QLineEdit IP地址校验

QLineEdit IP地址校验

原文出处：【上善若静水】

1.通过自定义类方式实现IP4地址范围限制输入：

//--------------------TLineEditIP.h--------------------
#ifndef TLINEEDITIP_H  
#define TLINEEDITIP_H  

#include <QLineEdit>  
#include <QEvent>  

class TLineEditIP : public QLineEdit
{
    Q_OBJECT

#define QTUTL_IP_SIZE 4

signals :
    void signalTextChanged(QLineEdit* pEdit);

public:
    TLineEditIP(QWidget *parent = 0);
    ~TLineEditIP();

    void setText(const QString &strIP);
    QString text() const;

public slots:
    void slotTextChanged(QLineEdit* pEdit);

protected:
    void paintEvent(QPaintEvent *event);
    bool eventFilter(QObject *obj, QEvent *ev);

    int getIndex(QLineEdit *pEdit);
    bool isTextValid(const QString &strIP);

private:
    static QString getIPItemStr(unsigned char item);

private:
    QLineEdit *m_lineEidt[4];
};

#endif // TLINEEDITIP_H 

//--------------------TLineEditIP.cpp--------------------
#include "TLineEditIP.h"  
#include <QRegExpValidator>  
#include <QPainter>  
#include <QHBoxLayout>  
#include <QKeyEvent>  
#include <QMessageBox>  
#include <QDebug>  

TLineEditIP::TLineEditIP(QWidget *parent)
:QLineEdit(parent)
{
    QRegExp rx("(2[0-5]{2}|2[0-4][0-9]|1?[0-9]{1,2})");
    QHBoxLayout *pHBox = new QHBoxLayout(this);
    pHBox->setSpacing(4);
    pHBox->setContentsMargins(4,4,2,4);
    for (int i = 0; i < 4; i++)
    {
        m_lineEidt[i] = new QLineEdit(this);
        m_lineEidt[i]->setFrame(false);
        m_lineEidt[i]->setMaxLength(3);
        m_lineEidt[i]->setTextMargins(0,0,0,0);
        m_lineEidt[i]->setAlignment(Qt::AlignCenter);
        m_lineEidt[i]->installEventFilter(this);
        m_lineEidt[i]->setValidator(new QRegExpValidator(rx, this));
        m_lineEidt[i]->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred);
        m_lineEidt[i]->setStyleSheet("QLineEdit{font: 12px \"Microsoft YaHei\";color:rgb(119,119,119);background-color:rgb(255,255,255);border:none;}");
        m_lineEidt[i]->setAttribute(Qt::WA_MacShowFocusRect, 0);
        m_lineEidt[i]->setContextMenuPolicy(Qt::NoContextMenu);
        pHBox->addWidget(m_lineEidt[i]);
    }
    this->setReadOnly(true);
    this->setContextMenuPolicy(Qt::NoContextMenu);
    installEventFilter(this);
    connect(this, SIGNAL(signalTextChanged(QLineEdit*)),
        this, SLOT(slotTextChanged(QLineEdit*)),
        Qt::QueuedConnection);
}

TLineEditIP::~TLineEditIP()
{

}

void TLineEditIP::paintEvent(QPaintEvent *event)
{
    QLineEdit::paintEvent(event);
    QPainter painter(this);
    QBrush brush;
    brush.setStyle(Qt::BrushStyle::SolidPattern);
    brush.setColor(Qt::black);
    painter.setBrush(brush);

    int width = 0;
    for (int i = 0; i < 3; i++)
    {
        width += m_lineEidt[i]->width() + (i == 0 ? 4 : 5);//布局的间隔  
        painter.drawEllipse(width, height() / 2 - 1, 1, 1);
    }
}

QString TLineEditIP::getIPItemStr(unsigned char item)
{
    return QString("%1\n").arg(item);
}

void TLineEditIP::slotTextChanged(QLineEdit* pEdit)
{
    for (unsigned int i = 0; i != QTUTL_IP_SIZE; ++i)
    {
        if (pEdit == m_lineEidt[i])
        {
            if (pEdit->text().size() == getIPItemStr(UCHAR_MAX).size() &&
                pEdit->text().size() == pEdit->cursorPosition())
            {
                // auto-move to next item
                if (i + 1 != QTUTL_IP_SIZE)
                {
                    m_lineEidt[i + 1]->setFocus();
                    m_lineEidt[i + 1]->selectAll();
                }
            }
        }
    }
}

int TLineEditIP::getIndex(QLineEdit *pEdit)
{
    int index = -1;
    for (int i = 0; i < 4; i++)
    {
        if (pEdit == m_lineEidt[i])
            index = i;
    }
    return index;
}

bool TLineEditIP::eventFilter(QObject *obj, QEvent *event)
{
    bool bRes = QLineEdit::eventFilter(obj, event);
    if (event->type() == QEvent::Show)
    {
        if (obj == this)
        {
            m_lineEidt[0]->setFocus();
            m_lineEidt[0]->setCursorPosition(m_lineEidt[0]->text().size());
            m_lineEidt[0]->selectAll();
        }
    }
    else if (event->type() == QEvent::KeyPress)
    {
        QKeyEvent* pEvent = dynamic_cast<QKeyEvent*>(event);
        if (pEvent)
        {
            for (unsigned int i = 0; i != QTUTL_IP_SIZE; ++i)
            {
                QLineEdit* pEdit = m_lineEidt[i];
                if (pEdit == obj)
                {
                    switch (pEvent->key())
                    {
                    case Qt::Key_Left:
                        if (pEdit->cursorPosition() == 0)
                        {
                            // user wants to move to previous item 
                            m_lineEidt[i > 0 ? i - 1 : QTUTL_IP_SIZE - 1]->setFocus();
                            m_lineEidt[i > 0 ? i - 1 : QTUTL_IP_SIZE - 1]->setCursorPosition(m_lineEidt[i > 0 ? i - 1 : QTUTL_IP_SIZE - 1]->text().size());
                            m_lineEidt[i > 0 ? i - 1 : QTUTL_IP_SIZE - 1]->selectAll();
                        }
                        break;
                    case Qt::Key_Right:
                        if (pEdit->text().isEmpty() ||(pEdit->text().size() == pEdit->cursorPosition()))
                        {
                            // user wants to move to next item                        
                            m_lineEidt[i + 1 != QTUTL_IP_SIZE ? i + 1 : 0]->setFocus();
                            m_lineEidt[i + 1 != QTUTL_IP_SIZE ? i + 1 : 0]->setCursorPosition(0);
                        }
                        break;
                    case Qt::Key_Return:
                    case Qt::Key_Tab:
                    {
                        m_lineEidt[i + 1 != QTUTL_IP_SIZE ? i + 1 : 0]->setFocus();
                        m_lineEidt[i + 1 != QTUTL_IP_SIZE ? i + 1 : 0]->setCursorPosition(0);
                        m_lineEidt[i + 1 != QTUTL_IP_SIZE ? i + 1 : 0]->selectAll();
                        return true;
                    }
                    case Qt::Key_Backspace:
                    {
                        QString strText = pEdit->text();
                        if (!strText.length() || strText.length() && !pEdit->cursorPosition())
                        {
                            int index = getIndex(pEdit);
                            if (index != -1 && index != 0)
                            {
                                m_lineEidt[index - 1]->setFocus();
                                int length = m_lineEidt[index - 1]->text().length();
                                m_lineEidt[index - 1]->setCursorPosition(length ? length : 0);
                            }
                        }
                        return QLineEdit::eventFilter(obj, event);
                    }
                    default:
                        emit signalTextChanged(pEdit);
                    }
                    break;
                }
            }
        }
    }
    return bRes;
}
void TLineEditIP::setText(const QString &strIP)
{
    if (!isTextValid(strIP))
    {
        QMessageBox::warning(this, "Attention", "Your IP Address is Invalid!", QMessageBox::StandardButton::Ok);
        return;
    }
    else
    {
        int i = 0;
        QStringList ipList = strIP.split(".");
        foreach (const QString &ip, ipList)
        {
            m_lineEidt[i]->setText(ip);
            i++;
        }
    }
    m_lineEidt[0]->selectAll();
}

bool TLineEditIP::isTextValid(const QString &strIP)
{
    QRegExp rx2("\\b(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\b");
    if (!rx2.exactMatch(strIP))
        return false;
    return true;
}

QString TLineEditIP::text() const
{
    return QString("%1.%2.%3.%4")
        .arg(m_lineEidt[0]->text().isEmpty() ? "0" : m_lineEidt[0]->text())
        .arg(m_lineEidt[1]->text().isEmpty() ? "0" : m_lineEidt[1]->text())
        .arg(m_lineEidt[2]->text().isEmpty() ? "0" : m_lineEidt[2]->text())
        .arg(m_lineEidt[3]->text().isEmpty() ? "0" : m_lineEidt[3]->text());
}

2.通过QLineEdit成员函数setInputMask("000.000.000.000;_")+setValidator也能实现相关IP输入(但光标效果和删除效果不大理想，具体接口可参看QLineEdit文档)；