Spreadsheet: Track selections across sheet switches

Author: https://github.com/alimpfard
Commit: https://github.com/SerenityOS/serenity/commit/dd4bd0943aa
Pull-request: https://github.com/SerenityOS/serenity/pull/3312
Reviewed-by: https://github.com/awesomekling

Applications/Spreadsheet/Spreadsheet.h

@@ -150,7 +150,8 @@ public:
 
     JsonObject gather_documentation() const;
 
-    Optional<Position> selected_cell() const { return m_selected_cell; }
+    const HashTable<Position>& selected_cells() const { return m_selected_cells; }
+    HashTable<Position>& selected_cells() { return m_selected_cells; }
     const HashMap<Position, NonnullOwnPtr<Cell>>& cells() const { return m_cells; }
     HashMap<Position, NonnullOwnPtr<Cell>>& cells() { return m_cells; }
 
@@ -200,7 +201,7 @@ private:
     Vector<String> m_columns;
     size_t m_rows { 0 };
     HashMap<Position, NonnullOwnPtr<Cell>> m_cells;
-    Optional<Position> m_selected_cell; // FIXME: Make this a collection.
+    HashTable<Position> m_selected_cells;
 
     Workbook& m_workbook;
     mutable SheetGlobalObject* m_global_object;

Applications/Spreadsheet/SpreadsheetView.cpp

@@ -79,6 +79,12 @@ SpreadsheetView::SpreadsheetView(Sheet& sheet)
     };
 
     m_table_view->on_selection_change = [&] {
+        m_sheet->selected_cells().clear();
+        for (auto& index : m_table_view->selection().indexes()) {
+            Position position {m_sheet->column(index.column()), (size_t)index.row()};
+            m_sheet->selected_cells().set(position);
+        }
+
         if (m_table_view->selection().is_empty() && on_selection_dropped)
             return on_selection_dropped();
 
@@ -94,6 +100,22 @@ SpreadsheetView::SpreadsheetView(Sheet& sheet)
     };
 }
 
+void SpreadsheetView::hide_event(GUI::HideEvent&)
+{
+    if (on_selection_dropped)
+        on_selection_dropped();
+}
+
+void SpreadsheetView::show_event(GUI::ShowEvent&)
+{
+    if (on_selection_changed && !m_table_view->selection().is_empty()) {
+        auto selection = m_table_view->selection().first();
+        Position position { m_sheet->column(selection.column()), (size_t)selection.row() };
+        auto& cell = m_sheet->ensure(position);
+        on_selection_changed(position, cell);
+    }
+}
+
 void SpreadsheetView::TableCellPainter::paint(GUI::Painter& painter, const Gfx::IntRect& rect, const Gfx::Palette& palette, const GUI::ModelIndex& index)
 {
     // Draw a border.

Applications/Spreadsheet/SpreadsheetView.h

@@ -47,6 +47,9 @@ public:
     Function<void()> on_selection_dropped;
 
 private:
+    virtual void hide_event(GUI::HideEvent&) override;
+    virtual void show_event(GUI::ShowEvent&) override;
+
     SpreadsheetView(Sheet&);
 
     class EditingDelegate : public GUI::StringModelEditingDelegate {