QLabel setText not displaying text immediately before running other method

Question

I have a basic label that is supposed to indicate to the user that the program is searching directories for several seconds. So it goes like...

self.label.setText(QString("Searching..."))
# method to search directories goes here
self.label.setText(QString("Search Complete"))

My problem is that the label never displays "Searching...". The execution always seems to jump straight to run the method to scan directories, and then the label text is set to "Search Complete" after the method which scans directories has finished.

I'd be grateful if someone could please explain why this is happening or suggest a better way to resolve the problem.

many thanks

score 34 · Accepted Answer · answered Dec 22 '10 at 16:30

34

Your "method to search directories" is blocking the GUI hence QLabel is not able to update the text. You can make your search routine asynchronous or go the easy way and force QLabel to update itself:

self.label.setText(QString("Searching..."))
self.label.repaint()
# method to search directories goes here
self.label.setText(QString("Search Complete"))

answered Dec 22 '10 at 16:30

ismail

46,010
9
86
95

2

I added qApp->processEvents() after repaint(), and that worked for me. See http://stackoverflow.com/a/2066916/2706918 – Nitinkumar Ambekar Dec 08 '14 at 11:29
Didn't fully work for me, some of the text was cut off. – Lightsout Jun 17 '16 at 02:09
@bakalolo That's a layout problem, irrelevant to this question. – ismail Jun 17 '16 at 04:25
Why would it display the full text part of the time then? My text was only cut off when I tried to update label before starting my calculation not after. – Lightsout Jun 17 '16 at 09:29

score 1 · Answer 2 · answered Jan 20 '17 at 09:37

1

Add include:

#include <qapplication.h>

Let Qt process events:

self.label.setText(QString("Searching..."))
qApp->processEvents();

Note: repaint() was not necessarie.

answered Jan 20 '17 at 09:37

Sebastian Ax

1,240
12
11

score 0 · Answer 3 · answered Jan 07 '22 at 08:53

0

In PyQt5, you don't need to use QString :

self.label.setText("Searching...")
self.label.repaint()
self.label.setText("Search Complete")

answered Jan 07 '22 at 08:53

tCot

307
2
7

QLabel setText not displaying text immediately before running other method

3 Answers3