/* * Copyright (C) 2009 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package android.view.accessibility; import android.os.Parcel; import android.os.Parcelable; import android.text.TextUtils; import java.util.ArrayList; import java.util.List; /** *
* This class represents accessibility events that are sent by the system when * something notable happens in the user interface. For example, when a * {@link android.widget.Button} is clicked, a {@link android.view.View} is focused, etc. *
** An accessibility event is fired by an individual view which populates the event with * data for its state and requests from its parent to send the event to interested * parties. The parent can optionally add an {@link AccessibilityRecord} for itself before * dispatching a similar request to its parent. A parent can also choose not to respect the * request for sending an event. The accessibility event is sent by the topmost view in the * view tree. Therefore, an {@link android.accessibilityservice.AccessibilityService} can * explore all records in an accessibility event to obtain more information about the * context in which the event was fired. *
** The main purpose of an accessibility event is to expose enough information for an * {@link android.accessibilityservice.AccessibilityService} to provide meaningful feedback * to the user. Sometimes however, an accessibility service may need more contextual * information then the one in the event pay-load. In such cases the service can obtain * the event source which is an {@link AccessibilityNodeInfo} (snapshot of a View state) * which can be used for exploring the window content. Note that the privilege for accessing * an event's source, thus the window content, has to be explicitly requested. For more * details refer to {@link android.accessibilityservice.AccessibilityService}. If an * accessibility service has not requested to retrieve the window content the event will * not contain reference to its source. Also for events of type * {@link #TYPE_NOTIFICATION_STATE_CHANGED} the source is never available. *
** This class represents various semantically different accessibility event * types. Each event type has an associated set of related properties. In other * words, each event type is characterized via a subset of the properties exposed * by this class. For each event type there is a corresponding constant defined * in this class. Follows a specification of the event types and their associated properties: *
*For more information about creating and processing AccessibilityEvents, read the * Accessibility * developer guide.
** VIEW TYPES *
** View clicked - represents the event of clicking on a {@link android.view.View} * like {@link android.widget.Button}, {@link android.widget.CompoundButton}, etc. * Type:{@link #TYPE_VIEW_CLICKED} * Properties: *
* View long clicked - represents the event of long clicking on a {@link android.view.View} * like {@link android.widget.Button}, {@link android.widget.CompoundButton}, etc * Type:{@link #TYPE_VIEW_LONG_CLICKED} * Properties: *
* View selected - represents the event of selecting an item usually in * the context of an {@link android.widget.AdapterView}. * Type: {@link #TYPE_VIEW_SELECTED} * Properties: *
* View focused - represents the event of focusing a * {@link android.view.View}. * Type: {@link #TYPE_VIEW_FOCUSED} * Properties: *
* View text changed - represents the event of changing the text of an * {@link android.widget.EditText}. * Type: {@link #TYPE_VIEW_TEXT_CHANGED} * Properties: *
* View text selection changed - represents the event of changing the text * selection of an {@link android.widget.EditText}. * Type: {@link #TYPE_VIEW_TEXT_SELECTION_CHANGED} * Properties: *
* View scrolled - represents the event of scrolling a view. If * the source is a descendant of {@link android.widget.AdapterView} the * scroll is reported in terms of visible items - the first visible item, * the last visible item, and the total items - because the the source * is unaware of its pixel size since its adapter is responsible for * creating views. In all other cases the scroll is reported as the current * scroll on the X and Y axis respectively plus the height of the source in * pixels. * Type: {@link #TYPE_VIEW_SCROLLED} * Properties: *
* TRANSITION TYPES *
** Window state changed - represents the event of opening a * {@link android.widget.PopupWindow}, {@link android.view.Menu}, * {@link android.app.Dialog}, etc. * Type: {@link #TYPE_WINDOW_STATE_CHANGED} * Properties: *
* Window content changed - represents the event of change in the * content of a window. This change can be adding/removing view, changing * a view size, etc. *
** Note: This event is fired only for the window source of the * last accessibility event different from {@link #TYPE_NOTIFICATION_STATE_CHANGED} * and its purpose is to notify clients that the content of the user interaction * window has changed. * Type: {@link #TYPE_WINDOW_CONTENT_CHANGED} * Properties: *
* NOTIFICATION TYPES *
** Notification state changed - represents the event showing * {@link android.app.Notification}. * Type: {@link #TYPE_NOTIFICATION_STATE_CHANGED} * Properties: *
* EXPLORATION TYPES *
** View hover enter - represents the event of beginning to hover * over a {@link android.view.View}. The hover may be generated via * exploring the screen by touch or via a pointing device. * Type: {@link #TYPE_VIEW_HOVER_ENTER} * Properties: *
* Touch exploration gesture start - represents the event of starting a touch * exploring gesture. * Type: {@link #TYPE_TOUCH_EXPLORATION_GESTURE_START} * Properties: *
* Touch exploration gesture end - represents the event of ending a touch * exploring gesture. * Type: {@link #TYPE_TOUCH_EXPLORATION_GESTURE_END} * Properties: *
* MISCELLANEOUS TYPES *
** Announcement - represents the event of an application making an * announcement. Usually this announcement is related to some sort of a context * change for which none of the events representing UI transitions is a good fit. * For example, announcing a new page in a book. * Type: {@link #TYPE_ANNOUNCEMENT} * Properties: *
* Security note *
* Since an event contains the text of its source privacy can be compromised by leaking * sensitive information such as passwords. To address this issue any event fired in response * to manipulation of a PASSWORD field does NOT CONTAIN the text of the password. *
* * @see android.view.accessibility.AccessibilityManager * @see android.accessibilityservice.AccessibilityService * @see AccessibilityNodeInfo */ public final class AccessibilityEvent extends AccessibilityRecord implements Parcelable { private static final boolean DEBUG = false; /** * Invalid selection/focus position. * * @see #getCurrentItemIndex() */ public static final int INVALID_POSITION = -1; /** * Maximum length of the text fields. * * @see #getBeforeText() * @see #getText() * * Note: This constant is no longer needed since there * is no limit on the length of text that is contained * in an accessibility event anymore. */ @Deprecated public static final int MAX_TEXT_LENGTH = 500; /** * Represents the event of clicking on a {@link android.view.View} like * {@link android.widget.Button}, {@link android.widget.CompoundButton}, etc. */ public static final int TYPE_VIEW_CLICKED = 0x00000001; /** * Represents the event of long clicking on a {@link android.view.View} like * {@link android.widget.Button}, {@link android.widget.CompoundButton}, etc. */ public static final int TYPE_VIEW_LONG_CLICKED = 0x00000002; /** * Represents the event of selecting an item usually in the context of an * {@link android.widget.AdapterView}. */ public static final int TYPE_VIEW_SELECTED = 0x00000004; /** * Represents the event of setting input focus of a {@link android.view.View}. */ public static final int TYPE_VIEW_FOCUSED = 0x00000008; /** * Represents the event of changing the text of an {@link android.widget.EditText}. */ public static final int TYPE_VIEW_TEXT_CHANGED = 0x00000010; /** * Represents the event of opening a {@link android.widget.PopupWindow}, * {@link android.view.Menu}, {@link android.app.Dialog}, etc. */ public static final int TYPE_WINDOW_STATE_CHANGED = 0x00000020; /** * Represents the event showing a {@link android.app.Notification}. */ public static final int TYPE_NOTIFICATION_STATE_CHANGED = 0x00000040; /** * Represents the event of a hover enter over a {@link android.view.View}. */ public static final int TYPE_VIEW_HOVER_ENTER = 0x00000080; /** * Represents the event of a hover exit over a {@link android.view.View}. */ public static final int TYPE_VIEW_HOVER_EXIT = 0x00000100; /** * Represents the event of starting a touch exploration gesture. */ public static final int TYPE_TOUCH_EXPLORATION_GESTURE_START = 0x00000200; /** * Represents the event of ending a touch exploration gesture. */ public static final int TYPE_TOUCH_EXPLORATION_GESTURE_END = 0x00000400; /** * Represents the event of changing the content of a window and more * specifically the sub-tree rooted at the event's source. */ public static final int TYPE_WINDOW_CONTENT_CHANGED = 0x00000800; /** * Represents the event of scrolling a view. */ public static final int TYPE_VIEW_SCROLLED = 0x00001000; /** * Represents the event of changing the selection in an {@link android.widget.EditText}. */ public static final int TYPE_VIEW_TEXT_SELECTION_CHANGED = 0x00002000; /** * Represents the event of an application making an announcement. */ public static final int TYPE_ANNOUNCEMENT = 0x00004000; /** * Represents the event of gaining accessibility focus. */ public static final int TYPE_VIEW_ACCESSIBILITY_FOCUSED = 0x00008000; /** * Represents the event of clearing accessibility focus. */ public static final int TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED = 0x00010000; /** * Represents the event of traversing the text of a view at a given movement granularity. */ public static final int TYPE_VIEW_TEXT_TRAVERSED_AT_MOVEMENT_GRANULARITY = 0x00020000; /** * Mask for {@link AccessibilityEvent} all types. * * @see #TYPE_VIEW_CLICKED * @see #TYPE_VIEW_LONG_CLICKED * @see #TYPE_VIEW_SELECTED * @see #TYPE_VIEW_FOCUSED * @see #TYPE_VIEW_TEXT_CHANGED * @see #TYPE_WINDOW_STATE_CHANGED * @see #TYPE_NOTIFICATION_STATE_CHANGED * @see #TYPE_VIEW_HOVER_ENTER * @see #TYPE_VIEW_HOVER_EXIT * @see #TYPE_TOUCH_EXPLORATION_GESTURE_START * @see #TYPE_TOUCH_EXPLORATION_GESTURE_END * @see #TYPE_WINDOW_CONTENT_CHANGED * @see #TYPE_VIEW_SCROLLED * @see #TYPE_VIEW_TEXT_SELECTION_CHANGED * @see #TYPE_ANNOUNCEMENT * @see #TYPE_VIEW_TEXT_TRAVERSED_AT_MOVEMENT_GRANULARITY */ public static final int TYPES_ALL_MASK = 0xFFFFFFFF; private static final int MAX_POOL_SIZE = 10; private static final Object sPoolLock = new Object(); private static AccessibilityEvent sPool; private static int sPoolSize; private AccessibilityEvent mNext; private boolean mIsInPool; private int mEventType; private CharSequence mPackageName; private long mEventTime; int mMovementGranularity; int mAction; private final ArrayListevent
.
*
* @param event The other event.
* @return An instance.
*/
public static AccessibilityEvent obtain(AccessibilityEvent event) {
AccessibilityEvent eventClone = AccessibilityEvent.obtain();
eventClone.init(event);
final int recordCount = event.mRecords.size();
for (int i = 0; i < recordCount; i++) {
AccessibilityRecord record = event.mRecords.get(i);
AccessibilityRecord recordClone = AccessibilityRecord.obtain(record);
eventClone.mRecords.add(recordClone);
}
return eventClone;
}
/**
* Returns a cached instance if such is available or a new one is
* instantiated.
*
* @return An instance.
*/
public static AccessibilityEvent obtain() {
synchronized (sPoolLock) {
if (sPool != null) {
AccessibilityEvent event = sPool;
sPool = sPool.mNext;
sPoolSize--;
event.mNext = null;
event.mIsInPool = false;
return event;
}
return new AccessibilityEvent();
}
}
/**
* Recycles an instance back to be reused.
* * Note: You must not touch the object after calling this function. *
* * @throws IllegalStateException If the event is already recycled. */ @Override public void recycle() { if (mIsInPool) { throw new IllegalStateException("Event already recycled!"); } clear(); synchronized (sPoolLock) { if (sPoolSize <= MAX_POOL_SIZE) { mNext = sPool; sPool = this; mIsInPool = true; sPoolSize++; } } } /** * Clears the state of this instance. * * @hide */ @Override protected void clear() { super.clear(); mEventType = 0; mMovementGranularity = 0; mAction = 0; mPackageName = null; mEventTime = 0; while (!mRecords.isEmpty()) { AccessibilityRecord record = mRecords.remove(0); record.recycle(); } } /** * Creates a new instance from a {@link Parcel}. * * @param parcel A parcel containing the state of a {@link AccessibilityEvent}. */ public void initFromParcel(Parcel parcel) { mSealed = (parcel.readInt() == 1); mEventType = parcel.readInt(); mMovementGranularity = parcel.readInt(); mAction = parcel.readInt(); mPackageName = TextUtils.CHAR_SEQUENCE_CREATOR.createFromParcel(parcel); mEventTime = parcel.readLong(); mConnectionId = parcel.readInt(); readAccessibilityRecordFromParcel(this, parcel); // Read the records. final int recordCount = parcel.readInt(); for (int i = 0; i < recordCount; i++) { AccessibilityRecord record = AccessibilityRecord.obtain(); readAccessibilityRecordFromParcel(record, parcel); record.mConnectionId = mConnectionId; mRecords.add(record); } } /** * Reads an {@link AccessibilityRecord} from a parcel. * * @param record The record to initialize. * @param parcel The parcel to read from. */ private void readAccessibilityRecordFromParcel(AccessibilityRecord record, Parcel parcel) { record.mBooleanProperties = parcel.readInt(); record.mCurrentItemIndex = parcel.readInt(); record.mItemCount = parcel.readInt(); record.mFromIndex = parcel.readInt(); record.mToIndex = parcel.readInt(); record.mScrollX = parcel.readInt(); record.mScrollY = parcel.readInt(); record.mMaxScrollX = parcel.readInt(); record.mMaxScrollY = parcel.readInt(); record.mAddedCount = parcel.readInt(); record.mRemovedCount = parcel.readInt(); record.mClassName = TextUtils.CHAR_SEQUENCE_CREATOR.createFromParcel(parcel); record.mContentDescription = TextUtils.CHAR_SEQUENCE_CREATOR.createFromParcel(parcel); record.mBeforeText = TextUtils.CHAR_SEQUENCE_CREATOR.createFromParcel(parcel); record.mParcelableData = parcel.readParcelable(null); parcel.readList(record.mText, null); record.mSourceWindowId = parcel.readInt(); record.mSourceNodeId = parcel.readLong(); record.mSealed = (parcel.readInt() == 1); } /** * {@inheritDoc} */ public void writeToParcel(Parcel parcel, int flags) { parcel.writeInt(isSealed() ? 1 : 0); parcel.writeInt(mEventType); parcel.writeInt(mMovementGranularity); parcel.writeInt(mAction); TextUtils.writeToParcel(mPackageName, parcel, 0); parcel.writeLong(mEventTime); parcel.writeInt(mConnectionId); writeAccessibilityRecordToParcel(this, parcel, flags); // Write the records. final int recordCount = getRecordCount(); parcel.writeInt(recordCount); for (int i = 0; i < recordCount; i++) { AccessibilityRecord record = mRecords.get(i); writeAccessibilityRecordToParcel(record, parcel, flags); } } /** * Writes an {@link AccessibilityRecord} to a parcel. * * @param record The record to write. * @param parcel The parcel to which to write. */ private void writeAccessibilityRecordToParcel(AccessibilityRecord record, Parcel parcel, int flags) { parcel.writeInt(record.mBooleanProperties); parcel.writeInt(record.mCurrentItemIndex); parcel.writeInt(record.mItemCount); parcel.writeInt(record.mFromIndex); parcel.writeInt(record.mToIndex); parcel.writeInt(record.mScrollX); parcel.writeInt(record.mScrollY); parcel.writeInt(record.mMaxScrollX); parcel.writeInt(record.mMaxScrollY); parcel.writeInt(record.mAddedCount); parcel.writeInt(record.mRemovedCount); TextUtils.writeToParcel(record.mClassName, parcel, flags); TextUtils.writeToParcel(record.mContentDescription, parcel, flags); TextUtils.writeToParcel(record.mBeforeText, parcel, flags); parcel.writeParcelable(record.mParcelableData, flags); parcel.writeList(record.mText); parcel.writeInt(record.mSourceWindowId); parcel.writeLong(record.mSourceNodeId); parcel.writeInt(record.mSealed ? 1 : 0); } /** * {@inheritDoc} */ public int describeContents() { return 0; } @Override public String toString() { StringBuilder builder = new StringBuilder(); builder.append("EventType: ").append(eventTypeToString(mEventType)); builder.append("; EventTime: ").append(mEventTime); builder.append("; PackageName: ").append(mPackageName); builder.append("; MovementGranularity: ").append(mMovementGranularity); builder.append("; Action: ").append(mAction); builder.append(super.toString()); if (DEBUG) { builder.append("\n"); builder.append("; sourceWindowId: ").append(mSourceWindowId); builder.append("; mSourceNodeId: ").append(mSourceNodeId); for (int i = 0; i < mRecords.size(); i++) { AccessibilityRecord record = mRecords.get(i); builder.append(" Record "); builder.append(i); builder.append(":"); builder.append(" [ ClassName: " + record.mClassName); builder.append("; Text: " + record.mText); builder.append("; ContentDescription: " + record.mContentDescription); builder.append("; ItemCount: " + record.mItemCount); builder.append("; CurrentItemIndex: " + record.mCurrentItemIndex); builder.append("; IsEnabled: " + record.isEnabled()); builder.append("; IsPassword: " + record.isPassword()); builder.append("; IsChecked: " + record.isChecked()); builder.append("; IsFullScreen: " + record.isFullScreen()); builder.append("; Scrollable: " + record.isScrollable()); builder.append("; BeforeText: " + record.mBeforeText); builder.append("; FromIndex: " + record.mFromIndex); builder.append("; ToIndex: " + record.mToIndex); builder.append("; ScrollX: " + record.mScrollX); builder.append("; ScrollY: " + record.mScrollY); builder.append("; AddedCount: " + record.mAddedCount); builder.append("; RemovedCount: " + record.mRemovedCount); builder.append("; ParcelableData: " + record.mParcelableData); builder.append(" ]"); builder.append("\n"); } } else { builder.append("; recordCount: ").append(getRecordCount()); } return builder.toString(); } /** * Returns the string representation of an event type. For example, * {@link #TYPE_VIEW_CLICKED} is represented by the string TYPE_VIEW_CLICKED. * * @param eventType The event type * @return The string representation. */ public static String eventTypeToString(int eventType) { switch (eventType) { case TYPE_VIEW_CLICKED: return "TYPE_VIEW_CLICKED"; case TYPE_VIEW_LONG_CLICKED: return "TYPE_VIEW_LONG_CLICKED"; case TYPE_VIEW_SELECTED: return "TYPE_VIEW_SELECTED"; case TYPE_VIEW_FOCUSED: return "TYPE_VIEW_FOCUSED"; case TYPE_VIEW_TEXT_CHANGED: return "TYPE_VIEW_TEXT_CHANGED"; case TYPE_WINDOW_STATE_CHANGED: return "TYPE_WINDOW_STATE_CHANGED"; case TYPE_VIEW_HOVER_ENTER: return "TYPE_VIEW_HOVER_ENTER"; case TYPE_VIEW_HOVER_EXIT: return "TYPE_VIEW_HOVER_EXIT"; case TYPE_NOTIFICATION_STATE_CHANGED: return "TYPE_NOTIFICATION_STATE_CHANGED"; case TYPE_TOUCH_EXPLORATION_GESTURE_START: return "TYPE_TOUCH_EXPLORATION_GESTURE_START"; case TYPE_TOUCH_EXPLORATION_GESTURE_END: return "TYPE_TOUCH_EXPLORATION_GESTURE_END"; case TYPE_WINDOW_CONTENT_CHANGED: return "TYPE_WINDOW_CONTENT_CHANGED"; case TYPE_VIEW_TEXT_SELECTION_CHANGED: return "TYPE_VIEW_TEXT_SELECTION_CHANGED"; case TYPE_VIEW_SCROLLED: return "TYPE_VIEW_SCROLLED"; case TYPE_ANNOUNCEMENT: return "TYPE_ANNOUNCEMENT"; case TYPE_VIEW_ACCESSIBILITY_FOCUSED: return "TYPE_VIEW_ACCESSIBILITY_FOCUSED"; case TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED: return "TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED"; case TYPE_VIEW_TEXT_TRAVERSED_AT_MOVEMENT_GRANULARITY: return "TYPE_CURRENT_AT_GRANULARITY_MOVEMENT_CHANGED"; default: return null; } } /** * @see Parcelable.Creator */ public static final Parcelable.Creator