content/browser/accessibility/browser_accessibility_manager_android.h

   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 #ifndef CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_ANDROID_H_
   6 #define CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_ANDROID_H_
   7
   8 #include "base/android/scoped_java_ref.h"
   9 #include "content/browser/accessibility/browser_accessibility_manager.h"
  10 #include "content/browser/android/content_view_core_impl.h"
  11
  12 namespace content {
  13
  14 namespace aria_strings {
  15   extern const char kAriaLivePolite[];
  16   extern const char kAriaLiveAssertive[];
  17 }
  18
  19 // From android.view.accessibility.AccessibilityNodeInfo in Java:
  20 enum AndroidMovementGranularity {
  21   ANDROID_ACCESSIBILITY_NODE_INFO_MOVEMENT_GRANULARITY_CHARACTER = 1,
  22   ANDROID_ACCESSIBILITY_NODE_INFO_MOVEMENT_GRANULARITY_WORD = 2,
  23   ANDROID_ACCESSIBILITY_NODE_INFO_MOVEMENT_GRANULARITY_LINE = 4
  24 };
  25
  26 // From android.view.accessibility.AccessibilityEvent in Java:
  27 enum {
  28   ANDROID_ACCESSIBILITY_EVENT_TEXT_CHANGED = 16,
  29   ANDROID_ACCESSIBILITY_EVENT_TEXT_SELECTION_CHANGED = 8192,
  30   ANDROID_ACCESSIBILITY_EVENT_TEXT_TRAVERSED_AT_MOVEMENT_GRANULARITY = 131072
  31 };
  32
  33 class BrowserAccessibilityAndroid;
  34
  35 class CONTENT_EXPORT BrowserAccessibilityManagerAndroid
  36     : public BrowserAccessibilityManager {
  37  public:
  38   BrowserAccessibilityManagerAndroid(
  39       base::android::ScopedJavaLocalRef<jobject> content_view_core,
  40       const ui::AXTreeUpdate& initial_tree,
  41       BrowserAccessibilityDelegate* delegate,
  42       BrowserAccessibilityFactory* factory = new BrowserAccessibilityFactory());
  43
  44   ~BrowserAccessibilityManagerAndroid() override;
  45
  46   static ui::AXTreeUpdate GetEmptyDocument();
  47
  48   void SetContentViewCore(
  49       base::android::ScopedJavaLocalRef<jobject> content_view_core);
  50
  51   // Implementation of BrowserAccessibilityManager.
  52   void NotifyAccessibilityEvent(ui::AXEvent event_type,
  53                                 BrowserAccessibility* node) override;
  54
  55   // --------------------------------------------------------------------------
  56   // Methods called from Java via JNI
  57   // --------------------------------------------------------------------------
  58
  59   // Tree methods.
  60   jint GetRootId(JNIEnv* env, jobject obj);
  61   jboolean IsNodeValid(JNIEnv* env, jobject obj, jint id);
  62   void HitTest(JNIEnv* env, jobject obj, jint x, jint y);
  63
  64   // Methods to get information about a specific node.
  65   jboolean IsEditableText(JNIEnv* env, jobject obj, jint id);
  66   jint GetEditableTextSelectionStart(JNIEnv* env, jobject obj, jint id);
  67   jint GetEditableTextSelectionEnd(JNIEnv* env, jobject obj, jint id);
  68
  69   // Populate Java accessibility data structures with info about a node.
  70   jboolean PopulateAccessibilityNodeInfo(
  71       JNIEnv* env, jobject obj, jobject info, jint id);
  72   jboolean PopulateAccessibilityEvent(
  73       JNIEnv* env, jobject obj, jobject event, jint id, jint event_type);
  74
  75   // Perform actions.
  76   void Click(JNIEnv* env, jobject obj, jint id);
  77   void Focus(JNIEnv* env, jobject obj, jint id);
  78   void Blur(JNIEnv* env, jobject obj);
  79   void ScrollToMakeNodeVisible(JNIEnv* env, jobject obj, jint id);
  80   void SetTextFieldValue(JNIEnv* env, jobject obj, jint id, jstring value);
  81   void SetSelection(JNIEnv* env, jobject obj, jint id, jint start, jint end);
  82   jboolean AdjustSlider(JNIEnv* env, jobject obj, jint id, jboolean increment);
  83
  84   // Return the id of the next node in tree order in the direction given by
  85   // |forwards|, starting with |start_id|, that matches |element_type|,
  86   // where |element_type| is a special uppercase string from TalkBack or
  87   // BrailleBack indicating general categories of web content like
  88   // "SECTION" or "CONTROL".  Return 0 if not found.
  89   jint FindElementType(JNIEnv* env, jobject obj, jint start_id,
  90                        jstring element_type, jboolean forwards);
  91
  92   // Respond to a ACTION_[NEXT/PREVIOUS]_AT_MOVEMENT_GRANULARITY action
  93   // and move the cursor/selection within the given node id. We keep track
  94   // of our own selection in BrowserAccessibilityManager.java for static
  95   // text, but if this is an editable text node, updates the selected text
  96   // in Blink, too, and either way calls
  97   // Java_BrowserAccessibilityManager_finishGranularityMove with the
  98   // result.
  99   jboolean NextAtGranularity(JNIEnv* env, jobject obj,
 100                              jint granularity, jboolean extend_selection,
 101                              jint id, jint cursor_index);
 102   jboolean PreviousAtGranularity(JNIEnv* env, jobject obj,
 103                                  jint granularity, jboolean extend_selection,
 104                                  jint id, jint cursor_index);
 105
 106   // Helper functions to compute the next start and end index when moving
 107   // forwards or backwards by character, word, or line. This part is
 108   // unit-tested; the Java interfaces above are just wrappers. Both of these
 109   // take a single cursor index as input and return the boundaries surrounding
 110   // the next word or line. If moving by character, the output start and
 111   // end index will be the same.
 112   bool NextAtGranularity(
 113       int32 granularity, int cursor_index,
 114       BrowserAccessibilityAndroid* node, int32* start_index, int32* end_index);
 115   bool PreviousAtGranularity(
 116       int32 granularity, int cursor_index,
 117       BrowserAccessibilityAndroid* node, int32* start_index, int32* end_index);
 118
 119   // Set accessibility focus. This sends a message to the renderer to
 120   // asynchronously load inline text boxes for this node only, enabling more
 121   // accurate movement by granularities on this node.
 122   void SetAccessibilityFocus(JNIEnv* env, jobject obj, jint id);
 123
 124  protected:
 125   // AXTreeDelegate overrides.
 126   void OnAtomicUpdateFinished(
 127       bool root_changed,
 128       const std::vector<ui::AXTreeDelegate::Change>& changes) override;
 129
 130   bool UseRootScrollOffsetsWhenComputingBounds() override;
 131
 132  private:
 133   // This gives BrowserAccessibilityManager::Create access to the class
 134   // constructor.
 135   friend class BrowserAccessibilityManager;
 136
 137   // A weak reference to the Java BrowserAccessibilityManager object.
 138   // This avoids adding another reference to BrowserAccessibilityManager and
 139   // preventing garbage collection.
 140   // Premature garbage collection is prevented by the long-lived reference in
 141   // ContentViewCore.
 142   JavaObjectWeakGlobalRef java_ref_;
 143
 144   // Handle a hover event from the renderer process.
 145   void HandleHoverEvent(BrowserAccessibility* node);
 146
 147   DISALLOW_COPY_AND_ASSIGN(BrowserAccessibilityManagerAndroid);
 148 };
 149
 150 bool RegisterBrowserAccessibilityManager(JNIEnv* env);
 151
 152 }
 153
 154 #endif  // CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_ANDROID_H_