Replace STDIN with a Serial port

[mrdebug]

It' very easy to do. I know and use Olimex A20 with serial devices and graphic interaction.
I suggest you to write a class based on QSerialPort and implement events on special data.
If you want I can to it for you.

Which kind of hardware do you use?

[Epileftric]

What i'm missing is: should I create a new thread for it to monitor the serial port and create the events? or not?

[mrdebug]

In this case I normally use an Object based on QThread to manage the serial device. I normally add to the object the Tcp features, because sometimes the serial device can be attached with a rs232 - tct converter.
The object has to manage the device and can emit an event at particular situations.
For example, if you have a usb - rfid reader, when a tag will read, the object emit an event with the read tag code.

[Epileftric]

So it has to be something like this:

@
class Keypad : public Qthread {

public: 
Keypad(){
 initialize_serial_port();
 this->start();

}

private:
QSerialPort serial;
void run() {
   while(1) {
       serial.get_stff();
      generate_event_for_gui();
 }

}
};@

[SGaist]

Technically, threads are not mandatory at all in this case unless you start heavy processing on the data you received.

[Epileftric]

But I don't see where and how to create a loop for the events in the GUI.

[SGaist]

You already have an event loop after you call app.exec(). Use QSerialPort in asynchronous mode

[Epileftric]

but how do I get in that loop!?! That's what I don't get

[SGaist]

You don't need to get in that loop, once app.exec is called, the loop runs. Events are sent, signals and slots activates when needed etc.

[Epileftric]

Yeah.. that's what I'm trying to do now. Since I can't use the serial port in a separated thread.

So what now? Do I have to create a signal handler for the serial?
I'm quite new to GUIs writing, I'm mainly a microcontroller programmer. Sorry if this are really n00b questions.

[SGaist]

I never said it won't work in a separated thread, just that it's really not needed.

Something like this:

@
class KeyPad :: public QObject {
Q_OBJECT
public:
KeyPad(QObject *parent = 0 ) :
QObject(parent)
{
connect(&serialPort, SIGNAL(readyRead()), SLOT(processData()));
}

bool initialize(const QString &portName)
{
serialPort.setPortName(portName);
// setup port

return serialPort.open(QIODevice::ReadWrite); // or ReadOnly if you won't write anything in it

}

signals:
valueChanged(int newValue);

private slots:
void processData() {
data.append(serialPort.readAll());
// check if enough data is there
// parse data
// removed processed data from buffer
// emit signal(s)
}

private:
QByteArray data;
QSerialPort serialPort;
};
@

I've wrote everything in the "header" for brevity only

[Epileftric]

@ connect(&serialPort, SIGNAL(readyRead()), SLOT(processData()));@

I get it now, I was doing right that as you write! SO that's what gets it in the "main event loop" right?

Of course you didn't said it won't work in a separated thread, but I tried just that and it didn't work because of some "can't create new thread issue"

THANKS A LOT!!

[Epileftric]

So I got it, now I can navigate the menues with the serial port as I did with the keyboard. But the only thing that's not working are text entries. Whenever I need to input some text in a QLineEdit widget it doesn't recognizes the input as a keystroke!

@
void Keypad::SerialPortHandler (void){
char buff;

serial->read(&buff,1);

QKeyEvent *last_key = new QKeyEvent( QEvent::KeyPress, buff , Qt::GroupSwitchModifier, QString(buff) );

QCoreApplication::sendEvent(pycgui,last_key);
}
@

I use Qt::GroupSwitchModifier only to differentiate the events I create from the real one so I can manually delete them. But it's not the reason the input is not working!

[SGaist]

AFAIK, text input requires a press and a release event