PyQt app in seperate thread

[Phil Thompson]

On Wednesday 22 November 2006 2:06 pm, anders wrote:
> Phil Thompson wrote:
> > On Wednesday 22 November 2006 12:37 pm, anders wrote:
> > > I am writing a plugin for a piece of software in python, and I want to
> > > start up a PyQt GUI in the plugin, without stalling the main thread
> > > while the gui is running (later i will want to pass messages between
> > > the main thread and the gui thread).
> > >
> > > I'm new to pyqt, so I'm probably doing something very silly, but for
> > > the moment I'm just trying to get the first pyqt tutorial example
> > > running in a seperate thread:
> > >
> > > ----8<--------
> > >
> > > import sys
> > > from PyQt4 import QtGui
> > > from PyQt4 import QtCore
> > >
> > > class MyThread( QtCore.QThread ):
> > > 	def __init__( self ):
> > > 		QtCore.QThread.__init__( self )
> > >
> > > 	def run( self ):
> > > 		app = QtGui.QApplication( sys.argv )
> > > 		hello = QtGui.QPushButton( 'Hello world!' )
> > > 		hello.resize( 500, 500 )
> > > 		hello.show()
> > > 		app.exec_()
> > > 		QtCore.QThread.terminate(  )
> > >
> > >
> > >
> > > mt = MyThread()
> > > mt.start()
> > > print 'Main thread continuing...'
> > > mt.wait()
> > > print 'GUI thread finished.'
> > >
> > > ----8<--------
> > >
> > > The app starts up (with a warning WARNING: QApplication was not created
> > > in the main() thread. ). I get a window, but no button, and clicking on
> > > the close button does nothing and I have to force the program to quit.
> > >
> > > There's got to be a way to get this working, right? Can anyone help me
> > > along the right path?
> >
> > Read http://doc.trolltech.com/4.2/threads.html
> >
> > In particular the bit that says that exec_() must be called from the main
> > thread and not from a QThread.
> >
> > Phil
>
> OK so that's all good... so how do I go about doing what I want then?
> Can I set up a window in the second thread and start its event loop
> without running the event loop in the core app?

No. Read the second sentence of the paragraph I referred to. Also read the 
section "QObject Reentrancy".

Phil