How to make QCheckBox readonly, but not grayed-out

Following the below my code:

this->ui->cb_RealWorld->setAttribute(Qt::WA_TransparentForMouseEvents);
this->ui->cb_RealWorld->setFocusPolicy(Qt::NoFocus);

Inherit from QCheckBox and override nextCheckState method https://doc.qt.io/qt-5/qcheckbox.html#nextCheckState do the trick.

void ReadOnlyCheckBox::nextCheckState()
{

}

On Windows, remember to #include "windows.h" and set flags as follows:

this->ui->cb_RealWorld->setWindowFlags(this->ui->cb_RealWorld->windowFlags() | Qt::WindowTransparentForInput);

This is Devopia's solution as a function:

void SetReadOnly(QCheckBox* checkBox, bool readOnly)
{
   checkBox->setAttribute(Qt::WA_TransparentForMouseEvents, readOnly);
   checkBox->setFocusPolicy(readOnly ? Qt::NoFocus : Qt::StrongFocus);
}