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      1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef UI_VIEWS_ACCESSIBLE_PANE_VIEW_H_
      6 #define UI_VIEWS_ACCESSIBLE_PANE_VIEW_H_
      7 
      8 #include "base/containers/hash_tables.h"
      9 #include "base/memory/scoped_ptr.h"
     10 #include "base/memory/weak_ptr.h"
     11 #include "ui/base/accelerators/accelerator.h"
     12 #include "ui/views/focus/focus_manager.h"
     13 #include "ui/views/view.h"
     14 
     15 namespace views {
     16 class FocusSearch;
     17 
     18 // This class provides keyboard access to any view that extends it, typically
     19 // a toolbar.  The user sets focus to a control in this view by pressing
     20 // F6 to traverse all panes, or by pressing a shortcut that jumps directly
     21 // to this pane.
     22 class VIEWS_EXPORT AccessiblePaneView : public View,
     23                                         public FocusChangeListener,
     24                                         public FocusTraversable {
     25  public:
     26   AccessiblePaneView();
     27   virtual ~AccessiblePaneView();
     28 
     29   // Set focus to the pane with complete keyboard access.
     30   // Focus will be restored to the last focused view if the user escapes.
     31   // If |initial_focus| is not NULL, that control will get
     32   // the initial focus, if it's enabled and focusable. Returns true if
     33   // the pane was able to receive focus.
     34   virtual bool SetPaneFocus(View* initial_focus);
     35 
     36   // Set focus to the pane with complete keyboard access, with the
     37   // focus initially set to the default child. Focus will be restored
     38   // to the last focused view if the user escapes.
     39   // Returns true if the pane was able to receive focus.
     40   virtual bool SetPaneFocusAndFocusDefault();
     41 
     42   // Overridden from View:
     43   virtual FocusTraversable* GetPaneFocusTraversable() OVERRIDE;
     44   virtual bool AcceleratorPressed(const ui::Accelerator& accelerator)
     45       OVERRIDE;
     46   virtual void SetVisible(bool flag) OVERRIDE;
     47   virtual void GetAccessibleState(ui::AccessibleViewState* state) OVERRIDE;
     48   virtual void RequestFocus() OVERRIDE;
     49 
     50   // Overridden from FocusChangeListener:
     51   virtual void OnWillChangeFocus(View* focused_before,
     52                                  View* focused_now) OVERRIDE;
     53   virtual void OnDidChangeFocus(View* focused_before,
     54                                 View* focused_now) OVERRIDE;
     55 
     56   // Overridden from FocusTraversable:
     57   virtual FocusSearch* GetFocusSearch() OVERRIDE;
     58   virtual FocusTraversable* GetFocusTraversableParent() OVERRIDE;
     59   virtual View* GetFocusTraversableParentView() OVERRIDE;
     60 
     61   // For testing only.
     62   const ui::Accelerator& home_key() const { return home_key_; }
     63   const ui::Accelerator& end_key() const { return end_key_; }
     64   const ui::Accelerator& escape_key() const { return escape_key_; }
     65   const ui::Accelerator& left_key() const { return left_key_; }
     66   const ui::Accelerator& right_key() const { return right_key_; }
     67 
     68  protected:
     69   // A subclass can override this to provide a default focusable child
     70   // other than the first focusable child.
     71   virtual View* GetDefaultFocusableChild();
     72 
     73   // Returns the parent of |v|. Subclasses can override this if
     74   // they need custom focus search behavior.
     75   virtual View* GetParentForFocusSearch(View* v);
     76 
     77   // Returns true if |v| is contained within the hierarchy rooted at |root|
     78   // for the purpose of focus searching. Subclasses can override this if
     79   // they need custom focus search behavior.
     80   virtual bool ContainsForFocusSearch(View* root, const View* v);
     81 
     82   // Remove pane focus.
     83   virtual void RemovePaneFocus();
     84 
     85   View* GetFirstFocusableChild();
     86   View* GetLastFocusableChild();
     87 
     88   FocusManager* focus_manager() const { return focus_manager_; }
     89 
     90   // When finishing navigation by pressing ESC, it is allowed to surrender the
     91   // focus to another window if if |allow| is set and no previous view can be
     92   // found.
     93   void set_allow_deactivate_on_esc(bool allow) {
     94     allow_deactivate_on_esc_ = allow;
     95   }
     96 
     97  private:
     98   bool pane_has_focus_;
     99 
    100   // If true, the panel should be de-activated upon escape when no active view
    101   // is known where to return to.
    102   bool allow_deactivate_on_esc_;
    103 
    104   base::WeakPtrFactory<AccessiblePaneView> method_factory_;
    105 
    106   // Save the focus manager rather than calling GetFocusManager(),
    107   // so that we can remove focus listeners in the destructor.
    108   FocusManager* focus_manager_;
    109 
    110   // Our custom focus search implementation that traps focus in this
    111   // pane and traverses all views that are focusable for accessibility,
    112   // not just those that are normally focusable.
    113   scoped_ptr<FocusSearch> focus_search_;
    114 
    115   // Registered accelerators
    116   ui::Accelerator home_key_;
    117   ui::Accelerator end_key_;
    118   ui::Accelerator escape_key_;
    119   ui::Accelerator left_key_;
    120   ui::Accelerator right_key_;
    121 
    122   // View storage id for the last focused view that's not within this pane.
    123   int last_focused_view_storage_id_;
    124 
    125   friend class AccessiblePaneViewFocusSearch;
    126 
    127   DISALLOW_COPY_AND_ASSIGN(AccessiblePaneView);
    128 };
    129 
    130 }  // namespace views
    131 
    132 #endif  // UI_VIEWS_ACCESSIBLE_PANE_VIEW_H_
    133