How to Use QSettings: Difference between revisions

From Qt Wiki
Jump to navigation Jump to search
No edit summary
m (→‎Example: Syntax highlighted code example Small fix)
Line 14: Line 14:
=== mainwindow.h ===
=== mainwindow.h ===


<code>
<syntaxhighlight lang="c++">
#ifndef MAINWINDOW_H
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#define MAINWINDOW_H
Line 25: Line 25:


namespace Ui {
namespace Ui {
class MainWindow;
  class MainWindow;
}
}


Line 33: Line 33:
public:
public:


explicit MainWindow(QWidget '''parent = 0);
explicit MainWindow(QWidget '''parent = 0);
  virtual ~MainWindow();
  virtual ~MainWindow();


Line 52: Line 52:
  QString m_sSettingsFile;
  QString m_sSettingsFile;


  QLabel''' m_pLabel;
  QLabel* m_pLabel;


QLineEdit* m_pEdit;
QLineEdit* m_pEdit;


QPushButton* m_pButton;
QPushButton* m_pButton;
};
};


#endif // MAINWINDOW_H
#endif // MAINWINDOW_H
 
</syntaxhighlight>
</code>


=== mainwindow.cpp ===
=== mainwindow.cpp ===


<code>
<syntaxhighlight lang="c++">
#include "mainwindow.h"
#include "mainwindow.h"
#include <QCoreApplication>
#include <QCoreApplication>
#include <QSettings>
#include <QSettings>
#include <QApplication>
#include <QApplication>
Line 81: Line 78:
  initGui();
  initGui();


m_sSettingsFile = QApplication::applicationDirPath().left(1) + ":/demosettings.ini";
m_sSettingsFile = QApplication::applicationDirPath().left(1) + ":/demosettings.ini";
  loadSettings();
  loadSettings();


if (m_pButton)
if (m_pButton)
  {
  {
connect(m_pButton, SIGNAL (released()),this, SLOT (handleButton()));
  connect(m_pButton, SIGNAL (released()),this, SLOT (handleButton()));
  }
  }
}
}
Line 106: Line 103:
  if (m_pLabel)
  if (m_pLabel)
  {
  {
m_pLabel->setText(sText);
  m_pLabel->setText(sText);
  }
  }
}
}
Line 117: Line 114:
  if (m_pLabel)
  if (m_pLabel)
  {
  {
m_pLabel->setText(sText);
  m_pLabel->setText(sText);
  }
  }
}
}
Line 130: Line 127:


}
}
</code>
</syntaxhighlight>


=== main.cpp ===
=== main.cpp ===


<code>
<syntaxhighlight lang="c++">
#include "mainwindow.h"
#include "mainwindow.h"


Line 143: Line 140:
  QApplication app(argc, argv);
  QApplication app(argc, argv);


MainWindow mainWindow;
MainWindow mainWindow;
  mainWindow.showMaximized();
  mainWindow.showMaximized();
  return app.exec();
  return app.exec();
}
}
</syntaxhighlight>

Revision as of 00:32, 9 May 2017

En Ar Bg De El Es Fa Fi Fr Hi Hu It Ja Kn Ko Ms Nl Pl Pt Ru Sq Th Tr Uk Zh

QSettings class provides platform-independent application settings. The following example shows how to save and load settings to an ini file. The instance of QSettings will take care of writing and reading the settings from the ini file.

Method setValue should be used to save a value of a key (aka the name of the setting).

The value of a setting can be obtained using the method value.

Example

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

#include <QLabel>
#include <QLineEdit>
#include <QPushButton>

namespace Ui {
  class MainWindow;
}

class MainWindow : public QMainWindow
{
 Q_OBJECT
public:

 explicit MainWindow(QWidget '''parent = 0);
 virtual ~MainWindow();

private:

 void initGui();

 void loadSettings();

 void saveSettings();

private slots:

 void handleButton();

private:

 QString m_sSettingsFile;

 QLabel* m_pLabel;

 QLineEdit* m_pEdit;

 QPushButton* m_pButton;
};

#endif // MAINWINDOW_H

mainwindow.cpp

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

MainWindow::MainWindow(QWidget *parent)
 : QMainWindow(parent),
 m_pLabel(NULL),
 m_pEdit(NULL),
 m_pButton(NULL)
{
 initGui();

 m_sSettingsFile = QApplication::applicationDirPath().left(1) + ":/demosettings.ini";
 loadSettings();

if (m_pButton)
 {
  connect(m_pButton, SIGNAL (released()),this, SLOT (handleButton()));
 }
}

void MainWindow::initGui()
{
 m_pLabel = new QLabel("", this);
 m_pLabel->setGeometry(0,0, 200,40);
 m_pEdit = new QLineEdit("", this);
 m_pEdit->setGeometry(0,40, 200,40);
 m_pButton = new QPushButton("OK", this);
 m_pButton->setGeometry(0,80, 200,40);
}

void MainWindow::loadSettings()
{
 QSettings settings(m_sSettingsFile, QSettings::NativeFormat);
 QString sText = settings.value("text", "").toString();
 if (m_pLabel)
 {
  m_pLabel->setText(sText);
 }
}

void MainWindow::saveSettings()
{
 QSettings settings(m_sSettingsFile, QSettings::NativeFormat);
 QString sText = (m_pEdit) ? m_pEdit->text() : "";
 settings.setValue("text", sText);
 if (m_pLabel)
 {
  m_pLabel->setText(sText);
 }
}

void MainWindow::handleButton()
{
 saveSettings();
}

MainWindow::~MainWindow()
{

}

main.cpp

#include "mainwindow.h"

#include <QApplication>

int main(int argc, char *argv[])
{
 QApplication app(argc, argv);

 MainWindow mainWindow;
 mainWindow.showMaximized();
 return app.exec();
}