I'm building a Qt client for the open-source client/server 4X strategy game Thousand Parsec. This a Google Summer of Code project. I'm however stuck at a dead end. Basically, the client interfaces with the server via a C++ protocol layer that facilitates client/server communication. The protocol's documentation is available here.
Now my problem is that the protocol requires you to create a subclass of the virtual EventLoop class (link) in your client. There is an example SimpleEventLoop used for console clients on the same link. I'm having difficulty figuring out how I can design my own event loop subclass that handles the protocol's events while hooking into the Qt application at the same time. My research has lead me to believe QAbstractEventDispatcher is the Qt class I want to use but the documentation seems pretty slim and I'm not exactly sure how I would go about doing this.
Does anyone else have experience linking external event loops with a Qt application? I've also found this example on the Qt page but it wasn't very helpful - or at least I didn't really understand it.
I haven't done too much Qt development recently, but if I remember correctly, you can call
QApplication::processEvents() within your own event loop (instead of starting the Qt main loop through
Edit: I have used the opportunity of a slow Sunday morning to test-drive / learn something about PyQt (Python bindings for Qt) and cobbled together a proof-of-concept code below. Replacing the call to
QApplication::exec() with a custom event loop based on
QApplication::processEvents() seems to work.
I have also quickly looked at
tpclient-cpptext main.cpp. From the looks of it, it shoud be fine to just add
QApplication::processEvents() somewhere in the main loop of
SimpleEventLoop::runEventLoop(). To add it to the main loop, I would probably replace the
tv interval for the
select() function in lines
tv.tv_sec = 0; tv.tv_usec = 10000; // run processEvents() every 0.01 seconds app->processEvents();
and change the signature in line
void SimpleEventLoop::runEventLoop(QApplication *app). It should than be fine to add your usual Qt stuff to your implementation of the client (your replacement of
Looks like a hack, though. I would probably start with something like this to get started. I think that your idea of wrapping
TPSocket and the timer within Qt's respective concepts in order to forward them with the
QAbstractEventDispatcher to the
QEventLoop is the better long-term solution. It should then be sufficient that your
runEventLoop() simply calls
QApplication::exec(). But I have never used
QAbstractEventDispatcher before, so take my comments for what they are.
import sys import time from PyQt4 import QtGui from PyQt4 import QtCore # Global variable used as a quick and dirty way to notify my # main event loop that the MainWindow has been exited APP_RUNNING = False class SampleMainWindow(QtGui.QMainWindow): def __init__(self, parent=None): QtGui.QMainWindow.__init__(self) global APP_RUNNING APP_RUNNING = True # main window self.setGeometry(300, 300, 250, 150) self.setWindowTitle('Test') self.statusBar().showMessage('Ready') # exit action (assumes that the exit icon from # http://upload.wikimedia.org/wikipedia/commons/b/bc/Exit.png # is saved as Exit.png in the same folder as this file) exitAction = QtGui.QAction(QtGui.QIcon('Exit.png') ,'Exit' ,self) exitAction.setShortcut('Ctrl+Q') exitAction.setStatusTip('Exit application') self.connect(exitAction ,QtCore.SIGNAL('triggered()') ,QtCore.SLOT('close()')) # main menu menubar = self.menuBar() fileMenu = menubar.addMenu('&File') fileMenu.addAction(exitAction) # toolbar self.toolbar = self.addToolBar('Exit') self.toolbar.addAction(exitAction) # text editor textEdit = QtGui.QTextEdit() self.setCentralWidget(textEdit) #tool tip textEdit.setToolTip('Enter some text') QtGui.QToolTip.setFont(QtGui.QFont('English', 12)) def closeEvent(self, event): reply = QtGui.QMessageBox.question(self ,'Message' ,"Are you sure?" ,QtGui.QMessageBox.Yes ,QtGui.QMessageBox.No) if reply == QtGui.QMessageBox.Yes: event.accept() global APP_RUNNING APP_RUNNING = False else: event.ignore() # main program app = QtGui.QApplication(sys.argv) testWindow = SampleMainWindow() testWindow.show() # run custom event loop instead of app.exec_() while APP_RUNNING: app.processEvents() # sleep to prevent that my "great" event loop eats 100% cpu time.sleep(0.01)