如何使用 PYQT QAbstractItemModel 正确处理拖放 [英] How to handle Drag and Drop Properly using PYQT QAbstractItemModel
问题描述
这是我在疯狂使用 TreeView/Model 两天后得到的代码.这个主题似乎比我想象的要广泛得多.我几乎不能花这么多时间来创建一个单一的小部件.反正.已启用 TreeView 项目的拖放功能.但除了一些有趣的打印输出之外，没有太多.双击一个项目允许用户输入一个不会被选中的新项目名称.
Here is a code I ended up after two days of TreeView/Model madness. The subject appeared to be much more broad than I thought. I barely can spend so much time creating a singe widget. Anyway. The drag-and-drop functionality of TreeView items has been enabled. But other than few interesting printout there is not much there. The double click on an item allows the user to enter a new item name which won't be picked up.
用户可以通过拖放、创建/复制/删除和重命名来操作 TreeView 项目.TreeView 项目在通过点击打印"按钮(而不是 os.makedirs())在驱动器上创建之前以分层方式表示目录或文件夹，该工具仍然只是将每个目录打印为字符串.
我会说我对结果很满意.感谢 hackyday 以及所有回答和帮助我解决问题的人.
The user can manipulate the TreeView items by drag and dropping, creating/duplicating/deleting and renaming. The TreeView items are representing the directories or folders in hierarchical fashion before they are created on a drive by hitting 'Print' button (instead of os.makedirs() the tool still simply prints each directory as a string.
I would say I am pretty happy with the result. Thanks to hackyday and to everyone who responded and helped with my questions.
最后的几个愿望...
- 我希望 PrintOut() 方法将使用更优雅、更智能的函数来循环遍历 TreeView 项以构建传递给 make_dirs_from_dict() 方法的字典.
愿望编号 02:
- 我希望删除项目会更稳定.由于某种未知原因，工具在第三次/第四次删除"按钮点击时崩溃.到目前为止，我无法追踪问题.
愿望编号 03:3. 祝大家一切顺利，感谢您的帮助:
A wish number 03: 3. I wish everyone the best and thanks for your help :
import sys, os
from PyQt4 import QtGui, QtCore
from PyQt4.QtGui import *
from PyQt4.QtCore import *
from copy import deepcopy
import cPickle
class TreeItem(object):
def __init__(self, name, parent=None):
self.name = QtCore.QString(name)
self.parent = parent
self.children = []
self.setParent(parent)
def setParent(self, parent):
if parent != None:
self.parent = parent
self.parent.appendChild(self)
else: self.parent = None
def appendChild(self, child):
self.children.append(child)
def childAtRow(self, row):
if len(self.children)>row:
return self.children[row]
def rowOfChild(self, child):
for i, item in enumerate(self.children):
if item == child: return i
return -1
def removeChild(self, row):
value = self.children[row]
self.children.remove(value)
return True
def __len__(self):
return len(self.children)
class TreeModel(QtCore.QAbstractItemModel):
def __init__(self):
QtCore.QAbstractItemModel.__init__(self)
self.columns = 1
self.clickedItem=None
self.root = TreeItem('root', None)
levelA = TreeItem('levelA', self.root)
levelB = TreeItem('levelB', levelA)
levelC1 = TreeItem('levelC1', levelB)
levelC2 = TreeItem('levelC2', levelB)
levelC3 = TreeItem('levelC3', levelB)
levelD = TreeItem('levelD', levelC3)
levelE = TreeItem('levelE', levelD)
levelF = TreeItem('levelF', levelE)
def nodeFromIndex(self, index):
return index.internalPointer() if index.isValid() else self.root
def index(self, row, column, parent):
node = self.nodeFromIndex(parent)
return self.createIndex(row, column, node.childAtRow(row))
def parent(self, child):
# print '\n parent(child)', child # PyQt4.QtCore.QModelIndex
if not child.isValid(): return QModelIndex()
node = self.nodeFromIndex(child)
if node is None: return QModelIndex()
parent = node.parent
if parent is None: return QModelIndex()
grandparent = parent.parent
if grandparent==None: return QModelIndex()
row = grandparent.rowOfChild(parent)
assert row != - 1
return self.createIndex(row, 0, parent)
def rowCount(self, parent):
node = self.nodeFromIndex(parent)
if node is None: return 0
return len(node)
def columnCount(self, parent):
return self.columns
def data(self, index, role):
if role == Qt.DecorationRole:
return QVariant()
if role == Qt.TextAlignmentRole:
return QVariant(int(Qt.AlignTop | Qt.AlignLeft))
if role != Qt.DisplayRole:
return QVariant()
node = self.nodeFromIndex(index)
if index.column() == 0:
return QVariant(node.name)
elif index.column() == 1:
return QVariant(node.state)
elif index.column() == 2:
return QVariant(node.description)
else: return QVariant()
def supportedDropActions(self):
return Qt.CopyAction | Qt.MoveAction
def flags(self, index):
defaultFlags = QAbstractItemModel.flags(self, index)
if index.isValid(): return Qt.ItemIsEditable | Qt.ItemIsDragEnabled | Qt.ItemIsDropEnabled | defaultFlags
else: return Qt.ItemIsDropEnabled | defaultFlags
def setData(self, index, value, role):
if role == Qt.EditRole:
if value.toString() and len(value.toString())>0:
self.nodeFromIndex(index).name = value.toString()
self.dataChanged.emit(index, index)
return True
def mimeTypes(self):
return ['bstream', 'text/xml']
def mimeData(self, indexes):
mimedata = QtCore.QMimeData()
bstream = cPickle.dumps(self.nodeFromIndex(indexes[0]))
mimedata.setData('bstream', bstream)
return mimedata
def dropMimeData(self, mimedata, action, row, column, parentIndex):
if action == Qt.IgnoreAction: return True
droppedNode=cPickle.loads(str(mimedata.data('bstream')))
droppedIndex = self.createIndex(row, column, droppedNode)
parentNode = self.nodeFromIndex(parentIndex)
newNode = deepcopy(droppedNode)
newNode.setParent(parentNode)
self.insertRow(len(parentNode)-1, parentIndex)
self.emit(SIGNAL("dataChanged(QModelIndex,QModelIndex)"), parentIndex, parentIndex)
return True
def insertRow(self, row, parent):
return self.insertRows(row, 1, parent)
def insertRows(self, row, count, parent):
self.beginInsertRows(parent, row, (row + (count - 1)))
self.endInsertRows()
return True
def removeRow(self, row, parentIndex):
return self.removeRows(row, 1, parentIndex)
def removeRows(self, row, count, parentIndex):
self.beginRemoveRows(parentIndex, row, row)
node = self.nodeFromIndex(parentIndex)
node.removeChild(row)
self.endRemoveRows()
return True
class GUI(QtGui.QDialog):
def build(self, myWindow):
myWindow.resize(600, 400)
self.myWidget = QWidget(myWindow)
self.boxLayout = QtGui.QVBoxLayout(self.myWidget)
self.treeView = QtGui.QTreeView()
self.treeModel = TreeModel()
self.treeView.setModel(self.treeModel)
self.treeView.expandAll()
self.treeView.setDragDropMode(QtGui.QAbstractItemView.InternalMove)
self.treeView.connect(self.treeView.model(), SIGNAL("dataChanged(QModelIndex,QModelIndex)"), self.onDataChanged)
QtCore.QObject.connect(self.treeView, QtCore.SIGNAL("clicked (QModelIndex)"), self.treeItemClicked)
self.boxLayout.addWidget(self.treeView)
self.PrintButton= QtGui.QPushButton("Print")
self.PrintButton.clicked.connect(self.PrintOut)
self.boxLayout.addWidget(self.PrintButton)
self.DeleteButton= QtGui.QPushButton("Delete")
self.DeleteButton.clicked.connect(self.DeleteLevel)
self.boxLayout.addWidget(self.DeleteButton)
self.insertButton= QtGui.QPushButton("Insert")
self.insertButton.clicked.connect(self.insertLevel)
self.boxLayout.addWidget(self.insertButton)
self.duplicateButton= QtGui.QPushButton("Duplicate")
self.duplicateButton.clicked.connect(self.duplicateLevel)
self.boxLayout.addWidget(self.duplicateButton)
myWindow.setCentralWidget(self.myWidget)
def make_dirs_from_dict(self, dirDict, current_dir='/'):
for key, val in dirDict.items():
#os.mkdir(os.path.join(current_dir, key))
print "\t\t Creating directory: ", os.path.join(current_dir, key)
if type(val) == dict:
self.make_dirs_from_dict(val, os.path.join(current_dir, key))
def PrintOut(self):
result_dict = {}
for a1 in self.treeView.model().root.children:
result_dict[str(a1.name)]={}
for a2 in a1.children:
result_dict[str(a1.name)][str(a2.name)]={}
for a3 in a2.children:
result_dict[str(a1.name)][str(a2.name)][str(a3.name)]={}
for a4 in a3.children:
result_dict[ str(a1.name)][str(a2.name)][str(a3.name)][str(a4.name)]={}
for a5 in a4.children:
result_dict[ str(a1.name)][str(a2.name)][str(a3.name)][str(a4.name)][str(a5.name)]={}
for a6 in a5.children:
result_dict[str(a1.name)][str(a2.name)][str(a3.name)][str(a4.name)][str(a5.name)][str(a6.name)]={}
for a7 in a6.children:
result_dict[str(a1.name)][str(a2.name)][str(a3.name)][str(a4.name)][str(a5.name)][str(a6.name)][str(a7.name)]={}
self.make_dirs_from_dict(result_dict)
def DeleteLevel(self):
if len(self.treeView.selectedIndexes())==0: return
currentIndex = self.treeView.selectedIndexes()[0]
currentRow=currentIndex.row()
currentColumn=currentIndex.column()
currentNode = currentIndex.internalPointer()
parentNode = currentNode.parent
parentIndex = self.treeView.model().createIndex(currentRow, currentColumn, parentNode)
print '\n\t\t\t CurrentNode:', currentNode.name, ', ParentNode:', currentNode.parent.name, ', currentColumn:', currentColumn, ', currentRow:', currentRow
# self.treeView.model().removeRow(len(parentNode)-1, parentIndex)
self.treeView.model().removeRows(currentRow, 1, parentIndex )
#self.treeView.model().removeRow(len(parentNode), parentIndex)
#self.treeView.model().emit(SIGNAL("dataChanged(QModelIndex,QModelIndex)"), parentIndex, parentIndex)
def insertLevel(self):
if len(self.treeView.selectedIndexes())==0: return
currentIndex = self.treeView.selectedIndexes()[0]
currentNode = currentIndex.internalPointer()
newItem = TreeItem('Brand New', currentNode)
self.treeView.model().insertRow(len(currentNode)-1, currentIndex)
self.treeView.model().emit(SIGNAL("dataChanged(QModelIndex,QModelIndex)"), currentIndex, currentIndex)
def duplicateLevel(self):
if len(self.treeView.selectedIndexes())==0: return
currentIndex = self.treeView.selectedIndexes()[0]
currentRow=currentIndex.row()
currentColumn=currentIndex.column()
currentNode=currentIndex.internalPointer()
parentNode=currentNode.parent
parentIndex=self.treeView.model().createIndex(currentRow, currentColumn, parentNode)
parentRow=parentIndex.row()
parentColumn=parentIndex.column()
newNode = deepcopy(currentNode)
newNode.setParent(parentNode)
self.treeView.model().insertRow(len(parentNode)-1, parentIndex)
self.treeView.model().emit(SIGNAL("dataChanged(QModelIndex,QModelIndex)"), parentIndex, parentIndex)
print '\n\t\t\t CurrentNode:', currentNode.name, ', ParentNode:', parentNode.name, ', currentColumn:', currentColumn, ', currentRow:', currentRow, ', parentColumn:', parentColumn, ', parentRow:', parentRow
self.treeView.update()
self.treeView.expandAll()
def treeItemClicked(self, index):
print "\n clicked item ----------->", index.internalPointer().name
def onDataChanged(self, indexA, indexB):
print "\n onDataChanged NEVER TRIGGERED! ####################### \n ", index.internalPointer().name
self.treeView.update(indexA)
self.treeView.expandAll()
self.treeView.expanded()
if __name__ == '__main__':
app = QtGui.QApplication(sys.argv)
myWindow = QMainWindow()
myGui = GUI()
myGui.build(myWindow)
myWindow.show()
sys.exit(app.exec_())
推荐答案
我不完全确定您要实现的目标，但听起来您想在放置操作中检索拖动的项目，并双击保存一个新的节点名称.
I am not totally sure what you are trying to achieve, but it sounds like you want to retrieve the dragged item in the drop operation, and have double click save a new node name.
首先，您需要将拖动的项目保存到mimeData.目前，您只保存字符串 'mimeData'，它不会告诉您太多信息.它保存为的 mimeType 字符串(这里我使用了 'bstream')实际上可以是任何东西.只要它与您用来检索数据的内容相匹配，并且在模型的 mimeTypes 方法返回的列表中.要传递对象本身，您必须首先对其进行序列化(您也可以将对象转换为 xml，如果您打算这样做的话)，因为它不是 mime 数据的标准类型.
Firstly, you need to save the dragged item into the mimeData. Currently, you are only saving the string 'mimeData', which doesn't tell you much. The mimeType string that it is saved as (here I used 'bstream') can actually be anything. As long as it matches what you use to retrieve the data, and is in the list returned by the mimeTypes method of the model. To pass the object itself, you must first serialize it (you can convert your object to xml alternatively, if that was something you are planning on doing), since it is not a standard type for mime data.
为了保存您输入的数据，您必须重新实现模型的 setData 方法并定义 EditRole 的行为.
In order for the data you enter to be saved you must re-implement the setData method of the model and define behaviour for EditRole.
相关方法:
def setData(self, index, value, role):
if role == Qt.EditRole:
self.nodeFromIndex(index).name = value
self.dataChanged.emit(index, index)
return True
def mimeTypes(self):
return ['bstream', 'text/xml']
def mimeData(self, indexes):
mimedata = QtCore.QMimeData()
# assuming single dragged item ...
# only pass the node name
# mimedata.setData('text/xml', str(self.nodeFromIndex(indexes[0]).name))
# pass the entire object
bstream = cPickle.dumps(self.nodeFromIndex(indexes[0]))
mimedata.setData('bstream', bstream)
return mimedata
def dropMimeData(self, mimedata, action, row, column, parentIndex):
if action == Qt.IgnoreAction: return True
parentNode = self.nodeFromIndex(parentIndex)
# data = mimedata.data('text/xml')
data = cPickle.loads(str(mimedata.data('bstream')))
print '\n\t incoming row number:', row, ', incoming column:', column, \
', action:', action, ' mimedata: ', data.name
print "\n\t Item's name on which drop occurred: ", parentNode.name, \
', number of its childred:', len(parentNode.children)
if len(parentNode.children)>0: print '\n\t zero indexed child:', parentNode.children[0].name
return True
这是您更新的大量代码，但我会强调您强调的要点.避免在模型类之外调用 createIndex.这是 Qt 中受保护的方法；Python 不强制执行私有/受保护的变量或方法，但是当使用来自其他语言的库时，我会尽量尊重类的预期组织和对它们的访问.
That is a lot of code you updated, but I will oblige on the points you highlighted. Avoid calling createIndex outside of the model class. This is a protected method in Qt; Python doesn't enforce private/protected variables or methods, but when using a library from another language that does, I try to respect the intended organization of the classes, and access to them.
该模型的目的是为您的数据提供一个接口.您应该使用模型的 index、data、parent 等公共函数访问它.要获取给定索引的父项，请使用该索引(或模型)的 parent 函数，该函数也将返回 QModelIndex.这样，您就不必浏览(或确实了解)数据的内部结构.这就是我在 deleteLevel 方法中所做的.
The purpose of the model is to provide an interface to your data. You should access it using the index, data, parent etc. public functions of the model. To get the parent of a given index, use that index's (or the model's) parent function, which will also return a QModelIndex. This way, you don't have to go through (or indeed know about) the internal structure of the data. This is what I did in the deleteLevel method.
来自 qt docs:
为了确保数据的表示与其访问方式保持分离，引入了模型索引的概念.模型可以获取的每条信息都由模型索引表示……只有模型需要知道如何获取数据，模型管理的数据类型可以相当笼统地定义.
To ensure that the representation of the data is kept separate from the way it is accessed, the concept of a model index is introduced. Each piece of information that can be obtained via a model is represented by a model index... only the model needs to know how to obtain data, and the type of data managed by the model can be defined fairly generally.
此外，您可以使用递归来简化打印方法.
Also, you can use recursion to simplify the print method.
def printOut(self):
result_dict = dictify(self.treeView.model().root)
self.make_dirs_from_dict(result_dict)
def deleteLevel(self):
if len(self.treeView.selectedIndexes()) == 0:
return
currentIndex = self.treeView.selectedIndexes()[0]
self.treeView.model().removeRow(currentIndex.row(), currentIndex.parent())
我把这个和课堂分开了
def dictify(node):
kids = {}
for child in node.children:
kids.update(dictify(child))
return {str(node.name): kids}
这篇关于如何使用 PYQT QAbstractItemModel 正确处理拖放的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
