openlp/openlp/core/lib/listwidgetwithdnd.py

# -*- coding: utf-8 -*-
# vim: autoindent shiftwidth=4 expandtab textwidth=80 tabstop=4 softtabstop=4

###############################################################################
# OpenLP - Open Source Lyrics Projection                                      #
# --------------------------------------------------------------------------- #
# Copyright (c) 2008-2011 Raoul Snyman                                        #
# Portions copyright (c) 2008-2011 Tim Bentley, Gerald Britton, Jonathan      #
# Corwin, Michael Gorven, Scott Guerrieri, Matthias Hub, Meinert Jordan,      #
# Armin Köhler, Joshua Millar, Stevan Pettit, Andreas Preikschat, Mattias     #
# Põldaru, Christian Richter, Philip Ridout, Jeffrey Smith, Maikel            #
# Stuivenberg, Martin Thompson, Jon Tibble, Frode Woldsund                    #
# --------------------------------------------------------------------------- #
# This program is free software; you can redistribute it and/or modify it     #
# under the terms of the GNU General Public License as published by the Free  #
# Software Foundation; version 2 of the License.                              #
#                                                                             #
# This program is distributed in the hope that it will be useful, but WITHOUT #
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or       #
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for    #
# more details.                                                               #
#                                                                             #
# You should have received a copy of the GNU General Public License along     #
# with this program; if not, write to the Free Software Foundation, Inc., 59  #
# Temple Place, Suite 330, Boston, MA 02111-1307 USA                          #
###############################################################################
"""
Extend QListWidget to handle drag and drop functionality
"""
from PyQt4 import QtCore, QtGui

class ListWidgetWithDnD(QtGui.QListWidget):
    """
    Provide a list widget to store objects and handle drag and drop events
    """
    def __init__(self, parent=None, name=u''):
        """
        Initialise the list widget
        """
        QtGui.QListWidget.__init__(self, parent)
        self.mimeDataText = name
        assert(self.mimeDataText)

    def mouseMoveEvent(self, event):
        """
        Drag and drop event does not care what data is selected
        as the recipient will use events to request the data move
        just tell it what plugin to call
        """
        if event.buttons() != QtCore.Qt.LeftButton:
            event.ignore()
            return
        if not self.selectedItems():
            event.ignore()
            return
        drag = QtGui.QDrag(self)
        mimeData = QtCore.QMimeData()
        drag.setMimeData(mimeData)
        mimeData.setText(self.mimeDataText)
        drag.start(QtCore.Qt.CopyAction)