libdeng2: Widget behavior flags and focus cycle

doomsday/libdeng2/include/de/widgets/widget.h

@@ -38,6 +38,20 @@ class DENG2_PUBLIC Widget
     /// Widget that was expected to exist was not found. @ingroup errors
     DENG2_ERROR(NotFoundError);
 
+    enum Behavior
+    {
+        /// Widget is invisible: not drawn. Hidden widgets also receive no events.
+        Hidden = 0x1,
+
+        /// Widget will only receive events if it has focus.
+        HandleEventsOnlyWhenFocused = 0x2,
+
+        DefaultBehavior = 0
+    };
+    Q_DECLARE_FLAGS(Behaviors, Behavior)
+
+    typedef QList<Widget *> Children;
+
 public:
     Widget(String const &name = "");
     virtual ~Widget();
@@ -51,13 +65,33 @@ class DENG2_PUBLIC Widget
     inline void hide() { show(false); }
     void show(bool doShow = true);
 
+    /**
+     * Sets or clears one or more behavior flags.
+     *
+     * @param behavior  Flags.
+     * @param set       @c true to set, @c false to clear.
+     */
+    void setBehavior(Behaviors behavior, bool set = true);
+
+    Behaviors behavior() const;
+
+    /**
+     * Sets the identifier of the widget that will receive focus when
+     * a focus navigation is requested.
+     *
+     * @param name  Name of a widget.
+     */
+    void setFocusNext(String const &name);
+
+    String focusNext() const;
+
     // Tree organization.
     void clear();
     Widget &add(Widget *child);
     Widget *remove(Widget &child);
     Widget *find(String const &name);
     Widget const *find(String const &name) const;
-    QList<Widget *> children() const;
+    Children children() const;
     Widget *parent() const;
 
     // Utilities.

doomsday/libdeng2/src/widgets/widget.cpp

@@ -29,14 +29,15 @@ struct Widget::Instance
     Widget &self;
     String name;
     Widget *parent;
-    bool hidden;
+    Behaviors behavior;
+    String focusNext;
 
     typedef QList<Widget *> Children;
     typedef QMap<String, Widget *> NamedChildren;
     Children children;
     NamedChildren index;
 
-    Instance(Widget &w, String const &n) : self(w), name(n), parent(0), hidden(false)
+    Instance(Widget &w, String const &n) : self(w), name(n), parent(0)
     {}
 
     ~Instance()
@@ -123,14 +124,41 @@ bool Widget::isHidden() const
 {
     for(Widget const *w = this; w != 0; w = w->d->parent)
     {
-        if(w->d->hidden) return true;
+        if(w->d->behavior.testFlag(Hidden)) return true;
     }
     return false;
 }
 
 void Widget::show(bool doShow)
 {
-    d->hidden = !doShow;
+    setBehavior(Hidden, !doShow);
+}
+
+void Widget::setBehavior(Behaviors behavior, bool set)
+{
+    if(set)
+    {
+        d->behavior |= behavior;
+    }
+    else
+    {
+        d->behavior &= ~behavior;
+    }
+}
+
+Widget::Behaviors Widget::behavior() const
+{
+    return d->behavior;
+}
+
+void Widget::setFocusNext(String const &name)
+{
+    d->focusNext = name;
+}
+
+String Widget::focusNext() const
+{
+    return d->focusNext;
 }
 
 void Widget::clear()
@@ -218,6 +246,19 @@ bool Widget::dispatchEvent(Event const *event, bool (Widget::*memberFunc)(Event
     // Hidden widgets do not get events.
     if(isHidden()) return false;
 
+    bool const thisHasFocus = (hasRoot() && root().focus() == this);
+
+    if(d->behavior.testFlag(HandleEventsOnlyWhenFocused) && !thisHasFocus)
+    {
+        return false;
+    }
+
+    if(thisHasFocus)
+    {
+        // The focused widget is offered events before dispatching to the tree.
+        return false;
+    }
+
     // Tree is traversed in reverse order.
     for(int i = d->children.size() - 1; i >= 0; --i)
     {
@@ -236,7 +277,7 @@ bool Widget::dispatchEvent(Event const *event, bool (Widget::*memberFunc)(Event
     return false;
 }
 
-QList<Widget *> Widget::children() const
+Widget::Children Widget::children() const
 {
     return d->children;
 }

doomsday/libshell/src/textwidget.cpp

@@ -126,13 +126,26 @@ bool TextWidget::handleEvent(Event const *event)
     if(event->type() == Event::KeyPress)
     {
         DENG2_ASSERT(dynamic_cast<KeyEvent const *>(event) != 0);
+
         KeyEvent const *keyEvent = static_cast<KeyEvent const *>(event);
 
         foreach(Action *act, d->actions)
         {
             // Event will be used by actions.
             if(act->tryTrigger(*keyEvent)) return true;
         }
+
+        // Focus navigation.
+        if(keyEvent->key() == Qt::Key_Tab && hasFocus() && !focusNext().isEmpty())
+        {
+            Widget *next = root().find(focusNext());
+            if(next)
+            {
+                root().setFocus(next);
+                root().requestDraw();
+                return true;
+            }
+        }
     }
 
     return Widget::handleEvent(event);