问题
Im trying to build a little list of entries within a QTreeView, and based on the example posted here, I got it to delete any child items via the right click context menu i added. but when i delete it the parent tree i have collapses. And in some cases if i delete a certain item in a certain order this crashes
My understanding is that this is because upon deletion the indices of the items changes, and to prevent that QtCore.QPersistentModelIndex() can be utilized according to this thread: How to delete multiple rows in a QTableView widget?
Although that example uses a QStandardItemModel(), since mine uses a QAbstractItemModel() how can I implement a similar concept, and also prevent this from crashing...?
import sys
from functools import partial
from PyQt4 import QtGui, QtCore
HORIZONTAL_HEADERS = ("Asset Name", "Date Added")
class AssetClass(object):
'''
a trivial custom data object
'''
def __init__(self, **kwargs):
if not kwargs.get('name') or not kwargs.get('type'):
return
self.name = kwargs.get('name')
self.date_added = kwargs.get('date_added')
self.type = kwargs.get('type')
def __repr__(self):
return "%s - %s %s" % (self.type, self.name, self.date_added)
class TreeItem(object):
'''
a python object used to return row/column data, and keep note of
it's parents and/or children
'''
def __init__(self, asset, header, parent_item):
self.asset = asset
self.parent_item = parent_item
self.header = header
self.child_items = []
def appendChild(self, item):
self.child_items.append(item)
def removeChild(self, item):
print 'removeChild: item is %s' % item
print 'removeChild: self.child_items is %s' % self.child_items
self.child_items.remove(item)
def child(self, row):
return self.child_items[row]
def childCount(self):
return len(self.child_items)
def columnCount(self):
return 2
def data(self, column):
if self.asset == None:
if column == 0:
return QtCore.QVariant(self.header)
if column == 1:
return QtCore.QVariant("")
else:
if column == 0:
return QtCore.QVariant(self.asset.name)
if column == 1:
return QtCore.QVariant(self.asset.date_added)
return QtCore.QVariant()
def parent(self):
return self.parent_item
def row(self):
if self.parent_item:
return self.parent_item.child_items.index(self)
return 0
class TreeModel(QtCore.QAbstractItemModel):
'''
a model to display a few names, ordered by sex
'''
def __init__(self, parent=None):
super(TreeModel, self).__init__(parent)
self.assets = []
model_data = (("VEHICLE", "Truck", 'May 27th, 2020'),
("VEHICLE", "Car", 'May 25th, 2020'),
("CHARACTER", "Peter", 'May 27th, 2020'),
("CHARACTER", "Rachel", 'May 29th, 2020'),
("PROP", "Chair", 'May 27th, 2020'),
("PROP", "Axe", 'May 17th, 2020'))
for asset_type, name, date in model_data:
asset = AssetClass(type=asset_type, name=name, date_added=date)
self.assets.append(asset)
self.rootItem = TreeItem(None, "ALL", None)
self.parents = {0: self.rootItem}
self.setupModelData()
def columnCount(self, parent=None):
if parent and parent.isValid():
return parent.internalPointer().columnCount()
else:
return len(HORIZONTAL_HEADERS)
def data(self, index, role):
if not index.isValid():
return QtCore.QVariant()
item = index.internalPointer()
if role == QtCore.Qt.DisplayRole:
return item.data(index.column())
if role == QtCore.Qt.UserRole:
if item:
return item.asset
return QtCore.QVariant()
def headerData(self, column, orientation, role):
if (orientation == QtCore.Qt.Horizontal and
role == QtCore.Qt.DisplayRole):
try:
return QtCore.QVariant(HORIZONTAL_HEADERS[column])
except IndexError:
pass
return QtCore.QVariant()
def index(self, row, column, parent):
if not self.hasIndex(row, column, parent):
return QtCore.QModelIndex()
if not parent.isValid():
parent_item = self.rootItem
else:
parent_item = parent.internalPointer()
childItem = parent_item.child(row)
if childItem:
return self.createIndex(row, column, childItem)
else:
return QtCore.QModelIndex()
def parent(self, index):
if not index.isValid():
return QtCore.QModelIndex()
childItem = index.internalPointer()
if not childItem:
return QtCore.QModelIndex()
parent_item = childItem.parent()
if parent_item == self.rootItem:
return QtCore.QModelIndex()
return self.createIndex(parent_item.row(), 0, parent_item)
def rowCount(self, parent=QtCore.QModelIndex()):
if parent.column() > 0:
return 0
if not parent.isValid():
p_Item = self.rootItem
else:
p_Item = parent.internalPointer()
return p_Item.childCount()
def setupModelData(self):
for asset in self.assets:
asset_type = asset.type
if not self.parents.has_key(asset_type):
new_parent = TreeItem(None, asset_type, self.rootItem)
self.rootItem.appendChild(new_parent)
self.parents[asset_type] = new_parent
print 'self.parents: ', self.parents
parent_item = self.parents[asset_type]
new_item = TreeItem(asset, "", parent_item)
parent_item.appendChild(new_item)
def addSubRow(self, new_asset):
asset_type, name, date = new_asset
asset = AssetClass(type=asset_type, name=name, date_added=date)
parent_item = self.parents[asset_type]
already_exists = False
for child in parent_item.child_items:
if child.asset.name == name and child.asset.type == asset_type:
already_exists = True
if already_exists:
print 'this asset already exists'
return
new_item = TreeItem(asset, "", parent_item)
parent_item.appendChild(new_item)
def removeRow(self, rowIndexes):
child_tree_item = rowIndexes[0].internalPointer()
asset_type = rowIndexes[0].parent().data().toString()
parent_item = self.parents[str(asset_type)]
# hint to keep the tree open after deleting: https://stackoverflow.com/questions/48121393/how-to-delete-multiple-rows-in-a-qtableview-widget
self.beginRemoveRows(QtCore.QModelIndex(), rowIndexes[0].row(), rowIndexes[0].row() + 1)
parent_item.removeChild(child_tree_item)
self.endRemoveRows()
def searchModel(self, asset):
'''
get the modelIndex for a given appointment
'''
def searchNode(node):
'''
a function called recursively, looking at all nodes beneath node
'''
for child in node.child_items:
print child.childCount()
if asset == child.asset:
index = self.createIndex(child.row(), 0, child)
return index
if child.childCount() > 0:
result = searchNode(child)
if result:
return result
retarg = searchNode(self.parents[0])
print retarg
return retarg
def findAssetName(self, name):
app = None
for asset in self.assets:
print asset.name
if asset.name == name:
app = asset
break
if app != None:
index = self.searchModel(app)
return (True, index)
return (False, None)
class TreeView(QtGui.QTreeView):
right_button_clicked = QtCore.pyqtSignal(list, int)
def __init__(self, parent=None):
super(TreeView, self).__init__(parent)
# self.clicked.connect(self.on_treeView_clicked)
self.setContextMenuPolicy(QtCore.Qt.CustomContextMenu)
self.customContextMenuRequested.connect(self.openMenu)
def selectedRows(self):
rows = []
for index in self.selectedIndexes():
if index.column() == 0:
rows.append(index.row())
print type(rows)
return rows
def openMenu(self, position):
indexes = self.selectedIndexes()
if len(indexes) > 0:
level = 0
index = indexes[0]
while index.parent().isValid():
index = index.parent()
level += 1
menu = QtGui.QMenu()
editMenu = None
if level == 0:
editMenu = QtGui.QAction("Edit person", self)
menu.addAction(editMenu)
elif level == 1:
editMenu = QtGui.QAction("Delete", self)
menu.addAction(editMenu)
elif level == 2:
editMenu = QtGui.QAction("Edit object", self)
menu.addAction(editMenu)
if editMenu:
editMenu.triggered.connect(partial(self._on_right_click, indexes, level))
menu.exec_(self.viewport().mapToGlobal(position))
def _on_right_click(self, indexes, level):
self.right_button_clicked.emit(indexes, level)
def delete_test(self):
print 'addButton clicked'
new_asset = ("CHARACTER", "Smith", 'May 28th, 2020')
asset_type, name, date = new_asset
asset = AssetClass(type=asset_type, name=name, date_added=date)
parent_item = self.tree_view.model().parents[asset_type]
already_exists = False
for child in parent_item.child_items:
if child.asset.name == name and child.asset.type == asset_type:
already_exists = True
if already_exists:
print 'this asset already exists'
return
new_item = TreeItem(asset, "", parent_item)
parent_item.appendChild(new_item)
self.tree_view.model().layoutChanged.emit()
class Dialog(QtGui.QDialog):
add_signal = QtCore.pyqtSignal(int)
def __init__(self, parent=None):
super(Dialog, self).__init__(parent)
self.setMinimumSize(300, 150)
self.model = TreeModel()
layout = QtGui.QVBoxLayout(self)
self.tree_view = TreeView(self)
self.tree_view.setModel(self.model)
self.tree_view.setAlternatingRowColors(True)
self.tree_view.right_button_clicked.connect(self.deleteButtonClicked)
layout.addWidget(self.tree_view)
label = QtGui.QLabel("Search for the following person")
layout.addWidget(label)
buts = []
frame = QtGui.QFrame(self)
layout2 = QtGui.QHBoxLayout(frame)
for asset in self.model.assets:
but = QtGui.QPushButton(asset.name, frame)
buts.append(but)
layout2.addWidget(but)
QtCore.QObject.connect(but, QtCore.SIGNAL("clicked()"), self.but_clicked)
layout.addWidget(frame)
self.add_button = QtGui.QPushButton("Add \"Character - Smith\"")
layout.addWidget(self.add_button)
QtCore.QObject.connect(self.add_button, QtCore.SIGNAL("clicked()"), self.addButtonClicked)
self.delete_button = QtGui.QPushButton("Delete Selected")
layout.addWidget(self.delete_button)
QtCore.QObject.connect(self.delete_button, QtCore.SIGNAL("clicked()"), self.tree_view.clearSelection)
self.but = QtGui.QPushButton("Clear Selection")
layout.addWidget(self.but)
QtCore.QObject.connect(self.but, QtCore.SIGNAL("clicked()"), self.tree_view.clearSelection)
QtCore.QObject.connect(self.tree_view, QtCore.SIGNAL("clicked (QModelIndex)"), self.row_clicked)
def row_clicked(self, index):
'''
when a row is clicked... show the name
'''
print 'row_clicked index type: %s' % index
print self.tree_view.model().data(index, QtCore.Qt.UserRole)
def but_clicked(self):
'''
when a name button is clicked, I iterate over the model,
find the person with this name, and set the treeviews current item
'''
name = self.sender().text()
print "BUTTON CLICKED:", name
result, index = self.model.findAssetName(name)
if result:
if index:
self.tree_view.setCurrentIndex(index)
return
self.tree_view.clearSelection()
def addButtonClicked(self):
print 'addButton clicked'
new_asset = ("CHARACTER", "Smith", 'May 28th, 2020')
self.tree_view.model().addSubRow(new_asset)
self.tree_view.model().layoutChanged.emit()
@QtCore.pyqtSlot(list, int)
def deleteButtonClicked(self, indexes, level):
print 'deleteButton clicked'
self.tree_view.model().removeRow(indexes)
self.tree_view.model().layoutChanged.emit()
if __name__ == "__main__":
app = QtGui.QApplication(sys.argv)
dialog = Dialog()
dialog.show()
sys.exit(app.exec_())
回答1:
beginRemoveRows() expects the QModelIndex, which is the parent of the QModelIndex to be removed, as the first parameter. Regarding the example that you indicate in the comments of your code in the table type models, the indexes do not have a parent, so it is passed an invalid QModelIndex.
def removeRow(self, rowIndexes):
child_tree_item = rowIndexes[0].internalPointer()
parent_item = child_tree_item.parent()
self.beginRemoveRows(
rowIndexes[0].parent(), rowIndexes[0].row(), rowIndexes[0].row() + 1
)
parent_item.removeChild(child_tree_item)
self.endRemoveRows()
来源：https://stackoverflow.com/questions/63367912/qtreeview-qabstractitemmodel-parent-collapses-after-deleting-item-and-sometimes