#ifndef PASSWORDLINEEDIT_H
#define PASSWORDLINEEDIT_H

#include <QAction>
#include <QLineEdit>
#include <QToolButton>

class PasswordLineEdit : public QLineEdit {
public:
? PasswordLineEdit(QWidget *parent = nullptr);
private slots:
? void onPressed();
? void onReleased();

protected:
? void enterEvent(QEvent *event);
? void leaveEvent(QEvent *event);
? void focusInEvent(QFocusEvent *event);
? void focusOutEvent(QFocusEvent *event);

private:
? QToolButton *button;
};

#endif // PASSWORDLINEEDIT_H

PasswordLineEdit.cpp

#include "passwordlineedit.h"

PasswordLineEdit::PasswordLineEdit(QWidget *parent) : QLineEdit(parent)
{
? ? setEchoMode(QLineEdit::Password);
? ? QAction *action = addAction(QIcon(":/eyeOff"), QLineEdit::TrailingPosition);
? ? button = qobject_cast<QToolButton *>(action->associatedWidgets().last());
? ? button->hide();
? ? button->setCursor(QCursor(Qt::PointingHandCursor));
? ? connect(button, &QToolButton::pressed, this, &PasswordLineEdit::onPressed);
? ? connect(button, &QToolButton::released, this, &PasswordLineEdit::onReleased);
}

void PasswordLineEdit::onPressed()
{
? ? QToolButton *button = qobject_cast<QToolButton *>(sender());
? ? button->setIcon(QIcon(":/eyeOn"));
? ? setEchoMode(QLineEdit::Normal);
}

void PasswordLineEdit::onReleased()
{
? ? QToolButton *button = qobject_cast<QToolButton *>(sender());
? ? button->setIcon(QIcon(":/eyeOff"));
? ? setEchoMode(QLineEdit::Password);
}

void PasswordLineEdit::enterEvent(QEvent *event)
{
? ? button->show();
? ? QLineEdit::enterEvent(event);
}

void PasswordLineEdit::leaveEvent(QEvent *event)
{
? ? button->hide();
? ? QLineEdit::leaveEvent(event);
}

void PasswordLineEdit::focusInEvent(QFocusEvent *event)
{
? ? button->show();
? ? QLineEdit::focusInEvent(event);
}

void PasswordLineEdit::focusOutEvent(QFocusEvent *event)
{
? ? button->hide();
? ? QLineEdit::focusOutEvent(event);
}

main.cpp

#include "passwordlineedit.h"

#include <QApplication>
#include <QFormLayout>

int main(int argc, char *argv[])
{
? ? QApplication a(argc, argv);

? ? QWidget w;
? ? PasswordLineEdit *w1 = new PasswordLineEdit;
? ? QLineEdit *w2 = new QLineEdit;
? ? QFormLayout *lay = new QFormLayout(&w);
? ? lay->addRow("PasswordLineEdit: ", w1);
? ? lay->addRow("QLineEdit: ", w2);
? ? w.show();

? ? return a.exec();
}