ui/views/widget/root_view.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_WIDGET_ROOT_VIEW_H_
#define UI_VIEWS_WIDGET_ROOT_VIEW_H_

#include <string>

#include "base/memory/ref_counted.h"
#include "ui/events/event_processor.h"
#include "ui/views/focus/focus_manager.h"
#include "ui/views/focus/focus_search.h"
#include "ui/views/view.h"

namespace views {

namespace test {
class WidgetTest;
}

class Widget;

// This is a views-internal API and should not be used externally.
// Widget exposes this object as a View*.
namespace internal {
class PreEventDispatchHandler;

////////////////////////////////////////////////////////////////////////////////
// RootView class
//
//  The RootView is the root of a View hierarchy. A RootView is attached to a
//  Widget. The Widget is responsible for receiving events from the host
//  environment, converting them to views-compatible events and then forwarding
//  them to the RootView for propagation into the View hierarchy.
//
//  A RootView can have only one child, called its "Contents View" which is
//  sized to fill the bounds of the RootView (and hence the client area of the
//  Widget). Call SetContentsView() after the associated Widget has been
//  initialized to attach the contents view to the RootView.
//  TODO(beng): Enforce no other callers to AddChildView/tree functions by
//              overriding those methods as private here.
//  TODO(beng): Clean up API further, make Widget a friend.
//  TODO(sky): We don't really want to export this class.
//
class VIEWS_EXPORT RootView : public View,
                              public FocusTraversable,
                              public ui::EventProcessor {
 public:
  static const char kViewClassName[];

  // Creation and lifetime -----------------------------------------------------
  explicit RootView(Widget* widget);
  virtual ~RootView();

  // Tree operations -----------------------------------------------------------

  // Sets the "contents view" of the RootView. This is the single child view
  // that is responsible for laying out the contents of the widget.
  void SetContentsView(View* contents_view);
  View* GetContentsView();

  // Called when parent of the host changed.
  void NotifyNativeViewHierarchyChanged();

  // Focus ---------------------------------------------------------------------

  // Used to set the FocusTraversable parent after the view has been created
  // (typically when the hierarchy changes and this RootView is added/removed).
  virtual void SetFocusTraversableParent(FocusTraversable* focus_traversable);

  // Used to set the View parent after the view has been created.
  virtual void SetFocusTraversableParentView(View* view);

  // System events -------------------------------------------------------------

  // Public API for broadcasting theme change notifications to this View
  // hierarchy.
  void ThemeChanged();

  // Public API for broadcasting locale change notifications to this View
  // hierarchy.
  void LocaleChanged();

  // Overridden from FocusTraversable:
  virtual FocusSearch* GetFocusSearch() OVERRIDE;
  virtual FocusTraversable* GetFocusTraversableParent() OVERRIDE;
  virtual View* GetFocusTraversableParentView() OVERRIDE;

  // Overridden from ui::EventProcessor:
  virtual ui::EventTarget* GetRootTarget() OVERRIDE;
  virtual ui::EventDispatchDetails OnEventFromSource(ui::Event* event) OVERRIDE;

  // Overridden from View:
  virtual const Widget* GetWidget() const OVERRIDE;
  virtual Widget* GetWidget() OVERRIDE;
  virtual bool IsDrawn() const OVERRIDE;
  virtual void Layout() OVERRIDE;
  virtual const char* GetClassName() const OVERRIDE;
  virtual void SchedulePaintInRect(const gfx::Rect& rect) OVERRIDE;
  virtual bool OnMousePressed(const ui::MouseEvent& event) OVERRIDE;
  virtual bool OnMouseDragged(const ui::MouseEvent& event) OVERRIDE;
  virtual void OnMouseReleased(const ui::MouseEvent& event) OVERRIDE;
  virtual void OnMouseCaptureLost() OVERRIDE;
  virtual void OnMouseMoved(const ui::MouseEvent& event) OVERRIDE;
  virtual void OnMouseExited(const ui::MouseEvent& event) OVERRIDE;
  virtual bool OnMouseWheel(const ui::MouseWheelEvent& event) OVERRIDE;
  virtual void SetMouseHandler(View* new_mouse_handler) OVERRIDE;
  virtual void GetAccessibleState(ui::AXViewState* state) OVERRIDE;
  virtual void UpdateParentLayer() OVERRIDE;

 protected:
  // TODO(tdanderson): Remove RootView::DispatchGestureEvent() once
  //                   its targeting and dispatch logic has been moved
  //                   elsewhere. See crbug.com/348083.
  virtual void DispatchGestureEvent(ui::GestureEvent* event);

  // Overridden from View:
  virtual void ViewHierarchyChanged(
      const ViewHierarchyChangedDetails& details) OVERRIDE;
  virtual void VisibilityChanged(View* starting_from, bool is_visible) OVERRIDE;
  virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE;
  virtual gfx::Vector2d CalculateOffsetToAncestorWithLayer(
      ui::Layer** layer_parent) OVERRIDE;
  virtual View::DragInfo* GetDragInfo() OVERRIDE;

 private:
  friend class ::views::View;
  friend class ::views::Widget;
  friend class ::views::test::WidgetTest;

  // Input ---------------------------------------------------------------------

  // Update the cursor given a mouse event. This is called by non mouse_move
  // event handlers to honor the cursor desired by views located under the
  // cursor during drag operations. The location of the mouse should be in the
  // current coordinate system (i.e. any necessary transformation should be
  // applied to the point prior to calling this).
  void UpdateCursor(const ui::MouseEvent& event);

  // Updates the last_mouse_* fields from e. The location of the mouse should be
  // in the current coordinate system (i.e. any necessary transformation should
  // be applied to the point prior to calling this).
  void SetMouseLocationAndFlags(const ui::MouseEvent& event);

  // |view| is the view receiving |event|. This function sends the event to all
  // the Views up the hierarchy that has |notify_enter_exit_on_child_| flag
  // turned on, but does not contain |sibling|.
  void NotifyEnterExitOfDescendant(const ui::MouseEvent& event,
                                   ui::EventType type,
                                   View* view,
                                   View* sibling);

  // Overridden from ui::EventDispatcherDelegate:
  virtual bool CanDispatchToTarget(ui::EventTarget* target) OVERRIDE;
  virtual ui::EventDispatchDetails PreDispatchEvent(ui::EventTarget* target,
                                                    ui::Event* event) OVERRIDE;
  virtual ui::EventDispatchDetails PostDispatchEvent(
      ui::EventTarget* target, const ui::Event& event) OVERRIDE;

  //////////////////////////////////////////////////////////////////////////////
  // Tree operations -----------------------------------------------------------

  // The host Widget
  Widget* widget_;

  // Input ---------------------------------------------------------------------

  // The view currently handing down - drag - up
  View* mouse_pressed_handler_;

  // The view currently handling enter / exit
  View* mouse_move_handler_;

  // The last view to handle a mouse click, so that we can determine if
  // a double-click lands on the same view as its single-click part.
  View* last_click_handler_;

  // true if mouse_pressed_handler_ has been explicitly set
  bool explicit_mouse_handler_;

  // Last position/flag of a mouse press/drag. Used if capture stops and we need
  // to synthesize a release.
  int last_mouse_event_flags_;
  int last_mouse_event_x_;
  int last_mouse_event_y_;

  // The view currently handling gesture events. When set, this handler receives
  // all gesture events, except when there is an event handler for the specific
  // gesture (e.g. scroll).
  View* gesture_handler_;

  // The view currently handling scroll gesture events.
  View* scroll_gesture_handler_;

  scoped_ptr<internal::PreEventDispatchHandler> pre_dispatch_handler_;
  scoped_ptr<internal::PostEventDispatchHandler> post_dispatch_handler_;

  // Focus ---------------------------------------------------------------------

  // The focus search algorithm.
  FocusSearch focus_search_;

  // Whether this root view belongs to the current active window.
  // bool activated_;

  // The parent FocusTraversable, used for focus traversal.
  FocusTraversable* focus_traversable_parent_;

  // The View that contains this RootView. This is used when we have RootView
  // wrapped inside native components, and is used for the focus traversal.
  View* focus_traversable_parent_view_;

  View* event_dispatch_target_;
  View* old_dispatch_target_;

  // Drag and drop -------------------------------------------------------------

  // Tracks drag state for a view.
  View::DragInfo drag_info_;

  DISALLOW_IMPLICIT_CONSTRUCTORS(RootView);
};

}  // namespace internal
}  // namespace views

#endif  // UI_VIEWS_WIDGET_ROOT_VIEW_H_