在QT中将qDebug()等输出到文件

2021-12-18
qInstallMessageHandler 安装之前已定义的消息处理程序，返回一个指向前一个消息处理程序,
调用qInstallMessageHandler(0)可以恢复消息处理程序
/* 将程序中的qDebug()等 输出至指定文件 */
void customMessageHandler(QtMsgType type, const QMessageLogContext& context, const QString &msg)
{
    QString curtime = QDateTime::currentDateTime().toString("[hh:mm:ss,zzz]");
    QString txt;
    switch(type)
    {
        case QtDebugMsg:
        {
            // 在.pro文件中新增：
            // DEFINES += QT_MESSAGELOGCONTEXT    release:DEFINES += QT_NO_WARNING_OUTPUT QT_NO_DEBUG_OUTPUT 如果是release版本则不打印
            // 打印日志时一并打印行号信息等
            txt = QString(" [Debug] [%1] [%2] [%3] %4").arg(context.file).arg(context.function).arg(context.line).arg(msg);
            break;
        }
        case QtWarningMsg:
        {
            txt = "QtWarningMsg:";
            txt += msg;
            return;
        }
        case QtCriticalMsg:
        {
            txt = "QtCriticalMsg:";
            txt += msg;
            break;
        }
            case QtFatalMsg:
        {
            txt = "QtFatalMsg:";
            txt += msg;
            break;
        }
        case QtInfoMsg:
        {
            txt = "QtInfoMsg:";
            txt += msg;
            break;
        }
    }
    QString strlogfile = YxApplication::getAppSettingDir() + QString("/log");
    QDir *logdir = new QDir;
    if (!logdir->exists(strlogfile))
        logdir->mkdir(strlogfile);
    else
    {
        QDir dir(strlogfile);
        // 设置类型过滤器，只为文件格式
        dir.setFilter(QDir::Files | QDir::NoSymLinks);
        QStringList filters;
        filters<<QString("*.log");
        dir.setNameFilters(filters);
        QStringList string_list;
	 for (uint i=0; i<dir.count();i++)
        {
            QString file_path = strlogfile;
            file_path += "/";
            // 文件全路径
            file_path += dir[i];
            if (file_path.indexOf("logger_") != -1)
                string_list.append(file_path);
        }
        for (int i = 0;i<string_list.size()-5;i++)
        {
            QFile::remove(string_list[i]);
        }
    }
    delete logdir;
    logdir = NULL;
    if (s_logfilename.isEmpty())
    {
        QString strtime = QDateTime::currentDateTime().toString("yyyy-MM-dd");
        strtime += ".log";
        strlogfile += "/logger_";
        strlogfile += strtime;
        s_logfilename = strlogfile;
    }
    if (s_sChromecextensionlogpath.length()>1)
        s_logfilename = s_sChromecextensionlogpath;
    QFile outFile(s_logfilename);
    outFile.open(QIODevice::WriteOnly | QIODevice::Append);
    QTextStream ts(&outFile);
    ts << curtime << txt  << endl;
}