chrome/browser/ui/views/accessibility/accessibility_event_router_views.h

   1 // Copyright (c) 2012 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 CHROME_BROWSER_UI_VIEWS_ACCESSIBILITY_ACCESSIBILITY_EVENT_ROUTER_VIEWS_H_
   6 #define CHROME_BROWSER_UI_VIEWS_ACCESSIBILITY_ACCESSIBILITY_EVENT_ROUTER_VIEWS_H_
   7
   8 #include <string>
   9
  10 #include "base/basictypes.h"
  11 #include "base/gtest_prod_util.h"
  12 #include "base/strings/string16.h"
  13 #include "chrome/browser/accessibility/accessibility_events.h"
  14 #include "content/public/browser/notification_observer.h"
  15 #include "content/public/browser/notification_registrar.h"
  16 #include "ui/base/accessibility/accessibility_types.h"
  17
  18 class Profile;
  19
  20 template <typename T> struct DefaultSingletonTraits;
  21
  22 namespace views {
  23 class View;
  24 }
  25
  26 // NOTE: This class is part of the Accessibility Extension API, which lets
  27 // extensions receive accessibility events. It's distinct from code that
  28 // implements platform accessibility APIs like MSAA or ATK.
  29 //
  30 // Singleton class that adds listeners to many views, then sends an
  31 // accessibility notification whenever a relevant event occurs in an
  32 // accessible view.
  33 //
  34 // Views are not accessible by default. When you register a root widget,
  35 // that widget and all of its descendants will start sending accessibility
  36 // event notifications. You can then override the default behavior for
  37 // specific descendants using other methods.
  38 //
  39 // You can use Profile::PauseAccessibilityEvents to prevent a flurry
  40 // of accessibility events when a window is being created or initialized.
  41 class AccessibilityEventRouterViews : public content::NotificationObserver {
  42  public:
  43   // Get the single instance of this class.
  44   static AccessibilityEventRouterViews* GetInstance();
  45
  46   // Handle an accessibility event generated by a view.
  47   void HandleAccessibilityEvent(
  48       views::View* view, ui::AccessibilityTypes::Event event_type);
  49
  50   // Handle a menu item being focused (separate because a menu item is
  51   // not necessarily its own view).
  52   void HandleMenuItemFocused(const string16& menu_name,
  53                              const string16& menu_item_name,
  54                              int item_index,
  55                              int item_count,
  56                              bool has_submenu);
  57
  58   // NotificationObserver implementation.
  59   virtual void Observe(int type,
  60                        const content::NotificationSource& source,
  61                        const content::NotificationDetails& details) OVERRIDE;
  62
  63  private:
  64   friend struct DefaultSingletonTraits<AccessibilityEventRouterViews>;
  65
  66   FRIEND_TEST_ALL_PREFIXES(AccessibilityEventRouterViewsTest,
  67                            TestFocusNotification);
  68
  69   AccessibilityEventRouterViews();
  70   virtual ~AccessibilityEventRouterViews();
  71
  72   // Call DispatchAccessibilityEvent using a view storage id.
  73   static void DispatchEventOnViewStorageId(
  74       int view_storage_id,
  75       ui::AccessibilityTypes::Event event);
  76
  77   // Checks the type of the view and calls one of the more specific
  78   // Send*Notification methods, below.
  79   void DispatchAccessibilityEvent(
  80       views::View* view,
  81       ui::AccessibilityTypes::Event event);
  82
  83   // Each of these methods constructs an AccessibilityControlInfo object
  84   // and sends a notification of a specific accessibility event.
  85   static void SendButtonNotification(
  86       views::View* view,
  87       ui::AccessibilityTypes::Event event,
  88       Profile* profile);
  89   static void SendLinkNotification(
  90       views::View* view,
  91       ui::AccessibilityTypes::Event event,
  92       Profile* profile);
  93   static void SendMenuNotification(
  94       views::View* view,
  95       ui::AccessibilityTypes::Event event,
  96       Profile* profile);
  97   static void SendMenuItemNotification(
  98       views::View* view,
  99       ui::AccessibilityTypes::Event event,
 100       Profile* profile);
 101   static void SendTextfieldNotification(
 102       views::View* view,
 103       ui::AccessibilityTypes::Event event,
 104       Profile* profile);
 105   static void SendComboboxNotification(
 106       views::View* view,
 107       ui::AccessibilityTypes::Event event,
 108       Profile* profile);
 109   static void SendCheckboxNotification(
 110       views::View* view,
 111       ui::AccessibilityTypes::Event event,
 112       Profile* profile);
 113   static void SendWindowNotification(
 114       views::View* view,
 115       ui::AccessibilityTypes::Event event,
 116       Profile* profile);
 117   static void SendSliderNotification(
 118       views::View* view,
 119       ui::AccessibilityTypes::Event event,
 120       Profile* profile);
 121
 122   // Return the name of a view.
 123   static std::string GetViewName(views::View* view);
 124
 125   // Get the context of a view - the name of the enclosing group, toolbar, etc.
 126   static std::string GetViewContext(views::View* view);
 127
 128   // Return a descendant of this view with a given accessible role, if found.
 129   static views::View* FindDescendantWithAccessibleRole(
 130       views::View* view,
 131       ui::AccessibilityTypes::Role role);
 132
 133   // Recursively explore all menu items of |menu| and return in |count|
 134   // the total number of items, and in |index| the 0-based index of
 135   // |item|, if found. Initialize |count| to zero before calling this
 136   // method. |index| will be unchanged if the item is not found, so
 137   // initialize it to -1 to detect this case.
 138   static void RecursiveGetMenuItemIndexAndCount(views::View* menu,
 139                                                 views::View* item,
 140                                                 int* index,
 141                                                 int* count);
 142
 143   // Recursively explore the subviews and return the text from the first
 144   // subview with a role of STATIC_TEXT.
 145   static std::string RecursiveGetStaticText(views::View* view);
 146
 147   // The profile associated with the most recent window event  - used to
 148   // figure out where to route a few events that can't be directly traced
 149   // to a window with a profile (like menu events).
 150   Profile* most_recent_profile_;
 151
 152   // Notification registrar so we can clear most_recent_profile_ when a
 153   // profile is destroyed.
 154   content::NotificationRegistrar registrar_;
 155
 156   DISALLOW_COPY_AND_ASSIGN(AccessibilityEventRouterViews);
 157 };
 158
 159 #endif  // CHROME_BROWSER_UI_VIEWS_ACCESSIBILITY_ACCESSIBILITY_EVENT_ROUTER_VIEWS_H_