AccessibilityEvent

public final class AccessibilityEvent
extends AccessibilityRecord implements Parcelable

This class represents accessibility events that are sent by the system when something notable happens in the user interface. For example, when a Button is clicked, a 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 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 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 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 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 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 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:

VIEW TYPES

View clicked - represents the event of clicking on a View like Button, CompoundButton, etc.
Type:TYPE_VIEW_CLICKED
Properties:

• getEventType() - The type of the event.
• getSource() - The source info (for registered clients).
• getClassName() - The class name of the source.
• getPackageName() - The package name of the source.
• getEventTime() - The event time.
• getText() - The text of the source's sub-tree.
• isEnabled() - Whether the source is enabled.
• isPassword() - Whether the source is password.
• isChecked() - Whether the source is checked.
• getContentDescription() - The content description of the source.
• getScrollX() - The offset of the source left edge in pixels (without descendants of AdapterView).
• getScrollY() - The offset of the source top edge in pixels (without descendants of AdapterView).
• getFromIndex() - The zero based index of the first visible item of the source, inclusive (for descendants of AdapterView).
• getToIndex() - The zero based index of the last visible item of the source, inclusive (for descendants of AdapterView).
• getItemCount() - The total items of the source (for descendants of AdapterView).

View long clicked - represents the event of long clicking on a View like Button, CompoundButton, etc
Type:TYPE_VIEW_LONG_CLICKED
Properties:

• getEventType() - The type of the event.
• getSource() - The source info (for registered clients).
• getClassName() - The class name of the source.
• getPackageName() - The package name of the source.
• getEventTime() - The event time.
• getText() - The text of the source's sub-tree.
• isEnabled() - Whether the source is enabled.
• isPassword() - Whether the source is password.
• isChecked() - Whether the source is checked.
• getContentDescription() - The content description of the source.
• getScrollX() - The offset of the source left edge in pixels (without descendants of AdapterView).
• getScrollY() - The offset of the source top edge in pixels (without descendants of AdapterView).
• getFromIndex() - The zero based index of the first visible item of the source, inclusive (for descendants of AdapterView).
• getToIndex() - The zero based index of the last visible item of the source, inclusive (for descendants of AdapterView).
• getItemCount() - The total items of the source (for descendants of AdapterView).

View selected - represents the event of selecting an item usually in the context of an AdapterView.
Type: TYPE_VIEW_SELECTED
Properties:

• getEventType() - The type of the event.
• getSource() - The source info (for registered clients).
• getClassName() - The class name of the source.
• getPackageName() - The package name of the source.
• getEventTime() - The event time.
• getText() - The text of the source's sub-tree.
• isEnabled() - Whether the source is enabled.
• isPassword() - Whether the source is password.
• isChecked() - Whether the source is checked.
• getItemCount() - The number of selectable items of the source.
• getCurrentItemIndex() - The currently selected item index.
• getContentDescription() - The content description of the source.
• getScrollX() - The offset of the source left edge in pixels (without descendants of AdapterView).
• getScrollY() - The offset of the source top edge in pixels (without descendants of AdapterView).
• getFromIndex() - The zero based index of the first visible item of the source, inclusive (for descendants of AdapterView).
• getToIndex() - The zero based index of the last visible item of the source, inclusive (for descendants of AdapterView).
• getItemCount() - The total items of the source (for descendants of AdapterView).

View focused - represents the event of focusing a View.
Type: TYPE_VIEW_FOCUSED
Properties:

• getEventType() - The type of the event.
• getSource() - The source info (for registered clients).
• getClassName() - The class name of the source.
• getPackageName() - The package name of the source.
• getEventTime() - The event time.
• getText() - The text of the source's sub-tree.
• isEnabled() - Whether the source is enabled.
• isPassword() - Whether the source is password.
• isChecked() - Whether the source is checked.
• getItemCount() - The number of focusable items on the screen.
• getCurrentItemIndex() - The currently focused item index.
• getContentDescription() - The content description of the source.
• getScrollX() - The offset of the source left edge in pixels (without descendants of AdapterView).
• getScrollY() - The offset of the source top edge in pixels (without descendants of AdapterView).
• getFromIndex() - The zero based index of the first visible item of the source, inclusive (for descendants of AdapterView).
• getToIndex() - The zero based index of the last visible item of the source, inclusive (for descendants of AdapterView).
• getItemCount() - The total items of the source (for descendants of AdapterView).

View text changed - represents the event of changing the text of an EditText.
Type: TYPE_VIEW_TEXT_CHANGED
Properties:

• getEventType() - The type of the event.
• getSource() - The source info (for registered clients).
• getClassName() - The class name of the source.
• getPackageName() - The package name of the source.
• getEventTime() - The event time.
• getText() - The text of the source.
• isEnabled() - Whether the source is enabled.
• isPassword() - Whether the source is password.
• isChecked() - Whether the source is checked.
• getFromIndex() - The text change start index.
• getAddedCount() - The number of added characters.
• getRemovedCount() - The number of removed characters.
• getBeforeText() - The text of the source before the change.
• getContentDescription() - The content description of the source.

View text selection changed - represents the event of changing the text selection of an EditText.
Type: TYPE_VIEW_TEXT_SELECTION_CHANGED
Properties:

• getEventType() - The type of the event.
• getSource() - The source info (for registered clients).
• getClassName() - The class name of the source.
• getPackageName() - The package name of the source.
• getEventTime() - The event time.
• getText() - The text of the source.
• isPassword() - Whether the source is password.
• getFromIndex() - The selection start index.
• getToIndex() - The selection end index.
• getItemCount() - The length of the source text.
• isEnabled() - Whether the source is enabled.
• getContentDescription() - The content description of the source.

• getEventType() - The type of the event.
• getSource() - The source info (for registered clients).
• getClassName() - The class name of the source.
• getPackageName() - The package name of the source.
• getEventTime() - The event time.
• getMovementGranularity() - Sets the granularity at which a view's text was traversed.
• getText() - The text of the source's sub-tree.
• getFromIndex() - The start the text that was skipped over in this movement. This is the starting point when moving forward through the text, but not when moving back.
• getToIndex() - The end of the text that was skipped over in this movement. This is the ending point when moving forward through the text, but not when moving back.
• isPassword() - Whether the source is password.
• isEnabled() - Whether the source is enabled.
• getContentDescription() - The content description of the source.
• getMovementGranularity() - Sets the granularity at which a view's text was traversed.
• getAction() - Gets traversal action which specifies the direction.

View scrolled - represents the event of scrolling a view. If the source is a descendant of 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: TYPE_VIEW_SCROLLED
Properties:

• getEventType() - The type of the event.
• getSource() - The source info (for registered clients).
• getClassName() - The class name of the source.
• getPackageName() - The package name of the source.
• getEventTime() - The event time.
• getText() - The text of the source's sub-tree.
• isEnabled() - Whether the source is enabled.
• getContentDescription() - The content description of the source.
• getScrollX() - The offset of the source left edge in pixels (without descendants of AdapterView).
• getScrollY() - The offset of the source top edge in pixels (without descendants of AdapterView).
• getFromIndex() - The zero based index of the first visible item of the source, inclusive (for descendants of AdapterView).
• getToIndex() - The zero based index of the last visible item of the source, inclusive (for descendants of AdapterView).
• getItemCount() - The total items of the source (for descendants of AdapterView).

TRANSITION TYPES

Window state changed - represents the event of opening a PopupWindow, Menu, Dialog, etc.
Type: TYPE_WINDOW_STATE_CHANGED
Properties:

• getEventType() - The type of the event.
• getSource() - The source info (for registered clients).
• getClassName() - The class name of the source.
• getPackageName() - The package name of the source.
• getEventTime() - The event time.
• getText() - The text of the source's sub-tree.
• isEnabled() - Whether the source is enabled.

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 TYPE_NOTIFICATION_STATE_CHANGED and its purpose is to notify clients that the content of the user interaction window has changed.
Type: TYPE_WINDOW_CONTENT_CHANGED
Properties:

• getEventType() - The type of the event.
• getContentChangeTypes() - The type of content changes.
• getSource() - The source info (for registered clients).
• getClassName() - The class name of the source.
• getPackageName() - The package name of the source.
• getEventTime() - The event time.

Windows changed - represents the event of changes in the windows shown on the screen such as a window appeared, a window disappeared, a window size changed, a window layer changed, etc.
Type: TYPE_WINDOWS_CHANGED
Properties:

• getEventType() - The type of the event.
• getEventTime() - The event time.

NOTIFICATION TYPES

Notification state changed - represents the event showing Notification.
Type: TYPE_NOTIFICATION_STATE_CHANGED
Properties:

• getEventType() - The type of the event.
• getClassName() - The class name of the source.
• getPackageName() - The package name of the source.
• getEventTime() - The event time.
• getParcelableData() - The posted Notification.
• getText() - Text for providing more context.

EXPLORATION TYPES

View hover enter - represents the event of beginning to hover over a View. The hover may be generated via exploring the screen by touch or via a pointing device.
Type: TYPE_VIEW_HOVER_ENTER
Properties:

• getEventType() - The type of the event.
• getSource() - The source info (for registered clients).
• getClassName() - The class name of the source.
• getPackageName() - The package name of the source.
• getEventTime() - The event time.
• getText() - The text of the source's sub-tree.
• isEnabled() - Whether the source is enabled.
• getContentDescription() - The content description of the source.
• getScrollX() - The offset of the source left edge in pixels (without descendants of AdapterView).
• getScrollY() - The offset of the source top edge in pixels (without descendants of AdapterView).
• getFromIndex() - The zero based index of the first visible item of the source, inclusive (for descendants of AdapterView).
• getToIndex() - The zero based index of the last visible item of the source, inclusive (for descendants of AdapterView).
• getItemCount() - The total items of the source (for descendants of AdapterView).

• getEventType() - The type of the event.
• getSource() - The source info (for registered clients).
• getClassName() - The class name of the source.
• getPackageName() - The package name of the source.
• getEventTime() - The event time.
• getText() - The text of the source's sub-tree.
• isEnabled() - Whether the source is enabled.
• getContentDescription() - The content description of the source.
• getScrollX() - The offset of the source left edge in pixels (without descendants of AdapterView).
• getScrollY() - The offset of the source top edge in pixels (without descendants of AdapterView).
• getFromIndex() - The zero based index of the first visible item of the source, inclusive (for descendants of AdapterView).
• getToIndex() - The zero based index of the last visible item of the source, inclusive (for descendants of AdapterView).
• getItemCount() - The total items of the source (for descendants of AdapterView).

Touch interaction start - represents the event of starting a touch interaction, which is the user starts touching the screen.
Type: TYPE_TOUCH_INTERACTION_START
Properties:

• getEventType() - The type of the event.

Touch interaction end - represents the event of ending a touch interaction, which is the user stops touching the screen.
Type: TYPE_TOUCH_INTERACTION_END
Properties:

• getEventType() - The type of the event.

Touch exploration gesture start - represents the event of starting a touch exploring gesture.
Type: TYPE_TOUCH_EXPLORATION_GESTURE_START
Properties:

• getEventType() - The type of the event.

Touch exploration gesture end - represents the event of ending a touch exploring gesture.
Type: TYPE_TOUCH_EXPLORATION_GESTURE_END
Properties:

• getEventType() - The type of the event.

Touch gesture detection start - represents the event of starting a user gesture detection.
Type: TYPE_GESTURE_DETECTION_START
Properties:

• getEventType() - The type of the event.

Touch gesture detection end - represents the event of ending a user gesture detection.
Type: TYPE_GESTURE_DETECTION_END
Properties:

• getEventType() - The type of the event.

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: TYPE_ANNOUNCEMENT
Properties:

• getEventType() - The type of the event.
• getSource() - The source info (for registered clients).
• getClassName() - The class name of the source.
• getPackageName() - The package name of the source.
• getEventTime() - The event time.
• getText() - The text of the announcement.
• isEnabled() - Whether the source is enabled.

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.

Summary

Inherited constants

From interface android.os.Parcelable int CONTENTS_FILE_DESCRIPTOR Descriptor bit used with describeContents(): indicates that the Parcelable object's flattened representation includes a file descriptor. int PARCELABLE_WRITE_RETURN_VALUE Flag for use with writeToParcel(Parcel, int): the object being written is a return value, that is the result of a function such as "Parcelable someFunction()", "void someFunction(out Parcelable)", or "void someFunction(inout Parcelable)".

Inherited methods
From class android.view.accessibility.AccessibilityRecord int getAddedCount() Gets the number of added characters. CharSequence getBeforeText() Sets the text before a change. CharSequence getClassName() Gets the class name of the source. CharSequence getContentDescription() Gets the description of the source. int getCurrentItemIndex() Gets the index of the source in the list of items the can be visited. int getFromIndex() Gets the index of the first character of the changed sequence, or the beginning of a text selection or the index of the first visible item when scrolling. int getItemCount() Gets the number of items that can be visited. int getMaxScrollX() Gets the max scroll offset of the source left edge in pixels. int getMaxScrollY() Gets the max scroll offset of the source top edge in pixels. Parcelable getParcelableData() Gets the Parcelable data. int getRemovedCount() Gets the number of removed characters. int getScrollX() Gets the scroll offset of the source left edge in pixels. int getScrollY() Gets the scroll offset of the source top edge in pixels. AccessibilityNodeInfo getSource() Gets the AccessibilityNodeInfo of the event source. List<CharSequence> getText() Gets the text of the event. int getToIndex() Gets the index of text selection end or the index of the last visible item when scrolling. int getWindowId() Gets the id of the window from which the event comes from. boolean isChecked() Gets if the source is checked. boolean isEnabled() Gets if the source is enabled. boolean isFullScreen() Gets if the source is taking the entire screen. boolean isPassword() Gets if the source is a password field. boolean isScrollable() Gets if the source is scrollable. static AccessibilityRecord obtain() Returns a cached instance if such is available or a new one is instantiated. static AccessibilityRecord obtain(AccessibilityRecord record) Returns a cached instance if such is available or a new one is instantiated. void recycle() Return an instance back to be reused. void setAddedCount(int addedCount) Sets the number of added characters. void setBeforeText(CharSequence beforeText) Sets the text before a change. void setChecked(boolean isChecked) Sets if the source is checked. void setClassName(CharSequence className) Sets the class name of the source. void setContentDescription(CharSequence contentDescription) Sets the description of the source. void setCurrentItemIndex(int currentItemIndex) Sets the index of the source in the list of items that can be visited. void setEnabled(boolean isEnabled) Sets if the source is enabled. void setFromIndex(int fromIndex) Sets the index of the first character of the changed sequence or the beginning of a text selection or the index of the first visible item when scrolling. void setFullScreen(boolean isFullScreen) Sets if the source is taking the entire screen. void setItemCount(int itemCount) Sets the number of items that can be visited. void setMaxScrollX(int maxScrollX) Sets the max scroll offset of the source left edge in pixels. void setMaxScrollY(int maxScrollY) Sets the max scroll offset of the source top edge in pixels. void setParcelableData(Parcelable parcelableData) Sets the Parcelable data of the event. void setPassword(boolean isPassword) Sets if the source is a password field. void setRemovedCount(int removedCount) Sets the number of removed characters. void setScrollX(int scrollX) Sets the scroll offset of the source left edge in pixels. void setScrollY(int scrollY) Sets the scroll offset of the source top edge in pixels. void setScrollable(boolean scrollable) Sets if the source is scrollable. void setSource(View root, int virtualDescendantId) Sets the source to be a virtual descendant of the given root. void setSource(View source) Sets the event source. void setToIndex(int toIndex) Sets the index of text selection end or the index of the last visible item when scrolling. String toString() Returns a string representation of the object.
From class java.lang.Object Object clone() Creates and returns a copy of this object. boolean equals(Object obj) Indicates whether some other object is "equal to" this one. void finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. final Class<?> getClass() Returns the runtime class of this Object. int hashCode() Returns a hash code value for the object. final void notify() Wakes up a single thread that is waiting on this object's monitor. final void notifyAll() Wakes up all threads that are waiting on this object's monitor. String toString() Returns a string representation of the object. final void wait(long millis, int nanos) Causes the current thread to wait until another thread invokes the notify() method or the notifyAll() method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed. final void wait(long millis) Causes the current thread to wait until either another thread invokes the notify() method or the notifyAll() method for this object, or a specified amount of time has elapsed. final void wait() Causes the current thread to wait until another thread invokes the notify() method or the notifyAll() method for this object.
From interface android.os.Parcelable abstract int describeContents() Describe the kinds of special objects contained in this Parcelable instance's marshaled representation. abstract void writeToParcel(Parcel dest, int flags) Flatten this object in to a Parcel.

Constants

int CONTENT_CHANGE_TYPE_CONTENT_DESCRIPTION

int CONTENT_CHANGE_TYPE_SUBTREE

int CONTENT_CHANGE_TYPE_TEXT

int CONTENT_CHANGE_TYPE_UNDEFINED

int INVALID_POSITION

int MAX_TEXT_LENGTH

int TYPES_ALL_MASK

int TYPE_ANNOUNCEMENT

int TYPE_ASSIST_READING_CONTEXT

int TYPE_GESTURE_DETECTION_END

int TYPE_GESTURE_DETECTION_START

int TYPE_NOTIFICATION_STATE_CHANGED

int TYPE_TOUCH_EXPLORATION_GESTURE_END

int TYPE_TOUCH_EXPLORATION_GESTURE_START

int TYPE_TOUCH_INTERACTION_END

int TYPE_TOUCH_INTERACTION_START

int TYPE_VIEW_ACCESSIBILITY_FOCUSED

int TYPE_VIEW_ACCESSIBILITY_FOCUS_CLEARED

int TYPE_VIEW_CLICKED

int TYPE_VIEW_CONTEXT_CLICKED

int TYPE_VIEW_FOCUSED

int TYPE_VIEW_HOVER_ENTER

int TYPE_VIEW_HOVER_EXIT

int TYPE_VIEW_LONG_CLICKED

int TYPE_VIEW_SCROLLED

int TYPE_VIEW_SELECTED

int TYPE_VIEW_TEXT_CHANGED

int TYPE_VIEW_TEXT_SELECTION_CHANGED

int TYPE_VIEW_TEXT_TRAVERSED_AT_MOVEMENT_GRANULARITY

int TYPE_WINDOWS_CHANGED

int TYPE_WINDOW_CONTENT_CHANGED

int TYPE_WINDOW_STATE_CHANGED

Fields

Creator<AccessibilityEvent> CREATOR

Public methods

void appendRecord (AccessibilityRecord record)

int describeContents ()

String eventTypeToString (int eventType)

int getAction ()

int getContentChangeTypes ()

long getEventTime ()

int getEventType ()

int getMovementGranularity ()

CharSequence getPackageName ()

AccessibilityRecord getRecord (int index)

int getRecordCount ()

void initFromParcel (Parcel parcel)

AccessibilityEvent obtain (AccessibilityEvent event)

AccessibilityEvent obtain ()

AccessibilityEvent obtain (int eventType)

void recycle ()

void setAction (int action)

void setContentChangeTypes (int changeTypes)

void setEventTime (long eventTime)

void setEventType (int eventType)

void setMovementGranularity (int granularity)

void setPackageName (CharSequence packageName)

String toString ()

void writeToParcel (Parcel parcel, 
                int flags)