PyQT4：将文件拖放到QListWidget中

Question

我最近在做一个OCR书籍扫描的项目（它通过读取页码来重命名页面），现在已经从简单的命令行脚本转到图形用户界面（GUI）了。

我在使用PyQT4，并且查阅了很多关于拖放功能的文档，但都没有成功。它就是不接受那些文件！我在设计用户界面时参考了这两篇文章：

1. http://tech.xster.net/tips/pyqt-drag-images-into-list-widget-for-thumbnail-list/

2. http://zetcode.com/tutorials/pyqt4/dragdrop/

我注意到有很多种方法可以设置PyQT4的图形界面。哪一种效果最好呢？

哦，对了，这里是项目的源代码。

主要脚本：

import sys
from PyQt4 import QtCore
from PyQt4 import QtGui
from PyQt4.QtGui import QListWidget
from layout import Ui_window

class StartQT4(QtGui.QMainWindow):
  def __init__(self, parent = None):
    QtGui.QWidget.__init__(self, parent)

    self.ui = Ui_window()
    self.ui.setupUi(self)

    QtCore.QObject.connect(self.ui.listWidget, QtCore.SIGNAL("dropped"), self.picture_dropped)

  def picture_dropped(self, l):
    for url in l:
     if os.path.exists(url):
      picture = Image.open(url)
      picture.thumbnail((72, 72), Image.ANTIALIAS)
      icon = QIcon(QPixmap.fromImage(ImageQt.ImageQt(picture)))
      item = QListWidgetItem(os.path.basename(url)[:20] + "...", self.pictureListWidget)
      item.setStatusTip(url)
      item.setIcon(icon)

class DragDropListWidget(QListWidget):
 def __init__(self, type, parent = None):
  super(DragDropListWidget, self).__init__(parent)
  self.setAcceptDrops(True)
  self.setIconSize(QSize(72, 72))

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

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

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

if __name__ == "__main__":
  app = QtGui.QApplication(sys.argv)
  myapp = StartQT4()
  myapp.show()
  sys.exit(app.exec_())

还有用户界面文件...

# Form implementation generated from reading ui file 'layout.ui'
#
# Created: Thu Nov 11 00:22:52 2010
#      by: PyQt4 UI code generator 4.8.1
#
# WARNING! All changes made in this file will be lost!

from PyQt4 import QtCore, QtGui

try:
    _fromUtf8 = QtCore.QString.fromUtf8
except AttributeError:
    _fromUtf8 = lambda s: s

class Ui_window(object):
    def setupUi(self, window):
        window.setObjectName(_fromUtf8("window"))
        window.resize(543, 402)
        window.setAcceptDrops(True)
        self.centralwidget = QtGui.QWidget(window)
        self.centralwidget.setObjectName(_fromUtf8("centralwidget"))
        self.verticalLayout = QtGui.QVBoxLayout(self.centralwidget)
        self.verticalLayout.setObjectName(_fromUtf8("verticalLayout"))
        self.listWidget = QtGui.QListWidget(self.centralwidget)
        self.listWidget.setProperty(_fromUtf8("cursor"), QtCore.Qt.SizeHorCursor)
        self.listWidget.setAcceptDrops(True)
        self.listWidget.setObjectName(_fromUtf8("listWidget"))
        self.verticalLayout.addWidget(self.listWidget)
        window.setCentralWidget(self.centralwidget)

        self.retranslateUi(window)
        QtCore.QMetaObject.connectSlotsByName(window)

    def retranslateUi(self, window):
        window.setWindowTitle(QtGui.QApplication.translate("window", "PyNamer OCR", None, QtGui.QApplication.UnicodeUTF8))

感谢任何能提供帮助的人！

Answer 1

你用的示例代码看起来运行得不错，而且写得很简洁。根据你的评论，你的列表小部件没有被初始化，这应该是你遇到问题的根本原因。我稍微简化了一下你的代码，并在我的Ubuntu 10.04LTS上试了一下，结果也很好。下面是我的代码，看看能不能对你有帮助。你应该能够把文件拖放到列表小部件里；一旦放下，就会添加一个新项目，显示图片和图片的文件名。

import sys
import os
from PyQt4 import QtGui, QtCore

class TestListView(QtGui.QListWidget):
    def __init__(self, type, parent=None):
        super(TestListView, self).__init__(parent)
        self.setAcceptDrops(True)
        self.setIconSize(QtCore.QSize(72, 72))

    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 MainForm(QtGui.QMainWindow):
    def __init__(self, parent=None):
        super(MainForm, self).__init__(parent)

        self.view = TestListView(self)
        self.connect(self.view, QtCore.SIGNAL("dropped"), self.pictureDropped)
        self.setCentralWidget(self.view)

    def pictureDropped(self, l):
        for url in l:
            if os.path.exists(url):
                print(url)                
                icon = QtGui.QIcon(url)
                pixmap = icon.pixmap(72, 72)                
                icon = QtGui.QIcon(pixmap)
                item = QtGui.QListWidgetItem(url, self.view)
                item.setIcon(icon)        
                item.setStatusTip(url)        

def main():
    app = QtGui.QApplication(sys.argv)
    form = MainForm()
    form.show()
    app.exec_()

if __name__ == '__main__':
    main()

希望这能帮到你，祝好