On Tue, Mar 10, 2009 at 8:03 PM, Darren Dale <dsdal...@gmail.com> wrote:
> On Tue, Mar 10, 2009 at 5:28 PM, Darren Dale <dsdal...@gmail.com> wrote:
>
>> Hello,
>>
>> I am trying to create a simple model and view for a simple nested
>> dictionary like d:
>>
>> c1 = {'id':1, 'description':'child 1'}
>> c2 = {'id':2, 'description':'child 2'}
>> d = {'id':0, 'description':'whatever', 'children':[c1, c2]}
>>
>> I have a self-contained, relatively simple script attached. When I run it
>> and try to open the top-level entry by clicking on the +, I get errors like:
>>
>> Traceback (most recent call last):
>> File "tree_test.py", line 111, in parent
>> parent = index.internalPointer().parent
>> AttributeError: 'ItemDataRole' object has no attribute 'parent'
>> Traceback (most recent call last):
>> File "tree_test.py", line 111, in parent
>> parent = index.internalPointer().parent
>> AttributeError: parent
>>
>> Traceback (most recent call last):
>> File "tree_test.py", line 111, in parent
>> parent = index.internalPointer().parent
>> AttributeError: 'exceptions.AttributeError' object has no attribute
>> 'parent'
>> Bus error
>>
>> sometimes I get a different error:
>>
>> Traceback (most recent call last):
>> File "tree_test.py", line 111, in parent
>> parent = index.internalPointer().parent
>> AttributeError: 'ItemDataRole' object has no attribute 'parent'
>> Segmentation fault
>>
>>
>> Could anyone please help me understand what is happening? I dont
>> understand why index.internalPointer() is returning an ItemDataRole object
>> or an exceptions.AttributeError object.
>>
>> Im running Qt-4.5.0, sip-4.7.9 and PyQt-4.4.4.
>
>
> I just checked this script on a 64-bit kubuntu intrepid system with
> qt-4.4.3 and PyQt4-4.4.4, sip-4.7.9 and python-2.5.2 and I get segfaults
> here too. I guess that rules out some issue specific to qt-4.5.
>
I've been looking into this some more, and I managed to isolate the problem.
The attached script runs ok when CACHE_CHILDREN = True, but it will yield
bus errors or segfaults when CACHE_CHILDREN is False. Unfortunately, I am
modeling an object that can be changed elsewhere in the application, so it
is imperitive that I am able to recalculate the child list. I have done the
exact same thing using Enthought's Traits package with the Traits Qt4
backend, and never saw segfaults, so I know it must be possible.
Please, can anyone suggest why this causes a crash?
Thank you,
Darren
"""
"""
from PyQt4 import QtCore, QtGui
CACHE_CHILDREN = True
class TreeItem(object):
def __init__(self, data, parent=None):
self._parent = parent
self._data = data
@property
def children(self):
return []
@property
def columns(self):
return [self.data['id'], self.data['description']]
@property
def data(self):
return self._data
@property
def parent(self):
return self._parent
@property
def row(self):
if self.parent:
return self.parent.children.index(self)
return 0
@property
def rows(self):
return len(self.children)
class RootItem(TreeItem):
def __init__(self):
self._parent = None
self._children = []
@property
def children(self):
return self._children
@property
def columns(self):
return ['ID', 'Description']
def appendChild(self, child):
self._children.append(child)
class DictItem(TreeItem):
def __init__(self, data, parent=None):
super(DictItem, self).__init__(data, parent)
@property
def children(self):
if CACHE_CHILDREN:
try:
return self._children
except AttributeError:
self._children = [TreeItem(child, self)
for child in self.data['children']]
return self._children
else:
return [TreeItem(child, self) for child in self.data['children']]
class FileModel(QtCore.QAbstractItemModel):
"""
"""
def __init__(self, parent=None):
super(FileModel, self).__init__(parent)
self._rootItem = RootItem()
@property
def rootItem(self):
return self._rootItem
def columnCount(self, parent):
if parent.isValid():
return len(parent.internalPointer().columns)
else:
return len(self.rootItem.columns)
def data(self, index, role):
if not index.isValid() or role != QtCore.Qt.DisplayRole:
return QtCore.QVariant()
item = index.internalPointer()
return QtCore.QVariant(item.columns[index.column()])
def headerData(self, section, orientation, role):
if orientation == QtCore.Qt.Horizontal and \
role == QtCore.Qt.DisplayRole:
return QtCore.QVariant(self.rootItem.columns[section])
return QtCore.QVariant()
def index(self, row, column, parent):
if not self.hasIndex(row, column, parent):
return QtCore.QModelIndex()
if parent.isValid():
parentItem = parent.internalPointer()
else:
parentItem = self.rootItem
child = parentItem.children[row]
return self.createIndex(row, column, child)
def parent(self, index):
if not index.isValid():
return QtCore.QModelIndex()
try:
parent = index.internalPointer().parent
if parent == self.rootItem or parent is None:
return QtCore.QModelIndex()
return self.createIndex(parent.row, 0, parent)
except AttributeError:
return QtCore.QModelIndex()
def rowCount(self, parent):
if parent.isValid():
parentItem = parent.internalPointer()
else:
parentItem = self.rootItem
return parentItem.rows
def appendDict(self, d):
assert 'id' in d
assert 'description' in d
self.rootItem.appendChild(DictItem(d))
class FileView(QtGui.QTreeView):
def __init__(self, model=None, parent=None):
super(FileView, self).__init__(parent)
self.setModel(model)
if __name__ == '__main__':
import sys
app = QtGui.QApplication(sys.argv)
model = FileModel()
form = FileView(model)
c1 = {'id':1, 'description':'child 1'}
c2 = {'id':2, 'description':'child 2'}
d = {'id':0, 'description':'whatever', 'children':[c1, c2]}
model.appendDict(d)
form.show()
sys.exit(app.exec_())
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