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 // Restricts |val| to the range [min, max].
  30 int Clamp(int val, int min, int max) {
  31   return std::min(std::max(val, min), max);
  32 }
  33
  34 }  // anonymous namespace
  35
  36 namespace content {
  37
  38 namespace aria_strings {
  39   const char kAriaLivePolite[] = "polite";
  40   const char kAriaLiveAssertive[] = "assertive";
  41 }
  42
  43 // static
  44 BrowserAccessibilityManager* BrowserAccessibilityManager::Create(
  45     const ui::AXNodeData& src,
  46     BrowserAccessibilityDelegate* delegate,
  47     BrowserAccessibilityFactory* factory) {
  48   return new BrowserAccessibilityManagerAndroid(ScopedJavaLocalRef<jobject>(),
  49                                                 src, delegate, factory);
  50 }
  51
  52 BrowserAccessibilityManagerAndroid*
  53 BrowserAccessibilityManager::ToBrowserAccessibilityManagerAndroid() {
  54   return static_cast<BrowserAccessibilityManagerAndroid*>(this);
  55 }
  56
  57 BrowserAccessibilityManagerAndroid::BrowserAccessibilityManagerAndroid(
  58     ScopedJavaLocalRef<jobject> content_view_core,
  59     const ui::AXNodeData& src,
  60     BrowserAccessibilityDelegate* delegate,
  61     BrowserAccessibilityFactory* factory)
  62     : BrowserAccessibilityManager(src, delegate, factory) {
  63   SetContentViewCore(content_view_core);
  64 }
  65
  66 BrowserAccessibilityManagerAndroid::~BrowserAccessibilityManagerAndroid() {
  67   JNIEnv* env = AttachCurrentThread();
  68   ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
  69   if (obj.is_null())
  70     return;
  71
  72   Java_BrowserAccessibilityManager_onNativeObjectDestroyed(env, obj.obj());
  73 }
  74
  75 // static
  76 ui::AXNodeData BrowserAccessibilityManagerAndroid::GetEmptyDocument() {
  77   ui::AXNodeData empty_document;
  78   empty_document.id = 0;
  79   empty_document.role = ui::AX_ROLE_ROOT_WEB_AREA;
  80   empty_document.state = 1 << ui::AX_STATE_READONLY;
  81   return empty_document;
  82 }
  83
  84 void BrowserAccessibilityManagerAndroid::SetContentViewCore(
  85     ScopedJavaLocalRef<jobject> content_view_core) {
  86   if (content_view_core.is_null())
  87     return;
  88
  89   JNIEnv* env = AttachCurrentThread();
  90   java_ref_ = JavaObjectWeakGlobalRef(
  91       env, Java_BrowserAccessibilityManager_create(
  92           env, reinterpret_cast<intptr_t>(this),
  93           content_view_core.obj()).obj());
  94 }
  95
  96 void BrowserAccessibilityManagerAndroid::NotifyAccessibilityEvent(
  97     ui::AXEvent event_type,
  98     BrowserAccessibility* node) {
  99   JNIEnv* env = AttachCurrentThread();
 100   ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
 101   if (obj.is_null())
 102     return;
 103
 104   if (event_type == ui::AX_EVENT_HIDE)
 105     return;
 106
 107   // Always send AccessibilityEvent.TYPE_WINDOW_CONTENT_CHANGED to notify
 108   // the Android system that the accessibility hierarchy rooted at this
 109   // node has changed.
 110   Java_BrowserAccessibilityManager_handleContentChanged(
 111       env, obj.obj(), node->renderer_id());
 112
 113   switch (event_type) {
 114     case ui::AX_EVENT_LOAD_COMPLETE:
 115       Java_BrowserAccessibilityManager_handlePageLoaded(
 116           env, obj.obj(), focus_->renderer_id());
 117       break;
 118     case ui::AX_EVENT_FOCUS:
 119       Java_BrowserAccessibilityManager_handleFocusChanged(
 120           env, obj.obj(), node->renderer_id());
 121       break;
 122     case ui::AX_EVENT_CHECKED_STATE_CHANGED:
 123       Java_BrowserAccessibilityManager_handleCheckStateChanged(
 124           env, obj.obj(), node->renderer_id());
 125       break;
 126     case ui::AX_EVENT_SCROLLED_TO_ANCHOR:
 127       Java_BrowserAccessibilityManager_handleScrolledToAnchor(
 128           env, obj.obj(), node->renderer_id());
 129       break;
 130     case ui::AX_EVENT_ALERT:
 131       // An alert is a special case of live region. Fall through to the
 132       // next case to handle it.
 133     case ui::AX_EVENT_SHOW: {
 134       // This event is fired when an object appears in a live region.
 135       // Speak its text.
 136       BrowserAccessibilityAndroid* android_node =
 137           static_cast<BrowserAccessibilityAndroid*>(node);
 138       Java_BrowserAccessibilityManager_announceLiveRegionText(
 139           env, obj.obj(),
 140           base::android::ConvertUTF16ToJavaString(
 141               env, android_node->GetText()).obj());
 142       break;
 143     }
 144     case ui::AX_EVENT_SELECTED_TEXT_CHANGED:
 145       Java_BrowserAccessibilityManager_handleTextSelectionChanged(
 146           env, obj.obj(), node->renderer_id());
 147       break;
 148     case ui::AX_EVENT_CHILDREN_CHANGED:
 149     case ui::AX_EVENT_TEXT_CHANGED:
 150     case ui::AX_EVENT_VALUE_CHANGED:
 151       if (node->IsEditableText()) {
 152         Java_BrowserAccessibilityManager_handleEditableTextChanged(
 153             env, obj.obj(), node->renderer_id());
 154       }
 155       break;
 156     default:
 157       // There are some notifications that aren't meaningful on Android.
 158       // It's okay to skip them.
 159       break;
 160   }
 161 }
 162
 163 jint BrowserAccessibilityManagerAndroid::GetRootId(JNIEnv* env, jobject obj) {
 164   return static_cast<jint>(root_->renderer_id());
 165 }
 166
 167 jboolean BrowserAccessibilityManagerAndroid::IsNodeValid(
 168     JNIEnv* env, jobject obj, jint id) {
 169   return GetFromRendererID(id) != NULL;
 170 }
 171
 172 jint BrowserAccessibilityManagerAndroid::HitTest(
 173     JNIEnv* env, jobject obj, jint x, jint y) {
 174   BrowserAccessibilityAndroid* result =
 175       static_cast<BrowserAccessibilityAndroid*>(
 176           root_->BrowserAccessibilityForPoint(gfx::Point(x, y)));
 177
 178   if (!result)
 179     return root_->renderer_id();
 180
 181   if (result->IsFocusable())
 182     return result->renderer_id();
 183
 184   // Examine the children of |result| to find the nearest accessibility focus
 185   // candidate
 186   BrowserAccessibility* nearest_node = FuzzyHitTest(x, y, result);
 187   if (nearest_node)
 188     return nearest_node->renderer_id();
 189
 190   return root_->renderer_id();
 191 }
 192
 193 jboolean BrowserAccessibilityManagerAndroid::PopulateAccessibilityNodeInfo(
 194     JNIEnv* env, jobject obj, jobject info, jint id) {
 195   BrowserAccessibilityAndroid* node = static_cast<BrowserAccessibilityAndroid*>(
 196       GetFromRendererID(id));
 197   if (!node)
 198     return false;
 199
 200   if (node->parent()) {
 201     Java_BrowserAccessibilityManager_setAccessibilityNodeInfoParent(
 202         env, obj, info, node->parent()->renderer_id());
 203   }
 204   for (unsigned i = 0; i < node->PlatformChildCount(); ++i) {
 205     Java_BrowserAccessibilityManager_addAccessibilityNodeInfoChild(
 206         env, obj, info, node->children()[i]->renderer_id());
 207   }
 208   Java_BrowserAccessibilityManager_setAccessibilityNodeInfoBooleanAttributes(
 209       env, obj, info,
 210       id,
 211       node->IsCheckable(),
 212       node->IsChecked(),
 213       node->IsClickable(),
 214       node->IsEnabled(),
 215       node->IsFocusable(),
 216       node->IsFocused(),
 217       node->IsPassword(),
 218       node->IsScrollable(),
 219       node->IsSelected(),
 220       node->IsVisibleToUser());
 221   Java_BrowserAccessibilityManager_setAccessibilityNodeInfoStringAttributes(
 222       env, obj, info,
 223       base::android::ConvertUTF8ToJavaString(env, node->GetClassName()).obj(),
 224       base::android::ConvertUTF16ToJavaString(env, node->GetText()).obj());
 225
 226   gfx::Rect absolute_rect = node->GetLocalBoundsRect();
 227   gfx::Rect parent_relative_rect = absolute_rect;
 228   if (node->parent()) {
 229     gfx::Rect parent_rect = node->parent()->GetLocalBoundsRect();
 230     parent_relative_rect.Offset(-parent_rect.OffsetFromOrigin());
 231   }
 232   bool is_root = node->parent() == NULL;
 233   Java_BrowserAccessibilityManager_setAccessibilityNodeInfoLocation(
 234       env, obj, info,
 235       absolute_rect.x(), absolute_rect.y(),
 236       parent_relative_rect.x(), parent_relative_rect.y(),
 237       absolute_rect.width(), absolute_rect.height(),
 238       is_root);
 239
 240   // New KitKat APIs
 241   Java_BrowserAccessibilityManager_setAccessibilityNodeInfoKitKatAttributes(
 242       env, obj, info,
 243       node->CanOpenPopup(),
 244       node->IsContentInvalid(),
 245       node->IsDismissable(),
 246       node->IsMultiLine(),
 247       node->AndroidInputType(),
 248       node->AndroidLiveRegionType());
 249   if (node->IsCollection()) {
 250     Java_BrowserAccessibilityManager_setAccessibilityNodeInfoCollectionInfo(
 251         env, obj, info,
 252         node->RowCount(),
 253         node->ColumnCount(),
 254         node->IsHierarchical());
 255   }
 256   if (node->IsCollectionItem() || node->IsHeading()) {
 257     Java_BrowserAccessibilityManager_setAccessibilityNodeInfoCollectionItemInfo(
 258         env, obj, info,
 259         node->RowIndex(),
 260         node->RowSpan(),
 261         node->ColumnIndex(),
 262         node->ColumnSpan(),
 263         node->IsHeading());
 264   }
 265   if (node->IsRangeType()) {
 266     Java_BrowserAccessibilityManager_setAccessibilityNodeInfoRangeInfo(
 267         env, obj, info,
 268         node->AndroidRangeType(),
 269         node->RangeMin(),
 270         node->RangeMax(),
 271         node->RangeCurrentValue());
 272   }
 273
 274   return true;
 275 }
 276
 277 jboolean BrowserAccessibilityManagerAndroid::PopulateAccessibilityEvent(
 278     JNIEnv* env, jobject obj, jobject event, jint id, jint event_type) {
 279   BrowserAccessibilityAndroid* node = static_cast<BrowserAccessibilityAndroid*>(
 280       GetFromRendererID(id));
 281   if (!node)
 282     return false;
 283
 284   Java_BrowserAccessibilityManager_setAccessibilityEventBooleanAttributes(
 285       env, obj, event,
 286       node->IsChecked(),
 287       node->IsEnabled(),
 288       node->IsPassword(),
 289       node->IsScrollable());
 290   Java_BrowserAccessibilityManager_setAccessibilityEventClassName(
 291       env, obj, event,
 292       base::android::ConvertUTF8ToJavaString(env, node->GetClassName()).obj());
 293   Java_BrowserAccessibilityManager_setAccessibilityEventListAttributes(
 294       env, obj, event,
 295       node->GetItemIndex(),
 296       node->GetItemCount());
 297   Java_BrowserAccessibilityManager_setAccessibilityEventScrollAttributes(
 298       env, obj, event,
 299       node->GetScrollX(),
 300       node->GetScrollY(),
 301       node->GetMaxScrollX(),
 302       node->GetMaxScrollY());
 303
 304   switch (event_type) {
 305     case ANDROID_ACCESSIBILITY_EVENT_TYPE_VIEW_TEXT_CHANGED:
 306       Java_BrowserAccessibilityManager_setAccessibilityEventTextChangedAttrs(
 307           env, obj, event,
 308           node->GetTextChangeFromIndex(),
 309           node->GetTextChangeAddedCount(),
 310           node->GetTextChangeRemovedCount(),
 311           base::android::ConvertUTF16ToJavaString(
 312               env, node->GetTextChangeBeforeText()).obj(),
 313           base::android::ConvertUTF16ToJavaString(env, node->GetText()).obj());
 314       break;
 315     case ANDROID_ACCESSIBILITY_EVENT_TYPE_VIEW_TEXT_SELECTION_CHANGED:
 316       Java_BrowserAccessibilityManager_setAccessibilityEventSelectionAttrs(
 317           env, obj, event,
 318           node->GetSelectionStart(),
 319           node->GetSelectionEnd(),
 320           node->GetEditableTextLength(),
 321           base::android::ConvertUTF16ToJavaString(env, node->GetText()).obj());
 322       break;
 323     default:
 324       break;
 325   }
 326
 327   // Backwards-compatible fallback for new KitKat APIs.
 328   Java_BrowserAccessibilityManager_setAccessibilityEventKitKatAttributes(
 329       env, obj, event,
 330       node->CanOpenPopup(),
 331       node->IsContentInvalid(),
 332       node->IsDismissable(),
 333       node->IsMultiLine(),
 334       node->AndroidInputType(),
 335       node->AndroidLiveRegionType());
 336   if (node->IsCollection()) {
 337     Java_BrowserAccessibilityManager_setAccessibilityEventCollectionInfo(
 338         env, obj, event,
 339         node->RowCount(),
 340         node->ColumnCount(),
 341         node->IsHierarchical());
 342   }
 343   if (node->IsCollectionItem() || node->IsHeading()) {
 344     Java_BrowserAccessibilityManager_setAccessibilityEventCollectionItemInfo(
 345         env, obj, event,
 346         node->RowIndex(),
 347         node->RowSpan(),
 348         node->ColumnIndex(),
 349         node->ColumnSpan(),
 350         node->IsHeading());
 351   }
 352   if (node->IsRangeType()) {
 353     Java_BrowserAccessibilityManager_setAccessibilityEventRangeInfo(
 354         env, obj, event,
 355         node->AndroidRangeType(),
 356         node->RangeMin(),
 357         node->RangeMax(),
 358         node->RangeCurrentValue());
 359   }
 360
 361   return true;
 362 }
 363
 364 void BrowserAccessibilityManagerAndroid::Click(
 365     JNIEnv* env, jobject obj, jint id) {
 366   BrowserAccessibility* node = GetFromRendererID(id);
 367   if (node)
 368     DoDefaultAction(*node);
 369 }
 370
 371 void BrowserAccessibilityManagerAndroid::Focus(
 372     JNIEnv* env, jobject obj, jint id) {
 373   BrowserAccessibility* node = GetFromRendererID(id);
 374   if (node)
 375     SetFocus(node, true);
 376 }
 377
 378 void BrowserAccessibilityManagerAndroid::Blur(JNIEnv* env, jobject obj) {
 379   SetFocus(root_, true);
 380 }
 381
 382 BrowserAccessibility* BrowserAccessibilityManagerAndroid::FuzzyHitTest(
 383     int x, int y, BrowserAccessibility* start_node) {
 384   BrowserAccessibility* nearest_node = NULL;
 385   int min_distance = INT_MAX;
 386   FuzzyHitTestImpl(x, y, start_node, &nearest_node, &min_distance);
 387   return nearest_node;
 388 }
 389
 390 // static
 391 void BrowserAccessibilityManagerAndroid::FuzzyHitTestImpl(
 392     int x, int y, BrowserAccessibility* start_node,
 393     BrowserAccessibility** nearest_candidate, int* nearest_distance) {
 394   BrowserAccessibilityAndroid* node =
 395       static_cast<BrowserAccessibilityAndroid*>(start_node);
 396   int distance = CalculateDistanceSquared(x, y, node);
 397
 398   if (node->IsFocusable()) {
 399     if (distance < *nearest_distance) {
 400       *nearest_candidate = node;
 401       *nearest_distance = distance;
 402     }
 403     // Don't examine any more children of focusable node
 404     // TODO(aboxhall): what about focusable children?
 405     return;
 406   }
 407
 408   if (!node->GetText().empty()) {
 409     if (distance < *nearest_distance) {
 410       *nearest_candidate = node;
 411       *nearest_distance = distance;
 412     }
 413     return;
 414   }
 415
 416   for (uint32 i = 0; i < node->PlatformChildCount(); i++) {
 417     BrowserAccessibility* child = node->PlatformGetChild(i);
 418     FuzzyHitTestImpl(x, y, child, nearest_candidate, nearest_distance);
 419   }
 420 }
 421
 422 // static
 423 int BrowserAccessibilityManagerAndroid::CalculateDistanceSquared(
 424     int x, int y, BrowserAccessibility* node) {
 425   gfx::Rect node_bounds = node->GetLocalBoundsRect();
 426   int nearest_x = Clamp(x, node_bounds.x(), node_bounds.right());
 427   int nearest_y = Clamp(y, node_bounds.y(), node_bounds.bottom());
 428   int dx = std::abs(x - nearest_x);
 429   int dy = std::abs(y - nearest_y);
 430   return dx * dx + dy * dy;
 431 }
 432
 433 void BrowserAccessibilityManagerAndroid::NotifyRootChanged() {
 434   JNIEnv* env = AttachCurrentThread();
 435   ScopedJavaLocalRef<jobject> obj = java_ref_.get(env);
 436   if (obj.is_null())
 437     return;
 438
 439   Java_BrowserAccessibilityManager_handleNavigate(env, obj.obj());
 440 }
 441
 442 bool
 443 BrowserAccessibilityManagerAndroid::UseRootScrollOffsetsWhenComputingBounds() {
 444   // The Java layer handles the root scroll offset.
 445   return false;
 446 }
 447
 448 bool RegisterBrowserAccessibilityManager(JNIEnv* env) {
 449   return RegisterNativesImpl(env);
 450 }
 451
 452 }  // namespace content