如何从一个 QListWidget 拖放到另一个 [英] How to Drag and Drop from One QListWidget to Another

问题描述

在同一个对话窗口中有两个 QListWIdget.两者都启用了拖放功能.如果我将文件拖放到两个 ListWidges 中的任何一个，程序会识别它并打印出所放置文件的列表.但除了拖放文件之外，我希望能够将列表小部件项目从一个拖放到另一个.如果我拖动 ListItems，则会触发拖放事件.但它无法识别哪些项目被放到小部件上.示例代码如下.目标是将列表项从一个 ListWidget 拖放到另一个.

There are two QListWIdgets sitting in a same dialog window. The DragDrop functionality has been enabled for both. If I drag and drop a file to any of two ListWidges the program recognizes it and prints out the list of the files dropped. But aside from drag and dropping files I would like to be able to drag and drop the List widget Items from one to another. If I drag the ListItems the drag and drop event is triggered. But it is not able to recognize what Items were dropped onto the widget. The example code is below. The goal is to drag-drop the list items from one ListWidget to another.

import sys, os
from PyQt4 import QtCore, QtGui   
class ThumbListWidget(QtGui.QListWidget):
    def __init__(self, type, parent=None):
        super(ThumbListWidget, self).__init__(parent)
        self.setAcceptDrops(True)
        self.setIconSize(QtCore.QSize(124, 124))

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

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

    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:
            event.ignore()


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 )
        myBoxLayout.addWidget(self.listWidgetA)

        self.listWidgetB = ThumbListWidget(self)
        myBoxLayout.addWidget(self.listWidgetB)   

        self.listWidgetA.setDragDropMode(QtGui.QAbstractItemView.InternalMove)
        self.listWidgetA.setSelectionMode(QtGui.QAbstractItemView.ExtendedSelection)
        self.connect(self.listWidgetA, QtCore.SIGNAL("dropped"), self.items_dropped)
        self.listWidgetA.currentItemChanged.connect(self.item_clicked)

        self.listWidgetB.setDragDropMode(QtGui.QAbstractItemView.InternalMove)
        self.listWidgetB.setSelectionMode(QtGui.QAbstractItemView.ExtendedSelection)
        self.connect(self.listWidgetB, QtCore.SIGNAL("dropped"), self.items_dropped)
        self.listWidgetB.currentItemChanged.connect(self.item_clicked)

    def items_dropped(self, arg):
        print arg

    def item_clicked(self, arg):
        print arg

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

编辑#2

这是完成所有工作的代码.但是没有办法追踪被丢弃的物体.dropOnA() 和 dropOnB() 方法仍然不起作用.

EDIT # 2

Here is the code that does it all. But there is no way to track down what object was dropped. The droppedOnA() and droppedOnB() methods are still not working.

from PyQt4 import QtGui, QtCore
import sys, os


class MyClassItem(QtGui.QListWidgetItem):
    def __init__(self, parent=None):
        super(QtGui.QListWidgetItem, self).__init__(parent)       


class ThumbListWidget(QtGui.QListWidget):
    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)

    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):
        print 'dropEvent', 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:
            event.setDropAction(QtCore.Qt.MoveAction)
            super(ThumbListWidget, self).dropEvent(event)


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)
        self.listWidgetB = ThumbListWidget(self)

        for i in range(7):
            listItemAInstance=MyClassItem()
            listItemAInstance.setText('A'+'%04d'%i)
            listItemAInstance.setBackgroundColor(QtCore.Qt.darkGray)   
            if i%2: listItemAInstance.setBackgroundColor(QtCore.Qt.gray)
            self.listWidgetA.addItem(listItemAInstance) 

            listItemBInstance=MyClassItem()
            listItemBInstance.setText('B'+'%04d'%i)

            if i%2: listItemBInstance.setBackgroundColor(QtCore.Qt.lightGray)
            self.listWidgetB.addItem(listItemBInstance) 

        myBoxLayout.addWidget(self.listWidgetA)      

        myBoxLayout.addWidget(self.listWidgetB)   
        self.connect(self.listWidgetA, QtCore.SIGNAL("dropped"), self.droppedOnA)
        self.connect(self.listWidgetB, QtCore.SIGNAL("dropped"), self.droppedOnB)


    def droppedOnA(self, arg):
        print '\n\t droppedOnA', arg.text

    def droppedOnB(self, arg):
        print '\n\t droppedOnB', arg.text


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

编辑#3

这是这次使用 MIME 将删除的 Item 对象传递给 ListWidget 的另一种尝试.不幸的是，cPickle 拒绝接受抛出

EDIT # 3

Here is another attempt this time using MIME to pass dropped Item's objects to ListWidget. Unfortunately cPickle refuses to accept binary objects throwing a

TypeError: sip.wrapper 类型不能被实例化或子类化

TypeError: the sip.wrapper type cannot be instantiated or sub-classed

为了解决这个问题，我将每个对象名称转换为字符串，并将其与 self.listItems={} 字典一起用作检索列表项的二进制对象的键.这似乎运作良好.但是最后，当我几乎完成所有操作时，没有可见错误的 ListWidget 不会将删除的列表项添加到自身中......这很奇怪.

To get around it I convert each object names to string and use it with self.listItems={} dictionary as its key to retrieve list Item's binary objects. Which seems to be working well. But at the end when I almost though it as all done, a ListWidget with no visible errors doesn't add the dropped list Item to itself... It's strange.

self.listWidgetB.addItem(droppedItemInstance)

self.listWidgetB.addItem(droppedItemInstance)

.

from PyQt4 import QtGui, QtCore
import sys, os
import cPickle 

class MyClassItem(QtGui.QListWidgetItem):
    def __init__(self, parent=None):
        super(QtGui.QListWidgetItem, self).__init__(parent)       


class ThumbListWidget(QtGui.QListWidget):
    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)

    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()))

        else:
            event.setDropAction(QtCore.Qt.MoveAction)
            super(ThumbListWidget, self).dropEvent(event)


    def mimeTypes(self):
        return ['bstream', 'text/xml']

    def mimeData(self, droppedItems):
        mimedata = QtCore.QMimeData()

        droppedItemsAsStrings=[]
        for each in droppedItems:            
            droppedItemsAsStrings.append( str(each) )

        bstream = cPickle.dumps(droppedItemsAsStrings)
        mimedata.setData('bstream', bstream)        
        return mimedata


    def dropMimeData(self, action, mimedata, row):

        if action == QtCore.Qt.IgnoreAction: return True  

        dropped=cPickle.loads(str(mimedata.data('bstream')))

        self.emit(QtCore.SIGNAL("dropped"), dropped)  

        return True


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)
        self.listWidgetB = ThumbListWidget(self)

        for i in range(7):
            listItemAInstance=MyClassItem()
            listItemAInstance.setText('A'+'%04d'%i)
            listItemAInstance.setBackgroundColor(QtCore.Qt.darkGray)   
            if i%2: listItemAInstance.setBackgroundColor(QtCore.Qt.gray)
            self.listWidgetA.addItem(listItemAInstance) 

            listItemBInstance=MyClassItem()
            listItemBInstance.setText('B'+'%04d'%i)

            if i%2: listItemBInstance.setBackgroundColor(QtCore.Qt.lightGray)
            self.listWidgetB.addItem(listItemBInstance) 

            self.listItems[str(listItemAInstance)]=listItemAInstance
            self.listItems[str(listItemBInstance)]=listItemBInstance

        myBoxLayout.addWidget(self.listWidgetA)      

        myBoxLayout.addWidget(self.listWidgetB)   
        self.connect(self.listWidgetA, QtCore.SIGNAL("dropped"), self.droppedOnA)
        self.connect(self.listWidgetB, QtCore.SIGNAL("dropped"), self.droppedOnB)


    def droppedOnA(self, droppedItemsAsStrings):
        print '\n\t droppedOnA()'
        for each in droppedItemsAsStrings:
            if each in self.listItems.keys():
                droppedItemInstance = self.listItems[each]
                print 'adding', droppedItemInstance.text()
                self.listWidgetA.addItem(droppedItemInstance) 


    def droppedOnB(self, droppedItemsAsStrings):
        print '\n\t droppedOnB()'
        for each in droppedItemsAsStrings:
            if each in self.listItems.keys():
                droppedItemInstance = self.listItems[each]
                self.listWidgetB.addItem(droppedItemInstance) 
                print 'adding', droppedItemInstance.text()


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

推荐答案

这里是修改后的代码.它就像一个魅力！好样的！

Here is a revised code. It is working like a charm! Bravo!

from PyQt4 import QtGui, QtCore
import sys, os

class ThumbListWidget(QtGui.QListWidget):
    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)

    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):
        print 'dropEvent', 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:
            event.setDropAction(QtCore.Qt.MoveAction)
            super(ThumbListWidget, self).dropEvent(event)


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 )
        myBoxLayout.addWidget(self.listWidgetA)

        self.listWidgetB = ThumbListWidget(self)
        myBoxLayout.addWidget(self.listWidgetB)   

        self.connect(self.listWidgetA, QtCore.SIGNAL("dropped"), self.items_dropped)
        self.listWidgetA.currentItemChanged.connect(self.item_clicked)

        self.connect(self.listWidgetB, QtCore.SIGNAL("dropped"), self.items_dropped)
        self.listWidgetB.currentItemChanged.connect(self.item_clicked)

    def items_dropped(self, arg):
        print 'items_dropped', arg

    def item_clicked(self, arg):
        print arg

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

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