ui/views/accessible_pane_view.cc

   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 #include "ui/views/accessible_pane_view.h"
   6
   7 #include "base/message_loop/message_loop.h"
   8 #include "ui/accessibility/ax_view_state.h"
   9 #include "ui/views/focus/focus_search.h"
  10 #include "ui/views/focus/view_storage.h"
  11 #include "ui/views/widget/widget.h"
  12
  13 namespace views {
  14
  15 // Create tiny subclass of FocusSearch that overrides GetParent and Contains,
  16 // delegating these to methods in AccessiblePaneView. This is needed so that
  17 // subclasses of AccessiblePaneView can customize the focus search logic and
  18 // include views that aren't part of the AccessiblePaneView's view
  19 // hierarchy in the focus order.
  20 class AccessiblePaneViewFocusSearch : public FocusSearch {
  21  public:
  22   explicit AccessiblePaneViewFocusSearch(AccessiblePaneView* pane_view)
  23       : FocusSearch(pane_view, true, true),
  24         accessible_pane_view_(pane_view) {}
  25
  26  protected:
  27   View* GetParent(View* v) override {
  28     return accessible_pane_view_->ContainsForFocusSearch(root(), v) ?
  29         accessible_pane_view_->GetParentForFocusSearch(v) : NULL;
  30   }
  31
  32   // Returns true if |v| is contained within the hierarchy rooted at |root|.
  33   // Subclasses can override this if they need custom focus search behavior.
  34   bool Contains(View* root, const View* v) override {
  35     return accessible_pane_view_->ContainsForFocusSearch(root, v);
  36   }
  37
  38  private:
  39   AccessiblePaneView* accessible_pane_view_;
  40   DISALLOW_COPY_AND_ASSIGN(AccessiblePaneViewFocusSearch);
  41 };
  42
  43 AccessiblePaneView::AccessiblePaneView()
  44     : pane_has_focus_(false),
  45       allow_deactivate_on_esc_(false),
  46       focus_manager_(NULL),
  47       home_key_(ui::VKEY_HOME, ui::EF_NONE),
  48       end_key_(ui::VKEY_END, ui::EF_NONE),
  49       escape_key_(ui::VKEY_ESCAPE, ui::EF_NONE),
  50       left_key_(ui::VKEY_LEFT, ui::EF_NONE),
  51       right_key_(ui::VKEY_RIGHT, ui::EF_NONE),
  52       method_factory_(this) {
  53   focus_search_.reset(new AccessiblePaneViewFocusSearch(this));
  54   last_focused_view_storage_id_ = ViewStorage::GetInstance()->CreateStorageID();
  55 }
  56
  57 AccessiblePaneView::~AccessiblePaneView() {
  58   if (pane_has_focus_) {
  59     focus_manager_->RemoveFocusChangeListener(this);
  60   }
  61 }
  62
  63 bool AccessiblePaneView::SetPaneFocus(views::View* initial_focus) {
  64   if (!visible())
  65     return false;
  66
  67   if (!focus_manager_)
  68     focus_manager_ = GetFocusManager();
  69
  70   View* focused_view = focus_manager_->GetFocusedView();
  71   if (focused_view && !ContainsForFocusSearch(this, focused_view)) {
  72     ViewStorage* view_storage = ViewStorage::GetInstance();
  73     view_storage->RemoveView(last_focused_view_storage_id_);
  74     view_storage->StoreView(last_focused_view_storage_id_, focused_view);
  75   }
  76
  77   // Use the provided initial focus if it's visible and enabled, otherwise
  78   // use the first focusable child.
  79   if (!initial_focus ||
  80       !ContainsForFocusSearch(this, initial_focus) ||
  81       !initial_focus->visible() ||
  82       !initial_focus->enabled()) {
  83     initial_focus = GetFirstFocusableChild();
  84   }
  85
  86   // Return false if there are no focusable children.
  87   if (!initial_focus)
  88     return false;
  89
  90   focus_manager_->SetFocusedView(initial_focus);
  91
  92   // If we already have pane focus, we're done.
  93   if (pane_has_focus_)
  94     return true;
  95
  96   // Otherwise, set accelerators and start listening for focus change events.
  97   pane_has_focus_ = true;
  98   ui::AcceleratorManager::HandlerPriority normal =
  99       ui::AcceleratorManager::kNormalPriority;
 100   focus_manager_->RegisterAccelerator(home_key_, normal, this);
 101   focus_manager_->RegisterAccelerator(end_key_, normal, this);
 102   focus_manager_->RegisterAccelerator(escape_key_, normal, this);
 103   focus_manager_->RegisterAccelerator(left_key_, normal, this);
 104   focus_manager_->RegisterAccelerator(right_key_, normal, this);
 105   focus_manager_->AddFocusChangeListener(this);
 106
 107   return true;
 108 }
 109
 110 bool AccessiblePaneView::SetPaneFocusAndFocusDefault() {
 111   return SetPaneFocus(GetDefaultFocusableChild());
 112 }
 113
 114 views::View* AccessiblePaneView::GetDefaultFocusableChild() {
 115   return NULL;
 116 }
 117
 118 View* AccessiblePaneView::GetParentForFocusSearch(View* v) {
 119   return v->parent();
 120 }
 121
 122 bool AccessiblePaneView::ContainsForFocusSearch(View* root, const View* v) {
 123   return root->Contains(v);
 124 }
 125
 126 void AccessiblePaneView::RemovePaneFocus() {
 127   focus_manager_->RemoveFocusChangeListener(this);
 128   pane_has_focus_ = false;
 129
 130   focus_manager_->UnregisterAccelerator(home_key_, this);
 131   focus_manager_->UnregisterAccelerator(end_key_, this);
 132   focus_manager_->UnregisterAccelerator(escape_key_, this);
 133   focus_manager_->UnregisterAccelerator(left_key_, this);
 134   focus_manager_->UnregisterAccelerator(right_key_, this);
 135 }
 136
 137 views::View* AccessiblePaneView::GetFirstFocusableChild() {
 138   FocusTraversable* dummy_focus_traversable;
 139   views::View* dummy_focus_traversable_view;
 140   return focus_search_->FindNextFocusableView(
 141       NULL, false, views::FocusSearch::DOWN, false,
 142       &dummy_focus_traversable, &dummy_focus_traversable_view);
 143 }
 144
 145 views::View* AccessiblePaneView::GetLastFocusableChild() {
 146   FocusTraversable* dummy_focus_traversable;
 147   views::View* dummy_focus_traversable_view;
 148   return focus_search_->FindNextFocusableView(
 149       this, true, views::FocusSearch::DOWN, false,
 150       &dummy_focus_traversable, &dummy_focus_traversable_view);
 151 }
 152
 153 ////////////////////////////////////////////////////////////////////////////////
 154 // View overrides:
 155
 156 views::FocusTraversable* AccessiblePaneView::GetPaneFocusTraversable() {
 157   if (pane_has_focus_)
 158     return this;
 159   else
 160     return NULL;
 161 }
 162
 163 bool AccessiblePaneView::AcceleratorPressed(
 164     const ui::Accelerator& accelerator) {
 165
 166   views::View* focused_view = focus_manager_->GetFocusedView();
 167   if (!ContainsForFocusSearch(this, focused_view))
 168     return false;
 169
 170   switch (accelerator.key_code()) {
 171     case ui::VKEY_ESCAPE: {
 172       RemovePaneFocus();
 173       View* last_focused_view = ViewStorage::GetInstance()->RetrieveView(
 174           last_focused_view_storage_id_);
 175       if (last_focused_view) {
 176         focus_manager_->SetFocusedViewWithReason(
 177             last_focused_view, FocusManager::kReasonFocusRestore);
 178       } else if (allow_deactivate_on_esc_) {
 179         focused_view->GetWidget()->Deactivate();
 180       }
 181       return true;
 182     }
 183     case ui::VKEY_LEFT:
 184       focus_manager_->AdvanceFocus(true);
 185       return true;
 186     case ui::VKEY_RIGHT:
 187       focus_manager_->AdvanceFocus(false);
 188       return true;
 189     case ui::VKEY_HOME:
 190       focus_manager_->SetFocusedViewWithReason(
 191           GetFirstFocusableChild(), views::FocusManager::kReasonFocusTraversal);
 192       return true;
 193     case ui::VKEY_END:
 194       focus_manager_->SetFocusedViewWithReason(
 195           GetLastFocusableChild(), views::FocusManager::kReasonFocusTraversal);
 196       return true;
 197     default:
 198       return false;
 199   }
 200 }
 201
 202 void AccessiblePaneView::SetVisible(bool flag) {
 203   if (visible() && !flag && pane_has_focus_) {
 204     RemovePaneFocus();
 205     focus_manager_->RestoreFocusedView();
 206   }
 207   View::SetVisible(flag);
 208 }
 209
 210 void AccessiblePaneView::GetAccessibleState(ui::AXViewState* state) {
 211   state->role = ui::AX_ROLE_PANE;
 212 }
 213
 214 void AccessiblePaneView::RequestFocus() {
 215   SetPaneFocusAndFocusDefault();
 216 }
 217
 218 ////////////////////////////////////////////////////////////////////////////////
 219 // FocusChangeListener overrides:
 220
 221 void AccessiblePaneView::OnWillChangeFocus(views::View* focused_before,
 222                                            views::View* focused_now) {
 223   //  Act when focus has changed.
 224 }
 225
 226 void AccessiblePaneView::OnDidChangeFocus(views::View* focused_before,
 227                                           views::View* focused_now) {
 228   if (!focused_now)
 229     return;
 230
 231   views::FocusManager::FocusChangeReason reason =
 232       focus_manager_->focus_change_reason();
 233
 234   if (!ContainsForFocusSearch(this, focused_now) ||
 235       reason == views::FocusManager::kReasonDirectFocusChange) {
 236     // We should remove pane focus (i.e. make most of the controls
 237     // not focusable again) because the focus has left the pane,
 238     // or because the focus changed within the pane due to the user
 239     // directly focusing to a specific view (e.g., clicking on it).
 240     RemovePaneFocus();
 241   }
 242 }
 243
 244 ////////////////////////////////////////////////////////////////////////////////
 245 // FocusTraversable overrides:
 246
 247 views::FocusSearch* AccessiblePaneView::GetFocusSearch() {
 248   DCHECK(pane_has_focus_);
 249   return focus_search_.get();
 250 }
 251
 252 views::FocusTraversable* AccessiblePaneView::GetFocusTraversableParent() {
 253   DCHECK(pane_has_focus_);
 254   return NULL;
 255 }
 256
 257 views::View* AccessiblePaneView::GetFocusTraversableParentView() {
 258   DCHECK(pane_has_focus_);
 259   return NULL;
 260 }
 261
 262 }  // namespace views