How to pass String Value in decimal to QlineEdit?

Christian Ehrlicher

@Wasee said in How to pass String Value in decimal to QlineEdit?:

now I want to convert this string to decimal value.

Then do it... https://doc.qt.io/qt-5/qstring.html

JoeCFD

std::string continuous_value =***;
QString str( QString::fromStdString( continuous_value ) );
bool ok{ false };
double or float value = str.toDouble( &ok );
if ( true == ok ) {
    line edit->setText( QString::number( value ) );
/* if format is needed */
    line edit->setText( QString( "%1" ).arg( value, some format ) );
}

Wasee

@Christian-Ehrlicher @JoeCFD
I am reading like this:
/@
QProcess Temp_reading;
Temp_reading.start("sudo devmem2 0x80000000");
Temp_reading.waitForFinished(-1); // will wait forever until finished
QString Temp_read = Temp_reading.readAllStandardOutput();

ui->lineedit->setText(Temp_read);

//Its giving me value 0x1 in hex format but I need to convert in decimal value and pass to lineedit//

@/

JonB

@Wasee

QString str = "0x1";
bool ok;
int num = str.toInt(&ok, 0);

Christian Ehrlicher

@Wasee said in How to pass String Value in decimal to QlineEdit?:

but I need to convert in decimal value and pass to lineedit//

Then convert it from hex string to a double value and then back to a QString as it's documented in the documentation (link in my first post)

Wasee

@Christian-Ehrlicher @JoeCFD @JonB ;
Thanks to your reply! I follow the following code but get again conversion errors.
"/@
QProcess Temp_reading;
std:: string ct_value=Temp_reading.start("sudo devmem2 0x80000000");
QString str (QString::fromStdString(ct_value));
bool okk{false};
double or float value = str.toDuble(&okk);
if(true == &okk){
ui->linedit->setText(QString::number(value));
}

Thanks in advance

jsulm

@Wasee said in How to pass String Value in decimal to QlineEdit?:

"sudo devmem2 0x80000000"

Do you realise that your string contains not only a number but allso non-number string ("sudo devmem2 ")?
That part of course can't be converted to a number.
You need first to extract the hex-number part and only convert that part to a number.
You can use https://doc.qt.io/qt-5/qstring.html#split to split your string using "0x" as separator.

JonB

@jsulm
I think you need to clean your reading glasses and try again... ;-)

The OP is using that string as argument to QProcess::start(), not as the string to parse!

@Wasee

QProcess Temp_reading;
std:: string ct_value=Temp_reading.start("sudo devmem2 0x80000000");
QString str (QString::fromStdString(ct_value));

void QProcess::start() does not return any value, so this won't compile, will it....

Can you just slow down a bit. What are you actually trying to do? I can only guess you have in mind:

Temp_reading.start("sudo devmem2 0x80000000");
Temp_reading.waitForFinished();
QString output(Temp_reading.readAllStandardOutput());
bool ok;
int num = output.toInt(&ok, 0);

Actually I see you had this earlier. All you needed to do was do the QString::toInt() on what you got back followed by QString::number() to put it into the line edit. And if that is delivering the right answer have a look at the output from the command which you are trying to parse.

P.S.
You originally said the number you need to parse is (like) 0x1. I showed you the above code with output.toInt(&ok, 0); is how to do that. If you are using QString::toDouble() as you show that will not work, as it cannot parse a leading 0x.

Wasee

@jsulm Hi;
I followed following code to split the string
/@
QString band1_2="sudo devmem2 0x80000000 w 0x";
QString str = QStringLiteral("sudo devmem2 0x80000000 w 0x");
QStringList list1 = str.split(QLatin1Char('.'));
qDebug()<<"Split:"<<list1;
@/
Its giving me value like "11". But it is not passing to lineedit why? Even I code to convert into integer below.
QString list;
bool ok;
int d;
d = Qstring(list).toInt(&ok);
ui->lineedit->setText(d);

Thanks in advance

jsulm

@Wasee said in How to pass String Value in decimal to QlineEdit?:

QString list;
bool ok;
int d;
d = Qstring(list).toInt(&ok);

This does not make sense at all: you create a string from an empty string (list) and then try to convert it to int.

Please read once more what I wrote. I never suggested to split using '."

But actually you should read what @JonB suggested, as my answer was based on my misunderstanding.

Wasee

@JonB Hi;
How I can resolve problem i didn't understand.Please write piece of code.
thanks

jsulm

@Wasee said in How to pass String Value in decimal to QlineEdit?:

.Please write piece of code

He already did.
What is not clear?

Wasee

@jsulm ;
Thanks!
But I am getting error of invalid conversion from int to const string for lineedit.

ui->lineedit->setText(num);

jsulm

@Wasee Do you understand that setText expects a string, not int?

Wasee

Hi; everyone;
I am unable to fix my problem. Please provide exact information to do that.

jsulm

@Wasee said in How to pass String Value in decimal to QlineEdit?:

Please provide exact information to do that

I will do once more your work, but last time now. I will not spend more of my time if you refuse to learn basics.
Go to https://doc.qt.io/qt-5/qlineedit.html#text-prop and check what the type is.
Type is QString.
C++ most basic knowledge: QString != int.
So, you can't pass an int as parameter to QLineEdit::setText, because setText() expects a QString.
I really fail to understand what is not clear about it?!
Maybe you should read a C++ book?

Temp_reading.start("sudo devmem2 0x80000000");
Temp_reading.waitForFinished();
QString output(Temp_reading.readAllStandardOutput());
ui->lineedit->setText(output);

Wasee

@jsulm Hi;
Its giving me Values continuous but I need to print these values after 0x in integer form in line-edit.
(0xb6f44000):0x11EACAC
(0xb6efe00):0x11EACAC
(0xb6fd4000):0x11EACAC
(0xb6fde000):0x11EACAC

jsulm

@Wasee What's wrong with https://doc.qt.io/qt-5/qstring.html#number-1?

d = Qstring(list).toInt(&ok, 16); // Since you handle hex numbers you need to tell toInt that it is a hex number - so pass 16 as base
ui->lineedit->setText(QString::number(d));

Wasee

@jsulm Hi;
Its giving me value 0 in my lineedit.

jsulm

@Wasee That means that the conversion from string to int failed. I'm now out of this thread. Debug your code to see what happens and fix the issues...