qt: pyqt: QTreeView 内部拖放几乎可以正常工作...被拖动的项目消失了 [英] qt: pyqt: QTreeView internal drag and drop almost working... dragged item disappears
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问题描述
我几乎在 QTreeView 中有一个完全正常的拖放重新排序.一切似乎都很好，除了丢弃的对象从未出现(尽管我可以引用它许多不同的方式，向我证明它确实存在于它应该存在的地方).如果有人有时间并且可以运行以下代码并让我知道我做错了什么，我将非常感激.一个多星期以来，我一直在反对这个过程:
I almost have a completely working drag and drop re-order within a QTreeView. Everything seems to be ok except the dropped object never appears (though I can reference it numerous different ways that proves to me that it actually exists where it should be). If anyone has a moment and could run the following code and let me know what I am doing wrong I would really appreciate it. I have been banging my head against this process for over a week now:
您应该能够只复制并运行以下代码(我在其中有一堆打印语句，似乎表明一切正常，但显然有问题):
You should be able to just copy and run the following code (I have a bunch of print statements in it that seem to indicate that everything is working correctly but obviously something is off):
import sys
from PyQt4 import QtGui
from PyQt4 import QtCore
################################################################################
class Branch(object):
"""
Basic branch/leaf node.
"""
#---------------------------------------------------------------------------
def __init__(self, name, value, parent=None):
"""
Constructor.
"""
super(Branch, self).__init__()
#name and parent are both to be stored directly as variables
self.name = name
self.parent = parent
self.value = value
#store sub-objects (usually other branches)
self.objD = dict()
self.nameL = list()
#---------------------------------------------------------------------------
def get_name(self):
"""
Getter.
"""
return self.name
#---------------------------------------------------------------------------
def get_parent(self):
"""
Returns the parent of this object.
"""
return self.parent
#---------------------------------------------------------------------------
def set_value(self, value):
"""
Generic setter for all settings.
"""
self.value = value
#---------------------------------------------------------------------------
def get_value(self):
"""
Generic getter for all settings. Returns the display value
"""
return self.value
#---------------------------------------------------------------------------
def add_child_obj(self, obj, row=None):
"""
Adds the param object to the dict and list.
"""
self.objD[obj.get_name()] = obj
if row == None:
self.nameL.append(obj.get_name())
else:
self.nameL.insert(row, obj.get_name())
print "JUST ADDED CHILD AT ROW:", self.nameL.index(obj.get_name())
#---------------------------------------------------------------------------
def remove_child_at_row(self, row):
"""
Removes the param object from the dict and list.
"""
childName = self.nameL[row]
del(self.nameL[row])
del(self.objD[childName])
#---------------------------------------------------------------------------
def get_child_count(self):
"""
Returns the number of children in this branch.
"""
return len(self.nameL)
#---------------------------------------------------------------------------
def get_child_list(self):
"""
Returns a list of the visible children names.
"""
return self.nameL
#---------------------------------------------------------------------------
def get_child_at_row(self, row):
"""
Returns a specific child object based on its ordinal (only consider
visible children).
"""
childName = self.nameL[row]
return self.objD[childName]
#---------------------------------------------------------------------------
def get_child_by_name(self, childName):
"""
Returns a specific child object based on its name.
"""
return self.objD[childName]
#---------------------------------------------------------------------------
def get_index(self):
"""
Returns this object's index position with regard to its siblings.
"""
siblingsL = self.parent.get_child_list()
return siblingsL.index(self.get_name())
################################################################################
class MyTreeView(QtGui.QTreeView):
"""
Overrides the QTreeView to handle keypress events.
"""
#---------------------------------------------------------------------------
def __init__(self, model, parent=None):
"""
Constructor for the TreeView class.
"""
super(MyTreeView, self).__init__(parent)
self.setModel(model)
################################################################################
class MyTreeModel(QtCore.QAbstractItemModel):
"""
My tree view data model
"""
#---------------------------------------------------------------------------
def __init__(self, root):
"""
Constructor for the TreeModel class
"""
super(MyTreeModel, self).__init__()
self.root = root
self.fontSize = 8
self.selection = None
#---------------------------------------------------------------------------
def columnCount(self, index=QtCore.QModelIndex()):
"""
Returns the number of columns in the treeview.
"""
return 1
#---------------------------------------------------------------------------
def rowCount(self, index=QtCore.QModelIndex()):
"""
Returns the number of children of the current index obj.
"""
if index.column() > 0:
return 0
if not index.isValid():
item = self.root
else:
item = index.internalPointer()
if item:
return item.get_child_count()
return 0
#---------------------------------------------------------------------------
def index(self, row, column, parent):
"""
Returns a QModelIndex item for the current row, column, and parent.
"""
if not self.hasIndex(row, column, parent):
return QtCore.QModelIndex()
if not parent.isValid():
parentItem = self.root
else:
parentItem = parent.internalPointer()
childItem = parentItem.get_child_at_row(row)
if childItem:
return self.createIndex(row, column, childItem)
else:
return QtCore.QModelIndex()
#---------------------------------------------------------------------------
def parent(self, index):
"""
Returns a QModelIndex item for the parent of the given index.
"""
if not index.isValid():
return QtCore.QModelIndex()
childItem = index.internalPointer()
if not childItem:
return QtCore.QModelIndex()
parentItem = childItem.get_parent()
if parentItem == self.root:
return QtCore.QModelIndex()
return self.createIndex(parentItem.get_index(), 0, parentItem)
#---------------------------------------------------------------------------
def data(self, index, role=QtCore.Qt.DisplayRole):
"""
Returns the text or formatting for a particular cell, depending on the
role supplied.
"""
#invalid indexes return invalid results
if not index.isValid():
return QtCore.QVariant()
#access the underlying referenced object
item = index.internalPointer()
#edit role displays the raw values
if role == QtCore.Qt.EditRole:
return item.get_value()
#return the data to display
if role == QtCore.Qt.DisplayRole or role == QtCore.Qt.EditRole:
return item.get_value()
return QtCore.QVariant()
#---------------------------------------------------------------------------
def headerData(self, index, orientation, role=QtCore.Qt.DisplayRole):
"""
Returns the text for the horizontal headers (parameter names)
"""
if role == QtCore.Qt.TextAlignmentRole:
if orientation == QtCore.Qt.Horizontal:
alignment = int(QtCore.Qt.AlignLeft|QtCore.Qt.AlignVCenter)
return QtCore.QVariant(alignment)
alignment = int(QtCore.Qt.AlignLeft|QtCore.Qt.AlignVCenter)
return QtCore.QVariant(alignment)
if role != QtCore.Qt.DisplayRole:
return QtCore.QVariant()
if orientation == QtCore.Qt.Horizontal:
if int(index) == 0:
return "Name"
#---------------------------------------------------------------------------
def supportedDropActions(self):
"""
We allow re-ordering.
"""
return QtCore.Qt.MoveAction
#---------------------------------------------------------------------------
def flags(self, index):
"""
Returns whether or not the current item is editable/selectable/etc.
"""
if not index.isValid():
return QtCore.Qt.ItemIsEnabled
#by default, you can't do anything
enabled = QtCore.Qt.ItemIsEnabled
selectable = QtCore.Qt.ItemIsSelectable
editable = QtCore.Qt.ItemIsEditable
draggable = QtCore.Qt.ItemIsDragEnabled
droppable = QtCore.Qt.ItemIsDropEnabled
#return our flags.
return enabled | selectable| editable| draggable| droppable
#---------------------------------------------------------------------------
def setData(self, index, value, role=QtCore.Qt.EditRole):
"""
Sets the data.
"""
#convert the value into a string
if value:
item = index.internalPointer()
item.set_value(value)
self.emit(QtCore.SIGNAL("dataChanged(QModelIndex,QModelIndex)"),
index, index)
return True
#---------------------------------------------------------------------------
def supportedDropActions(self):
"""
Only allow moves
"""
return QtCore.Qt.MoveAction
#---------------------------------------------------------------------------
def mimeTypes(self):
"""
Only accept the internal custom drop type which is plain text
"""
types = QtCore.QStringList()
types.append('text/plain')
return types
#---------------------------------------------------------------------------
def mimeData(self, index):
"""
Wrap the index up as a list of rows and columns of each
parent/grandparent/etc
"""
rc = ""
theIndex = index[0] #<- for testing purposes we only deal with 1st item
while theIndex.isValid():
rc = rc + str(theIndex.row()) + ";" + str(theIndex.column())
theIndex = self.parent(theIndex)
if theIndex.isValid():
rc = rc + ","
mimeData = QtCore.QMimeData()
mimeData.setText(rc)
return mimeData
#---------------------------------------------------------------------------
def dropMimeData(self, data, action, row, column, parentIndex):
"""
Extract the whole ancestor list of rows and columns and rebuild the
index item that was originally dragged
"""
if action == QtCore.Qt.IgnoreAction:
return True
if data.hasText():
ancestorL = str(data.text()).split(",")
ancestorL.reverse() #<- stored from the child up, we read from ancestor down
pIndex = QtCore.QModelIndex()
for ancestor in ancestorL:
srcRow = int(ancestor.split(";")[0])
srcCol = int(ancestor.split(";")[1])
itemIndex = self.index(srcRow, srcCol, pIndex)
pIndex = itemIndex
item = itemIndex.internalPointer()
parent = parentIndex.internalPointer()
#modify the row if it is -1 (we want to append to the end of the list)
if row == -1:
row = parent.get_child_count()
self.beginInsertRows(parentIndex, row-1, row)
print "------------------"
parentIndex.internalPointer().add_child_obj(item)
print "------------------"
self.endInsertRows()
print "sanity check:"
print "dragged Node", item.get_name()
print "parent Node", parent.get_name()
print "inserted at row",row
print "inserted Node:",parent.get_child_at_row(row).get_name()
print row, column
print "from index():",self.index(row, 0, parentIndex).internalPointer().get_name()
self.emit(QtCore.SIGNAL("dataChanged(QModelIndex,QModelIndex)"),
self.index(row, 0, parentIndex),
self.index(row, 0, parentIndex))
return True
#---------------------------------------------------------------------------
def insertRow(self, row, parent):
print "insertRow"
return self.insertRows(row, 1, parent)
#---------------------------------------------------------------------------
def insertRows(self, row, count, parent):
print "insertRows"
self.beginInsertRows(parent, row, (row + (count - 1)))
self.endInsertRows()
return True
#---------------------------------------------------------------------------
def removeRow(self, row, parentIndex):
print "removeRow"
return self.removeRows(row, 1, parentIndex)
#---------------------------------------------------------------------------
def removeRows(self, row, count, parentIndex):
self.beginRemoveRows(parentIndex, row, row)
print "about to remove child at row:",row
print "which is under the parent named:",parentIndex.internalPointer().get_name()
print "and whose own name is:",parentIndex.internalPointer().get_child_at_row(row).get_name()
parentIndex.internalPointer().remove_child_at_row(row)
self.endRemoveRows()
return True
class Ui_MainWindow(object):
def printChildren(self, item):
print item.name
for child in item.get_child_list():
self.printChildren(item.get_child_by_name(child))
def printit(self):
self.printChildren(self.root)
def setupUi(self, MainWindow):
root = Branch("root", "root", QtCore.QVariant)
item1 = Branch("ITEM1","ITEM1",root)
item2 = Branch("ITEM2","ITEM2",root)
item3 = Branch("ITEM3","ITEM3",root)
root.add_child_obj(item1)
root.add_child_obj(item2)
root.add_child_obj(item3)
item1a = Branch("thinga","thinga",item1)
item1b = Branch("thingb","thingb",item1)
item1.add_child_obj(item1a)
item1.add_child_obj(item1b)
item2a = Branch("thingc","thingc",item2)
item2b = Branch("thingd","thingd",item2)
item2.add_child_obj(item2a)
item2.add_child_obj(item2b)
item3a = Branch("thinge","thinge",item3)
item3b = Branch("thingf","thingf",item3)
item3.add_child_obj(item3a)
item3.add_child_obj(item3b)
item1a1 = Branch("___A","___A",item1a)
item1a2 = Branch("___B","___B",item1a)
item1a.add_child_obj(item1a1)
item1a.add_child_obj(item1a2)
item1b1 = Branch("___C","___C",item1b)
item1b2 = Branch("___D","___D",item1b)
item1b.add_child_obj(item1b1)
item1b.add_child_obj(item1b2)
item2a1 = Branch("___E","___E",item2a)
item2a2 = Branch("___F","___F",item2a)
item2a.add_child_obj(item2a1)
item2a.add_child_obj(item2a2)
item2b1 = Branch("___G","___G",item2b)
item2b2 = Branch("___H","___H",item2b)
item2b.add_child_obj(item2b1)
item2b.add_child_obj(item2b2)
item3a1 = Branch("___J","___J",item3a)
item3a2 = Branch("___K","___K",item3a)
item3a.add_child_obj(item3a1)
item3a.add_child_obj(item3a2)
item3b1 = Branch("___L","___L",item3b)
item3b2 = Branch("___M","___M",item3b)
item3b.add_child_obj(item3b1)
item3b.add_child_obj(item3b2)
self.root = root
MainWindow.setObjectName("MainWindow")
MainWindow.resize(600, 400)
self.centralwidget = QtGui.QWidget(MainWindow)
self.centralwidget.setObjectName("centralwidget")
self.horizontalLayout = QtGui.QHBoxLayout(self.centralwidget)
self.horizontalLayout.setObjectName("horizontalLayout")
self.myModel = MyTreeModel(root)
self.treeView = MyTreeView(self.myModel, self.centralwidget)
self.treeView.setObjectName("treeView")
self.treeView.dragEnabled()
self.treeView.acceptDrops()
self.treeView.showDropIndicator()
self.treeView.setDragDropMode(QtGui.QAbstractItemView.InternalMove)
self.treeView.expandAll()
self.horizontalLayout.addWidget(self.treeView)
self.btn = QtGui.QPushButton('print', MainWindow)
MainWindow.connect(self.btn, QtCore.SIGNAL("clicked()"), self.printit)
self.horizontalLayout.addWidget(self.btn)
MainWindow.setCentralWidget(self.centralwidget)
self.menubar = QtGui.QMenuBar(MainWindow)
self.menubar.setGeometry(QtCore.QRect(0, 0, 600, 22))
self.menubar.setObjectName("menubar")
MainWindow.setMenuBar(self.menubar)
self.statusbar = QtGui.QStatusBar(MainWindow)
self.statusbar.setObjectName("statusbar")
MainWindow.setStatusBar(self.statusbar)
self.retranslateUi(MainWindow)
QtCore.QMetaObject.connectSlotsByName(MainWindow)
def retranslateUi(self, MainWindow):
MainWindow.setWindowTitle(QtGui.QApplication.translate("MainWindow", "MainWindow", None, QtGui.QApplication.UnicodeUTF8))
if __name__ == "__main__":
app = QtGui.QApplication(sys.argv)
MainWindow = QtGui.QMainWindow()
ui = Ui_MainWindow()
ui.setupUi(MainWindow)
MainWindow.show()
sys.exit(app.exec_())
推荐答案
这并不能解决所有问题，但是将 dropMimeData() 更改为以下内容至少可以移动叶子项目.
This doesn't solve all the problems, but changing dropMimeData() to the following will at least allow moving leaf items.
self.beginInsertRows(parentIndex, row, row)
parentIndex.internalPointer().add_child_obj(Branch(item.get_name(), item.get_value(), parent), row)
self.endInsertRows()
拖放操作实际上是两个步骤，插入(在 dropMimeData 中完成)和删除(通过移动拖动操作自动完成).上面的更改插入了一个新项目，而不是尝试插入一个已经在模型中并且在插入发生后将从旧位置删除的项目.
A drag-drop operation is effectively two steps, an insert (done in dropMimeData) and a remove (done automatically by the Move drag operation). The changes above insert a new item rather than trying to insert an item which is already in the model and which will be removed from the old location after the insert occurs.
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