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 base::string16& menu_name,
  53                              const base::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   FRIEND_TEST_ALL_PREFIXES(AccessibilityEventRouterViewsTest,
  69                            MenuIndexAndCountForInvisibleMenu);
  70
  71   AccessibilityEventRouterViews();
  72   virtual ~AccessibilityEventRouterViews();
  73
  74   // Call DispatchAccessibilityEvent using a view storage id.
  75   static void DispatchEventOnViewStorageId(
  76       int view_storage_id,
  77       ui::AccessibilityTypes::Event event);
  78
  79   // Checks the type of the view and calls one of the more specific
  80   // Send*Notification methods, below.
  81   void DispatchAccessibilityEvent(
  82       views::View* view,
  83       ui::AccessibilityTypes::Event event);
  84
  85   // Each of these methods constructs an AccessibilityControlInfo object
  86   // and sends a notification of a specific accessibility event.
  87   static void SendButtonNotification(
  88       views::View* view,
  89       ui::AccessibilityTypes::Event event,
  90       Profile* profile);
  91   static void SendLinkNotification(
  92       views::View* view,
  93       ui::AccessibilityTypes::Event event,
  94       Profile* profile);
  95   static void SendMenuNotification(
  96       views::View* view,
  97       ui::AccessibilityTypes::Event event,
  98       Profile* profile);
  99   static void SendMenuItemNotification(
 100       views::View* view,
 101       ui::AccessibilityTypes::Event event,
 102       Profile* profile);
 103   static void SendTreeNotification(
 104       views::View* view,
 105       ui::AccessibilityTypes::Event event,
 106       Profile* profile);
 107   static void SendTreeItemNotification(
 108       views::View* view,
 109       ui::AccessibilityTypes::Event event,
 110       Profile* profile);
 111   static void SendTextfieldNotification(
 112       views::View* view,
 113       ui::AccessibilityTypes::Event event,
 114       Profile* profile);
 115   static void SendComboboxNotification(
 116       views::View* view,
 117       ui::AccessibilityTypes::Event event,
 118       Profile* profile);
 119   static void SendCheckboxNotification(
 120       views::View* view,
 121       ui::AccessibilityTypes::Event event,
 122       Profile* profile);
 123   static void SendWindowNotification(
 124       views::View* view,
 125       ui::AccessibilityTypes::Event event,
 126       Profile* profile);
 127   static void SendSliderNotification(
 128       views::View* view,
 129       ui::AccessibilityTypes::Event event,
 130       Profile* profile);
 131   static void SendAlertControlNotification(
 132       views::View* view,
 133       ui::AccessibilityTypes::Event event,
 134       Profile* profile);
 135
 136   // Return the name of a view.
 137   static std::string GetViewName(views::View* view);
 138
 139   // Get the context of a view - the name of the enclosing group, toolbar, etc.
 140   static std::string GetViewContext(views::View* view);
 141
 142   // Return a descendant of this view with a given accessible role, if found.
 143   static views::View* FindDescendantWithAccessibleRole(
 144       views::View* view,
 145       ui::AccessibilityTypes::Role role);
 146
 147   // Recursively explore all menu items of |menu| and return in |count|
 148   // the total number of items, and in |index| the 0-based index of
 149   // |item|, if found. Initialize |count| to zero before calling this
 150   // method. |index| will be unchanged if the item is not found, so
 151   // initialize it to -1 to detect this case.
 152   static void RecursiveGetMenuItemIndexAndCount(views::View* menu,
 153                                                 views::View* item,
 154                                                 int* index,
 155                                                 int* count);
 156
 157   // Recursively explore the subviews and return the text from the first
 158   // subview with a role of STATIC_TEXT.
 159   static std::string RecursiveGetStaticText(views::View* view);
 160
 161   // The profile associated with the most recent window event  - used to
 162   // figure out where to route a few events that can't be directly traced
 163   // to a window with a profile (like menu events).
 164   Profile* most_recent_profile_;
 165
 166   // Notification registrar so we can clear most_recent_profile_ when a
 167   // profile is destroyed.
 168   content::NotificationRegistrar registrar_;
 169
 170   DISALLOW_COPY_AND_ASSIGN(AccessibilityEventRouterViews);
 171 };
 172
 173 #endif  // CHROME_BROWSER_UI_VIEWS_ACCESSIBILITY_ACCESSIBILITY_EVENT_ROUTER_VIEWS_H_