How to set Input Mask and QValidator to a QLineEdit at a time in Qt?

Question

I want a line edit which accepts an ip address. If I give input mask as:

ui->lineEdit->setInputMask(\"000.000.000.000\");

It is accep

Answer 1

Hi I had almost the same problem. Solutions with inputmask or regExp were unsatisfactory. I decided to make my own bicycle.

Header:

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include 
#include 
#include 

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

private:
    Ui::MainWindow *ui;
};

//=============================================================================
class CustomIpEditor : public QFrame
{
    Q_OBJECT
public:
    explicit CustomIpEditor(QWidget *parent = 0);
    virtual ~CustomIpEditor() {}
};

//=============================================================================
class CustomLineEdit : public QLineEdit
{
    Q_OBJECT
public:
    explicit CustomLineEdit(const QString & contents = "", QWidget *parent = 0);
    virtual ~CustomLineEdit() {}

signals:
    void jumpForward();
    void jumpBackward();

public slots:
    void jumpIn();

protected:
    virtual void focusInEvent(QFocusEvent *event);
    virtual void keyPressEvent(QKeyEvent * event);
    virtual void mouseReleaseEvent(QMouseEvent *event);

private:
    bool selectOnMouseRelease;
};

#endif // MAINWINDOW_H

Source:

#include 
#include 

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    centralWidget()->setLayout(new QVBoxLayout);

    CustomIpEditor *myed = new CustomIpEditor;
    centralWidget()->layout()->addWidget(myed);

}

MainWindow::~MainWindow()
{
    delete ui;
}

//=============================================================================
CustomLineEdit::CustomLineEdit(const QString & contents, QWidget *parent) :
    QLineEdit(contents, parent), selectOnMouseRelease(false)
{
    QIntValidator *valid = new QIntValidator(0, 255, this);
    setValidator(valid);
}

void CustomLineEdit::jumpIn()
{
    setFocus();

    selectOnMouseRelease = false;
    selectAll();
}

void CustomLineEdit::focusInEvent(QFocusEvent *event)
{
    QLineEdit::focusInEvent(event);
    selectOnMouseRelease = true;
}

void CustomLineEdit::keyPressEvent(QKeyEvent * event)
{
    int key = event->key();
    int cursorPos = cursorPosition();

    // Jump forward by Space
    if (key == Qt::Key_Space) {
        emit jumpForward();
        event->accept();
        return;
    }

    // Jump Backward only from 0 cursor position
    if (cursorPos == 0) {
        if ((key == Qt::Key_Left) || (key == Qt::Key_Backspace)) {
            emit jumpBackward();
            event->accept();
            return;
        }
    }

    // Jump forward from last postion by right arrow
    if (cursorPos == text().count()) {
        if (key == Qt::Key_Right) {
            emit jumpForward();
            event->accept();
            return;
        }
    }

    // After key is placed cursor has new position
    QLineEdit::keyPressEvent(event);
    int freshCurPos = cursorPosition();

    if ((freshCurPos == 3) && (key != Qt::Key_Right))
        emit jumpForward();
}

void CustomLineEdit::mouseReleaseEvent(QMouseEvent *event)
{
    if(!selectOnMouseRelease)
        return;

    selectOnMouseRelease = false;
    selectAll();

    QLineEdit::mouseReleaseEvent(event);
}

//=============================================================================
void makeCommonStyle(QLineEdit* line) {
    line->setContentsMargins(0, 0, 0, 0);
    line->setAlignment(Qt::AlignCenter);
    line->setStyleSheet("QLineEdit { border: 0px none; }");
    line->setFrame(false);
    line->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Preferred);
}

QLineEdit* makeIpSpliter() {
    QLineEdit *spliter = new QLineEdit(".");
    makeCommonStyle(spliter);

    spliter->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred);
    spliter->setMaximumWidth(10);
    spliter->setReadOnly(true);
    spliter->setFocusPolicy(Qt::NoFocus);
    return spliter;
}

CustomIpEditor::CustomIpEditor(QWidget *parent) :
    QFrame(parent)
{
    setContentsMargins(0, 0, 0, 0);
    setStyleSheet("QFrame { background-color: white;  border: 1px solid white; border-radius: 15px; }");

    QList   lines;
    QList ::iterator linesIterator;

    lines.append(new CustomLineEdit);
    lines.append(new CustomLineEdit);
    lines.append(new CustomLineEdit);
    lines.append(new CustomLineEdit);

    QHBoxLayout *mainLayout = new QHBoxLayout;
    mainLayout->setSpacing(0);
    setLayout(mainLayout);

    for (linesIterator = lines.begin(); linesIterator != lines.end(); ++linesIterator) {
        makeCommonStyle(*linesIterator);
        mainLayout->addWidget(*linesIterator);

        if (*linesIterator != lines.last()) {
            connect(*linesIterator, &CustomLineEdit::jumpForward,
                    *(linesIterator+1), &CustomLineEdit::jumpIn);
            mainLayout->addWidget(makeIpSpliter());
        }
        if (*linesIterator != lines.first()) {
            connect(*linesIterator, &CustomLineEdit::jumpBackward,
                    *(linesIterator-1), &CustomLineEdit::jumpIn);
        }
    }

}