@dev_liya said in I want to generate random number between the 0 to 1. with the interval of 1 second in qt.:

but my requirement is to generate in infinite loop ad show in window.

If you do an infinite loop then the event loop will not run. That means that setting the random_label or anything like that will not show on the screen as the slots cannot be handled: your infinite loop will block the event loop. The effect is that you have a frozen application. So, trust @JonB.

As per your request: to wait for one second and block everything (you have been warned!): use QThread::sleep(1);

Sounds like you should not be using QSerial and instead design a custom solution outside of Qt. Qt is not for real-time processing and your description of the task seems to imply real-time constraints.

@imhs
I figured it out!
The problem was in the read function function where I call it every time toggling the run switch.
Inside that function there is a timer which aims to read the registers and update the UI. Every time I call that function a new timer was generated. Therefore after sometime many timers was running in parallel which caused the problem.
Take care about timers!

@Ankit.Jain said in Reducing delay when reading from database:

Running the same query in SQLiteStudio, the query takes similar time (2 to 2.5 secs), but I keep getting a status of "[09:09:49] Query finished in 0.006 second(s).". Because of this, I am not sure how this is calculated though.

If it takes similar time in SQLiteStudio, it's not surprising it takes similar from Qt.

I do not have rights for asking changes in the database. But just out of curiosity, how do you add an index to a column?

I have never used SQLite. But CREATE INDEX in SQL creates an index. No idea whether SQLite will or will not take advantage of such an index if it exists, though...

ok, the template solution is also working here.
Thanks a lot for your help!

Hi,

Usually, to play sound effect, the QSoundEffect class is used. Wouldn't that fill your need ?

The Android and Desktop backend don't necessarily work the same way since they rely on the platform multimedia APIs and they may use different types of data to store the video data.

One thing that I find strange in your code is that you are overwriting input with the content of buffer rather than returning it.

I don't understand what this means: "first excute ifconfig setting bteween second excute netmask setting deleay"
Could you please explain?
What delay do you mean?

I fixed it like so:

Comment out the default w.show() in my main.cpp. I created a Q_INVOKABLE class method on main window called showAppWindow() that merely does a this->show(). I did the steps to inject my C++ object (called cpp) into my Javascript via the C++ <==> Webkit bridge. In my index.html file, at the bottom before the ending BODY tag, I added this: <script type="text/javascript"> try { if (cpp) { setTimeout('cpp.showAppWindow();',100); } } catch(e){} </script>

@SGaist Hi, I resolved the issue. I was actually firing sendCustomRequest() api as I was using a specific url query in request which was needed in to fire via HEAD method. Before firing sendCustomRequest() api I was also creating & resetting my ssl configuration. So, instead I directly now use the head() api to fire my HEAD request. Now,finished signal by reply gets fired instantaneously & I am able to read my specific header value in response in no time.

Thanks for your time..!! :)

solved:

void Read(QString file){ QProcess process; process.startDetached(file); } int main(int argc, char *argv[]) { QCoreApplication a(argc, argv); QTimer t; QObject::connect(&t, &QTimer::timeout, [&](){ Read(s); t.stop(); }); t.start(60000); return a.exec(); }

@ChrisW67

Thank you for you help.
Probably the thing is, QSerialPort has a problem to work in a new thread.

I can handle the other QObject in a new thread very well, and the exception only happens when the Object contains QSerialPort.
Also, in my last post, I actually never user QList, although Qt tells me something wrong with QList.

I have given up on working serialThread. QSerialPort does work good in the main thread.