Qt5/Qt-Creator Debugging Window in a Splitter

--D. Thiebaut (talk) 09:12, 6 February 2014 (EST)

---

This toturial presents a simple set of steps needed to add a debugging window at the bottom of the GUI of a Qt-5 application.

Formatted Output with QStrings

Printing multiple arguments is easily accomplished using the arg() method of QString objects. The examples below illustrates different ways to print several pieces of information:

int n = 3;
float x = 10.5;

QString s = QString( "n = %1  x = %2\n" ).arg( n ).arg( x )
debug( s );

debug( QString( "%1: n=%3, x=%2" ).arg( "Initialization" ).arg( x ).arg( n ) );

Source Files

debugDemo.pro

#-------------------------------------------------
#
# Project created by QtCreator 2014-02-06T08:24:43
#
#-------------------------------------------------

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = debugDemo
TEMPLATE = app


SOURCES += main.cpp\
        mainwindow.cpp

HEADERS  += mainwindow.h

FORMS    += mainwindow.ui

main.cpp

 
#include "mainwindow.h"
#include <QApplication>

int main(int argc, char *argv[]){
  QApplication a(argc, argv);
  MainWindow w;
  w.show();

  return a.exec();
}

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
  QMainWindow(parent),
  ui(new Ui::MainWindow) {
  ui->setupUi(this);
}

MainWindow::~MainWindow() {
  delete ui;
}

void MainWindow::debug( QString s ) {
    ui->textBrowser->append( s );
}

void MainWindow::on_pushButton_clicked() {
    debug( "Click!" );
}

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

namespace Ui {
  class MainWindow;
}

class MainWindow : public QMainWindow {
  Q_OBJECT

public:
  explicit MainWindow(QWidget *parent = 0);
  ~MainWindow();
  void debug( QString s );

private slots:
  void on_pushButton_clicked();

private:
  Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

mainwindow.ui

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>MainWindow</class>
 <widget class="QMainWindow" name="MainWindow">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>438</width>
    <height>454</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>MainWindow</string>
  </property>
  <widget class="QWidget" name="centralWidget">
   <layout class="QGridLayout" name="gridLayout">
    <item row="0" column="0">
     <layout class="QHBoxLayout" name="horizontalLayout">
      <item>
       <widget class="QLabel" name="label">
        <property name="text">
         <string>File</string>
        </property>
       </widget>
      </item>
      <item>
       <widget class="QLineEdit" name="lineEdit"/>
      </item>
      <item>
       <widget class="QPushButton" name="pushButton">
        <property name="text">
         <string>Browse...</string>
        </property>
       </widget>
      </item>
     </layout>
    </item>
    <item row="1" column="0">
     <widget class="QSplitter" name="splitter">
      <property name="orientation">
       <enum>Qt::Vertical</enum>
      </property>
      <widget class="QCalendarWidget" name="calendarWidget"/>
      <widget class="QTextBrowser" name="textBrowser"/>
     </widget>
    </item>
   </layout>
  </widget>
  <widget class="QMenuBar" name="menuBar">
   <property name="geometry">
    <rect>
     <x>0</x>
     <y>0</y>
     <width>438</width>
     <height>22</height>
    </rect>
   </property>
  </widget>
  <widget class="QToolBar" name="mainToolBar">
   <attribute name="toolBarArea">
    <enum>TopToolBarArea</enum>
   </attribute>
   <attribute name="toolBarBreak">
    <bool>false</bool>
   </attribute>
  </widget>
  <widget class="QStatusBar" name="statusBar"/>
 </widget>
 <layoutdefault spacing="6" margin="11"/>
 <resources/>
 <connections/>
</ui>