Qt单实例运行 - QTCN开发网

#ifndef SINGLEAPPLICATION_H
#define SINGLEAPPLICATION_H

#include <QApplication>
#include <QWidget>

class QLocalServer;
class QWidget;

class SingleApplication : public QApplication
{
    Q_OBJECT

public:
    SingleApplication(int &argc, char **argv);
    ~SingleApplication();

public:
    bool isRunning();

    //保存主窗口指针
    void setSingleMainWindow(QWidget* w);

private slots:
    void newLocalConnection();

private:
    bool m_bRunning;
    QLocalServer *m_pServer;
    QWidget *m_widget;
};

#endif // SINGLEAPPLICATION_H

#include "singleapplication.h"
#include <QLocalSocket>
#include <QLocalServer>
#include <QFile>
#include <QTextStream>
#include <QWidget>
#include <QDebug>

static const char *ApplicationName = "myApp";

SingleApplication::SingleApplication(int &argc, char **argv):
    QApplication(argc, argv),
    m_mousePoint(0, 0),
    m_mousePressed(false),
    m_bRunning(false),
    m_pServer(Q_NULLPTR),
    m_widget(Q_NULLPTR)
{
    setOrganizationName(QStringLiteral("MyProject"));
    setApplicationName(QLatin1String(ApplicationName));

#if !defined(Q_OS_OSX)
    setWindowIcon(QIcon(QStringLiteral(":/image/calcapp.png")));
#endif

    QString strServerName = QString("%1%2")
            .arg(QCoreApplication::organizationName())
            .arg(QCoreApplication::applicationName());

    QLocalSocket socket;
    socket.connectToServer(strServerName);

    if (socket.waitForConnected(500)){
        QTextStream stream(&socket);
        QStringList args = QCoreApplication::arguments();
        QString strArg = (args.count() > 1) ? args.last() : "";
        stream << strArg;
        stream.flush();

        qDebug() << "Have already connected to server.";
        socket.waitForBytesWritten();
        m_bRunning = true;
    }
    else{
        // 如果不能连接到服务器,则创建
        m_pServer = new QLocalServer(this);

        connect(m_pServer, SIGNAL(newConnection()), this, SLOT(newLocalConnection()));

        if (m_pServer->listen(strServerName)){
            // 防止程序崩溃,残留进程服务,直接移除
            if ((m_pServer->serverError() == QAbstractSocket::AddressInUseError)
                    && QFile::exists(m_pServer->serverName())){
                QFile::remove(m_pServer->serverName());
                m_pServer->listen(strServerName);
            }
        }
    }

}

SingleApplication::~SingleApplication()
{

}

bool SingleApplication::isRunning()
{
    return m_bRunning;
}

void SingleApplication::setSingleMainWindow(QWidget *w)
{
    m_widget = w;
}

void SingleApplication::newLocalConnection()
{
    QLocalSocket *pSocket = m_pServer->nextPendingConnection();
    if (pSocket != Q_NULLPTR){
        pSocket->waitForReadyRead(1000);

        QTextStream in(pSocket);
        QString strValue;
        in >> strValue;
        delete pSocket;
        pSocket = Q_NULLPTR;

        //如果窗口不为空,则前端显示
        //核心代码
        if(m_widget){
            m_widget->showMaximized();
            m_widget->activateWindow();
            m_widget->raise();
        }
    }
}