How to change label value?

ELIF

I would like to change textmessage in a while loop how can I get it? Now same value is coming screen only once.Although I print ethernetThread->buffer[i] to console in a while loop, different values are coming
In header file I have

 public slots:
    void messageSlot();
 public:
    QLabel *radar_data_label;

In mainWindow.cpp

 void MainWindow::messageSlot(){
  int i=0;
  while(1){
    QString textmessage = QString(QChar::fromLatin1(ethernetThread->buffer[i]));
    radar_data_label->setText(textmessage);
    radar_data_label->setStyleSheet("QLabel { font: 18pt; color : white; }");
    i++;
  }

 }

JonB

@ELIF
You can't while you have a while(1), which blocks the Qt event loop and updates to the display. (Not to mention, your code runs forever keeping incrementing i, how does ethernetThread->buffer[i] not error?)

Use proper signals & slots to do your UI updating, when new characters are present in ethernetThread->buffer[i], allowing the Qt event loop to be re-entered so it can show the updated text.

And while I think of it, if ethernetThread is truly a thread you need to understand generally how to access/share data safely across threads before you go directly reading from buffers in one thread which another thread is writing to.....

ELIF

Can you write a simple code about signal slot for this code,really cant understand it.

JonB

@ELIF
If you don't understand how to write signals & slots in Qt you won't get anywhere. You don't want someone else to write it for you, you need to know how to write it yourself. There are thousands of examples in the Qt docs, examples and out there on the web. You need to read and understand https://doc.qt.io/qt-5/signalsandslots.html for a start.

ELIF

thank you I did it. :)

JonB

@ELIF
Now that is good, well done! Sorry to have been harsh, but this is much better so that you will understand signals, slots & connects going forward :)