Python working with Qt, event loop

Question

I have a problem with event loop. To understand, i want to update Label/textBrowser/lineEdit text during some loop while Stop button isn't pushed.

def __init__(self):
    QtGui.QMainWindow.__init__(self)
    self.ui = Ui_MainWindow()
    self.ui.setupUi(self)
    self.ui.btnStart.clicked.connect(self.btnStart_Clicked)
    self.ui.btnStop.clicked.connect(self.btnStop_Clicked)
    self.startTime = dt.datetime(2013, 1, 1, 0, 0, 0)
    self.nowTime = dt.datetime(2013, 1, 1, 0, 0, 0)
    self.ui.lineStart.setText(self.startTime.strftime("%Y-%m-%d %H:%M"))
    self.ui.lineNow.setText(self.nowTime.strftime("%Y-%m-%d %H:%M"))
    self.ui.textBrowser.setText(self.nowTime.strftime("%Y-%m-%d %H:%M"))



def btnStart_Clicked(self):
    print(12)
    while (not self.btnStop_Clicked()):
        print(23)
        self.nowTime += dt.timedelta(minutes = 25)
        self.ui.textBrowser.setText(self.nowTime.strftime("%Y-%m-%d %H:%M"))
        time.sleep(2)

What is the issue you are facing?

László Papp
– László Papp

2013-12-21 06:39:34 +00:00
Commented Dec 21, 2013 at 6:39 — László Papp
– László Papp, Commented Dec 21, 2013 at 6:39

Svend Feldt · Accepted Answer · 2013-12-21 07:01:04Z

2

Qt Updates its Gui when it's Idle. To overcome this, you should use threading or yield your update function e.g. by using a timer to update instead. Below is some code I use to reschedule an update each 100ms. The use case is similar to yours.

    self.timer = QtCore.QTimer(self.wid)
    self.timer.timeout.connect(self.UpdateTab)
    self.timer.start(100)

answered Dec 21, 2013 at 7:01

Svend Feldt

8786 silver badges17 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

ekhumoro · Accepted Answer · 2013-12-21 19:42:02Z

1

To request an immediate update, use processEvents:

while (not self.btnStop_Clicked()):
    self.nowTime += dt.timedelta(minutes = 25)
    self.ui.textBrowser.setText(self.nowTime.strftime("%Y-%m-%d %H:%M"))
    QtGui.qApp.processEvents()
    time.sleep(2)

answered Dec 21, 2013 at 19:42

ekhumoro

122k23 gold badges272 silver badges400 bronze badges

Collectives™ on Stack Overflow

Python working with Qt, event loop

2 Answers 2

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related