cleanup: move shown-text calculation from filter widget to core

The filter widget was caching whether the filter was active and
used that flag to calculate the "# dives shown" string. Move this
directly to the DiveFilter class to remove interdependencies and
to unify with mobile.

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

core/divefilter.cpp

@@ -2,6 +2,7 @@
 
 #include "divefilter.h"
 #include "divelist.h" // for filter_dive
+#include "gettextfromc.h"
 #include "qthelper.h"
 #include "subsurface-qt/divelistnotifier.h"
 #ifndef SUBSURFACE_MOBILE
@@ -151,6 +152,14 @@ bool DiveFilter::diveSiteMode() const
 }
 #endif
 
+QString DiveFilter::shownText() const
+{
+	if (diveSiteMode() || filterData.validFilter())
+		return gettextFromC::tr("%L1/%L2 shown").arg(shown_dives).arg(dive_table.nr);
+	else
+		return gettextFromC::tr("%L1 dives").arg(dive_table.nr);
+}
+
 void DiveFilter::setFilter(const FilterData &data)
 {
 	filterData = data;

core/divefilter.h

@@ -38,6 +38,7 @@ class DiveFilter {
 public:
 	static DiveFilter *instance();
 
+	QString shownText() const;
 	bool diveSiteMode() const; // returns true if we're filtering on dive site (on mobile always returns false)
 #ifndef SUBSURFACE_MOBILE
 	const QVector<dive_site *> &filteredDiveSites() const;