c/c++语言开发共享PyQt5使用mimeData实现拖拽事件教程示例解析下

目录

• 实现思路
• 1、简要介绍qmimedata
• 2、qmimedata的用例1
• 在qt实现外部文件拖拽并展示
• 3、qmimedata的用例2
• 两个qlistwidget之间的item交换

  # -*- coding: utf-8 -*-  import sys  from pyqt5.qtwidgets import qapplication, qmainwindow, qtextedit  from pyqt5.qtcore import qiodevice, qfile  class complexdrag(qmainwindow):      def __init__(self):          super(complexdrag, self).__init__()          self.setacceptdrops(true)          self.texteditor = none          self.initui()      def initui(self):          self.texteditor = qtextedit()          self.setcentralwidget(self.texteditor)          self.texteditor.setacceptdrops(false)          self.setacceptdrops(true)          self.setwindowtitle("拖拽")      def dragenterevent(self, event):          if event.mimedata().hasformat("text/uri-list"):          	# 关于这个函数和accept的区别在下面会展示              event.acceptproposedaction()      def dropevent(self, event):          urls = event.mimedata().urls()          if urls == "":              return          filename = urls.pop().tolocalfile()          if filename == "":              return          if self.readfile(filename):              self.setwindowtitle("drag file success")      def readfile(self, filename):          r = false          file = qfile(filename)          content = ""          if file.open(qiodevice.readonly):              content = file.readall()              r = true          self.texteditor.settext(str(content, "utf-8"))          return r  if __name__ == '__main__':      app = qapplication(sys.argv)      ex = complexdrag()      ex.show()      app.exec_()  

  # -*- coding: utf-8 -*-  import sys  from threading import event  from pyqt5.qtgui import qdrag, qpixmap  from pyqt5.qtwidgets import qapplication, qhboxlayout, qlistwidget, qdialog  from pyqt5.qtcore import qmimedata, qt  class mainwindow(qdialog):      def __init__(self):          super(mainwindow, self).__init__()          self.projecta = complexdrag(self)          self.projectb = complexdrag(self)          self.projecta.additem("giosue carducci")          self.projecta.additem("eyvind johnson")          self.projecta.additem("sally prudhomme")          self.projecta.additem("henryk sienkiewicz")          self.projecta.additem("carl spitteler")          self.projecta.additem("rabindranath tagore")          self.projecta.additem("kawabata yasunari")          self.projectb.additem("rudolf eucken")          self.projectb.additem("anatole france")          self.projectb.additem("rudyard kipling")          self.projectb.additem("thomas mann")          self.projectb.additem("eugene o'neill")          self.projectb.additem("sigrid undset")          lay = qhboxlayout()          lay.addwidget(self.projecta)          lay.addwidget(self.projectb)          self.setlayout(lay)  class complexdrag(qlistwidget):      ondropevent = event()      def __init__(self, parent=none):          super(complexdrag, self).__init__(parent)          self.setacceptdrops(true)          self.startpos = none      def removesel(self):          listitems = self.selecteditems()          if not listitems:              return          for item in listitems:              self.takeitem(self.row(item))      def mousepressevent(self, event):          if event.button() == qt.leftbutton:              self.startpos = event.pos()          super(complexdrag, self).mousepressevent(event)      def mousemoveevent(self, event):          distance = (event.pos() - self.startpos).manhattanlength()          if distance >= qapplication.startdragdistance():              item = self.currentitem()              if item:                  mimedata = qmimedata()                  mimedata.settext(item.text())                  drag = qdrag(self)                  drag.setmimedata(mimedata)                  pixmap = qpixmap("computer.svg").scaled(20, 20, qt.keepaspectratio)                  drag.setpixmap(pixmap)                  self.removeitemwidget(item)                  if drag.exec(qt.moveaction) == qt.moveaction:                      self.removesel()          super(complexdrag, self).mousemoveevent(event)      def dragmoveevent(self, event):          source = event.source()          if source and source != self:              event.setdropaction(qt.moveaction)      def dragenterevent(self, event):          source = event.source()          if source and source != self:              event.setdropaction(qt.moveaction)              event.accept()      def dropevent(self, event):          source = event.source()          if source and source != self:              self.additem(event.mimedata().text())              event.setdropaction(qt.moveaction)  if __name__ == '__main__':      app = qapplication(sys.argv)      ex = mainwindow()      ex.show()      app.exec_()    

  if drag.exec(qt.moveaction) == qt.moveaction:     self.removesel()