Question

I’ve written a large program with nested classes/threads and multiple modules.
I would now like to add a simple GUI and some Labels to display some variables.
However, the variables are scattered throughout the modules and classes.
I’m looking for a way to update these variables into the GUI without altering
the current code too much.

I have a rudimentary understanding of Pyqt4 (i will accept tkinter answers also).

I’ve tried not to use signals/emits because to my knowledge emits
must be sent from a Qthread which would mean a complete overhaul of my code, changing
classes and threads over to Qthreads. Id like to avoid needing to do this if possible.
Here is one example I’ve attempted.

test.py

class Update(Thread): 
    def __init__(self): 
        Thread.__init__(self) 
    def run(self): 

        for i in range(10): 
            time.sleep(2) 
            import test 
            wa.label.setText(str(i)) 

class MyWindow(QWidget):  
    def __init__(self, *args):  
        QWidget.__init__(self, *args) 

        self.label = QLabel(" ") 
        layout = QVBoxLayout() 
        layout.addWidget(self.label) 
        self.setLayout(layout) 

        Update1 = Update() 
        Update1.start() 
        Update1.refresh1 = 'ba' 

        self.label.setText(Update1.refresh1) 


if __name__ == "__main__":  
    app = QApplication(sys.argv)  
    wa = MyWindow()  
    wa.show()  
    sys.exit(app.exec_()) 

This code works, but my variables need to update from other modules/classes or threads. The moment I move ‘class Update’ into a new module like THIS:

test.py

import test2 


class MyWindow(QWidget):  
    def __init__(self, *args):  
        QWidget.__init__(self, *args) 

        self.label = QLabel(" ") 
        layout = QVBoxLayout() 
        layout.addWidget(self.label) 
        self.setLayout(layout) 

        Update1 = test2.Update() 
        Update1.start() 
        Update1.refresh1 = 'ba' 

        self.label.setText(Update1.refresh1) 


if __name__ == "__main__":  
    app = QApplication(sys.argv)  
    wa = MyWindow()  
    wa.show()  
    sys.exit(app.exec_()) 

test2.py #updates GUI

class Update(Thread): 
    def __init__(self): 
        Thread.__init__(self) 
    def run(self): 

        for i in range(10): 
            time.sleep(2) 
            import test 
            test.wa.label.setText(str(i)) 

I get: AttributeError: 'module' object has no attribute 'wa'

Also, I was also considering putting class Update() into a Qthread, running it from any module/class where a variable has been updated and using the emit function inside Update(). this would solve having to change my current classes/threads to be Qthreads.

If anyone knows of a simple way I could update my GUI simply by calling a class like update() an example would be appreciated

Answer 1

Because wa is only set when __name__ == "__main__" and that only happens when test.py is the main file.

When you do import test, you are running another instance of the test.py file which is not the main script so it has __name__ == 'test' not __main__. So, even if wa was set, you would be changing another instance of it.

Possible solution:

You can get a reference to the __main__ module and set on the test2.py module:

On test.py:

import test2
test2.parent = sys.modules[__name__]

Now, on test2.py (do not import test but make sure test imports test2):

parent.wa.label.setText('Blablabla')