替换拖放到上的QListView项目

Question

我有一台QTreeView和一台QListView。这两种方法都使用QStandardItemModel作为模型。QTreeView不应接受丢弃。QListView应该接受丢弃。

如果将项从QTreeView拖放到QListView中的项上，则从QTreeView中拖出的项的副本应替换它所放到的QListView中的项。如果将项目从QTreeView拖放到QListView的顶部、QListView中的现有项目之间或QListView的底部，则应将其复制到那里。

如果将项目从QListView拖放到QListView中的项目上，则应移动该项目以替换QListView中它拖放到的项目。如果将项从QListView拖放到QListView的顶部、QListView中的现有项之间或QListView的底部，则应将其移动到该位置。

QTreeView中的项目不应该是可编辑的。一旦将它们复制到QListView，它们就应该在QListView中变为可编辑。

Answer 1

from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
from PyQt5.QtCore import *

import sys


def decode_byte_array(byte_array):
    role_value_dict_list = []

    data_stream = QDataStream(byte_array, QIODevice.ReadOnly)
    while not data_stream.atEnd():
        row = data_stream.readInt32()
        column = data_stream.readInt32()
        count = data_stream.readInt32()

        role_value_dict = {}
        for i in range(count):
            role = data_stream.readInt32()
            value = QVariant()
            data_stream >> value
            role_value_dict[Qt.ItemDataRole(role)] = value

        role_value_dict_list.append(role_value_dict)

    return role_value_dict_list


class MyListModel(QStandardItemModel):
    def dropMimeData(self, data, action, row, column, parent):
        if data.hasFormat('application/x-qabstractitemmodeldatalist'):
            byte_array = QByteArray(data.data("application/x-qabstractitemmodeldatalist"))
            role_value_dict_list = decode_byte_array(byte_array)
            item_list = []
            for role_value_dict in role_value_dict_list:
                item = QStandardItem()
                for role, value in role_value_dict.items():
                    item.setData(value, role)

                item.setEditable(True)
                item_list.append(item)


            parent_item = self.itemFromIndex(parent)

            if row == -1 and column == -1:
                if parent_item == None:
                    # Drop is after last row.
                    for item in item_list:
                        self.appendRow(item)

                else:
                    # Drop is on row.
                    self.setItem(parent.row(), parent.column(), item_list[0])
                    row = parent.row() + 1

                    for item in item_list[1:]:
                        self.insertRow(row, item)
                        row = row + 1

            elif row >= 0 and column >= 0:
                # Drop is before first row or between rows.
                for item in item_list:
                    self.insertRow(row, item)
                    row = row + 1

            else:
                return False

        else:
            return False

        return True


class MainWindow(QMainWindow):
    def __init__(self):
        super(MainWindow, self).__init__()

        centralWidget = QWidget()
        layout = QHBoxLayout()


        tree_view_model = QStandardItemModel()

        parent_item = tree_view_model.invisibleRootItem()

        item_1 = QStandardItem('item 1')
        item_1.setDragEnabled(False)
        item_1.setEditable(False)

        item_2 = QStandardItem('item 2')
        item_2.setEditable(False)

        item_3 = QStandardItem('item 3')
        item_3.setEditable(False)

        item_1.appendRow(item_2)
        item_1.appendRow(item_3)
        parent_item.appendRow(item_1)

        tree_view = QTreeView()
        tree_view.setModel(tree_view_model)

        tree_view.setHeaderHidden(True)
        tree_view.header().setSectionResizeMode(QHeaderView.ResizeToContents)
        tree_view.setDragEnabled(True)


        list_view_model = MyListModel()

        list_view = QListView()
        list_view.setModel(list_view_model)

        list_view.setDragEnabled(True)
        list_view.setAcceptDrops(True)
        list_view.setDefaultDropAction(Qt.MoveAction)
        list_view.setDragDropOverwriteMode(False)
        list_view.setSelectionBehavior(QListView.SelectRows)
        list_view.setSelectionMode(QListView.SingleSelection)


        layout.addWidget(tree_view)
        layout.addWidget(list_view)


        centralWidget.setLayout(layout)

        self.setCentralWidget(centralWidget)


app = QApplication([])

f = QFont('Courier')
f.setPointSize(16)

app.setFont(f)

window = MainWindow()
window.show()

sys.exit(app.exec_())