stats: fix visibility check of the statistics tab on desktop

Apparently, the visibility flag of the view is not inherited
from the statistics widget. Therefore, the statistics is
redrawn on every action even if not visible.

Set the visibility explicitly in the show- and hide-events.

This is crazy.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

desktop-widgets/statswidget.cpp

@@ -93,6 +93,8 @@ StatsWidget::StatsWidget(QWidget *parent) : QWidget(parent)
 	view = qobject_cast<StatsView *>(root);
 	if (!view)
 		qWarning("Oops. The root of the StatsView is not a StatsView.");
+	if (view)
+		view->setVisible(isVisible()); // Synchronize visibility of widget and QtQuick-view.
 }
 
 // Initialize QComboBox with list of variables
@@ -209,6 +211,17 @@ void StatsWidget::showEvent(QShowEvent *e)
 	unrestrict();
 	updateUi();
 	QWidget::showEvent(e);
+	// Apparently, we have to manage the visibility of the view ourselves. That's mad.
+	if (view)
+		view->setVisible(true);
+}
+
+void StatsWidget::hideEvent(QHideEvent *e)
+{
+	QWidget::hideEvent(e);
+	// Apparently, we have to manage the visibility of the view ourselves. That's mad.
+	if (view)
+		view->setVisible(false);
 }
 
 void StatsWidget::restrict()

desktop-widgets/statswidget.h

@@ -37,6 +37,7 @@ private:
 
 	ChartListModel charts;
 	void showEvent(QShowEvent *) override;
+	void hideEvent(QHideEvent *) override;
 };
 
 #endif // STATSWIDGET_H