如何在QListWidget中启用拖动后启用拖动选择？

Question

我有一个列表小部件，我需要将项目从它拖到另一个列表小部件。启用拖动后

self.setDragDropMode(QtGui.QAbstractItemView.DragDrop)

我无法再拖动选择了。我认为它与mousePressEvent有关。如何重新实现它以启用列表小部件空白区域右侧的拖动选择？

my code

from PyQt4 import QtGui, QtCore
from PyQt4.QtCore import Qt, QString
import sys
import os


class ThumbListWidget(QtGui.QListWidget):

    _rows_to_del = []

    def __init__(self, type, parent=None):
        super(ThumbListWidget, self).__init__(parent)
        self.setIconSize(QtCore.QSize(124, 124))

        self.setDragDropMode(QtGui.QAbstractItemView.DragDrop)

        self.setSelectionMode(QtGui.QAbstractItemView.ExtendedSelection)
        self.setAcceptDrops(True)
        self._dropping = False

        self.setSelectionRectVisible(True)

        self.connect(self, QtCore.SIGNAL("dropped"), self.items_dropped)

    def dragEnterEvent(self, event):
        if event.mimeData().hasUrls():
            event.accept()
        else:
            super(ThumbListWidget, self).dragEnterEvent(event)

    def dragMoveEvent(self, event):
        if event.mimeData().hasUrls():
            event.setDropAction(QtCore.Qt.CopyAction)
            event.accept()
        else:
            super(ThumbListWidget, self).dragMoveEvent(event)

    def dropEvent(self, event):
        if event.mimeData().hasUrls():
            event.setDropAction(QtCore.Qt.CopyAction)
            event.accept()
            links = []
            for url in event.mimeData().urls():
                links.append(str(url.toLocalFile()))
            self.emit(QtCore.SIGNAL("dropped"), links)
        else:

            if event.source() is self:
                event.setDropAction(QtCore.Qt.MoveAction)
            else:

                event.setDropAction(QtCore.Qt.CopyAction)

            self._dropping = True
            super(ThumbListWidget, self).dropEvent(event)

            self._dropping = False

    def rowsInserted(self, parent, start, end):
        if self._dropping:

            self.emit(QtCore.SIGNAL("dropped"), (start, end))
        super(ThumbListWidget, self).rowsInserted(parent, start, end)

    def dataChanged(self, start, end):
        if self._dropping:

            for row in range(start.row(), end.row() + 1):
                index = self.indexFromItem(self.item(row))
                shot = index.data().toString()
                print len(self.findItems(shot, Qt.MatchExactly))
                if len(self.findItems(shot, Qt.MatchExactly)) > 1:
                    self._rows_to_del.append(row)

            self._rows_to_del.reverse()

            for row in self._rows_to_del:
                self.takeItem(row)

            self._rows_to_del = []

    def items_dropped(self, arg):
        start, end = arg
        print range(start, end + 1)
        for row in range(start, end + 1):
            item = self.item(row)
            item.setFlags(item.flags() | Qt.ItemIsUserCheckable)
            item.setCheckState(Qt.Checked)

    def keyPressEvent(self, event):

        if event.key() == Qt.Key_Space:
            if self.selectedItems():
                new_state = Qt.Unchecked if self.selectedItems()[0].checkState() else Qt.Checked
                for item in self.selectedItems():
                    if item.flags() & Qt.ItemIsUserCheckable:
                        # print 'set new state:', new_state
                        item.setCheckState(new_state)

            self.reset()

        elif event.key() == Qt.Key_Delete:
            for item in self.selectedItems():
                self.takeItem(self.row(item))


class Dialog_01(QtGui.QMainWindow):

    def __init__(self):
        super(QtGui.QMainWindow, self).__init__()
        self.listItems = {}

        myQWidget = QtGui.QWidget()
        myBoxLayout = QtGui.QVBoxLayout()
        myQWidget.setLayout(myBoxLayout)
        self.setCentralWidget(myQWidget)

        self.listWidgetA = ThumbListWidget(self)
        for i in range(12):
            QtGui.QListWidgetItem('Item ' + str(i), self.listWidgetA)

        all_items = self.listWidgetA.findItems(QString('*'), Qt.MatchWrap | Qt.MatchWildcard)
        for item in all_items:
            item.setFlags(item.flags() & ~Qt.ItemIsUserCheckable)

        myBoxLayout.addWidget(self.listWidgetA)

        self.listWidgetB = ThumbListWidget(self)

        self.listWidgetA.setAcceptDrops(False)

        myBoxLayout.addWidget(self.listWidgetB)

if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    dialog_1 = Dialog_01()
    dialog_1.show()
    dialog_1.resize(480, 320)
    sys.exit(app.exec_())

gyfcat of current look或

如果我注释掉该行，我将能够拖动选择，如下面的屏幕演示所示。

gyfcat of desired look或