LibGUI: Add AbstractView::move_cursor() and share some movement logic

A view can now be told to move its cursor in one of multiple directions
as specified by the CursorMovement enum.

View subclasses can override move_cursor(CursorMovement) to implement
their own cursor behavior. By default, AbstractView::move_cursor() is
a no-op.

This patch improves code sharing between TableView and TreeView. :^)

Libraries/LibGUI/AbstractTableView.cpp

@@ -383,4 +383,39 @@ void AbstractTableView::set_row_height(int height)
     update_row_sizes();
 }
 
+void AbstractTableView::keydown_event(KeyEvent& event)
+{
+    if (event.key() == KeyCode::Key_Left) {
+        move_cursor(CursorMovement::Left);
+        event.accept();
+        return;
+    }
+    if (event.key() == KeyCode::Key_Right) {
+        move_cursor(CursorMovement::Right);
+        event.accept();
+        return;
+    }
+    if (event.key() == KeyCode::Key_Up) {
+        move_cursor(CursorMovement::Up);
+        event.accept();
+        return;
+    }
+    if (event.key() == KeyCode::Key_Down) {
+        move_cursor(CursorMovement::Down);
+        event.accept();
+        return;
+    }
+    if (event.key() == KeyCode::Key_Home) {
+        move_cursor(CursorMovement::Home);
+        event.accept();
+        return;
+    }
+    if (event.key() == KeyCode::Key_End) {
+        move_cursor(CursorMovement::End);
+        event.accept();
+        return;
+    }
+    return AbstractView::keydown_event(event);
+}
+
 }

Libraries/LibGUI/AbstractTableView.h

@@ -96,6 +96,7 @@ protected:
     virtual void mousedown_event(MouseEvent&) override;
     virtual void doubleclick_event(MouseEvent&) override;
     virtual void context_menu_event(ContextMenuEvent&) override;
+    virtual void keydown_event(KeyEvent&) override;
     virtual void resize_event(ResizeEvent&) override;
 
     virtual void did_update_model(unsigned flags) override;

Libraries/LibGUI/AbstractView.h

@@ -33,9 +33,22 @@
 namespace GUI {
 
 class AbstractView : public ScrollableWidget {
-    C_OBJECT_ABSTRACT(AbstractView)
+    C_OBJECT_ABSTRACT(AbstractView);
 
 public:
+    enum class CursorMovement {
+        Up,
+        Down,
+        Left,
+        Right,
+        Home,
+        End,
+        PageUp,
+        PageDown,
+    };
+
+    virtual void move_cursor(CursorMovement) { }
+
     void set_model(RefPtr<Model>);
     Model* model() { return m_model.ptr(); }
     const Model* model() const { return m_model.ptr(); }

Libraries/LibGUI/TableView.cpp

@@ -154,28 +154,44 @@ void TableView::keydown_event(KeyEvent& event)
 {
     if (!model())
         return;
-    auto& model = *this->model();
     if (event.key() == KeyCode::Key_Return) {
         activate_or_edit_selected();
         return;
     }
-    if (event.key() == KeyCode::Key_Left) {
+    return AbstractTableView::keydown_event(event);
+}
+
+void TableView::move_cursor(CursorMovement movement)
+{
+    if (!model())
+        return;
+    auto& model = *this->model();
+    switch (movement) {
+    case CursorMovement::Left:
         move_selection(0, -1);
-        return;
+        break;
-    }
+    case CursorMovement::Right:
-    if (event.key() == KeyCode::Key_Right) {
         move_selection(0, 1);
-        return;
+        break;
-    }
+    case CursorMovement::Up:
-    if (event.key() == KeyCode::Key_Up) {
         move_selection(-1, 0);
-        return;
+        break;
-    }
+    case CursorMovement::Down:
-    if (event.key() == KeyCode::Key_Down) {
         move_selection(1, 0);
-        return;
+        break;
+    case CursorMovement::Home: {
+        auto index = model.index(0, 0);
+        set_selection(index);
+        scroll_into_view(index, Gfx::Orientation::Vertical);
+        break;
     }
-    if (event.key() == KeyCode::Key_PageUp) {
+    case CursorMovement::End: {
+        auto index = model.index(model.row_count() - 1, 0);
+        set_selection(index);
+        scroll_into_view(index, Gfx::Orientation::Vertical);
+        break;
+    }
+    case CursorMovement::PageUp: {
         int items_per_page = visible_content_rect().height() / row_height();
         auto old_index = selection().first();
         auto new_index = model.index(max(0, old_index.row() - items_per_page), old_index.column());
@@ -184,9 +200,9 @@ void TableView::keydown_event(KeyEvent& event)
             scroll_into_view(new_index, Orientation::Vertical);
             update();
         }
-        return;
+        break;
     }
-    if (event.key() == KeyCode::Key_PageDown) {
+    case CursorMovement::PageDown: {
         int items_per_page = visible_content_rect().height() / row_height();
         auto old_index = selection().first();
         auto new_index = model.index(min(model.row_count() - 1, old_index.row() + items_per_page), old_index.column());
@@ -195,9 +211,9 @@ void TableView::keydown_event(KeyEvent& event)
             scroll_into_view(new_index, Orientation::Vertical);
             update();
         }
-        return;
+        break;
+    }
     }
-    return Widget::keydown_event(event);
 }
 
 }

Libraries/LibGUI/TableView.h

@@ -38,6 +38,8 @@ public:
 protected:
     TableView();
 
+    virtual void move_cursor(CursorMovement) override;
+
     virtual void keydown_event(KeyEvent&) override;
     virtual void paint_event(PaintEvent&) override;
 };

Libraries/LibGUI/TreeView.cpp

@@ -418,43 +418,6 @@ void TreeView::keydown_event(KeyEvent& event)
         return;
     }
 
-    if (event.key() == KeyCode::Key_Up) {
-        ModelIndex previous_index;
-        ModelIndex found_index;
-        traverse_in_paint_order([&](const ModelIndex& index, const Gfx::IntRect&, const Gfx::IntRect&, int) {
-            if (index == cursor_index) {
-                found_index = previous_index;
-                return IterationDecision::Break;
-            }
-            previous_index = index;
-            return IterationDecision::Continue;
-        });
-        if (found_index.is_valid()) {
-            selection().set(found_index);
-            scroll_into_view(selection().first(), Orientation::Vertical);
-            update();
-        }
-        return;
-    }
-    if (event.key() == KeyCode::Key_Down) {
-        ModelIndex previous_index;
-        ModelIndex found_index;
-        traverse_in_paint_order([&](const ModelIndex& index, const Gfx::IntRect&, const Gfx::IntRect&, int) {
-            if (previous_index == cursor_index) {
-                found_index = index;
-                return IterationDecision::Break;
-            }
-            previous_index = index;
-            return IterationDecision::Continue;
-        });
-        if (found_index.is_valid()) {
-            selection().set(found_index);
-            scroll_into_view(selection().first(), Orientation::Vertical);
-            update();
-        }
-        return;
-    }
-
     auto open_tree_node = [&](bool open, MetadataForIndex& metadata) {
         if (on_toggle)
             on_toggle(cursor_index, open);
@@ -509,6 +472,73 @@ void TreeView::keydown_event(KeyEvent& event)
             return;
         }
     }
+
+    AbstractTableView::keydown_event(event);
+}
+
+void TreeView::move_cursor(CursorMovement movement)
+{
+    auto cursor_index = selection().first();
+
+    switch (movement) {
+    case CursorMovement::Up: {
+        ModelIndex previous_index;
+        ModelIndex found_index;
+        traverse_in_paint_order([&](const ModelIndex& index, const Gfx::IntRect&, const Gfx::IntRect&, int) {
+            if (index == cursor_index) {
+                found_index = previous_index;
+                return IterationDecision::Break;
+            }
+            previous_index = index;
+            return IterationDecision::Continue;
+        });
+        if (found_index.is_valid()) {
+            selection().set(found_index);
+            scroll_into_view(selection().first(), Orientation::Vertical);
+            update();
+        }
+        break;
+    }
+    case CursorMovement::Down: {
+        ModelIndex previous_index;
+        ModelIndex found_index;
+        traverse_in_paint_order([&](const ModelIndex& index, const Gfx::IntRect&, const Gfx::IntRect&, int) {
+            if (previous_index == cursor_index) {
+                found_index = index;
+                return IterationDecision::Break;
+            }
+            previous_index = index;
+            return IterationDecision::Continue;
+        });
+        if (found_index.is_valid()) {
+            selection().set(found_index);
+            scroll_into_view(selection().first(), Orientation::Vertical);
+            update();
+        }
+        return;
+    }
+
+    case CursorMovement::Home:
+        // FIXME: Implement.
+        break;
+
+    case CursorMovement::End:
+        // FIXME: Implement.
+        break;
+
+    case CursorMovement::PageUp:
+        // FIXME: Implement.
+        break;
+
+    case CursorMovement::PageDown:
+        // FIXME: Implement.
+        break;
+
+    case CursorMovement::Left:
+    case CursorMovement::Right:
+        // There is no left/right in a treeview, those keys expand/collapse items instead.
+        break;
+    }
 }
 
 int TreeView::item_count() const

Libraries/LibGUI/TreeView.h

@@ -52,8 +52,10 @@ protected:
     virtual void paint_event(PaintEvent&) override;
     virtual void doubleclick_event(MouseEvent&) override;
     virtual void keydown_event(KeyEvent&) override;
+
     virtual void did_update_selection() override;
     virtual void did_update_model(unsigned flags) override;
+    virtual void move_cursor(CursorMovement) override;
 
 private:
     virtual ModelIndex index_at_event_position(const Gfx::IntPoint&, bool& is_toggle) const override;