QLineEdit autofill

[Natural_Bugger]

Hello,

i would like to know how to automatically correct the numerical value upon the input.
let's say, i type 10K in the QLineEdit field, but on the back i want this number autocratically translated into 10000.

aswel if i type 1N (Nano), that it would adjust the value to 0.000001.

would what the procedure?

regards

[VRonin]

Something like:

#include <QLineEdit>
#include <QValidator>
#include <QRegularExpression>
#include <QApplication>

class FixingValidator : public QDoubleValidator{
    Q_DISABLE_COPY(FixingValidator)
public:
    using QDoubleValidator::QDoubleValidator;
    State validate(QString & input, int & pos) const override{
        const QRegularExpressionMatch res = vaidRegExp.match(input);
        if(!res.hasMatch())
            return Invalid;
        QString nemericPart = res.captured(1);
        if(res.lastCapturedIndex()==1)
            return QDoubleValidator::validate(nemericPart,pos);
        else
            return QDoubleValidator::validate(nemericPart,pos) == Invalid ? Invalid : Intermediate;
    }
    void fixup(QString &input) const override{
        const QRegularExpressionMatch res = vaidRegExp.match(input);
        if(!res.hasMatch())
            return;
        if(res.capturedRef(2).isEmpty())
            return;
        double baseNumber = locale().toDouble(res.capturedRef(1));
        switch(res.capturedRef(2).at(0).unicode()){
        case 'k':
        case 'K':
            input=locale().toString(baseNumber*1000.0);
            break;
        case 'n':
        case 'N':
            input=locale().toString(baseNumber/1000000.0);
            break;
        }
    }
private:
    const QRegularExpression vaidRegExp=QRegularExpression(QStringLiteral(R"**(^(.+?)([kKnN]?)$)**"));
};

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QLineEdit laxEdit;
    FixingValidator* valid= new FixingValidator(&laxEdit);
    QObject::connect(&laxEdit,&QLineEdit::textChanged,[&laxEdit,valid](const QString& txt){
        QString oldText=txt;
        valid->fixup(oldText);
        laxEdit.setText(oldText);
    });
    laxEdit.setValidator(valid);
    laxEdit.show();
    return a.exec();
}

[Natural_Bugger]

@VRonin

thank your very much.

i copied it to my project, first the class and compiled, everything ok.
but than ...

FixingValidator* valid= new FixingValidator(&ui->lineEdit_1);

results in:

error: no matching function for call to 'FixingValidator::FixingValidator(QLineEdit**)'
     FixingValidator* valid= new FixingValidator(&ui->lineEdit_1);

i'm using a standard "project" with the designer and i try to reference the object in the *.ui file.
i have 4 QLineEdits on my "form" on witch i want to apply this effect.

[ODБOï]

@Natural_Bugger hi
a shoot in the dark

FixingValidator* valid= new FixingValidator(ui->lineEdit_1);

instead of

FixingValidator* valid= new FixingValidator(&ui->lineEdit_1);

[Natural_Bugger]

@LeLev

thank your very much, this error is eliminated.
but the next line contains 4/5 errors.
after correcting to your previous answer.

QObject::connect(ui->lineEdit_1,&QLineEdit::textChanged,[ui->lineEdit_1,valid](const QString& txt){

errors:

error: capture of non-variable 'MainWindow::ui'
         QObject::connect(ui->lineEdit_1,&QLineEdit::textChanged,[ui->lineEdit_1,valid](const QString& txt){


                                                                         ^

error: expected ',' before '->' token
         QObject::connect(ui->lineEdit_resistor,&QLineEdit::textChanged,[ui->lineEdit_resistor,valid](const QString& txt){
                                                                           ^

error: expected identifier before '->' token

error: expected ']' before ',' token
         QObject::connect(ui->lineEdit_1,&QLineEdit::textChanged,[ui->lineEdit_1,valid](const QString& txt){
                                                                                              ^

In lambda function:

 error: expected '{' before ',' token

In constructor 'MainWindow::MainWindow(QWidget*)':

error: expected ')' before ']' token
         QObject::connect(ui->lineEdit_1,&QLineEdit::textChanged,[ui->lineEdit_1,valid](const QString& txt){
                                                                                                    ^

[Natural_Bugger]

if you remove "[" & "]", than ...

2 errors remain.

expected primary-expression before 'const'
         QObject::connect(ui->lineEdit_1,&QLineEdit::textChanged,ui->lineEdit_1,valid(const QString& txt){
                                                                                                    ^

error: 'valid' cannot be used as a function
         QObject::connect(ui->lineEdit_1,&QLineEdit::textChanged,ui->lineEdit_1,valid(const QString& txt){
                                                                                                                      ^

than i changed ...

valid(const QString& txt) into valid->fixup(const QString& txt)

 QObject::connect(ui->lineEdit_1,&QLineEdit::textChanged,ui->lineEdit_1,valid->fixup(const QString& txt){

than i tried:

QObject::connect(ui->lineEdit_1,&QLineEdit::textChanged,ui->lineEdit_1,valid->fixup(ui->lineEdit_1->text()){

but ...

error: invalid initialization of non-const reference of type 'QString&' from an rvalue of type 'QString'
         QObject::connect(ui->lineEdit_1,&QLineEdit::textChanged,ui->lineEdit_1,valid->fixup(ui->lineEdit_1->text()){
                                                                                                                                      ^

note:   initializing argument 1 of 'virtual void FixingValidator::fixup(QString&) const'
     void fixup(QString &input) const override{
          ^

[VRonin]

just replace [ui->lineEdit_1,valid] with [=]

[Natural_Bugger]

@VRonin

Awesome!

but i have 2 different types of fields, but 4 on total on witch i wanna apply this effect.

FixingValidator* valid= new FixingValidator(ui->lineEdit_1);
...
..
.
FixingValidator* valid= new FixingValidator(ui->lineEdit_2);
...
..
.

i extended the class, ...

    void fixup(QString &input) const override{
            const QRegularExpressionMatch res = vaidRegExp.match(input);
            if(!res.hasMatch())
                return;
            if(res.capturedRef(2).isEmpty())
                return;
            double baseNumber = locale().toDouble(res.capturedRef(1));
            switch(res.capturedRef(2).at(0).unicode()){
            case 'k':
            case 'K':
                input=locale().toString(baseNumber*1000.0);
                break;
            case 'n':
            case 'N':
                input=locale().toString(baseNumber*1000000.0);
                break;
            }
        }
    
        void fixup2(QString &input) const override{
            const QRegularExpressionMatch res = vaidRegExp.match(input);
            if(!res.hasMatch())
                return;
            if(res.capturedRef(2).isEmpty())
                return;
            double baseNumber = locale().toDouble(res.capturedRef(1));
            switch(res.capturedRef(2).at(0).unicode()){
            case 'k':
            case 'K':
                input=locale().toString(baseNumber/1000.0);
                break;
            case 'n':
            case 'N':
                input=locale().toString(baseNumber/1000000.0);
                break;
            }
        }
    

results in:

error: 'void FixingValidator::fixup2(QString&) const' marked 'override', but does not override
     void fixup2(QString &input) const override{
          ^

i see that "virtual void fixup(QString &) const;" is part of QValidator.h
what's to do?

[jsulm]

@Natural_Bugger said in QLineEdit autofill:

error: 'void FixingValidator::fixup2(QString&) const' marked 'override', but does not override

Why fixup2?
fixup2 != fixup

[Natural_Bugger]

@jsulm

because i have 2 different type of QLineEdits formfields, one takes numbers bigger than 0 and the other takes number smaller than 0.

so i tried to extented the class and add an another method, called fixup2.

[jsulm]

@Natural_Bugger If you add a method which does not exist in the base class then you can't use override keyword as there is no such method in base class to override. So, remove override.

[Natural_Bugger]

@jsulm

it works, thank you very much.

[Natural_Bugger]

i still have problem with numbers containing a number using the method:
fixup2(QString &input).

1,2e-07
0,00012

those that contain a comma.

case 'n':
case 'N':
                input=locale().toString(baseNumber/1000000.0);
                break;

**"120n"**results in "0,00012" and doesn't work.
**"10n"**results in "1e-05" and does work.

no calculatiion takes place.

if(ui->lineEdit_1.toFloat() == 0.0){
       QMessageBox::information(this, "empty","",QMessageBox::Ok);
}

this gets triggered.