How to append the serial read data on to the QPlaintext on qt gui window

[veera]

I am reading a data as serial.readall()

 if(serial.waitForReadyRead(20000)){
                        //Data was returned
                       // QString ser_Buffer = serial.readAll();
                        qDebug()<<"Response: "<<serial.readAll();
                       //ui->ResWindow_plainTextEdit->appendPlainText(serial.readAll());

                        //QTextCursor cursor(plainTextEdit->document());
                        QTextCursor cursor(ui->ResWindow_plainTextEdit->document());
                        cursor.movePosition(QTextCursor::End);
                        //cursor.insertText(QString::fromUtf8(serialData));
                        cursor.insertText(QString::fromUtf8(serial.readAll()));


                       // ui->ResWindow_plainTextEdit->appendPlainText(serial.readAll());
                        usleep(200000);
                    }else{
                        //No data
                        qDebug()<<"Time out";
                    }

                    //I have finish alla operation
                    serial.close();
                }else{
                    qDebug()<<"Serial ttyS4 not opened. Error: "<<serial.errorString();
                }

still not able to display on the QPlainText...

[aha_1980]

@veera said in How to append the serial read data on to the QPlaintext on qt gui window:

if(serial.waitForReadyRead(20000)){

That may be the cause of your problem.

You will most likely use the readyRead signal and connect it to your slot where you read all the data.

I have given you already the link to the terminal example in you other thread, please take that as reference.

[VRonin]

after qDebug()<<"Response: "<<serial.readAll();, serial will empty its buffer so cursor.insertText(QString::fromUtf8(serial.readAll())); appends nothing.

const auto serialData = serial.readAll();
qDebug()<<"Response: "<<serialData;
QTextCursor cursor(ui->ResWindow_plainTextEdit->document());
cursor.movePosition(QTextCursor::End);
cursor.insertText(QString::fromUtf8(serialData));

[veera]

@VRonin

i got this


E�

E�

E�
E�
�







E�

E�

E�
E�
�

[VRonin]

What does qDebug()<<"Response: "<<serialData; print?

[veera]

yes its writing on plaintext window.......

qDebug()<<"Response: "<<serialData; print?

Response: "\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01"
The portName is "ttyS4"
currentPortName "ttyS4"
Response: "\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01"

[veera]

@VRonin
I am getting the response as a hex bytes only so how to display onto the QPlainText ..

[Tirupathi Korla]

@veera
Hi,
Serial.readall() returns QByteArray. Have you tried this?

QString res(serialData);
ui->ResWindow_plainTextEdit->appendPlainText(res);

And one more question. Is that if(serial.waitForReadyRead(20000)) condition running inside any loop?

-Tirupathi

[aha_1980]

@veera said in How to append the serial read data on to the QPlaintext on qt gui window:

@VRonin
I am getting the response as a hex bytes only so how to display onto the QPlainText ..

If you want to show the hex bytes in the text edit, you can use (modified @VRonin's example (the change is the toHex() in the first line):

const auto serialData = serial.readAll().toHex();
qDebug()<<"Response: "<<serialData;
QTextCursor cursor(ui->ResWindow_plainTextEdit->document());
cursor.movePosition(QTextCursor::End);
cursor.insertText(QString::fromUtf8(serialData));

Note that you could replace QString::fromUtf8() with QString::fromLatin1() in that case.

[VRonin]

@veera said in How to append the serial read data on to the QPlaintext on qt gui window:

Response: "\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01"

\x01 is not printable. What did you expect to see?

[veera]

okay fine ...but response is coming what i am expecting i am writing some data for serial port like
unsigned char rteenab[] = {0X01,0X0E,0X01,0X45,0XD1}; i am trying to print input and output onto the QPlaintext ......

[J.Hilk]

@veera
You'll have to create a formated QString out of your Qbytearray for that. @VRonin and @aha_1980 showed you how to do it, heres a 3rd Way(I prefere a seperation and a more readable String):

const auto serialData = serial.readAll()
qDebug()<<"Response: "<<serialData;

QString formatedText;
for(int i(0); i<serialData .size(); i++)
    formatedText.append(QString::number((serialData.at(i),16).toUpper().rightJustified(2,'0')+ QChar(0x20));

QTextCursor cursor(ui->ResWindow_plainTextEdit->document());
cursor.movePosition(QTextCursor::End);
cursor.insertText(formatedText);

[aha_1980]

@J.Hilk: Note that for Qt 5.9 I added an overload of QByteArray::toHex(char separator) [1] where you can do something like

QByteArray hexData = data.toHex(' '); directly :)

[1] http://doc.qt.io/qt-5/qbytearray.html#toHex-1

[J.Hilk]

@aha_1980 oO, I should read the change logs more thoroughly! Makes my life easier ;-) thanks!