// 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 AcceleratorTarget;
class AcceleratorManager;
class EventHandler;
class KeyEvent;
}
namespace views {
class FocusManagerDelegate;
class FocusSearch;
class RootView;
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();
// 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_; }
// 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_