起源
看到 QtDev wiki 中有一篇文章QDebug 输出的浏览窗口。实现了将qDebug、qWarning等输出显示到一个窗口部件（QTextBrowser）中。
看完后，个人似乎对这堆代码不太感冒，于是自己试着写写，有了下面的代码：
实现了什么?
定义了一个 MsgHandlerWapper 的类
- qDebug、qWarning 等的输出会通过该类的 message 信号发送出来
- 如果想让某个窗口接收消息，只需要定义一个槽，然后连接到该信号。
使用举例
如果要使用一个QPlainTextEdit作为log窗口，你只需要
- 简单定义一个槽
connect到MsgHandlerWapper实例的信号即可
#include <QPlainTextEdit>
#include "msghandlerwapper.h"
class TextEdit:public QPlainTextEdit
{
Q_OBJECT
public:
explicit TextEdit(QWidget * parent = 0)
:QPlainTextEdit(parent)
{
connect(MsgHandlerWapper::instance(),
SIGNAL(message(QtMsgType,QString)),
SLOT(outputMessage(QtMsgType,QString)));
}
public slots:
void outputMessage(QtMsgType type, const QString &msg)
{
appendPlainText(msg);
}
};
代码
- msghandlerwapper.h
/* (C) 2011 dbzhang800#gmail.com*/#ifndef MSGHANDLERWAPPER_H#define MSGHANDLERWAPPER_H#include <QtCore/QObject>class MsgHandlerWapper:public QObject{ Q_OBJECTpublic: static MsgHandlerWapper * instance();signals: void message(QtMsgType type, const QString &msg);private: MsgHandlerWapper(); static MsgHandlerWapper * m_instance;};#endif // MSGHANDLERWAPPER_Hs
- msghandlerwapper.cpp
/* (C) 2011 dbzhang800#gmail.com*/#include "msgwapper.h"#include <QtCore/QMetaType>#include <QtCore/QMutex>#include <QtCore/QMutexLocker>#include <QtCore/QCoreApplication>void static msgHandlerFunction(QtMsgType type, const char *msg){ QMetaObject::invokeMethod(MsgHandlerWapper::instance(), "message" , Q_ARG(QtMsgType, type) , Q_ARG(QString, QString::fromLocal8Bit(msg)));}MsgHandlerWapper * MsgHandlerWapper::m_instance = 0;MsgHandlerWapper * MsgHandlerWapper::instance(){ static QMutex mutex; if (!m_instance) { QMutexLocker locker(&mutex); if (!m_instance) m_instance = new MsgHandlerWapper; } return m_instance;}MsgHandlerWapper::MsgHandlerWapper() :QObject(qApp){ qRegisterMetaType<QtMsgType>("QtMsgType"); qInstallMsgHandler(msgHandlerFunction);}