from PyQt4 import QtCore, QtGui, uic

class MainWidget(QtGui.QMainWindow):
    def __init__(self, parent):
        QtGui.QMainWindow.__init__(self, parent)
        uiClass, baseClass = uic.loadUiType('main.ui')
        icon = QtGui.QIcon('icon.png')
        self.setWindowIcon(icon)
        self.ui = uiClass()
        self.ui.setupUi(self)
        self.tbicon = QtGui.QSystemTrayIcon(icon)
        self.tbicon.show()
        self.tbicon.showMessage(u'title',u'text',self.tbicon.MessageIcon(2), 3000)
        trayMenu = QtGui.QMenu(self)
        quitAction = QtGui.QAction(u'Выход', self)
        QtCore.QObject.connect(quitAction, QtCore.SIGNAL("triggered()"), QtGui.qApp, QtCore.SLOT("quit()"))
        trayMenu.addAction(quitAction)
        self.tbicon.setContextMenu(trayMenu)

class App(QtGui.QApplication):
    def __init__(self, argv):
        QtGui.QApplication.__init__(self, argv)
        self.ui = MainWidget(None)
        self.ui.show()
        self.setQuitOnLastWindowClosed(True)

if __name__ == '__main__':
    import sys
    app = App(sys.argv)
    sys.exit(app.exec_())

QApplication::qAppName: Please instantiate the QApplication object first

    
traySignal = "activated(QSystemTrayIcon::ActivationReason)"

def __icon_activated(self, reason):
        if reason == QSystemTrayIcon.DoubleClick and self.isVisible() == False:
            self.show()
        elif reason == QSystemTrayIcon.DoubleClick and self.isVisible() == True:
            self.hide()