore.Qt.Checked if oldCheckState == 0 else QtCore.Qt.Unchecked
def redo(self): #disoconnect to avoid recursive loop b/w signal-slot
self.item.model().itemDataChanged.disconnect(self.tree.itemDataChangedSlot)
self.item.setCheckState(self.newCheckState)
self.item.model().itemDataChanged.connect(self.tree.itemDataChangedSlot)
def undo(self):
self.item.model().itemDataChanged.disconnect(self.tree.itemDataChangedSlot)
self.item.setCheckState(self.oldCheckState)
self.item.model().itemDataChanged.connect(self.tree.itemDataChangedSlot)
class StandardItemModel(QtGui.QStandardItemModel):
itemDataChanged = QtCore.Signal(object, object, object, object)
class StandardItem(QtGui.QStandardItem):
def setData(self, newValue, role=QtCore.Qt.UserRole + 1):
if role == QtCore.Qt.EditRole:
oldValue = self.data(role)
QtGui.QStandardItem.setData(self, newValue, role)
model = self.model()
#only emit signal if newvalue is different from old
if model is not None and oldValue != newValue:
model.itemDataChanged.emit(self, oldValue, newValue, role)
return True
if role == QtCore.Qt.CheckStateRole:
oldValue = self.data(role)
QtGui.QStandardItem.setData(self, newValue, role)
model = self.model()
if model is not None and oldValue != newValue:
model.itemDataChanged.emit(self, oldValue, newValue, role)
return True
QtGui.QStandardItem.setData(self, newValue, role)
class UndoableTree(QtGui.QWidget):
def __init__(self, parent = None):
QtGui.QWidget.__init__(self, parent = None)
self.setAttribute(QtCore.Qt.WA_DeleteOnClose)
self.view = QtGui.QTreeView()
self.model = self.createModel()
self.view.setModel(self.model)
self.view.expandAll()
self.undoStack = QtGui.QUndoStack(self)
undoView = QtGui.QUndoView(self.undoStack)
buttonLayout = self.buttonSetup()
mainLayout = QtGui.QHBoxLayout(self)
mainLayout.addWidget(undoView)
mainLayout.addWidget(self.view)
mainLayout.addLayout(buttonLayout)
self.setLayout(mainLayout)
self.makeConnections()
def makeConnections(self):
self.model.itemDataChanged.connect(self.itemDataChangedSlot)
self.quitButton.clicked.connect(self.close)
self.undoButton.clicked.connect(self.undoStack.undo)
self.redoButton.clicked.connect(self.undoStack.redo)
def itemDataChangedSlot(self, item, oldValue, newValue, role):
if role == QtCore.Qt.EditRole:
command = CommandTextEdit(self, item, oldValue, newValue,
"Text changed from '{0}' to '{1}'".format(oldValue, newValue))
self.undoStack.push(command)
return True
if role == QtCore.Qt.CheckStateRole:
command = CommandCheckStateChange(self, item, oldValue, newValue,
"CheckState changed from '{0}' to '{1}'".format(oldValue, newValue))
self.undoStack.push(command)
return True
def buttonSetup(self):
self.undoButton = QtGui.QPushButton("Undo")
self.redoButton = QtGui.QPushButton("Redo")
self.quitButton = QtGui.QPushButton("Quit")
buttonLayout = QtGui.QVBoxLayout()
buttonLayout.addStretch()
buttonLayout.addWidget(self.undoButton)
buttonLayout.addWidget(self.redoButton)
buttonLayout.addStretch()
buttonLayout.addWidget(self.quitButton)
return buttonLayout
def createModel(self):
model = StandardItemModel()
model.setHorizontalHeaderLabels(['Titles', 'Summaries'])
rootItem = model.invisibleRootItem()
item0 = [StandardItem('Title0'), StandardItem('Summary0')]
item00 = [StandardItem('Title00'), StandardItem('Summary00')]
item01 = [StandardItem('Title01'), StandardItem('Summary01')]
item0[0].setCheckable(True)
item00[0].setCheckable(True)
item01[0].setCheckable(True)
rootItem.appendRow(item0)
item0[0].appendRow(item00)
item0[0].appendRow(item01)
return model
def main():
app = QtGui.QApplication(sys.argv)
newTree = UndoableTree()
newTree.show()
sys.exit(app.exec_())
if __name__ == "__main__":
main()
总的来说，这似乎比使用 clicked 更好.
Overall, this seems better than using clicked.
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