I've managed to figure out the issue.

It turns out that I needed to disable power management signalling (dpms). I added the following lines to my /home/pi/.config/lxsession/LXDE-pi/autostart file -

@xset s off
@xset -dpms
@xset s noblank

The GUI now remains fully responsive even after a full day of running.

Thank you for your time @SGaist

@Andrex_Qt said in Responsive QtMainWindow on Startup.:

i access them through C Api

Could it be possible you share a link to such API for the benefit of other users just in case?

Hi, Thank you for your reply.
I totally changed my implementation using the signal and slots.
Thank you so much again.

@kenchan I want to draw it on QOpenGLWidget and i want to relate it to an audio file so i can position it wherever i want

@HW-Developer Start here http://doc.qt.io/qt-5/qtxml-index.html

@sebs What I don't understand: you want an application with 3 threads, right? But why do you create new process?

Hi and welcome to devnet,

Can you show the code you are using ?
What exactly do you expect ?
What exactly do you get ?

Everything is correct. I have reinstalled and these three buttons are
done by as you already stated. Thanks! It was two reasons.
THANKS!!!

@JKSH

Yes, I had to reinstalled QT on Visual C++. Works OK...
THANKS!!!

@Christian-Ehrlicher
ahh, you are right. Good catch.
http://doc.qt.io/qt-5/qjsonvalue.html#toDouble
converts the QJsonValue to double if its that type().
in this case it will return defaultValue (0)

so its something like

QJsonValue bid1 = jsonObj.value("bid_1"); QString asStr=bid1.toString(); double n = asStr.toDouble(); qDebug() << n;

Hi and welcome to devnet,

There's no ready made "console widget", you can use QPlainTextEdit or depending on the amount of data a QListView with a custom QStyledItemDelegate for fancy rendering.

For getting the output of your cli application, you can use QProcess.

Hi
You did read ?
http://doc.qt.io/qt-5/stylesheet-examples.html#customizing-qscrollbar

@GhostWolf
Sounds like it crash.
Does the samples also crash ?

@jsulm Oh. I haven't considered that. I'm definitely going to try that. I don't know why it didn't came to my mind. Thank you very much. I really appreciate your advice. I have been stuck at this problem for a week. I am glad there are people who are willing to help beginners.

@moffa13 said in Slot called multiple times to a blocking function in the same thread:

One question : Is it bad to lock and unlock a mutex multiple times ?

No, that's exactly what they are deigned for

Hi,
sadly, I do not now. It looks like it can be a pain to integrate OpenGL with qtquick2, but it is possible. Widget-base approach is much more straightforward, but you loose "qtquickness" :P

Sorry for the delay, I had a long brake from work.

Here is a possible solution for solving this "missing check/mark" issue.

I implemented the CSS "indicator" solution I got from this qt form post which is problematic.

Sources of solution:

Doc page: here Implementation: here QPalette p = ui->checkBox->palette(); p.setColor(QPalette::Active, QPalette::Base, QColor(255, 255, 255)); p.setColor(QPalette::Button, QColor(255, 255, 255)); ui->checkBox->setAutoFillBackground(true); ui->checkBox->setPalette(p); QColor(255, 255, 255)

refers to your desired background color, possibly the same color as your window background, etc.

QPallete::Active, QPalette::base

refers to the active checkbox's background (the white box background)

QPalette::Button

refers to the "actual background" (behind the checkbox and the checkbox text)

Hope this helps!

@Onikouzou What is this checkbox used for?
If you only want to use a combobox then do:

QInputDialog showSounds; QStringList soundList; soundList << "Sound 1" << "Sound 2"; showSounds.setOptions(QInputDialog::UseListViewForComboBoxItems); // Remove this if you want a combobox instead of a list showSounds.setComboBoxItems(soundList); showSounds.setWindowTitle("Select sounds"); showSounds.exec();

Anreads I sent you my CV I am Sujan from India, if you give work visa I can relocate

@SGaist Thank you, I will try it!

@raven-worx Thank you for pointing me to the proper documentation pages – I'll have a look at them asap.
If the project actually takes off, I'll be a regular in the forums :-)

Best regards,
– Davide

if instead of checking the property you use the pseudo-state it should work

qwidget->setStyleSheet( "QWidget:disabled{color: #64B2D1;}" "QWidget{color: blue;}");

Hey @Wieland . Thanks for the help . It is working fine . ( i will customize it now to my needs )

Actually, my idea is to have a storage of different wooden blocks in user interface and drag them one-by-one to working area to design a house model and then generate a txt file containing the stream of the coordinates (including some other attributes like color, shape) of building blocks.

@Wieland, this float number is represent the speed Value of DC motor in RPM, may you mean I it should be in double type or something else!!.
in fact I don't know obviously whit's the type I should use this is the GUI I built
link text
you can see in Stack-overflow here:
link text
may you get what I need, I'am sory to be annoying but I spent alot of time in this problem :(

By the way, in QApplication's detailed documentation, you have an example of how start an application in "no-gui" mode.

Understood. Thank you.

Then you should take a look at this to get started.

See also Qt::AA_EnableHighDpiScaling in Qt's Application Attributes enumeration

Thank you for your depth explanations. I am able to understand a lot of things now. Its time to tweak around and learn as I go further :)

@JohanSolo

Ah ok, so it is due to the organization of C++ not Qt, and like you said, the difference of a class instances and pointers.

It has been long time since I've had to use C++ and I never did anything too advance with it other than a text-based adventure game. I generally am more focused on hardware oriented programing such as with C and Verilog, and MATLAB is the only more software (excluding Arduino interaction) oriented language I have decent experience with.

Thank you for pointing out why there needs to be a difference. I wasn't familar with pointer usage in C++.

@sush what if the Python app "publish" the values it reads from the sensor by some communication mechanism and you poll those values from the C++ displaying the GUI?

Could you provide more details about what sensor you're using, and how the Python app is interfacing with the sensor? I bet that's a very likley chance a C equivalent program can be written instead...

@alex_malyu
The original post is some 2 months old. So I wrote a whole lot of a post in reply to the original question ... well didn't my ears burn, when I noticed the post time ... I felt like a complete idiot. :)

Hi
Its sounds like the classic
worker - processing - display design with the twist of
caching signals in processing.

In my opinion is a very good design. :)

Got it to work. The only way I got it to work is to launch from command line. ex: gammaray --probe PROBE_OF_CHOICE PATH_TO_QT_EXE\qt_app.exe.

And of course the probe config must be the same as the app's build config. For reference, my environment is Windows 10. GammaRay on Qt 5.6 QtQuick 2.0 apps.

@SGaist
Ok. Thank you!