QPlainTextEdit - setViewportMargins, protected

Question

I have a simple app with text edit - QPlainTextEdit, created by qt designer. I just need from mainwindow.cpp setViewportMargins.But I get the following error message - void QAbstractScrollArea::setViewportMargins(int, int, int, int)' is protected.

Code:

ui->textEdit->setViewportMargins(10,10,10,10);

Is there any way to do this?

Answer 1

Protected functions can only be used within the class, so it generates the error. I have solved it by designing the CustomPlainText class and promoting it to the original QPlainTextEdit, inside it I have used setViewportMargins (10,10,10,10);. If you want to access that function from outside the class I have created the functions CustomSetViewportMargins({args}).

Right click and select: Promote to..

Write the name of the class and the header and add it.

And press promote.

customplaintext.cpp

#ifndef CUSTOMPLAINTEXT_H
#define CUSTOMPLAINTEXT_H

#include <QPlainTextEdit>

class CustomPlainText:public QPlainTextEdit
{
    Q_OBJECT
public:
    CustomPlainText(QWidget * parent = 0);
    void CustomSetViewportMargins(int left, int top, int right, int bottom);
    void CustomSetViewportMargins(const QMargins & margins);
};

#endif // CUSTOMPLAINTEXT_H

customplaintext.h

#include "customplaintext.h"

CustomPlainText::CustomPlainText(QWidget *parent): QPlainTextEdit(parent)
{
    setViewportMargins(10,10,10,10);
}

void CustomPlainText::CustomSetViewportMargins(int left, int top, int right, int bottom)
{
    setViewportMargins(left, top, right, bottom);
}

void CustomPlainText::CustomSetViewportMargins(const QMargins & margins)
{
    setViewportMargins(margins);
}

Before:

After:

Complete Code: https://github.com/eyllanesc/stackoverflow/tree/master/CustomPlainTextProject