qt single instance solution for PySide qt 4.7

据说，qt本来是有一个 QtSolution这么个东西的，后来更新不及时。

没有对应qt 4.7的版本。

经google，发现PySide官网就有解药。

http://developer.qt.nokia.com/forums/viewthread/5733

下面是大致解法说明。

// try to connect to your server
m_socket = QLocalSocket()
m_socket.connectToServer(qApp.applicationName(), QIODevice.ReadOnly)

//If this fail is because the app is not running then create the server, then in the next time the connect will work
m_server = QLocalServer()
m_server = QLocalServer.listen(qApp.applicationName())

晚点搞一个完整版本来试试看。

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再仔细一看，该页面最后一行，有人已经有解法了。

http://www.dallagnese.fr/en/computers-it/recette-python-qt4-qsingleapplication-pyside/

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"""
    The MIT License

    Copyright 2011 Thomas Dall'Agnese <thomas.dallagnese@gmail.com>

    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in
    all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    THE SOFTWARE.

"""
__author__ = "Thomas Dall'Agnese"
__email__ = "thomas.dallagnese@gmail.com"
__version__ = "1.0"
__URL__ = "http://www.dallagnese.fr"

from PySide.QtGui import QMessageBox, QApplication
from PySide.QtCore import QIODevice, QTimer, QCoreApplication
from PySide.QtNetwork import QLocalServer, QLocalSocket
import sys

class QSingleApplication(QApplication):
    def singleStart(self, mainWindow):
        self.mainWindow = mainWindow
        # Socket
        self.m_socket = QLocalSocket()
        self.m_socket.connected.connect(self.connectToExistingApp)
        self.m_socket.error.connect(self.startApplication)
        self.m_socket.connectToServer(self.applicationName(), QIODevice.WriteOnly)
    def connectToExistingApp(self):
        if len(sys.argv)>1 and sys.argv[1] is not None:
            self.m_socket.write(sys.argv[1])
            self.m_socket.bytesWritten.connect(self.quit)
        else:
            QMessageBox.warning(None, self.tr("Already running"), self.tr("The program is already running."))
            # Quit application in 250 ms
            QTimer.singleShot(250, self.quit)
    def startApplication(self):
        self.m_server = QLocalServer()
        if self.m_server.listen(self.applicationName()):
            self.m_server.newConnection.connect(self.getNewConnection)
            self.mainWindow.show()
        else:
            QMessageBox.critical(None, self.tr("Error"), self.tr("Error listening the socket."))
    def getNewConnection(self):
        self.new_socket = self.m_server.nextPendingConnection()
        self.new_socket.readyRead.connect(self.readSocket)
    def readSocket(self):
        f = self.new_socket.readLine()
        self.mainWindow.getArgsFromOtherInstance(str(f))
        self.mainWindow.activateWindow()
        self.mainWindow.show()

if __name__ == '__main__':
    from PySide.QtGui import QMainWindow, QLabel
    class DallAgneseWindow(QMainWindow):
        def __init__(self):
            QMainWindow.__init__(self)
            self.setWindowTitle("QSingleApplication Demo")
            labelText = "<b>dallagnese.fr recipe</b><br /><br />\
                        Allows you to start your program only once.<br />\
                        Parameters of later calls can be handled by this application."
            self.setCentralWidget(QLabel(labelText))
        def getArgsFromOtherInstance(self, args):
            QMessageBox.information(self, self.tr("Received args from another instance"),args)
    app = QSingleApplication(sys.argv)
    app.setApplicationName("dallagnese.fr recipe 01")
    myWindow = DallAgneseWindow()
    app.singleStart(myWindow)
    sys.exit(app.exec_())