Dive list: propagate current-item to frontend

The command-objects select a current item, but this selection
was not propagated to the front-end. The current item is the
base for keyboard-navigation through the dive-list and therefore
should be set correctly.

It took some experimentation to get the flags right:
 QItemSelectionModel::Current
Hopefully, these are the correct flags across all supported
Qt versions!

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

desktop-widgets/command_divelist.cpp

@@ -423,7 +423,12 @@ void DiveListBase::restoreSelection(const std::vector<dive *> &selection, dive *
 	});
 
 	bool currentDiveChanged = false;
-	if (current_dive != currentDive) {
+	// If currentDive is null, we have no current dive. In such a case always
+	// signal the frontend.
+	if (!currentDive) {
+		currentDiveChanged = true;
+		emit diveListNotifier.currentDiveChanged();
+	} else if (current_dive != currentDive) {
 		currentDiveChanged = true;
 
 		// We cannot simply change the currentd dive to the given dive.

desktop-widgets/divelistview.cpp

@@ -45,6 +45,7 @@ DiveListView::DiveListView(QWidget *parent) : QTreeView(parent), mouseClickSelec
 	setSelectionMode(ExtendedSelection);
 	header()->setContextMenuPolicy(Qt::ActionsContextMenu);
 	connect(DiveTripModel::instance(), &DiveTripModel::selectionChanged, this, &DiveListView::diveSelectionChanged);
+	connect(DiveTripModel::instance(), &DiveTripModel::newCurrentDive, this, &DiveListView::currentDiveChanged);
 
 	header()->setStretchLastSection(true);
 
@@ -207,6 +208,21 @@ void DiveListView::diveSelectionChanged(const QVector<QModelIndex> &indexes, boo
 	}
 }
 
+void DiveListView::currentDiveChanged(QModelIndex index)
+{
+	// Transform the index into a local index, since
+	// there might be sorting or filtering in effect.
+	MultiFilterSortModel *m = MultiFilterSortModel::instance();
+	QModelIndex localIndex = m->mapFromSource(index);
+
+	// Then, set the currently activated row.
+	// Note, we have to use the QItemSelectionModel::Current mode to avoid
+	// changing our selection (in contrast to Qt's documentation, which
+	// instructs to use QItemSelectionModel::NoUpdate, which results in
+	// funny side-effects).
+	selectionModel()->setCurrentIndex(localIndex, QItemSelectionModel::Current);
+}
+
 // If rows are added, check which of these rows is a trip and expand the first column
 void DiveListView::rowsInserted(const QModelIndex &parent, int start, int end)
 {

desktop-widgets/divelistview.h

@@ -59,6 +59,7 @@ slots:
 	void loadImages();
 	void loadWebImages();
 	void diveSelectionChanged(const QVector<QModelIndex> &indexes, bool select);
+	void currentDiveChanged(QModelIndex index);
 private:
 	bool mouseClickSelection;
 	QList<int> expandedRows;

desktop-widgets/mainwindow.cpp

@@ -530,11 +530,17 @@ void MainWindow::configureToolbar() {
 
 void MainWindow::selectionChanged()
 {
+	if (!current_dive) {
+		information()->clearTabs();
+		information()->updateDiveInfo(true);
+		graphics()->setEmptyState();
+	} else {
 		graphics()->plotDive(nullptr, false, true);
 		information()->updateDiveInfo();
 		configureToolbar();
 		MapWidget::instance()->reload();
 	}
+}
 
 void MainWindow::on_actionNew_triggered()
 {

qt-models/divetripmodel.cpp

@@ -442,6 +442,7 @@ DiveTripModel::DiveTripModel(QObject *parent) :
 	connect(&diveListNotifier, &DiveListNotifier::divesTimeChanged, this, &DiveTripModel::divesTimeChanged);
 	connect(&diveListNotifier, &DiveListNotifier::divesSelected, this, &DiveTripModel::divesSelected);
 	connect(&diveListNotifier, &DiveListNotifier::divesDeselected, this, &DiveTripModel::divesDeselected);
+	connect(&diveListNotifier, &DiveListNotifier::currentDiveChanged, this, &DiveTripModel::currentDiveChanged);
 }
 
 int DiveTripModel::columnCount(const QModelIndex&) const
@@ -1166,3 +1167,41 @@ void DiveTripModel::changeDiveSelection(dive_trip *trip, const QVector<dive *> &
 
 	emit selectionChanged(indexes, select);
 }
+
+void DiveTripModel::currentDiveChanged()
+{
+	// The current dive has changed. Transform the current dive into an index and pass it on to the view.
+	if (!current_dive) {
+		emit newCurrentDive(QModelIndex()); // No current dive -> tell view to clear current index with an invalid index
+		return;
+	}
+
+	dive_trip *trip = current_dive->divetrip;
+	if (!trip || currentLayout == LIST) {
+		// Either this is outside of a trip or we're in list mode.
+		int idx = findDiveIdx(current_dive);
+		if (idx < 0) {
+			// We don't know this dive. Something is wrong. Warn and bail.
+			qWarning() << "DiveTripModel::currentDiveChanged(): unknown top-level dive";
+			emit newCurrentDive(QModelIndex());
+			return;
+		}
+		emit newCurrentDive(createIndex(idx, 0, noParent));
+	} else {
+		int idx = findTripIdx(trip);
+		if (idx < 0) {
+			// We don't know the trip - this shouldn't happen. Warn and bail.
+			qWarning() << "DiveTripModel::currentDiveChanged(): unknown trip";
+			emit newCurrentDive(QModelIndex());
+			return;
+		}
+		int diveIdx = findDiveInTrip(idx, current_dive);
+		if (diveIdx < 0) {
+			// We don't know this dive. Something is wrong. Warn and bail.
+			qWarning() << "DiveTripModel::currentDiveChanged(): unknown top-level dive";
+			emit newCurrentDive(QModelIndex());
+			return;
+		}
+		emit newCurrentDive(createIndex(diveIdx, 0, idx));
+	}
+}

qt-models/divetripmodel.h

@@ -118,6 +118,7 @@ signals:
 	// indexes into local indexes according to current sorting/filtering and instructs the QSelectionModel to
 	// perform the appropriate actions.
 	void selectionChanged(const QVector<QModelIndex> &indexes, bool select);
+	void newCurrentDive(QModelIndex index);
 private slots:
 	void divesAdded(dive_trip *trip, bool addTrip, const QVector<dive *> &dives);
 	void divesDeleted(dive_trip *trip, bool deleteTrip, const QVector<dive *> &dives);
@@ -126,6 +127,7 @@ private slots:
 	void divesMovedBetweenTrips(dive_trip *from, dive_trip *to, bool deleteFrom, bool createTo, const QVector<dive *> &dives);
 	void divesSelected(dive_trip *trip, const QVector<dive *> &dives);
 	void divesDeselected(dive_trip *trip, const QVector<dive *> &dives);
+	void currentDiveChanged();
 private:
 	// The model has up to two levels. At the top level, we have either trips or dives
 	// that do not belong to trips. Such a top-level item is represented by the "Item"