继上节所讲，Qt可以很容易的将一些日志信息保存到文件中，那么日志信息如何输出到窗口呢？

用过VS或者其他IDE的童鞋对日志输出到窗口应该都很熟悉，开发者可以打开一个输出窗口很清晰的查看一些日志信息。

例如VS，如下：

代码如下：

**********log_browser.cpp**********

#include "log_browser.h"

LogBrowser::LogBrowser(QWidget *parent)

: QWidget(parent)

{

this->resize(400, 300);

is_finished = false;

browser = new QTextBrowser();

start_button = new QPushButton();

clear_button = new QPushButton();

start_button->setText("start");

clear_button->setText("clear");

QHBoxLayout *button_layout = new QHBoxLayout();

button_layout->addStretch();

button_layout->addWidget(start_button);

button_layout->addWidget(clear_button);

button_layout->setSpacing(10);

button_layout->setContentsMargins(0, 0, 10, 10);

QVBoxLayout *main_layout = new QVBoxLayout();

main_layout->addWidget(browser);

main_layout->addLayout(button_layout);

main_layout->setSpacing(10);

main_layout->setContentsMargins(0, 0, 0, 0);

this->setLayout(main_layout);

connect(start_button, &QPushButton::clicked, this, &LogBrowser::start);

connect(clear_button, &QPushButton::clicked, browser, &QTextBrowser::clear);

}

LogBrowser::~LogBrowser()

{

}

void LogBrowser::outputMessage(QtMsgType type, const QMessageLogContext &context, const QString &msg)

{

QString message;

switch(type)

{

case QtDebugMsg:

message = QString("Debug:");

break;

case QtWarningMsg:

message = QString("Warning:");

break;

case QtCriticalMsg:

message = QString("Critical:");

break;

case QtFatalMsg:

message = QString("Fatal:");

}

browser->append(message.append(msg));

}

void LogBrowser::start()

{

if(!is_finished)

{

for(int i=0; i<1000000; i++)

{

QCoreApplication::processEvents();

qDebug()<<QString("This is a Qt log browser").append(QString::number(i, 10));

}

is_finished = true;

}

}

void LogBrowser::closeEvent(QCloseEvent *event)

{

QMessageBox::StandardButton answer = QMessageBox::question(

this,

tr("Close Log Browser?"),

tr("Do you really want to close the log browser?"),

QMessageBox::Yes | QMessageBox::No

);

if (answer == QMessageBox::Yes)

event->accept();

else

event->ignore();

}

void LogBrowser::keyPressEvent(QKeyEvent *event)

{

event->ignore();

}

**********main.cpp**********

#include "log_browser.h"

#include

#include

QPointer log_broswer;

void outputMessage(QtMsgType type, const QMessageLogContext &context, const QString &msg)

{

if(log_broswer)

log_broswer->outputMessage(type, context, msg);

}

int main(int argc, char *argv[])

{

QApplication a(argc, argv);

log_broswer = new LogBrowser();

log_broswer->show();

qInstallMessageHandler(outputMessage);

return a.exec();

}

效果如下：

注：

技术在于交流、沟通，转载请注明出处并保持作品的完整性。

作者：╰☆奋斗ing❤孩子`  原文：http://blog.sina.com.cn/s/blog_a6fb6cc90101guz0.html。