Updating A Qtablewidget From Contextmenu Linedit-pyqt

I have a QTableWidget with which I would like to update from a QLinEdit embedded into a context menu. Now, in the QLinEdit a server name is entered, when the key is pressed the pr

Solution 1:

The design of your handleHeaderMenu is a bit off. One of the main issues with the way it is currently structured is that you connect a signal to the QLineEditafter the popup menu has already finished. So you would miss that signal.

action = self.menu.exec_(QtGui.QCursor.pos())
self.connect(self.custom_choice, 
                QtCore.SIGNAL("returnPressed()"),
                self.refreshdata)

QMenu.exec_() is a blocking call. It starts the event loop for the menu and waits for it to finish. Once it closes and returns the QAction that was selected, you then make a connection. I will get into a correction for this after my next point...

The menu you are building from scratch each time doesn't have to be saved to member attributes and used externally. There are two ways to go about doing a custom popup menu. If its primarily static, then you can build it once in your class init, or make it it's own class, and then just reuse the instance. Or in your case, you could build it up each time which is fine. But instead of relying on persistant references to the components of the menu and using a signal, why not just build it temporarily, and explicitly handle the results?

defhandleHeaderMenu(self, pos):
    menu = QtGui.QMenu()
    menu.setStyleSheet("""
        QMenu::item {
            background-color: #264F7D;
            color: white; 
            font-weight:bold;}
    """)
    text = menu.addAction("Choose Server to Monitor:")
    text.setEnabled(False)
    menu.addSeparator()

    actionJuliet = menu.addAction('Juliet')
    actionJulietleft = menu.addAction('JulietLeft')
    actionPong = menu.addAction('Pong')
    actionHulk = menu.addAction('Hulk')

    wac = QtGui.QWidgetAction(menu)
    custom_choice = QtGui.QLineEdit()
    custom_choice.setPlaceholderText("Server")
    wac.setDefaultWidget(custom_choice)
    menu.addAction(wac)

    menu.setActiveAction(wac)
    custom_choice.returnPressed.connect(wac.trigger)

    action = menu.exec_(QtGui.QCursor.pos())
    if action:
        if action == wac:
            self.tx = str(custom_choice.text()).strip()
        else:
            self.tx = str(action.text())

        self.refreshdata()

defrefreshdata(self):
    print self.tx

Here we just create a bunch of temp widgets for the menu that will get garbage collected. After showing the menu, we check the returned action and then manually set our table attribute, and call refresh. Also, we needed to set the signal from the custom QLineEdit to trigger its widget action internally.

Lastly, is it really necessary to do 8 sql queries and a whole bunch of data reorganizing every time you want to load this data? This could be highly simplified:

defget_data(self):

    table_check = """
        SELECT table_name FROM information_schema.tables 
        WHERE table_schema = %s AND table_name = %s 
        """

    table_name = self.tx
    count = self.model.execute(table_check, (self.theDatabaseName, table_name))
    ifnot count:
        # warn the user that the table name does not exist
        warn_user_of_bad_table()
        return

    sql = """
        SELECT 
            computer_name, idle_time, files_opened, 
            active_time, session_type, cpu, avg_disk_queue
        FROM %s 
        """ % table_name

    count = self.model.execute(sql)
    ifnot count:
        warn_database_error()
        return

    results = self.model.fetchall()
    user, idle , files, active, session, cpu, disk = zip(*results)
    self.lista = user
    self.listb = disk
    self.listc = cpu
    self.listd = active
    self.liste = files
    self.listf = session
    self.listg = idle  
    self.mystruct2 = {
        'A' : self.lista, 
        'B' : self.listb, 
        'C' : self.listc,
        'E' : self.liste,
        'D' : self.listd,
        'F' : self.listf,
        'G' : self.listg
    }

You only need two queries here. The first really simple one to check if the table exists, by using the scheme, instead of parsing through a big SHOW TABLES output. And the second which gets all your data in one query (as a bunch of rows, and then uses zip to regroup them into columns.