我对 Qt 的模型/视图架构有疑问。
我已经实现了一个TestModel继承自的类，具有插入新行和删除行QAbstractItemModel的自定义方法。我的模型具有层次结构，并且树中有不同的方法和不同的级别。TestModel.addRevision(...)TestModel.removeRevision(...)add_Xremove_X
当然，根据文档，我在插入或删除这样的行之前调用所需的函数（省略号处理基于我的数据源的信息检索，很长，我认为没有必要显示）
def add_revision(self, name:str):
parent_index = ...
new_row_in_parent = ...
self.beginInsertRows(parent_index, new_row_in_parent, new_row_in_parent)
...
self.endInsertRows()
我一一插入行，并注意我没有通过调用添加太多行的常见错误self.beginInsertRows(parent, start, end)with end = start +1。
去除方法具有非常相似的结构。
我可以通过附加 aQTreeView来验证我的模型工作正常。现在我还有一个更新方法，它执行以下操作（在伪代码中）：
# models.py
class TestModel(QtCore.QAbstractItemMOdel):
...
def __init__(self, parent=None):
...
self.update()
def update(self):
# remove all items one by one using remove_revision in a foreach loop
# scan the source for new (updated) revisions
# add all revisions found one by one in a foreach loop
在模型上，此功能也按预期工作，一旦我触发更新，视图也会自动更新。请注意，我update也在初始化期间使用。
下一步，我实现了一个用于排序和过滤的代理模型。我的问题甚至可以使用 default 重现QSortFilterProxyModel，而无需设置任何过滤器。
我这样设置视图：
...
view = QTreeView(self)
model = TestModel(self)
proxy_model = QSortFilterModel(self)
proxy_model.setSourceModel(model)
view.setModel(proxy_model)
初始化后，视图按预期显示（见下面的截图）
然后在我触发后update，视图显示变为
添加这些讨厌的空行的地方。与“好”行不同，它们是不可选择的，我不知道它们来自哪里。我尝试用QSortFilterProxyModela替换QIdentityProxyModel并且多余的行消失了，所以我非常有信心空行仅添加到QSortFilterProxModel. 但是，这是默认实现，我还没有覆盖任何排序和过滤方法。
有趣的是，当我使用 时QIdentityProxyModel，视图在调用 后显示所有项目处于折叠状态update，而QSortFilterProxyModel项目保持展开状态。
问题：
似乎调用beginInserRowsand是不够的endInsertRows。我是否需要发出其他信号来通知代理模型更新？
或者，在源模型中完成所有删除之前，代理模型是否更新得太快？
编辑 1
根据要求，这是update我模型的完整方法。我还包括了其他正在使用的类和方法：
更新模型：
def update(self, skip: bool = True):
revisions_to_remove = []
files_to_inspect = []
for (index, key) in enumerate(self.lookup_virtual_paths):
# first remove everything beneath file
obj = self.lookup_virtual_paths.get(key, None)
if obj is None:
continue
if isinstance(obj, Revision):
revisions_to_remove.append(obj)
if isinstance(obj, File):
files_to_inspect.append(obj)
# first remove revisions
for revision in revisions_to_remove:
self.remove_revision(revision)
pass
file: File
for file in files_to_inspect:
# add revisions
# construct the filesystem path to lookup
scraper: ScraperVFSObject = file.parent().parent()
if scraper is None:
log.warning('tbd')
return
path_scraper = Path(scraper.fs_storage_path())
if not path_scraper.exists():
w = 'path does not exist "%s"' % (
path_scraper.absolute().as_posix())
log.warning(w, path_scraper)
return
path_file = path_scraper / Path(file.machine_name)
if not path_file.exists():
w = 'path does not exist "%s"' % (
path_file.absolute().as_posix())
log.warning(w)
return
for elem in path_file.glob('*'):
if not elem.is_dir():
continue
if not len(elem.name) == len(ScraperModel.to_timeformat(datetime.now())):
continue
actual_file = elem / \
Path('%s_%s.html' % (file.machine_name, elem.name))
if not actual_file.exists():
continue
self.add_revision(
ScraperModel.from_timeformat(elem.name),
actual_file.absolute().as_posix(),
file.virtual_path())
添加修订：
def add_revision(self, dt: datetime, file: str, to: str, skip=False):
f = self.lookup_virtual_paths.get(to, None)
if f is None:
w = 'trying to add revision "%s" to virtual path "%s"' % (dt, to)
log.warning(w)
return
r = Revision(dt, file, f, self)
parent_index = r.parent().get_model_index()
start = r.get_row_in_parent()
self.beginInsertRows(parent_index, start, start)
self.add_to_lookup(r)
# announce that revision has been added
self.endInsertRows()
# immediately add thumbnail groups to the revision,
# because a thumbnail-group can only exist in the revision
known = ThumbnailGroupKnown(r, self)
unknown = ThumbnailGroupUnknown(r, self)
ignored = ThumbnailGroupIgnored(r, self)
start = known.get_row_in_parent()
end = ignored.get_row_in_parent()
self.beginInsertRows(r.get_model_index(), start, end)
self.add_to_lookup([known, unknown, ignored])
self.endInsertRows()
删除修订：
def remove_revision(self, revision: "Revision"):
# first get ModelIndex for the revision
parent_index = revision.parent().get_model_index()
start = revision.get_row_in_parent()
# first remove all thumbnail groups
tgs_to_remove = []
for tg in revision.children():
tgs_to_remove.append(tg)
tg: ThumbnailGroup
for tg in tgs_to_remove:
self.beginRemoveRows(tg.parent().get_model_index(),
tg.get_row_in_parent(),
tg.get_row_in_parent())
vpath = tg.virtual_path()
tg.setParent(None)
del self.lookup_virtual_paths[vpath]
self.endRemoveRows()
self.beginRemoveRows(parent_index, start, start)
key = revision.virtual_path()
# delete the revision from its parent
revision.setParent(None)
# delete the lookup
del self.lookup_virtual_paths[key]
self.endRemoveRows()
编辑 2
根据@Carlton 的建议，我重新排序了remove_revision. 我明白，这很容易成为问题（现在或以后）。现在的实现如下：
def remove_revision(self, revision: "Revision"):
# first remove all thumbnail groups
tgs_to_remove = []
for tg in revision.children():
tgs_to_remove.append(tg)
tg: ThumbnailGroup
for tg in tgs_to_remove:
self.beginRemoveRows(tg.parent().get_model_index(),
tg.get_row_in_parent(),
tg.get_row_in_parent())
vpath = tg.virtual_path()
tg.setParent(None)
del self.lookup_virtual_paths[vpath]
self.endRemoveRows()
parent_index = revision.parent().get_model_index()
start = revision.get_row_in_parent()
self.beginRemoveRows(parent_index, start, start)
key = revision.virtual_path()
# delete the revision from its parent
revision.setParent(None)
# delete the lookup
del self.lookup_virtual_paths[key]
self.endRemoveRows()
后来我打算直接传递索引，但是为了调试我决定暂时存储它。但是，有问题的行为仍然存在不变。
编辑 3
因此，根据@Carlton 的建议，“幻影行”似乎是rowCount与实际数据不匹配的问题。
我在方法中重新排列了更多代码，add_revision以便为缩略图组提供以下内容：
def add_revision(self, dt: datetime, file: str, to: str, skip=False):
...
# no changes before here
print('before (add_revision)', len(r.children()),
self.rowCount(r.get_model_index()))
self.beginInsertRows(r.get_model_index(), 0, 2)
known = ThumbnailGroupKnown(r, self)
unknown = ThumbnailGroupUnknown(r, self)
ignored = ThumbnailGroupIgnored(r, self)
self.add_to_lookup([known, unknown, ignored])
self.endInsertRows()
print('after (add_revision)', len(r.children()),
self.rowCount(r.get_model_index()))
如您所见，我手动选择了startandend参数。通过此修改，我可以将数据插入实际上放在两者之间beginInsertRows，endInsertRows并且“幻影行”消失了。但是，然后我有一个新问题：我通常无法事先知道新行将出现在哪些索引处。对于建议的信号，这似乎是一个很好的用途layoutAboutToBeChanged，但我怎样才能在pyside6中传递父列表？
编辑 4：MWE
这是一个最小的工作示例。您需要安装 PySide6。 MWE 和这里直接托管的相同代码：
import sys
from PySide6 import (
QtCore,
QtWidgets
)
class Node(QtCore.QObject):
def __init__(self, val: str, model, parent=None):
super().__init__(parent)
self.value = val
self._model = model
def child_count(self) -> int:
return len(self.children())
def get_child(self, row: int) -> "Node":
if row < 0 or row >= self.child_count():
return None
else:
return self.children()[row]
def get_model_index(self) -> QtCore.QModelIndex:
return self._model.index(self.get_row_in_parent(), 0, self.parent().get_model_index())
def get_row_in_parent(self) -> int:
p = self.parent()
if p is not None:
return p.children().index(self)
return -1
class RootNode(Node):
def get_row_in_parent(self) -> int:
return -1
def get_model_index(self) -> QtCore.QModelIndex:
return QtCore.QModelIndex()
class Model(QtCore.QAbstractItemModel):
def __init__(self, parent=None):
super().__init__(parent)
self.root_item = None
# simulate the changing data
self._data = [
(1, 'child 1 of 1'),
(1, 'child 2 of 1'),
(1, 'child 3 of 1'),
]
self._initialize_static_part()
self.update()
def _initialize_static_part(self):
"""This is the part of my model which never changes at runtime
"""
self.root_item = RootNode('root', self, self)
nodes_to_add = []
for i in range(0, 5):
new_node = Node(str(i), self)
nodes_to_add.append(new_node)
for node in nodes_to_add:
self.add_node(node, self.root_item)
def update(self):
"""This is the part which needs update during runtime
"""
rows_to_add = []
rows_to_delete = []
self.layoutAboutToBeChanged.emit()
for c in self.root_item.children():
for d in c.children():
rows_to_delete.append(d)
for (parent_identifier, name) in self._data:
node = Node(name, self)
# actually, the future parent is a different function, but for the MWE this suffices
future_parent = self.root_item.get_child(parent_identifier)
rows_to_add.append((future_parent, node))
for node in rows_to_delete:
self.remove_node(node)
for (parent, node) in rows_to_add:
self.add_node(node, parent)
self.layoutChanged.emit()
def add_node(self, node: Node, parent: Node):
self.beginInsertRows(parent.get_model_index(),
parent.child_count(),
parent.child_count())
node.setParent(parent)
self.endInsertRows()
def remove_node(self, node):
parent_node = node.parent()
row = parent_node.get_model_index().row()
self.beginRemoveRows(parent_node.get_model_index(
), row, row)
# print(parent_node.get_model_index().isValid())
node.setParent(None)
# print(node)
# print(parent_node.children())
self.endRemoveRows()
# reimplement virtual method
def columnCount(self, parent: QtCore.QModelIndex = QtCore.QModelIndex()) -> int:
return 1
# reimplement virtual method
def rowCount(self, parent: QtCore.QModelIndex = QtCore.QModelIndex()) -> int:
if not parent.isValid():
parent_item = self.root_item
else:
parent_item = parent.internalPointer()
return parent_item.child_count()
# reimplement virtual method
def index(self, row: int, column: int, parent: QtCore.QModelIndex = QtCore.QModelIndex()) -> QtCore.QModelIndex:
if not self.hasIndex(row, column, parent):
return QtCore.QModelIndex()
if not parent.isValid():
parent_item = self.root_item
else:
parent_item = parent.internalPointer()
child_item: Node = parent_item.get_child(row)
if child_item is not None:
return self.createIndex(row, column, child_item)
return QtCore.QModelIndex()
# reimplement virtual method
def parent(self, index: QtCore.QModelIndex) -> QtCore.QModelIndex:
if not index.isValid():
return QtCore.QModelIndex()
child_item: Node = index.internalPointer()
parent_item = child_item.parent()
if parent_item is not None:
return parent_item.get_model_index()
return QtCore.QModelIndex()
# reimplement virtual method
def data(self, index: QtCore.QModelIndex, role: int = QtCore.Qt.DisplayRole) -> object:
if not index.isValid():
return None
if role == QtCore.Qt.DisplayRole:
item: Node = index.internalPointer()
if item is not None:
return item.value
return 'whats this?'
return None
class MyWindow(QtWidgets.QMainWindow):
defaultsize = QtCore.QSize(780, 560)
def __init__(self, app, parent=None):
super().__init__(parent)
self.app = app
self.resize(self.defaultsize)
main_layout = QtWidgets.QSplitter(QtCore.Qt.Vertical)
self.panel = Panel(main_layout)
self.setCentralWidget(main_layout)
self.model = Model(self)
proxy_model1 = QtCore.QSortFilterProxyModel(self)
proxy_model1.setSourceModel(self.model)
proxy_model2 = QtCore.QIdentityProxyModel(self)
proxy_model2.setSourceModel(self.model)
view1 = QtWidgets.QTreeView(self.panel)
view1.setAlternatingRowColors(True)
view1.setModel(proxy_model1)
view1.expandAll()
view2 = QtWidgets.QTreeView(self.panel)
view2.setAlternatingRowColors(True)
view2.setModel(proxy_model2)
view2.expandAll()
self.panel.addWidget(view1)
self.panel.addWidget(view2)
# we simulate a change, which would usually be triggered manually
def manual_change_1():
self.model._data = [
(1, 'child 2 of 1'),
(1, 'child 3 of 1'),
]
self.model.update()
QtCore.QTimer.singleShot(2000, manual_change_1)
class App(QtWidgets.QApplication):
def __init__(self):
super().__init__()
self.window = MyWindow(self)
def run(self):
self.window.show()
result = self.exec_()
self.exit()
class Panel(QtWidgets.QSplitter):
pass
if __name__ == '__main__':
app = App()
app.startTimer(1000)
sys.exit(app.run())