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我正在尝试将树的选择限制为特定列。

我大量使用委托来创建自定义的每项每列行为、编辑器等。我希望我可以通过阻止事件或类似的东西从委托中以某种方式做到这一点。问题是,我认为我必须创建一个完全自定义的解决方案来模仿扩展选择。

但是,经过大量搜索和很少的示例后,听起来我想要在我的树视图上自定义 QItemSelectionModel。这个假设正确吗?

如何创建自定义 QItemSelectionModel 将使用扩展选择模式,但如果不在特定列中,则允许我忽略或还原选择。换句话说,单击另一列不应更改选择(不应选择或取消选择)

我知道如何添加选择模型。我正在寻求帮助实现派生类(除非这可以通过连接的信号来完成)。

我正在使用 Python,但会重视任何帮助。

谢谢,

[编辑:] 我发现了这些类似的问题: http: //lists.qt.nokia.com/pipermail/qt-interest/2010-September/027647.html

"子类 QItemSelectionModel 并重新实现这两种选择方法以获得您想要的行为。只需忽略列 > 0 的范围部分......或者可能只是重新实现 flags() 以使项目不可选择。我不知道是否那样会有任何副作用。”

我尝试在我的 QTreeWidgetItem 上重新实现标志,但它从未被调用:

def flags(self, index):
    print index.column()
    return super(DDOutlinerBaseItem, self).flags(index)
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2 回答 2

4

理论上,以下调整应该有效。

上述解决方案可以使用两个单独的方法和 @pyqtSlot 装饰器来消除重载方法名称的歧义:

@pyqtSlot(QModelIndex, QItemSelectionModel.SelectionFlags)
  def select(self, index, command):
    # ...

@pyqtSlot(QItemSelection, QItemSelectionModel.SelectionFlags)
  def select(self, selection, command):
    #...

这避免了在方法实现中检查某些类的实例的需要。

于 2012-11-30T15:09:40.187 回答
0

第一个有趣的事情是,由于 Python 不能重载方法,我的 select 方法似乎只是被调用了两次,参数 0 中的每种类型调用一次。这里有一个示例来说明这一点以及基本设置。我的 QTreeWidget 的树称为“树”(self.tree

    # in __init__ of my QTreeWidget:
    sel_model = ColumnSelectionModel(self.tree.model())
    self.tree.setSelectionModel(sel_model)

class ColumnSelectionModel(QtGui.QItemSelectionModel):
    def select(self, selection, selectionFlags):
    """
    Runs both QItemSelectionModel.select methods::

        1. select(QtCore.QModelIndex, QItemSelectionModel.SelectionFlags)
        2. select(QtGui.QItemSelection, QItemSelectionModel.SelectionFlags)

    The first seems to run on mouse down and mouse up.
    The second seems to run on mouse down, up and drag
    """
    print("select(%s,  %s)" % (type(selection), type(selectionFlags)))

    if isinstance(selection, QtGui.QItemSelection):
        infos = []
        for index in selection.indexes():
            infos.append(("index=%s row=%s column=%s" 
                                    % (index, index.row(), index.column())))

        print ", ".join(infos)
    elif isinstance(selection, QtCore.QModelIndex):
        index = selection
        print("index=%s row=%s column=%s" % (index, index.row(), index.column()))
    else:
        raise Exception("Unexpected type for arg 0: '%s'" % type(selection))

    super(ColumnSelectionModel, self).select(selection, selectionFlags)

这似乎解决了我的问题:

class ColumnSelectionModel(QtGui.QItemSelectionModel):
    def __init__(self, model):
        super(ColumnSelectionModel, self).__init__(model)

        self.selectable_columns = [0]
        """ Set the columns that are allowed to be selected """


    def select(self, selection, selectionFlags):
        """
        Ignores any selection changes if an item is not in one of the columns
        in the self.selectable_columns list.

        Is run by both QItemSelectionModel.select methods::

            1. select(QtCore.QModelIndex, QItemSelectionModel.SelectionFlags)
            2. select(QtGui.QItemSelection, QItemSelectionModel.SelectionFlags)

        The first seems to run on mouse down and mouse up.
        The second seems to run on mouse down, up and drag
        """
        if isinstance(selection, QtGui.QItemSelection):
            # This is the overload with the QItemSelection passed to arg 0
            # Loop over all the items and if any are not in selectable_columns
            #   ignore this event. This works because it is run for every change
            #   so the offending selection index will always be the newest
            indexes = selection.indexes()
            for i in xrange(len(indexes)):
                index = indexes[i]
                if not index.column() in self.selectable_columns:
                    return
        elif isinstance(selection, QtCore.QModelIndex):
            # This is the overload with the QModelIndex passed to arg 0
            # If this index isn't in selectable_columns, just ignore this event
            index = selection
            if not index.column() in self.selectable_columns:
                return
        else:  # Just in case
            raise Exception("Unexpected type for arg 0: '%s'" % type(selection))

        # Fall through. Select as normal
        super(ColumnSelectionModel, self).select(selection, selectionFlags)

在我的最终实现中,我计划将决定委托给我的委托系统,使其具有通用性,并且理论上能够动态地忽略我想要的任何索引。

于 2012-06-06T18:50:20.883 回答