Add function KItemListSelectionManager::isSelected(int index)

This function is used in KItemListView::updateWidgetProperties()
to find out if an item is selected in a more efficient way.
The new function is tested in KItemListSelectionManagerTest.
I've factored out some code from
KItemListSelectionManagerTest::testChangeSelection() to a new
member to simplify the test.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/kitemviews/kitemlistselectionmanager.h b/src/kitemviews/kitemlistselectionmanager.h
index a8ef5ca2d..82ae13abb 100644
--- a/src/kitemviews/kitemlistselectionmanager.h
+++ b/src/kitemviews/kitemlistselectionmanager.h
@@ -54,6 +54,7 @@ public:
 
     void setSelectedItems(const QSet<int>& items);
     QSet<int> selectedItems() const;
+    bool isSelected(int index) const;
     bool hasSelection() const;
 
     void setSelected(int index, int count = 1, SelectionMode mode = Select);