It is time.

ui/views/focus/focus_manager.h

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef UI_VIEWS_FOCUS_FOCUS_MANAGER_H_
-#define UI_VIEWS_FOCUS_FOCUS_MANAGER_H_
-
-#include <list>
-#include <map>
-
-#include "base/basictypes.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/observer_list.h"
-#include "ui/base/accelerators/accelerator.h"
-#include "ui/base/accelerators/accelerator_manager.h"
-#include "ui/gfx/native_widget_types.h"
-#include "ui/views/views_export.h"
-
-// The FocusManager class is used to handle focus traversal, store/restore
-// focused views and handle keyboard accelerators.
-//
-// There are 2 types of focus:
-// - the native focus, which is the focus that an gfx::NativeView has.
-// - the view focus, which is the focus that a views::View has.
-//
-// Each native view must register with their Focus Manager so the focus manager
-// gets notified when they are focused (and keeps track of the native focus) and
-// as well so that the tab key events can be intercepted.
-// They can provide when they register a View that is kept in synch in term of
-// focus. This is used in NativeControl for example, where a View wraps an
-// actual native window.
-// This is already done for you if you subclass the NativeControl class or if
-// you use the NativeViewHost class.
-//
-// When creating a top window (derived from views::Widget) that is not a child
-// window, it creates and owns a FocusManager to manage the focus for itself and
-// all its child windows.
-//
-// The FocusTraversable interface exposes the methods a class should implement
-// in order to be able to be focus traversed when tab key is pressed.
-// RootViews implement FocusTraversable.
-// The FocusManager contains a top FocusTraversable instance, which is the top
-// RootView.
-//
-// If you just use views, then the focus traversal is handled for you by the
-// RootView. The default traversal order is the order in which the views have
-// been added to their container. You can modify this order by using the View
-// method SetNextFocusableView().
-//
-// If you are embedding a native view containing a nested RootView (for example
-// by adding a NativeControl that contains a NativeWidgetWin as its native
-// component), then you need to:
-// - override the View::GetFocusTraversable() method in your outer component.
-//   It should return the RootView of the inner component. This is used when
-//   the focus traversal traverse down the focus hierarchy to enter the nested
-//   RootView. In the example mentioned above, the NativeControl overrides
-//   GetFocusTraversable() and returns hwnd_view_container_->GetRootView().
-// - call Widget::SetFocusTraversableParent() on the nested RootView and point
-//   it to the outer RootView. This is used when the focus goes out of the
-//   nested RootView. In the example:
-//   hwnd_view_container_->GetWidget()->SetFocusTraversableParent(
-//      native_control->GetRootView());
-// - call RootView::SetFocusTraversableParentView() on the nested RootView with
-//   the parent view that directly contains the native window. This is needed
-//   when traversing up from the nested RootView to know which view to start
-//   with when going to the next/previous view.
-//   In our example:
-//   hwnd_view_container_->GetWidget()->SetFocusTraversableParent(
-//      native_control);
-//
-// Note that FocusTraversable do not have to be RootViews: AccessibleToolbarView
-// is FocusTraversable.
-
-namespace ui {
-class AcceleratorManager;
-class AcceleratorTarget;
-class EventHandler;
-class KeyEvent;
-}
-
-namespace views {
-
-class FocusManagerDelegate;
-class FocusSearch;
-class View;
-class Widget;
-
-// The FocusTraversable interface is used by components that want to process
-// focus traversal events (due to Tab/Shift-Tab key events).
-class VIEWS_EXPORT FocusTraversable {
- public:
-  // Return a FocusSearch object that implements the algorithm to find
-  // the next or previous focusable view.
-  virtual FocusSearch* GetFocusSearch() = 0;
-
-  // Should return the parent FocusTraversable.
-  // The top RootView which is the top FocusTraversable returns NULL.
-  virtual FocusTraversable* GetFocusTraversableParent() = 0;
-
-  // This should return the View this FocusTraversable belongs to.
-  // It is used when walking up the view hierarchy tree to find which view
-  // should be used as the starting view for finding the next/previous view.
-  virtual View* GetFocusTraversableParentView() = 0;
-
- protected:
-  virtual ~FocusTraversable() {}
-};
-
-// This interface should be implemented by classes that want to be notified when
-// the focus is about to change.  See the Add/RemoveFocusChangeListener methods.
-class VIEWS_EXPORT FocusChangeListener {
- public:
-  // No change to focus state has occurred yet when this function is called.
-  virtual void OnWillChangeFocus(View* focused_before, View* focused_now) = 0;
-
-  // Called after focus state has changed.
-  virtual void OnDidChangeFocus(View* focused_before, View* focused_now) = 0;
-
- protected:
-  virtual ~FocusChangeListener() {}
-};
-
-class VIEWS_EXPORT FocusManager {
- public:
-  // The reason why the focus changed.
-  enum FocusChangeReason {
-    // The focus changed because the user traversed focusable views using
-    // keys like Tab or Shift+Tab.
-    kReasonFocusTraversal,
-
-    // The focus changed due to restoring the focus.
-    kReasonFocusRestore,
-
-    // The focus changed due to a click or a shortcut to jump directly to
-    // a particular view.
-    kReasonDirectFocusChange
-  };
-
-  // TODO: use Direction in place of bool reverse throughout.
-  enum Direction {
-    kForward,
-    kBackward
-  };
-
-  enum FocusCycleWrappingBehavior {
-    kWrap,
-    kNoWrap
-  };
-
-  FocusManager(Widget* widget, FocusManagerDelegate* delegate);
-  virtual ~FocusManager();
-
-  // Processes the passed key event for accelerators and keyboard traversal.
-  // Returns false if the event has been consumed and should not be processed
-  // further.
-  bool OnKeyEvent(const ui::KeyEvent& event);
-
-  // Returns true is the specified is part of the hierarchy of the window
-  // associated with this FocusManager.
-  bool ContainsView(View* view);
-
-  // Advances the focus (backward if reverse is true).
-  void AdvanceFocus(bool reverse);
-
-  // The FocusManager keeps track of the focused view within a RootView.
-  View* GetFocusedView() { return focused_view_; }
-  const View* GetFocusedView() const { return focused_view_; }
-
-  // Low-level methods to force the focus to change (and optionally provide
-  // a reason). If the focus change should only happen if the view is
-  // currenty focusable, enabled, and visible, call view->RequestFocus().
-  void SetFocusedViewWithReason(View* view, FocusChangeReason reason);
-  void SetFocusedView(View* view) {
-    SetFocusedViewWithReason(view, kReasonDirectFocusChange);
-  }
-
-  // Get the reason why the focus most recently changed.
-  FocusChangeReason focus_change_reason() const {
-    return focus_change_reason_;
-  }
-
-  // Clears the focused view. The window associated with the top root view gets
-  // the native focus (so we still get keyboard events).
-  void ClearFocus();
-
-  // Tries to advance focus if the focused view has become unfocusable. If there
-  // is no view available to advance focus to, focus will be cleared.
-  void AdvanceFocusIfNecessary();
-
-  // Validates the focused view, clearing it if the window it belongs too is not
-  // attached to the window hierarchy anymore.
-  void ValidateFocusedView();
-
-  // Stores the focused view. Used when the widget loses activation.
-  // |clear_native_focus| indicates whether this should invoke ClearFocus().
-  // Typically |true| should be passed in.
-  void StoreFocusedView(bool clear_native_focus);
-
-  // Restore the view saved with a previous call to StoreFocusedView(). Used
-  // when the widget becomes active. Returns true when the previous view was
-  // successfully refocused - otherwise false.
-  bool RestoreFocusedView();
-
-  // Sets the |view| to be restored when calling RestoreFocusView. This is used
-  // to set where the focus should go on restoring a Window created without
-  // focus being set.
-  void SetStoredFocusView(View* view);
-
-  // Returns the View that either currently has focus, or if no view has focus
-  // the view that last had focus.
-  View* GetStoredFocusView();
-
-  // Clears the stored focused view.
-  void ClearStoredFocusedView();
-
-  // Returns true if in the process of changing the focused view.
-  bool is_changing_focus() const { return is_changing_focus_; }
-
-  // Changes the text input focus to |view->GetTextInputClient()| iff |view|
-  // is focused.  Views must call this method when their internal
-  // TextInputClient instance changes.
-  void OnTextInputClientChanged(View* view);
-
-  // Moves the text input focus into/out from |view|.
-  void FocusTextInputClient(View* view);
-  void BlurTextInputClient(View* view);
-
-  // Disable shortcut handling.
-  static void set_shortcut_handling_suspended(bool suspended) {
-    shortcut_handling_suspended_ = suspended;
-  }
-  // Returns whether shortcut handling is currently suspended.
-  bool shortcut_handling_suspended() { return shortcut_handling_suspended_; }
-
-  // Register a keyboard accelerator for the specified target. If multiple
-  // targets are registered for an accelerator, a target registered later has
-  // higher priority.
-  // |accelerator| is the accelerator to register.
-  // |priority| denotes the priority of the handler.
-  // NOTE: In almost all cases, you should specify kNormalPriority for this
-  // parameter. Setting it to kHighPriority prevents Chrome from sending the
-  // shortcut to the webpage if the renderer has focus, which is not desirable
-  // except for very isolated cases.
-  // |target| is the AcceleratorTarget that handles the event once the
-  // accelerator is pressed.
-  // Note that we are currently limited to accelerators that are either:
-  // - a key combination including Ctrl or Alt
-  // - the escape key
-  // - the enter key
-  // - any F key (F1, F2, F3 ...)
-  // - any browser specific keys (as available on special keyboards)
-  void RegisterAccelerator(const ui::Accelerator& accelerator,
-                           ui::AcceleratorManager::HandlerPriority priority,
-                           ui::AcceleratorTarget* target);
-
-  // Unregister the specified keyboard accelerator for the specified target.
-  void UnregisterAccelerator(const ui::Accelerator& accelerator,
-                             ui::AcceleratorTarget* target);
-
-  // Unregister all keyboard accelerator for the specified target.
-  void UnregisterAccelerators(ui::AcceleratorTarget* target);
-
-  // Activate the target associated with the specified accelerator.
-  // First, AcceleratorPressed handler of the most recently registered target
-  // is called, and if that handler processes the event (i.e. returns true),
-  // this method immediately returns. If not, we do the same thing on the next
-  // target, and so on.
-  // Returns true if an accelerator was activated.
-  bool ProcessAccelerator(const ui::Accelerator& accelerator);
-
-  // Resets menu key state if |event| is not menu key release.
-  // This is effective only on x11.
-  void MaybeResetMenuKeyState(const ui::KeyEvent& key);
-
-  // Called by a RootView when a view within its hierarchy is removed
-  // from its parent. This will only be called by a RootView in a
-  // hierarchy of Widgets that this FocusManager is attached to the
-  // parent Widget of.
-  void ViewRemoved(View* removed);
-
-  // Adds/removes a listener.  The FocusChangeListener is notified every time
-  // the focused view is about to change.
-  void AddFocusChangeListener(FocusChangeListener* listener);
-  void RemoveFocusChangeListener(FocusChangeListener* listener);
-
-  // Returns the AcceleratorTarget that should be activated for the specified
-  // keyboard accelerator, or NULL if no view is registered for that keyboard
-  // accelerator.
-  ui::AcceleratorTarget* GetCurrentTargetForAccelerator(
-      const ui::Accelerator& accelertor) const;
-
-  // Whether the given |accelerator| has a priority handler associated with it.
-  bool HasPriorityHandler(const ui::Accelerator& accelerator) const;
-
-  // Clears the native view having the focus.
-  virtual void ClearNativeFocus();
-
-  // Focuses the next keyboard-accessible pane, taken from the list of
-  // views returned by WidgetDelegate::GetAccessiblePanes(). If there are
-  // no panes, the widget's root view is treated as a single pane.
-  // A keyboard-accessible pane should subclass from AccessiblePaneView in
-  // order to trap keyboard focus within that pane. If |wrap| is kWrap,
-  // it keeps cycling within this widget, otherwise it returns false after
-  // reaching the last pane so that focus can cycle to another widget.
-  bool RotatePaneFocus(Direction direction, FocusCycleWrappingBehavior wrap);
-
-  // Convenience method that returns true if the passed |key_event| should
-  // trigger tab traversal (if it is a TAB key press with or without SHIFT
-  // pressed).
-  static bool IsTabTraversalKeyEvent(const ui::KeyEvent& key_event);
-
-  // Sets whether arrow key traversal is enabled. When enabled, right/down key
-  // behaves like tab and left/up key behaves like shift-tab. Note when this
-  // is enabled, the arrow key movement within grouped views are disabled.
-  static void set_arrow_key_traversal_enabled(bool enabled) {
-    arrow_key_traversal_enabled_ = enabled;
-  }
-  // Returns whether arrow key traversal is enabled.
-  static bool arrow_key_traversal_enabled() {
-    return arrow_key_traversal_enabled_;
-  }
-
-  // Returns the next focusable view. Traversal starts at |starting_view|. If
-  // |starting_view| is NULL |starting_widget| is consuled to determine which
-  // Widget to start from. See
-  // WidgetDelegate::ShouldAdvanceFocusToTopLevelWidget() for details. If both
-  // |starting_view| and |starting_widget| are NULL, traversal starts at
-  // |widget_|.
-  View* GetNextFocusableView(View* starting_view,
-                             Widget* starting_widget,
-                             bool reverse,
-                             bool dont_loop);
-
- private:
-  // Returns the focusable view found in the FocusTraversable specified starting
-  // at the specified view. This traverses down along the FocusTraversable
-  // hierarchy.
-  // Returns NULL if no focusable view were found.
-  View* FindFocusableView(FocusTraversable* focus_traversable,
-                          View* starting_view,
-                          bool reverse);
-
-  // Process arrow key traversal. Returns true if the event has been consumed
-  // and should not be processed further.
-  bool ProcessArrowKeyTraversal(const ui::KeyEvent& event);
-
-  // Keeps track of whether shortcut handling is currently suspended.
-  static bool shortcut_handling_suspended_;
-
-  // Whether arrow key traversal is enabled.
-  static bool arrow_key_traversal_enabled_;
-
-  // The top-level Widget this FocusManager is associated with.
-  Widget* widget_;
-
-  // The object which handles an accelerator when |accelerator_manager_| doesn't
-  // handle it.
-  scoped_ptr<FocusManagerDelegate> delegate_;
-
-  // The view that currently is focused.
-  View* focused_view_;
-
-  // The AcceleratorManager this FocusManager is associated with.
-  scoped_ptr<ui::AcceleratorManager> accelerator_manager_;
-
-  // The storage id used in the ViewStorage to store/restore the view that last
-  // had focus.
-  int stored_focused_view_storage_id_;
-
-  // The reason why the focus most recently changed.
-  FocusChangeReason focus_change_reason_;
-
-  // The list of registered FocusChange listeners.
-  ObserverList<FocusChangeListener, true> focus_change_listeners_;
-
-  // See description above getter.
-  bool is_changing_focus_;
-
-  DISALLOW_COPY_AND_ASSIGN(FocusManager);
-};
-
-}  // namespace views
-
-#endif  // UI_VIEWS_FOCUS_FOCUS_MANAGER_H_