Add support for remembering settings

Use QSettings to provide persistent storage of settings. For example, we
store and restore the size of the MainWindow.

We use the organisation name hohndel.org and keep subsurface as the
application name.

A section is specified for things to do with the MainWindow; other
sections could be added e.g. for preferred units?

Signed-off-by: Amit Chaudhuri <amit.k.chaudhuri@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

qt-ui/mainwindow.cpp

@@ -12,6 +12,8 @@
 #include <QtDebug>
 #include <QDateTime>
 #include <QSortFilterProxyModel>
+#include <QSettings>
+#include <QCloseEvent>
 
 #include "divelistview.h"
 #include "starwidget.h"
@@ -31,6 +33,7 @@ MainWindow::MainWindow() : ui(new Ui::MainWindow()),
 	ui->ListWidget->setModel(sortModel);
 
 	setWindowIcon(QIcon(":subsurface-icon"));
+	readSettings();
 }
 
 void MainWindow::on_actionNew_triggered()
@@ -138,6 +141,11 @@ void MainWindow::on_actionPreferences_triggered()
 void MainWindow::on_actionQuit_triggered()
 {
 	qDebug("actionQuit");
+	if (unsaved_changes() && (askSaveChanges() == FALSE))
+	{
+		return;
+	}
+
 }
 
 void MainWindow::on_actionDownloadDC_triggered()
@@ -284,3 +292,32 @@ bool MainWindow::askSaveChanges()
 	}
 	return false;
 }
+
+void MainWindow::readSettings()
+{
+	QSettings settings("hohndel.org","subsurface");
+
+	/* note: section/key i.e. forward slash to separate */
+	QSize sz = settings.value("MainWindow/size").value<QSize>();
+	resize(sz);
+}
+
+void MainWindow::writeSettings()
+{
+	QSettings settings("hohndel.org","subsurface");
+	settings.beginGroup("MainWindow");
+	settings.setValue("size",size());
+	settings.endGroup();
+	/* other groups here; avoid '/' and '\' in keys with setValue(...) please */
+}
+
+void MainWindow::closeEvent(QCloseEvent *event)
+{
+	if (unsaved_changes() && (askSaveChanges() == FALSE))
+	{
+		event->ignore();
+		return;
+	}
+	event->accept();
+	writeSettings();
+}

qt-ui/mainwindow.h

@@ -66,12 +66,17 @@ private Q_SLOTS:
 	void on_actionAboutSubsurface_triggered();
 	void on_actionUserManual_triggered();
 
+protected:
+	void closeEvent(QCloseEvent *);
+
 private:
 	Ui::MainWindow *ui;
 	DiveTripModel *model;
 	QSortFilterProxyModel *sortModel;
 	QString filter();
 	bool askSaveChanges();
+	void readSettings();
+	void writeSettings();
 
 };