QProgressBar with % in decimal

What is the best/easiest way to modify QProgressBar to show the %-value as a decimal value? I presume somebody will have done this before, but I have not been able to find it.

See QProgressBar::format()

Not sure I see how setFormat() can be used to get a percentage value that is not integer. The placeholder "%p" gets an integer as a string. You could get a string like "9 of 37" from "%v of %m" but you cannot compute with these placeholders.

You could subclass QProgressBar and override QProgressBar::text():

Code:

---

#ifndef FRACTIONALPROGRESSBAR_H
#define FRACTIONALPROGRESSBAR_H
 
#include <QProgressBar>
 
class FractionalProgressBar : public QProgressBar
{
public:
    FractionalProgressBar(QWidget *p = nullptr);
 
    // QProgressBar interface
public:
    virtual QString text() const Q_DECL_OVERRIDE;
};
 
#endif // FRACTIONALPROGRESSBAR_H

---

Code:

---

#include "fractionalprogressbar.h"
 
FractionalProgressBar::FractionalProgressBar(QWidget *p):
    QProgressBar(p)
{
}
 
 
QString FractionalProgressBar::text() const
{
    if ( minimum() == maximum() ) // divide by zero guard
        return QString();
 
    double percent = 100.0 * (value() - minimum()) / (maximum() - minimum());
    return QString("%1%").arg(percent, 0, 'f', 1);
}

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But the setValue() method converts the input argument to int, so the fractional part of the value is lost.

Quote:

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But the setValue() method converts the input argument to int, so the fractional part of the value is lost.

---

Change the scale of the progress bar range. If you now have it set to range from 0 - 100, and you want one decimal place, change it to a range of 0 - 1000. Use ChrisW67's method to format the text by converting the value to a float, dividing by 10, and use the result to set a float formatted string.

You will also have to change the code that sets the value to multiply the number passed to setValue() by 10.

Works perfectly! Thanks. I tried to find a good excuse for not thinking of this myself, but couldn't find one ...