python3+PyQt5重新实现自定义数据拖放处理

本文分成两部分，第一部分通过python3+pyqt5实现自定义数据的拖放操作。第二部分则对第一部分的程序进行修改，增加拖放操作时，菜单提示是否移动或拷贝，还有可以通过ctrl键盘来设置移动过程中拷贝源而非会将源删除。

自定义数据mime数据类型qmimedata，mime是一种用于处理具有多个组成部分的自定义数据的标准化格式。mime数据由一个数据类型和一个子类型构成–例如，text/plain，text/html，image/png，要处理自定义mime数据，就必须要选用一种自定义数据类型和一种子类型，然后将数据封装到qmimedata对象中。本例子中，我们创建端为application/x-icon-and-text类型的新mime数据。

注：

dragenterevent这是一个拖拽事件的函数，我们把文件拖拽进程序界面打开，之前必须setacceptdrops(true)了以后拖拽，但是只设置acceptdrops还不够，还需要在dragenterevent事件中对拖入的对象进行筛选，判断mimedata的类型是否是你能处理的，如果是，则调用event.acceptproposedaction()放行。拖放结束后会产生dropevent事件，在那里进行最后的放置操作。总之这是拖拽事件函数的一个筛选事件并放置的函数。

第一部分：

#!/usr/bin/env python3
import os
import sys
from pyqt5.qtcore import (qbytearray, qdatastream, qiodevice, qmimedata,
    qpoint, qsize, qt)
from pyqt5.qtwidgets import (qapplication, qdialog,qgridlayout,
               qlineedit, qlistwidget,qlistwidgetitem, qwidget)
from pyqt5.qtgui import qicon,qcolor,qpainter,qfontmetricsf,qdrag

class droplineedit(qlineedit):

  def __init__(self, parent=none):
    super(droplineedit, self).__init__(parent)
    self.setacceptdrops(true)


  def dragenterevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      event.accept()
    else:
      event.ignore()


  def dragmoveevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      event.setdropaction(qt.copyaction)
      event.accept()
    else:
      event.ignore()


  def dropevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      data = event.mimedata().data("application/x-icon-and-text")
      stream = qdatastream(data, qiodevice.readonly)
      text = ""
      #stream >> text
      text=stream.readqstring()
      self.settext(text)
      event.setdropaction(qt.copyaction)
      event.accept()
    else:
      event.ignore()


class dndlistwidget(qlistwidget):

  def __init__(self, parent=none):
    super(dndlistwidget, self).__init__(parent)
    self.setacceptdrops(true)
    self.setdragenabled(true)


  def dragenterevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      event.accept()
    else:
      event.ignore()


  def dragmoveevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      event.setdropaction(qt.moveaction)
      event.accept()
    else:
      event.ignore()


  def dropevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      data = event.mimedata().data("application/x-icon-and-text")
      stream = qdatastream(data, qiodevice.readonly)
      text = ""
      icon = qicon()
      #stream >> text >> icon
      text=stream.readqstring()
      stream >> icon
      item = qlistwidgetitem(text, self)
      item.seticon(icon)
      event.setdropaction(qt.moveaction)
      event.accept()
    else:
      event.ignore()


  def startdrag(self, dropactions):
    item = self.currentitem()
    icon = item.icon()
    data = qbytearray()
    stream = qdatastream(data, qiodevice.writeonly)
    #stream << item.text() << icon
    stream.writeqstring(item.text())
    stream << icon
    mimedata = qmimedata()
    mimedata.setdata("application/x-icon-and-text", data)
    drag = qdrag(self)
    drag.setmimedata(mimedata)
    pixmap = icon.pixmap(24, 24)
    drag.sethotspot(qpoint(12, 12))
    drag.setpixmap(pixmap)
    if drag.exec(qt.moveaction) == qt.moveaction:
      self.takeitem(self.row(item))


class dndwidget(qwidget):

  def __init__(self, text, icon=qicon(), parent=none):
    super(dndwidget, self).__init__(parent)
    self.setacceptdrops(true)
    self.text = text
    self.icon = icon


  def minimumsizehint(self):
    fm = qfontmetricsf(self.font())
    if self.icon.isnull():
      return qsize(fm.width(self.text), fm.height() * 1.5)
    return qsize(34 + fm.width(self.text), max(34, fm.height() * 1.5))


  def paintevent(self, event):
    height = qfontmetricsf(self.font()).height()
    painter = qpainter(self)
    painter.setrenderhint(qpainter.antialiasing)
    painter.setrenderhint(qpainter.textantialiasing)
    painter.fillrect(self.rect(), qcolor(qt.yellow).lighter())
    if self.icon.isnull():
      painter.drawtext(10, height, self.text)
    else:
      pixmap = self.icon.pixmap(24, 24)
      painter.drawpixmap(0, 5, pixmap)
      painter.drawtext(34, height,
               self.text + " (drag to or from me!)")


  def dragenterevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      event.accept()
    else:
      event.ignore()


  def dragmoveevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      event.setdropaction(qt.copyaction)
      event.accept()
    else:
      event.ignore()


  def dropevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      data = event.mimedata().data("application/x-icon-and-text")
      stream = qdatastream(data, qiodevice.readonly)
      self.text = ""
      self.icon = qicon()
      #stream >> self.text >> self.icon
      self.text=stream.readqstring()
      stream>>self.icon

      event.setdropaction(qt.copyaction)
      event.accept()
      self.updategeometry()
      self.update()
    else:
      event.ignore()


  def mousemoveevent(self, event):
    self.startdrag()
    qwidget.mousemoveevent(self, event)


  def startdrag(self):
    icon = self.icon
    if icon.isnull():
      return
    data = qbytearray()
    stream = qdatastream(data, qiodevice.writeonly)
    #stream << self.text << icon
    stream.writeqstring(self.text)
    stream<<icon
    mimedata = qmimedata()
    mimedata.setdata("application/x-icon-and-text", data)
    drag = qdrag(self)
    drag.setmimedata(mimedata)
    pixmap = icon.pixmap(24, 24)
    drag.sethotspot(qpoint(12, 12))
    drag.setpixmap(pixmap)
    drag.exec(qt.copyaction)


class form(qdialog):

  def __init__(self, parent=none):
    super(form, self).__init__(parent)

    dndlistwidget = dndlistwidget()
    path = os.path.dirname(__file__)
    for image in sorted(os.listdir(os.path.join(path, "images"))):
      if image.endswith(".png"):
        item = qlistwidgetitem(image.split(".")[0].capitalize())
        item.seticon(qicon(os.path.join(path,
                  "images/{0}".format(image))))
        dndlistwidget.additem(item)
    dndiconlistwidget = dndlistwidget()
    dndiconlistwidget.setviewmode(qlistwidget.iconmode)
    dndwidget = dndwidget("drag to me!")
    droplineedit = droplineedit()

    layout = qgridlayout()
    layout.addwidget(dndlistwidget, 0, 0)
    layout.addwidget(dndiconlistwidget, 0, 1)
    layout.addwidget(dndwidget, 1, 0)
    layout.addwidget(droplineedit, 1, 1)
    self.setlayout(layout)

    self.setwindowtitle("custom drag and drop")

if __name__ == "__main__":
  app = qapplication(sys.argv)
  form = form()
  form.show()
  app.exec_()

运行结果：

第二部分：

#!/usr/bin/env python3
import os
import sys
from pyqt5.qtcore import (qbytearray, qdatastream, qiodevice, qmimedata,
    qpoint, qsize, qt)
from pyqt5.qtwidgets import (qapplication, qdialog,qgridlayout,
               qlineedit, qlistwidget,qlistwidgetitem, qwidget,qmenu)
from pyqt5.qtgui import qicon,qcolor,qpainter,qfontmetricsf,qdrag,qcursor

class droplineedit(qlineedit):

  def __init__(self, parent=none):
    super(droplineedit, self).__init__(parent)
    self.setacceptdrops(true)


  def dragenterevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      event.accept()
    else:
      event.ignore()


  def dragmoveevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      event.setdropaction(qt.copyaction)
      event.accept()
    else:
      event.ignore()


  def dropevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      data = event.mimedata().data("application/x-icon-and-text")
      stream = qdatastream(data, qiodevice.readonly)
      text = ""
      text=stream.readqstring()
      self.settext(text)
      event.setdropaction(qt.copyaction)
      event.accept()
    else:
      event.ignore()


class dndmenulistwidget(qlistwidget):

  def __init__(self, parent=none):
    super(dndmenulistwidget, self).__init__(parent)
    self.setacceptdrops(true)
    self.setdragenabled(true)
    self.dropaction = qt.copyaction


  def dragenterevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      event.accept()
    else:
      event.ignore()


  def dragmoveevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      event.setdropaction(qt.moveaction)
      event.accept()
    else:
      event.ignore()


  def dropevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      data = event.mimedata().data("application/x-icon-and-text")
      stream = qdatastream(data, qiodevice.readonly)
      text = ""
      icon = qicon()
      text=stream.readqstring()
      stream>>icon
      menu = qmenu(self)
      menu.addaction("&copy", self.setcopyaction)
      menu.addaction("&move", self.setmoveaction)
      if menu.exec_(qcursor.pos()):
        item = qlistwidgetitem(text, self)
        item.seticon(icon)
        event.setdropaction(self.dropaction)
        event.accept()
        return
      else:
        event.setdropaction(qt.ignoreaction)
    event.ignore()


  def setcopyaction(self):
    self.dropaction = qt.copyaction


  def setmoveaction(self):
    self.dropaction = qt.moveaction


  def startdrag(self, dropactions):
    item = self.currentitem()
    icon = item.icon()
    data = qbytearray()
    stream = qdatastream(data, qiodevice.writeonly)
    stream.writeqstring(item.text())
    stream<<icon
    mimedata = qmimedata()
    mimedata.setdata("application/x-icon-and-text", data)
    drag = qdrag(self)
    drag.setmimedata(mimedata)
    pixmap = icon.pixmap(24, 24)
    drag.sethotspot(qpoint(12, 12))
    drag.setpixmap(pixmap)
    if (drag.exec(qt.moveaction|qt.copyaction) == qt.moveaction):
      self.takeitem(self.row(item))


class dndctrllistwidget(qlistwidget):

  def __init__(self, parent=none):
    super(dndctrllistwidget, self).__init__(parent)
    self.setacceptdrops(true)
    self.setdragenabled(true)


  def dragenterevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      event.accept()
    else:
      event.ignore()


  def dragmoveevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      action = qt.moveaction
      if event.keyboardmodifiers() & qt.controlmodifier:
        action = qt.copyaction
      event.setdropaction(action)
      event.accept()
    else:
      event.ignore()


  def dropevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      data = event.mimedata().data("application/x-icon-and-text")
      stream = qdatastream(data, qiodevice.readonly)
      text = ""
      icon = qicon()
      text=stream.readqstring()
      stream>>icon
      item = qlistwidgetitem(text, self)
      item.seticon(icon)
      action = qt.moveaction
      if event.keyboardmodifiers() & qt.controlmodifier:
        action = qt.copyaction
      event.setdropaction(action)
      event.accept()
    else:
      event.ignore()


  def startdrag(self, dropactions):
    item = self.currentitem()
    icon = item.icon()
    data = qbytearray()
    stream = qdatastream(data, qiodevice.writeonly)
    stream.writeqstring(item.text())
    stream<<icon
    mimedata = qmimedata()
    mimedata.setdata("application/x-icon-and-text", data)
    drag = qdrag(self)
    drag.setmimedata(mimedata)
    pixmap = icon.pixmap(24, 24)
    drag.sethotspot(qpoint(12, 12))
    drag.setpixmap(pixmap)
    if (drag.exec(qt.moveaction|qt.copyaction) == qt.moveaction):
      self.takeitem(self.row(item))


class dndwidget(qwidget):

  def __init__(self, text, icon=qicon(), parent=none):
    super(dndwidget, self).__init__(parent)
    self.setacceptdrops(true)
    self.text = text
    self.icon = icon


  def minimumsizehint(self):
    fm = qfontmetricsf(self.font())
    if self.icon.isnull():
      return qsize(fm.width(self.text), fm.height() * 1.5)
    return qsize(34 + fm.width(self.text), max(34, fm.height() * 1.5))


  def paintevent(self, event):
    height = qfontmetricsf(self.font()).height()
    painter = qpainter(self)
    painter.setrenderhint(qpainter.antialiasing)
    painter.setrenderhint(qpainter.textantialiasing)
    painter.fillrect(self.rect(), qcolor(qt.yellow).lighter())
    if self.icon.isnull():
      painter.drawtext(10, height, self.text)
    else:
      pixmap = self.icon.pixmap(24, 24)
      painter.drawpixmap(0, 5, pixmap)
      painter.drawtext(34, height,
               self.text + " (drag to or from me!)")


  def dragenterevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      event.accept()
    else:
      event.ignore()


  def dragmoveevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      event.setdropaction(qt.copyaction)
      event.accept()
    else:
      event.ignore()


  def dropevent(self, event):
    if event.mimedata().hasformat("application/x-icon-and-text"):
      data = event.mimedata().data("application/x-icon-and-text")
      stream = qdatastream(data, qiodevice.readonly)
      self.text = ""
      self.icon = qicon()
      self.text=stream.readqstring()
      stream>>self.icon

      event.setdropaction(qt.copyaction)
      event.accept()
      self.updategeometry()
      self.update()
    else:
      event.ignore()


  def mousemoveevent(self, event):
    self.startdrag()
    qwidget.mousemoveevent(self, event)


  def startdrag(self):
    icon = self.icon
    if icon.isnull():
      return
    data = qbytearray()
    stream = qdatastream(data, qiodevice.writeonly)
    stream.writeqstring(self.text)
    stream<<icon
    mimedata = qmimedata()
    mimedata.setdata("application/x-icon-and-text", data)
    drag = qdrag(self)
    drag.setmimedata(mimedata)
    pixmap = icon.pixmap(24, 24)
    drag.sethotspot(qpoint(12, 12))
    drag.setpixmap(pixmap)
    drag.exec(qt.copyaction)


class form(qdialog):

  def __init__(self, parent=none):
    super(form, self).__init__(parent)

    dndlistwidget = dndmenulistwidget()
    path = os.path.dirname(__file__)
    for image in sorted(os.listdir(os.path.join(path, "images"))):
      if image.endswith(".png"):
        item = qlistwidgetitem(image.split(".")[0].capitalize())
        item.seticon(qicon(os.path.join(path,
                  "images/{0}".format(image))))
        dndlistwidget.additem(item)
    dndiconlistwidget = dndctrllistwidget()
    dndiconlistwidget.setviewmode(qlistwidget.iconmode)
    dndwidget = dndwidget("drag to me!")
    droplineedit = droplineedit()

    layout = qgridlayout()
    layout.addwidget(dndlistwidget, 0, 0)
    layout.addwidget(dndiconlistwidget, 0, 1)
    layout.addwidget(dndwidget, 1, 0)
    layout.addwidget(droplineedit, 1, 1)
    self.setlayout(layout)

    self.setwindowtitle("custom drag and drop")

if __name__ == "__main__":
  app = qapplication(sys.argv)
  form = form()
  form.show()
  app.exec_()

运行结果：

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。