QSerialPort Qchar + QByteArray

chiffaCff

Hello every one! I develop some application to write/read data from COM-port. I get data from lineEdit and send it to port like:

SerialPort->WriteToPort(ui->lineEdit_2->text().toLocal8Bit());

all work fine, but i need to add some char to start and and line like:

SerialPort->WriteToPort(QChar(253)+ui->lineEdit_2->text().toLocal8Bit()+QChar(254))

but i get and error... Please help, how i can convert Qchar to QByteArray. Thanks!

koahnig

@chiffaCff

Hi and welcome to devnet

This has nothing to do with QSerialPort. WriteToPort is not a routine of QSerialPort. It boils down to a pure QByteArray issue.

If I am not mistaken this may work:

SerialPort->WriteToPort(QByteArray(QChar(253)+ui->lineEdit_2->text().toLocal8Bit()+QChar(254)));

My guess is that you do not have a routine fitting the outcome. You should see in the error protocol of your compile run.

chiffaCff

get the error:
mainwindow.cpp:35: error: ambiguous overload for 'operator+' (operand types are 'QChar' and 'QByteArray')
SerialPort->WriteToPort(QByteArray(QChar(253)+ui->lineEdit_2->text().toLocal8Bit()+QChar(254)));
^

koahnig

@chiffaCff

What is the prototyp for WriteToPort look like?

QString tmp (QChar(253)+ui->lineEdit_2->text()+QChar(254));
SerialPort->WriteToPort(tmp.toLocal8Bit());

Not sure why you are using toLocal8bit. With standard string the statement above shall work, so it should be with QString, I guess.

mateczek

  QString s="string text";
  QByteArray b= s.toUtf8()+QByteArray("tekst")+QByteArray::fromHex("1310");
  SerialPort->WriteToPort(b);

chiffaCff

Thanks for everyone . Create like:

QByteArray data;
   data.append(char(253));
   data.append(ui->lineEdit_3->text().toLocal8Bit());
   data.append(char(254));