Unknown ouput with qdebugstream and qtextedit - c++

Question

The first output in the textedit is a number 3, I don't know why that number is coming form Qt::LogText. This question is based from a previous question I had asked, I'm using the same qdebugstream header file from the link below.
Redirect std::cout to a QTextEdit
The new project below is a QT Gui Application that will redirect the cout to a textedit. Also, since settextformat() is no longer a member of QTextEdit, I converted Qt::LogText into a string.
This was based on another post but I did not understand the solution.
QTextEdit::setTextFormat(Qt::LogText) does not exist anymore, what else can I use to log?.
Can someone provide more information on this?
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
ui->textEdit->setReadOnly(true);
ui->textEdit->setText(QString("%1").arg(Qt::LogText));
QDebugStream qout(std::cout, ui->textEdit);
cout << "Send this to the Text Edit!" << endl;
}
MainWindow::~MainWindow()
{
delete ui;
}
Mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include "qdebugstream.h"
#include "stdio.h"
#include "iostream"
using namespace std;
namespace Ui {
class MainWindow;
}
class QtextEdit;
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private:
Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H

Answer 1

You should use QPlainTextEdit in Qt 4.x which seems to be equivalent using Q3TextEdit(QTextEdit in Qt 3.x) with text format of Qt::LogText.
For QPlainTextEdit version of QDebugStream might be like followings.(you may be noticed that append() mem func is renamed into addPlainText() and that's it viola). Hope this helps.
#ifndef QDEBUGSTREAM_H
#define QDEBUGSTREAM_H
#include <iostream>
#include <streambuf>
#include <string>
#include <QPlainTextEdit>
class QDebugStream : public std::basic_streambuf<char>
{
public:
QDebugStream(std::ostream &stream, QPlainTextEdit* text_edit)
: m_stream(stream)
{
log_window = text_edit;
m_old_buf = stream.rdbuf();
stream.rdbuf(this);
}
~QDebugStream()
{
// output anything that is left
if (!m_string.empty())
log_window->appendPlainText(m_string.c_str());
m_stream.rdbuf(m_old_buf);
}
protected:
virtual int_type overflow(int_type v)
{
if (v == '\n')
{
log_window->appendPlainText(m_string.c_str());
m_string.erase(m_string.begin(), m_string.end());
}
else
m_string += v;
return v;
}
virtual std::streamsize xsputn(const char *p, std::streamsize n)
{
m_string.append(p, p + n);
int pos = 0;
while (pos != std::string::npos)
{
pos = m_string.find('\n');
if (pos != std::string::npos)
{
std::string tmp(m_string.begin(), m_string.begin() + pos);
log_window->appendPlainText(tmp.c_str());
m_string.erase(m_string.begin(), m_string.begin() + pos + 1);
}
}
return n;
}
private:
std::ostream &m_stream;
std::streambuf *m_old_buf;
std::string m_string;
QPlainTextEdit* log_window;
};
#endif