pyqt:尝试理解QAbstractDataModel和QTreeView的插入

Question

我使用PyQt使用QAbstractItemModel管理树视图.到目前为止,我已成功实现它,以便我可以加载数据,展开和折叠它,以及编辑值.

然而,我无法做的一件事是围绕插入和移除行.

我想做的简短版本:

当用户编辑特定单元格时,我需要实际删除对象层次结构中的基础项目并将其替换为另一个项目.我在我的模型的setData方法中实现它.因为我不完全理解我在做什么,所以我似乎已经将它设置为段错误.

基本上,我只需要更好地理解数据模型如何与QModelIndex交互,但阅读和重新阅读文档似乎并没有启发我.任何帮助(或指向一个体面的教程的任何链接 - 最好,但不一定,在python中 - 也将非常感激).

以下是我正在使用的代码示例:

#---------------------------------------------------------------------------
def setData(self, index, value, role=QtCore.Qt.EditRole):
    """
    Sets the data. 
    """
    if index.isValid() and (0 <= index.row() < self.rowCount()):

        item = index.internalPointer()
        value = value.toString()
        if index.column() == 5:
            # rip out the current object and replace it with a new one of 
            # the correct datatype.

            #next 4 lines get info from my underlying hierarchy of objects
            dataType = str(value)
            parent = item.get_parent()
            name = item.get_name()
            row = parent.get_row_of_child(name)

            #assuming everything is ok, I now am trying to manage the
            #underlying objects
            if row != None:

                #I am calling this because I think I need to, but don't
                #really know if it is called for here or not
                self.beginInsertRows(self.parent(index), row, 1)

                #Next 3 lines create and initialize a new underlying 
                #object that will be inserted.
                newItem = self.root.create_template_param_obj(dataType, 
                                                              name, 
                                                              parent)
                newItem.set_index(row)
                newItem.set_default_value(item.get_default_value())

                #now I remove the old object from my underlying
                #hierarchy and insert the new one
                parent.remove_child_at_row(row)
                parent.insert_child_at_row(newItem, row)

                #this is where I get lost. I *think* I need to point to 
                #the new underlying object (i.e. rebuild the index)
                #so I am going to call the data model's index method.
                #But that needs the index of the parent, so first I
                #call the data model's parent method to get the index
                #of the parent. But this code segfaults (I think it 
                #is the treeview that actually freaks out because this
                #setData method completes properly before the whole thing
                #crashes. Does anyone have a pointer to a decent tutorial
                #that will explain how data models and mode indexes work?
                self.index(row, 5, self.parent(index))
                self.endInsertRows()

        self.emit(QtCore.SIGNAL("dataChanged(QModelIndex,QModelIndex)"), 
                                 index, index)
        return True

    #Ignore any role other than the edit role
    return False

#---------------------------------------------------------------------------
def index(self, row, column, parent):
    """
    Connect the data model to the actual object hierarchy.
    """
    if not self.hasIndex(row, column, parent):
        return QtCore.QModelIndex()

    if not parent.isValid():
        parentItem = self.root
    else:
        parentItem = parent.internalPointer()

    childItem = parentItem.get_child_at_row(row)
    if childItem:
        return self.createIndex(row, column, childItem)
    else:
        return QtCore.QModelIndex()


#---------------------------------------------------------------------------
def parent(self, index):
    """
    Returns a QModelIndex of the parent
    """
    if not index.isValid():
        return QtCore.QModelIndex()

    childItem = index.internalPointer()
    if not childItem:
        return QtCore.QModelIndex()

    parentItem = childItem.get_parent()

    if parentItem == self.root:
        return QtCore.QModelIndex()

    return self.createIndex(parentItem.get_index(), 0, parentItem)

Answer 1

我会尝试给您一些提示，我记得当我必须为我的应用程序实现它时，这部分也引起了我的注意！

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因此，据我记得，您必须实现以下虚拟方法：

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virtual bool insertRows(int Row, int Count, const QModelIndex& rParent);\nvirtual bool removeRows(int Row, int Count, const QModelIndex& rParent = QModelIndex());\n\nbool SuperModel::insertRows(int Row, int Count, const QModelIndex& rParent)\n{\n ...\n    // On d\xc3\xa9bute l\'insertion des lignes.\n    beginInsertRows(rParent, Row, Row + Count -1);\n    // ... Perform insertion here, you\'ll have something like\n    pParent->addChild(Row);\n    endInsertRows();\n}\n\nbool SuperModel::removeRows(int Row, int Count, const QModelIndex& rParent)\n{\n    ...\n    beginRemoveRows(rParent, Row, Row + Count -1);\n    // ... Perform removing here, you\'ll have something like\n    pParent->removeChild(Row);\n    endRemoveRows();\n}\n

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更多信息：http://doc.qt.io/archives/qt-4.7/qabstractitemmodel.html#insertRows

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我希望它能对你有所帮助......它不在 PyQt 中，但希望它能给你一些提示......

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