content/browser/accessibility/browser_accessibility_manager_android.cc

   1 // Copyright 2013 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 "content/browser/accessibility/browser_accessibility_manager_android.h"
   6
   7 #include <cmath>
   8
   9 #include "base/android/jni_android.h"
  10 #include "base/android/jni_string.h"
  11 #include "base/strings/string_number_conversions.h"
  12 #include "base/strings/utf_string_conversions.h"
  13 #include "base/values.h"
  14 #include "content/browser/accessibility/browser_accessibility_android.h"
  15 #include "content/common/accessibility_messages.h"
  16 #include "jni/BrowserAccessibilityManager_jni.h"
  17
  18 using base::android::AttachCurrentThread;
  19 using base::android::ScopedJavaLocalRef;
  20
  21 namespace {
  22
  23 // These are enums from android.view.accessibility.AccessibilityEvent in Java:
  24 enum {
  25   ANDROID_ACCESSIBILITY_EVENT_TYPE_VIEW_TEXT_CHANGED = 16,
  26   ANDROID_ACCESSIBILITY_EVENT_TYPE_VIEW_TEXT_SELECTION_CHANGED = 8192
  27 };
  28
  29 enum AndroidHtmlElementType {
  30   HTML_ELEMENT_TYPE_SECTION,
  31   HTML_ELEMENT_TYPE_LIST,
  32   HTML_ELEMENT_TYPE_CONTROL,
  33   HTML_ELEMENT_TYPE_ANY
  34 };
  35
  36 // These are special unofficial strings sent from TalkBack/BrailleBack
  37 // to jump to certain categories of web elements.
  38 AndroidHtmlElementType HtmlElementTypeFromString(base::string16 element_type) {
  39   if (element_type == base::ASCIIToUTF16("SECTION"))
  40     return HTML_ELEMENT_TYPE_SECTION;
  41   else if (element_type == base::ASCIIToUTF16("LIST"))
  42     return HTML_ELEMENT_TYPE_LIST;
  43   else if (element_type == base::ASCIIToUTF16("CONTROL"))
  44     return HTML_ELEMENT_TYPE_CONTROL;
  45   else
  46     return HTML_ELEMENT_TYPE_ANY;
  47 }
  48
  49 }  // anonymous namespace
  50
  51 namespace content {
  52
  53 namespace aria_strings {
  54   const char kAriaLivePolite[] = "polite";
  55   const char kAriaLiveAssertive[] = "assertive";
  56 }
  57
  58 // static
  59 BrowserAccessibilityManager* BrowserAccessibilityManager::Create(
  60     const ui::AXTreeUpdate& initial_tree,
  61     BrowserAccessibilityDelegate* delegate,
  62     BrowserAccessibilityFactory* factory) {
  63   return new BrowserAccessibilityManagerAndroid(
  64       ScopedJavaLocalRef<jobject>(), initial_tree, delegate, factory);
  65 }
  66
  67 BrowserAccessibilityManagerAndroid*
  68 BrowserAccessibilityManager::ToBrowserAccessibilityManagerAndroid() {
  69   return static_cast<BrowserAccessibilityManagerAndroid*>(this);
  70 }
  71
  72 BrowserAccessibilityManagerAndroid::BrowserAccessibilityManagerAndroid(
  73     ScopedJavaLocalRef<jobject> content_view_core,
  74     const ui::AXTreeUpdate& initial_tree,
  75     BrowserAccessibilityDelegate* delegate,
  76     BrowserAccessibilityFactory* factory)
  77     : BrowserAccessibilityManager(initial_tree, delegate, factory) {
  78   SetContentViewCore(content_view_core);
  79 }
  80
  81 BrowserAccessibilityManagerAndroid::~BrowserAccessibilityManagerAndroid() {
  82   JNIEnv* env = AttachCurrentThread();
  83   ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
  84   if (obj.is_null())
  85     return;
  86
  87   Java_BrowserAccessibilityManager_onNativeObjectDestroyed(env, obj.obj());
  88 }
  89
  90 // static
  91 ui::AXTreeUpdate BrowserAccessibilityManagerAndroid::GetEmptyDocument() {
  92   ui::AXNodeData empty_document;
  93   empty_document.id = 0;
  94   empty_document.role = ui::AX_ROLE_ROOT_WEB_AREA;
  95   empty_document.state = 1 << ui::AX_STATE_READ_ONLY;
  96
  97   ui::AXTreeUpdate update;
  98   update.nodes.push_back(empty_document);
  99   return update;
 100 }
 101
 102 void BrowserAccessibilityManagerAndroid::SetContentViewCore(
 103     ScopedJavaLocalRef<jobject> content_view_core) {
 104   if (content_view_core.is_null())
 105     return;
 106
 107   JNIEnv* env = AttachCurrentThread();
 108   java_ref_ = JavaObjectWeakGlobalRef(
 109       env, Java_BrowserAccessibilityManager_create(
 110           env, reinterpret_cast<intptr_t>(this),
 111           content_view_core.obj()).obj());
 112 }
 113
 114 void BrowserAccessibilityManagerAndroid::NotifyAccessibilityEvent(
 115     ui::AXEvent event_type,
 116     BrowserAccessibility* node) {
 117   JNIEnv* env = AttachCurrentThread();
 118   ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
 119   if (obj.is_null())
 120     return;
 121
 122   if (event_type == ui::AX_EVENT_HIDE)
 123     return;
 124
 125   if (event_type == ui::AX_EVENT_HOVER) {
 126     HandleHoverEvent(node);
 127     return;
 128   }
 129
 130   // Always send AccessibilityEvent.TYPE_WINDOW_CONTENT_CHANGED to notify
 131   // the Android system that the accessibility hierarchy rooted at this
 132   // node has changed.
 133   Java_BrowserAccessibilityManager_handleContentChanged(
 134       env, obj.obj(), node->GetId());
 135
 136   switch (event_type) {
 137     case ui::AX_EVENT_LOAD_COMPLETE:
 138       Java_BrowserAccessibilityManager_handlePageLoaded(
 139           env, obj.obj(), focus_->id());
 140       break;
 141     case ui::AX_EVENT_FOCUS:
 142       Java_BrowserAccessibilityManager_handleFocusChanged(
 143           env, obj.obj(), node->GetId());
 144       break;
 145     case ui::AX_EVENT_CHECKED_STATE_CHANGED:
 146       Java_BrowserAccessibilityManager_handleCheckStateChanged(
 147           env, obj.obj(), node->GetId());
 148       break;
 149     case ui::AX_EVENT_SCROLL_POSITION_CHANGED:
 150       Java_BrowserAccessibilityManager_handleScrollPositionChanged(
 151           env, obj.obj(), node->GetId());
 152       break;
 153     case ui::AX_EVENT_SCROLLED_TO_ANCHOR:
 154       Java_BrowserAccessibilityManager_handleScrolledToAnchor(
 155           env, obj.obj(), node->GetId());
 156       break;
 157     case ui::AX_EVENT_ALERT:
 158       // An alert is a special case of live region. Fall through to the
 159       // next case to handle it.
 160     case ui::AX_EVENT_SHOW: {
 161       // This event is fired when an object appears in a live region.
 162       // Speak its text.
 163       BrowserAccessibilityAndroid* android_node =
 164           static_cast<BrowserAccessibilityAndroid*>(node);
 165       Java_BrowserAccessibilityManager_announceLiveRegionText(
 166           env, obj.obj(),
 167           base::android::ConvertUTF16ToJavaString(
 168               env, android_node->GetText()).obj());
 169       break;
 170     }
 171     case ui::AX_EVENT_TEXT_SELECTION_CHANGED:
 172       Java_BrowserAccessibilityManager_handleTextSelectionChanged(
 173           env, obj.obj(), node->GetId());
 174       break;
 175     case ui::AX_EVENT_CHILDREN_CHANGED:
 176     case ui::AX_EVENT_TEXT_CHANGED:
 177     case ui::AX_EVENT_VALUE_CHANGED:
 178       if (node->IsEditableText()) {
 179         Java_BrowserAccessibilityManager_handleEditableTextChanged(
 180             env, obj.obj(), node->GetId());
 181       }
 182       break;
 183     default:
 184       // There are some notifications that aren't meaningful on Android.
 185       // It's okay to skip them.
 186       break;
 187   }
 188 }
 189
 190 jint BrowserAccessibilityManagerAndroid::GetRootId(JNIEnv* env, jobject obj) {
 191   return static_cast<jint>(GetRoot()->GetId());
 192 }
 193
 194 jboolean BrowserAccessibilityManagerAndroid::IsNodeValid(
 195     JNIEnv* env, jobject obj, jint id) {
 196   return GetFromID(id) != NULL;
 197 }
 198
 199 void BrowserAccessibilityManagerAndroid::HitTest(
 200     JNIEnv* env, jobject obj, jint x, jint y) {
 201   if (delegate())
 202     delegate()->AccessibilityHitTest(gfx::Point(x, y));
 203 }
 204
 205 jboolean BrowserAccessibilityManagerAndroid::PopulateAccessibilityNodeInfo(
 206     JNIEnv* env, jobject obj, jobject info, jint id) {
 207   BrowserAccessibilityAndroid* node = static_cast<BrowserAccessibilityAndroid*>(
 208       GetFromID(id));
 209   if (!node)
 210     return false;
 211
 212   if (node->GetParent()) {
 213     Java_BrowserAccessibilityManager_setAccessibilityNodeInfoParent(
 214         env, obj, info, node->GetParent()->GetId());
 215   }
 216   for (unsigned i = 0; i < node->PlatformChildCount(); ++i) {
 217     Java_BrowserAccessibilityManager_addAccessibilityNodeInfoChild(
 218         env, obj, info, node->InternalGetChild(i)->GetId());
 219   }
 220   Java_BrowserAccessibilityManager_setAccessibilityNodeInfoBooleanAttributes(
 221       env, obj, info,
 222       id,
 223       node->IsCheckable(),
 224       node->IsChecked(),
 225       node->IsClickable(),
 226       node->IsEnabled(),
 227       node->IsFocusable(),
 228       node->IsFocused(),
 229       node->IsPassword(),
 230       node->IsScrollable(),
 231       node->IsSelected(),
 232       node->IsVisibleToUser());
 233   Java_BrowserAccessibilityManager_setAccessibilityNodeInfoClassName(
 234       env, obj, info,
 235       base::android::ConvertUTF8ToJavaString(env, node->GetClassName()).obj());
 236   Java_BrowserAccessibilityManager_setAccessibilityNodeInfoContentDescription(
 237       env, obj, info,
 238       base::android::ConvertUTF16ToJavaString(env, node->GetText()).obj(),
 239       node->IsLink());
 240
 241   gfx::Rect absolute_rect = node->GetLocalBoundsRect();
 242   gfx::Rect parent_relative_rect = absolute_rect;
 243   if (node->GetParent()) {
 244     gfx::Rect parent_rect = node->GetParent()->GetLocalBoundsRect();
 245     parent_relative_rect.Offset(-parent_rect.OffsetFromOrigin());
 246   }
 247   bool is_root = node->GetParent() == NULL;
 248   Java_BrowserAccessibilityManager_setAccessibilityNodeInfoLocation(
 249       env, obj, info,
 250       absolute_rect.x(), absolute_rect.y(),
 251       parent_relative_rect.x(), parent_relative_rect.y(),
 252       absolute_rect.width(), absolute_rect.height(),
 253       is_root);
 254
 255   // New KitKat APIs
 256   Java_BrowserAccessibilityManager_setAccessibilityNodeInfoKitKatAttributes(
 257       env, obj, info,
 258       node->CanOpenPopup(),
 259       node->IsContentInvalid(),
 260       node->IsDismissable(),
 261       node->IsMultiLine(),
 262       node->AndroidInputType(),
 263       node->AndroidLiveRegionType());
 264   if (node->IsCollection()) {
 265     Java_BrowserAccessibilityManager_setAccessibilityNodeInfoCollectionInfo(
 266         env, obj, info,
 267         node->RowCount(),
 268         node->ColumnCount(),
 269         node->IsHierarchical());
 270   }
 271   if (node->IsCollectionItem() || node->IsHeading()) {
 272     Java_BrowserAccessibilityManager_setAccessibilityNodeInfoCollectionItemInfo(
 273         env, obj, info,
 274         node->RowIndex(),
 275         node->RowSpan(),
 276         node->ColumnIndex(),
 277         node->ColumnSpan(),
 278         node->IsHeading());
 279   }
 280   if (node->IsRangeType()) {
 281     Java_BrowserAccessibilityManager_setAccessibilityNodeInfoRangeInfo(
 282         env, obj, info,
 283         node->AndroidRangeType(),
 284         node->RangeMin(),
 285         node->RangeMax(),
 286         node->RangeCurrentValue());
 287   }
 288
 289   return true;
 290 }
 291
 292 jboolean BrowserAccessibilityManagerAndroid::PopulateAccessibilityEvent(
 293     JNIEnv* env, jobject obj, jobject event, jint id, jint event_type) {
 294   BrowserAccessibilityAndroid* node = static_cast<BrowserAccessibilityAndroid*>(
 295       GetFromID(id));
 296   if (!node)
 297     return false;
 298
 299   Java_BrowserAccessibilityManager_setAccessibilityEventBooleanAttributes(
 300       env, obj, event,
 301       node->IsChecked(),
 302       node->IsEnabled(),
 303       node->IsPassword(),
 304       node->IsScrollable());
 305   Java_BrowserAccessibilityManager_setAccessibilityEventClassName(
 306       env, obj, event,
 307       base::android::ConvertUTF8ToJavaString(env, node->GetClassName()).obj());
 308   Java_BrowserAccessibilityManager_setAccessibilityEventListAttributes(
 309       env, obj, event,
 310       node->GetItemIndex(),
 311       node->GetItemCount());
 312   Java_BrowserAccessibilityManager_setAccessibilityEventScrollAttributes(
 313       env, obj, event,
 314       node->GetScrollX(),
 315       node->GetScrollY(),
 316       node->GetMaxScrollX(),
 317       node->GetMaxScrollY());
 318
 319   switch (event_type) {
 320     case ANDROID_ACCESSIBILITY_EVENT_TYPE_VIEW_TEXT_CHANGED:
 321       Java_BrowserAccessibilityManager_setAccessibilityEventTextChangedAttrs(
 322           env, obj, event,
 323           node->GetTextChangeFromIndex(),
 324           node->GetTextChangeAddedCount(),
 325           node->GetTextChangeRemovedCount(),
 326           base::android::ConvertUTF16ToJavaString(
 327               env, node->GetTextChangeBeforeText()).obj(),
 328           base::android::ConvertUTF16ToJavaString(env, node->GetText()).obj());
 329       break;
 330     case ANDROID_ACCESSIBILITY_EVENT_TYPE_VIEW_TEXT_SELECTION_CHANGED:
 331       Java_BrowserAccessibilityManager_setAccessibilityEventSelectionAttrs(
 332           env, obj, event,
 333           node->GetSelectionStart(),
 334           node->GetSelectionEnd(),
 335           node->GetEditableTextLength(),
 336           base::android::ConvertUTF16ToJavaString(env, node->GetText()).obj());
 337       break;
 338     default:
 339       break;
 340   }
 341
 342   // Backwards-compatible fallback for new KitKat APIs.
 343   Java_BrowserAccessibilityManager_setAccessibilityEventKitKatAttributes(
 344       env, obj, event,
 345       node->CanOpenPopup(),
 346       node->IsContentInvalid(),
 347       node->IsDismissable(),
 348       node->IsMultiLine(),
 349       node->AndroidInputType(),
 350       node->AndroidLiveRegionType());
 351   if (node->IsCollection()) {
 352     Java_BrowserAccessibilityManager_setAccessibilityEventCollectionInfo(
 353         env, obj, event,
 354         node->RowCount(),
 355         node->ColumnCount(),
 356         node->IsHierarchical());
 357   }
 358   if (node->IsCollectionItem() || node->IsHeading()) {
 359     Java_BrowserAccessibilityManager_setAccessibilityEventCollectionItemInfo(
 360         env, obj, event,
 361         node->RowIndex(),
 362         node->RowSpan(),
 363         node->ColumnIndex(),
 364         node->ColumnSpan(),
 365         node->IsHeading());
 366   }
 367   if (node->IsRangeType()) {
 368     Java_BrowserAccessibilityManager_setAccessibilityEventRangeInfo(
 369         env, obj, event,
 370         node->AndroidRangeType(),
 371         node->RangeMin(),
 372         node->RangeMax(),
 373         node->RangeCurrentValue());
 374   }
 375
 376   return true;
 377 }
 378
 379 void BrowserAccessibilityManagerAndroid::Click(
 380     JNIEnv* env, jobject obj, jint id) {
 381   BrowserAccessibility* node = GetFromID(id);
 382   if (node)
 383     DoDefaultAction(*node);
 384 }
 385
 386 void BrowserAccessibilityManagerAndroid::Focus(
 387     JNIEnv* env, jobject obj, jint id) {
 388   BrowserAccessibility* node = GetFromID(id);
 389   if (node)
 390     SetFocus(node, true);
 391 }
 392
 393 void BrowserAccessibilityManagerAndroid::Blur(JNIEnv* env, jobject obj) {
 394   SetFocus(GetRoot(), true);
 395 }
 396
 397 void BrowserAccessibilityManagerAndroid::ScrollToMakeNodeVisible(
 398     JNIEnv* env, jobject obj, jint id) {
 399   BrowserAccessibility* node = GetFromID(id);
 400   if (node)
 401     ScrollToMakeVisible(*node, gfx::Rect(node->GetLocation().size()));
 402 }
 403
 404 void BrowserAccessibilityManagerAndroid::HandleHoverEvent(
 405     BrowserAccessibility* node) {
 406   JNIEnv* env = AttachCurrentThread();
 407   ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
 408   if (obj.is_null())
 409     return;
 410
 411   BrowserAccessibilityAndroid* ancestor =
 412       static_cast<BrowserAccessibilityAndroid*>(node->GetParent());
 413   while (ancestor) {
 414     if (ancestor->PlatformIsLeaf() ||
 415         (ancestor->IsFocusable() && !ancestor->HasFocusableChild())) {
 416       node = ancestor;
 417       // Don't break - we want the highest ancestor that's focusable or a
 418       // leaf node.
 419     }
 420     ancestor = static_cast<BrowserAccessibilityAndroid*>(ancestor->GetParent());
 421   }
 422
 423   Java_BrowserAccessibilityManager_handleHover(
 424       env, obj.obj(), node->GetId());
 425 }
 426
 427 jint BrowserAccessibilityManagerAndroid::FindElementType(
 428     JNIEnv* env, jobject obj, jint start_id, jstring element_type_str,
 429     jboolean forwards) {
 430   BrowserAccessibility* node = GetFromID(start_id);
 431   if (!node)
 432     return 0;
 433
 434   AndroidHtmlElementType element_type = HtmlElementTypeFromString(
 435       base::android::ConvertJavaStringToUTF16(env, element_type_str));
 436
 437   node = forwards ? NextInTreeOrder(node) : PreviousInTreeOrder(node);
 438   while (node) {
 439     switch(element_type) {
 440       case HTML_ELEMENT_TYPE_SECTION:
 441         if (node->GetRole() == ui::AX_ROLE_ARTICLE ||
 442             node->GetRole() == ui::AX_ROLE_APPLICATION ||
 443             node->GetRole() == ui::AX_ROLE_BANNER ||
 444             node->GetRole() == ui::AX_ROLE_COMPLEMENTARY ||
 445             node->GetRole() == ui::AX_ROLE_CONTENT_INFO ||
 446             node->GetRole() == ui::AX_ROLE_HEADING ||
 447             node->GetRole() == ui::AX_ROLE_MAIN ||
 448             node->GetRole() == ui::AX_ROLE_NAVIGATION ||
 449             node->GetRole() == ui::AX_ROLE_SEARCH ||
 450             node->GetRole() == ui::AX_ROLE_REGION) {
 451           return node->GetId();
 452         }
 453         break;
 454       case HTML_ELEMENT_TYPE_LIST:
 455         if (node->GetRole() == ui::AX_ROLE_LIST ||
 456             node->GetRole() == ui::AX_ROLE_GRID ||
 457             node->GetRole() == ui::AX_ROLE_TABLE ||
 458             node->GetRole() == ui::AX_ROLE_TREE) {
 459           return node->GetId();
 460         }
 461         break;
 462       case HTML_ELEMENT_TYPE_CONTROL:
 463         if (static_cast<BrowserAccessibilityAndroid*>(node)->IsFocusable())
 464           return node->GetId();
 465         break;
 466       case HTML_ELEMENT_TYPE_ANY:
 467         // In theory, the API says that an accessibility service could
 468         // jump to an element by element name, like 'H1' or 'P'. This isn't
 469         // currently used by any accessibility service, and we think it's
 470         // better to keep them high-level like 'SECTION' or 'CONTROL', so we
 471         // just fall back on linear navigation when we don't recognize the
 472         // element type.
 473         if (static_cast<BrowserAccessibilityAndroid*>(node)->IsClickable())
 474           return node->GetId();
 475         break;
 476     }
 477
 478     node = forwards ? NextInTreeOrder(node) : PreviousInTreeOrder(node);
 479   }
 480
 481   return 0;
 482 }
 483
 484 void BrowserAccessibilityManagerAndroid::OnRootChanged(ui::AXNode* new_root) {
 485   JNIEnv* env = AttachCurrentThread();
 486   ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
 487   if (obj.is_null())
 488     return;
 489
 490   Java_BrowserAccessibilityManager_handleNavigate(env, obj.obj());
 491 }
 492
 493 bool
 494 BrowserAccessibilityManagerAndroid::UseRootScrollOffsetsWhenComputingBounds() {
 495   // The Java layer handles the root scroll offset.
 496   return false;
 497 }
 498
 499 bool RegisterBrowserAccessibilityManager(JNIEnv* env) {
 500   return RegisterNativesImpl(env);
 501 }
 502
 503 }  // namespace content