QT日志输出调试信息

本例主要介绍把QT调试信息，通过日志文件的形式输出，多用于Release版本。
在main.cpp修改如下代码：

#include <QApplication>
#include <QDateTime>
#include <QFile>
#include <QTextStream>
#include "mainwindow.h"
 
//输出调试信息
void outputMsg(QtMsgType type, const char* m_cpMesg)
{
    QString sLog;
    QDateTime curDateTime = QDateTime::currentDateTime();
    QString sSurDateTime = curDateTime.toString("yyyy-MM-dd hh:mm:ss.zzz");
    switch(type)
    {
    case QtDebugMsg:
        sLog = QString("%1 Debug: %2").arg(sSurDateTime).arg(m_cpMesg);
        break;
    case QtWarningMsg:
        sLog = QString("%1 Warning: %2").arg(sSurDateTime).arg(m_cpMesg);
        break;
    case QtCriticalMsg:
        sLog = QString("%1 Critical: %2").arg(sSurDateTime).arg(m_cpMesg);
        break;
    case QtFatalMsg:
        sLog = QString("%1 Fatal: %2").arg(sSurDateTime).arg(m_cpMesg);
        break;
    default:
        break;
    }
 
    QFile file("./debuglog.txt");
    file.open(QIODevice::WriteOnly|QIODevice::Append);
 
    QTextStream textstream(&file);
    textstream << endl << sLog << endl;
}
 
 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
 
    qInstallMsgHandler(outputMsg);
 
    MainWindow w;
    w.show();
    
    return a.exec();
}

当.exe程序运行时，会在把调试信息，存在文件debuglog.txt中