History log of /frameworks/base/core/java/android/view/accessibility/AccessibilityManager.java
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58d37b55bd228032355360ea3303e46a804e0516 18-Sep-2012 Svetoslav Ganov <svetoslavganov@google.com> Multi-user support for the accessibility layer.

1. This change converts the accessibility manager service to
maintain a state per user. When the user changes the services
for the user that is going away are disconnected, the local
accessibility managers in the processes for this user are
disabled, the state is swapped with the new user's one, and
the new user state is refreshed.

This change updates all calls into the system to use their
user specific versions when applicable. For example, regisetring
content observers, package monitors, calls into other system
services, etc.

There are some components that are shared across users such
as UI created by the system process and the SystemUI package.
Such components are managed as a global state shared across
all users and are updated accordingly on a user switch. Since
the SystemUI is running in a normal app process this change
adds hidden APIs on the local window manager to allow the
SystemUI to notify the accessibility layer that it will run
accross users.

Calls to AccessibiltyManager's isEnabled(), isTouchExplorationEnabled()
and sendAccessibilityEvent return false or a are a nop for a
background user sice he should not send accessibility events,
and should not perform touch exploration.

Update the internal accessibility tests due to changes in the
AccessibilityManager.

This change also fixes several issues that were encountered
such as calling out the accessibility manager service with a
lock held.

Removed some incorrect debugging code from the TouchExplorer
that was leading to a system crash.

bug:6967373

Change-Id: I2cf32ffdee1d827a8197ae4ce717dc0ff798b259
/frameworks/base/core/java/android/view/accessibility/AccessibilityManager.java
4213804541a8b05cd0587b138a2fd9a3b7fd9350 20-Mar-2012 Svetoslav Ganov <svetoslavganov@google.com> Accessibility focus - framework

Usefulness: Keep track of the current user location in the screen when
traversing the it. Enabling structural and directional
navigation over all elements on the screen. This enables
blind users that know the application layout to efficiently
locate desired elements as opposed to try touch exploring the
region where the the element should be - very tedious.

Rationale: There are two ways to implement accessibility focus One is
to let accessibility services keep track of it since they
have access to the screen content, and another to let the view
hierarchy keep track of it. While the first approach would
require almost no work on our part it poses several challenges
which make it a sub-optimal choice. Having the accessibility focus
in the accessibility service would require that service to scrape
the window content every time it changes to sync the view tree
state and the accessibility focus location. Pretty much the service
will have to keep an off screen model of the screen content. This
could be quite challenging to get right and would incur performance
cost for the multiple IPCs to repeatedly fetch the screen content.
Further, keeping virtual accessibility focus (i.e. in the service)
would require sync of the input and accessibility focus. This could
be challenging to implement right as well. Also, having an unlimited
number of accessibility services we cannot guarantee that they will
have a proper implementation, if any, to allow users to perform structural
navigation of the screen content. Assuming two accessibility
services implement structural navigation via accessibility focus,
there is not guarantee that they will behave similarly by default,
i.e. provide some standard way to navigate the screen content.
Also feedback from experienced accessibility researchers, specifically
T.V Raman, provides evidence that having virtual accessibility focus
creates many issues and it is very hard to get right.
Therefore, keeping accessibility focus in the system will avoid
keeping an off-screen model in accessibility services, it will always
be in sync with the state of the view hierarchy and the input focus.
Also this will allow having a default behavior for traversing the
screen via this accessibility focus that is consistent in all
accessibility services. We provide accessibility services with APIs to
override this behavior but all of them will perform screen traversal
in a consistent way by default.

Behavior: If accessibility is enabled the accessibility focus is the leading one
and the input follows it. Putting accessibility focus on a view moves
the input focus there. Clearing the accessibility focus of a view, clears
the input focus of this view. If accessibility focus is on a view that
cannot take input focus, then no other view should have input focus.
In accessibility mode we initially give accessibility focus to the topmost
view and no view has input focus. This ensures consistent behavior accross
all apps. Note that accessibility focus can move hierarchically in the
view tree and having it at the root is better than putting it where the
input focus would be - at the first input focusable which could be at
an arbitrary depth in the view tree. By default not all views are reported
for accessibility, only the important ones. A view may be explicitly labeled
as important or not for accessibility, or the system determines which one
is such - default. Important views for accessibility are all views that are
not dumb layout managers used only to arrange their chidren. Since the same
content arrangement can be obtained via different combintation of layout
managers, such managers cannot be used to reliably determine the application
structure. For example, a user should see a list as a list view with several
list items and each list item as a text view and a button as opposed to seeing
all the layout managers used to arrange the list item's content.
By default only important for accessibility views are regared for accessibility
purposes. View not regarded for accessibility neither fire accessibility events,
nor are reported being on the screen. An accessibility service may request the
system to regard all views. If the target SDK of an accessibility services is
less than JellyBean, then all views are regarded for accessibility.
Note that an accessibility service that requires all view to be ragarded for
accessibility may put accessibility focus on any view. Hence, it may implement
any navigational paradigm if desired. Especially considering the fact that
the system is detecting some standard gestures and delegates their processing
to an accessibility service. The default implementation of an accessibility
services performs the defualt navigation.

bug:5932640
bug:5605641

Change-Id: Ieac461d480579d706a847b9325720cb254736ebe
/frameworks/base/core/java/android/view/accessibility/AccessibilityManager.java
b303d8381d734f48c4e1de4f11bf25950b28adf1 13-Oct-2011 Scott Main <smain@google.com> docs: a couple notes for a11y methods in View and cleanup to the
A11y service HTML to be semantically correct and thus improve its accessibility :)

Change-Id: I483a8a441d802b056f68f82e0e782d86a73298ac
/frameworks/base/core/java/android/view/accessibility/AccessibilityManager.java
00aabf7d187bc05408199bd687a538b2e68bdc17 21-Jul-2011 Svetoslav Ganov <svetoslavganov@google.com> Touch exploration state set to clients asynchronously and depended on talking service being enabled.

1. Upon registration of an accessibility client the latter received only
the accessiiblity state and waiting for the touch exploration state
to be sent by the system in async manner. This led the very first
check of touch exploration state is checked a wrong value to be reported.
Now a state of the accessibility layer is returned to the client
upon registration.

2. Removing the dependency on talking accessibility service to be enabled
for getting into touch exploration mode. What if the user wants to use
an accessibility service that shows a dialog with the text of the touched
view?

bug:5051546

Change-Id: Ib377babb3f560929ee73bd3d8b0d277341ba23f7
/frameworks/base/core/java/android/view/accessibility/AccessibilityManager.java
35bfedeaba724aeadc6f6c890269cb6bf7ef42f5 15-Jul-2011 Svetoslav Ganov <svetoslavganov@google.com> Touch exploration separate setting and API to poll the latter state.

1. Seperated touch exploration to be a seperate setting rather being
magically enabled by the system of accessiiblity is on the there
is at leas one accessibility service that speaks enabled. Now
there is a setting for requesting touch exploration but still the
system will enabled it only if that makes sense i.e. accessibility
is on and one accessibility service that speaks is enabled.

2. Added public API for checking of touch exploration is enabled.

3. Added description attribute in accessibility service declaration
which will be shown to the user before enabling the service.

4. Added API for quick cloning of AccessibilityNodeInfo.

5. Added clone functionality to SparseArray, SparseIntArray, and
SparseBooleanArray.

bug:5034010
bug:5033928

Change-Id: Ia442edbe55c20309244061cd9d24e0545c01b54f
/frameworks/base/core/java/android/view/accessibility/AccessibilityManager.java
4dfecf55c1afcc7ffe0cef931df67c4934a13e34 01-Jul-2011 Jim Miller <jaggies@google.com> Fix runtime reboot loop.

Change-Id: Ib0614e64e81e376fdbbe7c42a5e4aa8fb9c88ce9
/frameworks/base/core/java/android/view/accessibility/AccessibilityManager.java
38e8b4e5bc3c93affdffbc064fd9db5aeccc3e8e 30-Jun-2011 Svetoslav Ganov <svetoslavganov@google.com> Updating accessibility documentation.

Change-Id: Ice8cf9ac6918b3bfa553776c68d4619fa6559cf8
/frameworks/base/core/java/android/view/accessibility/AccessibilityManager.java
8643aa0179e598e78d938c59035389054535a229 20-Apr-2011 Svetoslav Ganov <svetoslavganov@google.com> Interrogation of the view hierarchy from an AccessibilityService.

1. Views are represented as AccessibilityNodeInfos to AccessibilityServices.

2. An accessibility service receives AccessibilityEvents and can ask
for its source and gets an AccessibilityNodeInfo which can be used
to get its parent and children infos and so on.

3. AccessibilityNodeInfo contains some attributes and actions that
can be performed on the source.

4. AccessibilityService can request the system to preform an action
on the source of an AccessibilityNodeInfo.

5. ViewAncestor provides an interaction connection to the
AccessibiltyManagerService and an accessibility service uses
its connection to the latter to interact with screen content.

6. AccessibilityService can interact ONLY with the focused window
and all calls are routed through the AccessibilityManagerService
which imposes security.

7. Hidden APIs on AccessibilityService can find AccessibilityNodeInfos
based on some criteria. These API go through the AccessibilityManagerServcie
for security check.

8. Some actions are hidden and are exposes only to eng builds for UI testing.

Change-Id: Ie34fa4219f350eb3f4f6f9f45b24f709bd98783c
/frameworks/base/core/java/android/view/accessibility/AccessibilityManager.java
cc4053e031371456fe54d51bbad1db721db4ae38 23-May-2011 Svetoslav Ganov <svetoslavganov@google.com> Accessibility serviceconfiguration via meta-data

Note: This is a part of two CL change and contains the
system changes without updates to the settings.

1. Added a mechanism for configuring an accessibility service via
XML file specified in a meta-data tag (similar to IMEs).

2. Added property for specifying a settings activity for an
accessibility service.

3. Refactored the APIs in AccessibilityManager to return
lists of AccessiblityServiceInfo instead ServiceInfo
since the former describes an AccessibilityService in
particular (similar to IMEs).

Change-Id: Ie8781bb7e0cdb329e583b6702a612a507367ad7b
/frameworks/base/core/java/android/view/accessibility/AccessibilityManager.java
736c2756bf3c14ae9fef7255c119057f7a2be1ed 23-Apr-2011 Svetoslav Ganov <svetoslavganov@google.com> Touch exploration feature, event bubling, refactor

1. Added an Input Filter that interprets the touch screen motion
events to perfrom accessibility exploration. One finger explores.
Tapping within a given time and distance slop on the last exlopred
location does click and long press, respectively. Two fingers close
and in the same diretion drag. Multiple finglers or two fingers in
different directions or two fingers too far away are delegated to
the view hierarchy. Non moving fingers "accidentally grabbed the
device for the scrren" are ignored.

2. Added accessibility events for hover enter, hover exit, touch
exoloration gesture start, and end. Accessibility hover events
are fired by the hover pipeline. An accessibility event is
dispatched up the view tree and the topmost view fires it.
Thus predecessors can augment the fired event. An accessibility
event has several records and a predecessor can optionally
modify, delete, and add such to the event.

3. Added onPopulateAccessibilityEvent and refactored the existing
accessibility code to use it.

4. Added API for querying the currently enabled accessibility services
by feedback type.

Change-Id: Iea2258c07ffae9491071825d966dc453b07e5134
/frameworks/base/core/java/android/view/accessibility/AccessibilityManager.java
3fb3d7c4e756bd32d5abde0abca9ab52d559bc84 23-Apr-2011 Adam Powell <adamp@google.com> Revert "Touch exploration feature, event bubling, refactor"

This reverts commit ac84d3ba81f08036308b17e1ab919e43987a3df5.

There seems to be a problem with this API change. Reverting for now to
fix the build.

Change-Id: Ifa7426b080651b59afbcec2d3ede09a3ec49644c
/frameworks/base/core/java/android/view/accessibility/AccessibilityManager.java
ac84d3ba81f08036308b17e1ab919e43987a3df5 05-Apr-2011 Svetoslav Ganov <svetoslavganov@google.com> Touch exploration feature, event bubling, refactor

1. Added an Input Filter that interprets the touch screen motion
events to perfrom accessibility exploration. One finger explores.
Tapping within a given time and distance slop on the last exlopred
location does click and long press, respectively. Two fingers close
and in the same diretion drag. Multiple finglers or two fingers in
different directions or two fingers too far away are delegated to
the view hierarchy. Non moving fingers "accidentally grabbed the
device for the scrren" are ignored.

2. Added accessibility events for hover enter, hover exit, touch
exoloration gesture start, and end. Accessibility hover events
are fired by the hover pipeline. An accessibility event is
dispatched up the view tree and the topmost view fires it.
Thus predecessors can augment the fired event. An accessibility
event has several records and a predecessor can optionally
modify, delete, and add such to the event.

3. Added onPopulateAccessibilityEvent and refactored the existing
accessibility code to use it.

4. Added API for querying the currently enabled accessibility services
by feedback type.

Change-Id: Iec03c6c3fe298de3f14cb6efdbb9b198cd531a0c
/frameworks/base/core/java/android/view/accessibility/AccessibilityManager.java
43a17654cf4bfe7f1ec22bd8b7b32daccdf27c09 07-Apr-2011 Joe Onorato <joeo@google.com> Remove the deprecated things from Config.java. These haven't been working since before 1.0.

Change-Id: Ic2e8fa68797ea9d486f4117f3d82c98233cdab1e
/frameworks/base/core/java/android/view/accessibility/AccessibilityManager.java
af7adab3e35863fff24e701039d5d04afbc060c5 17-Apr-2010 Svetoslav Ganov <svetoslavganov@google.com> 2604184 Expose hidden APIs for testing the AccessibilityManager separately from the backing AccessibilityManagerServcie

Change-Id: Ief5df31baa3c0990467625977e97cd066a671959
/frameworks/base/core/java/android/view/accessibility/AccessibilityManager.java
dd64a9b0d6ff0f15b22d02a108c5342c74db995a 14-Apr-2010 Svetoslav Ganov <svetoslavganov@google.com> 2593833 AccessibilityManager not properly initialized immediately upon registration in the AccessibilityManagerService

Change-Id: I0226bafc5e9c5b800c54019c9309394f1e5f9e88
/frameworks/base/core/java/android/view/accessibility/AccessibilityManager.java
75986cf9bc57ef11ad70f36fb77fbbf5d63af6ec 15-May-2009 svetoslavganov <svetoslavganov@google.com> Accessibility feature - framework changes (replacing 698, 699, 700, 701 and merging with the latest Donut)
/frameworks/base/core/java/android/view/accessibility/AccessibilityManager.java