Since the enable touch exploration capability is dynamically granted by
the user for apps targeting pre-JellybeanMR2 API level, we have to properly
update the accessibility service info for that service and also avoid
caching copies of the service info.
bug:8633951
Change-Id: I83dd1c852706ec55d40cda7209ad842889fb970a
1. UiAutomation#executeAndWaitForEvent method was invoking the passed
runnable while holding the lock which may lead to a deadlock. For
example: a runnable that calls getActivity() gets us into a state
like this.
2. UI automation services did not get all capabilities such a
service can have. Now a UI test service gets all of them.
3. When UiAutomation was exiting for event fired as a result of a
performed action, it was checking whether the received evnet time
is strictly before the time of executing the command that should
fire the event. However, if the execution is fast enough, i.e.
less than one millisecond, then the event time and the execution
time are the same. This was leading to a missed signal in rare
cases.
4. AccessibilityNodeInfoCache was not clearing the relevant state
for accessibility focus clearing event.
5. Accessibility text traversal in TextView was partially using text
and partially content description - broken. Now we are using the
text since for text view and content desc for other views. In other
words, we are using the most precise text we have.
6. AccessibilityManagerService was not granting capabilities of a
UiAutomation service - plainly wrong.
CTS change:https://googleplex-android-review.googlesource.com/#/c/300693/
bug:8695422
bug:8657560
Change-Id: I9afc5c3c69eb51f1c01930959232f44681b15e86
Accessibility services can perform special operations such as retrieve
the screen content, enable explore by touch, etc. To ensure the user
is aware that the service will perform special operations we were using
permissions. However, the special operations cannot be performed unless
the service is really enabled by the user and it is at this point that
we want to notify the user about the service capabilities.
This change adds capability attributes to the accessibility service's
meta-data XML file. The service has to declare the capability and when
it is enabled we show the user the capabilities in the warining dialog.
bug:8633951
Change-Id: Id3442dc71dad018e606888afdc40834682fdb037
Now that we have gestures which are detected by the system and
interpreted by an accessibility service, there is an inconsistent
behavior between using the gestures and the keyboard. Some devices
have both. Therefore, an accessibility service should be able to
interpret keys in addition to gestures to provide consistent user
experience. Now an accessibility service can expose shortcuts for
each gestural action.
This change adds APIs for an accessibility service to observe and
intercept at will key events before they are dispatched to the
rest of the system. The service can return true or false from its
onKeyEvent to either consume the event or to let it be delivered
to the rest of the system. However, the service will *not* be
able to inject key events or modify the observed ones.
Previous ideas of allowing the service to say it "tracks" the event
so the latter is not delivered to the system until a subsequent
event is either "handled" or "not handled" will not work. If the
service tracks a key but no other key is pressed essentially this
key is not delivered to the app and at potentially much later point
this stashed event will be delivered in maybe a completely different
context.The correct way of implementing shortcuts is a combination
of modifier keys plus some other key/key sequence. Key events already
contain information about which modifier keys are down as well as
the service can track them as well.
bug:8088812
Change-Id: I81ba9a7de9f19ca6662661f27fdc852323e38c00
1. Accessibility service may set a flag to request a compressed
view of the node tree representing the screen. The compressed
state does not contain nodes that do to react to user actions
and do not draw content, i.e. they are dumb view managers. This
compressed hierarchy was very beneficial to the test team and
this change is exposing the APIs. The compression has to be
configurable since old tests are written against uncompressed
view tree. Basically we do not hide the fact that UIAutomation
is simply an accessibility service with some other useful APIs.
bug:8051095
2. Accessibility service can perform global actions such as opening
notifications, opening recent apps, etc. These are also needed
for UI testing since there is no other way to do it via the
existing UIAutomation APIs. Basically we do not hide the fact
that UIAutomation is simply an accessibility service with some
other useful APIs.
bug:8117582
Change-Id: I7b6e24b5f7a973fdada0cc199cff9f882b10720b
1. The accessibility manager service updates its internal state
based on which settings are enabled, what accessibility services
are installed and what features are requested by the enabled
services. It was trying to do the minimal amount of work to
react to contextual changes like these which resulted in missed
cases and complex code. Now there is a single method that reads
the contextual information and single method that reacts to
contextual changes. This makes the code much easier to maintain.
2. The accessibility manager service was not updating its internal
state when requested features from accessibility services change.
It was relying on changing system settings and reacting to the
settings change. This is problematic since the internal state is
not updated atomically which leads to race condition bugs. For
example, if touch exploration is enabled and a service requests
it is disabled, the internal state will not be updated but a
request for a settings change will be made. Now while the settings
change is propagating another request form the same service
comes to enable touch exploration but the system incorrectly
thinks touch exploration is enabled. At the end the feature is
disabled even though it was requested.
3. Fixed a potential NPE if the accessibility input filter's event
handler was nullified between processing two event batches.
4. Fixed a bug where, if magnification is enabled, it does not work
on the settings screen since the magnified bounds are not pushed
from the window manager to the accessibility manager.
Change-Id: Idf629a06480e12f0d88372762df6c024fe0d7856
Currently we have an "enhance web accessibility" setting that has to be
enabled to make sure web content is accessible. We added the setting to
get user consent because we are injecting JavaScript-based screen-reader
pulled from the Google infrastructure. However, many users do not know
that and (as expected) do not read the user documentation, resulting in
critique for lacking accessibility support in WebViews with JavaScript
enabled (Browser, Gmail, etc).
To smoothen the user experience now "enhance web accessibility" is a
feature an accessibility plug-in can request, similarly to explore by
touch. Now a user does not need to know that she has to explicitly
enable the setting and web accessibility will work out-of-the-box.
Before we were showing a dialog when a plug-in tries to put the device
in a touch exploration mode. However, now that we have one more feature
a plug-in can request, showing two dialogs (assume a plug-in wants both
features) will mean that a user should potentially deal with three
dialogs, one for enabling the service, and one for each feature. We
could merge the dialogs but still the user has to poke two dialogs.
It seems that the permission mechanism is a perfect fit for getting
user permission for an app to do something, in this case to enable
an accessibility feature. We need a separate permission for explore
by touch and enhance web accessibility since the former changes the
interaction model and the latter injects JavaScript in web pages. It
is critical to get user consent for the script injection part so we
need a well-documented permission rather a vague umbrella permission
for poking accessibility features. To allow better grouping of the
accessibility permissions this patch adds a permission group as well.
bug:8089372
Change-Id: Ic125514c34f191aea0416a469e4b3481ab3200b9
This change adds APIs support for implementing UI tests. Such tests do
not rely on internal application structure and can span across application
boundaries. UI automation APIs are encapsulated in the UiAutomation object
that is provided by an Instrumentation object. It is initialized by the
system and can be used for both introspecting the screen and performing
interactions simulating a user. UI test are normal instrumentation tests
and are executed on the device.
UiAutomation uses the accessibility APIs to introspect the screen and
a special delegate object to perform privileged operations such as
injecting input events. Since instrumentation tests are invoked by a shell
command, the shell program launching the tests creates a delegate object and
passes it as an argument to started instrumentation. This delegate
allows the APK that runs the tests to access some privileged operations
protected by a signature level permissions which are explicitly granted
to the shell user.
The UiAutomation object also supports running tests in the legacy way
where the tests are run as a Java shell program. This enables existing
UiAutomator tests to keep working while the new ones should be implemented
using the new APIs. The UiAutomation object exposes lower level APIs which
allow simulation of arbitrary user interactions and writing complete UI test
cases. Clients, such as UiAutomator, are encouraged to implement higher-
level APIs which minimize development effort and can be used as a helper
library by the test developer.
The benefit of this change is decoupling UiAutomator from the system
since the former was calling hidden APIs which required that it is
bundled in the system image. This prevented UiAutomator from being
evolved separately from the system. Also UiAutomator was creating
additional API surface in the system image. Another benefit of the new
design is that now test cases have access to a context and can use
public platform APIs in addition to the UiAutomator ones. Further,
third-parties can develop their own higher level test APIs on top
of the lower level ones exposes by UiAutomation.
bug:8028258
Also this change adds the fully qualified resource name of the view's
id in the emitted AccessibilityNodeInfo if a special flag is set while
configuring the accessibility service. Also added is API for looking
up node infos by this id. The id resource name is relatively more stable
compared to the generaed id number which may change from one build to
another. This API facilitate reuing the already defined ids for UI
automation.
bug:7678973
Change-Id: I589ad14790320dec8a33095953926c2a2dd0228b
Improves the throughput of IME event handling by ensuring that
input events do not get serialized behind UI traversal and
drawing messages such as when the UI is animating.
Added support for creating an asynchronous Handler as part of a
HandlerCaller. It turns out we should be using an asynchronous
Handler not only in IME dispatch but also in accessibility and
wallpaper events where HandlerCaller is used. So fixed those
services to also use an asynchronous Handler.
Change-Id: I0b19140c9d5ca6ee300c1a150c48312fd55ed8eb
1. The screen magnification feature was implemented entirely as a part of the accessibility
manager. To achieve that the window manager had to implement a bunch of hooks for an
external client to observe its internal state. This was problematic since it dilutes
the window manager interface and allows code that is deeply coupled with the window
manager to reside outside of it. Also the observer callbacks were IPCs which cannot
be called with the window manager's lock held. To avoid that the window manager had
to post messages requesting notification of interested parties which makes the code
consuming the callbacks to run asynchronously of the window manager. This causes timing
issues and adds unnecessary complexity.
Now the magnification logic is split in two halves. The first half that is responsible
to track the magnified portion of the screen and serve as a policy which windows can be
magnified and it is a part of the window manager. This part exposes higher level APIs
allowing interested parties with the right permissions to control the magnification
of a given display. The APIs also allow a client to be registered for callbacks on
interesting changes such as resize of the magnified region, etc. This part servers
as a mediator between magnification controllers and the window manager.
The second half is a controller that is responsible to drive the magnification
state based on touch interactions. It also presents a highlight when magnified to
suggest the magnified potion of the screen. The controller is responsible for auto
zooming out in case the user context changes - rotation, new actitivity. The controller
also auto pans if a dialog appears and it does not interesect the magnified frame.
bug:7410464
2. By design screen magnification and touch exploration work separately and together. If
magnification is enabled the user sees a larger version of the widgets and a sub section
of the screen content. Accessibility services use the introspection APIs to "see" what
is on the screen so they can speak it, navigate to the next item in response to a
gesture, etc. Hence, the information returned to accessibility services has to reflect
what a sighted user would see on the screen. Therefore, if the screen is magnified
we need to adjust the bounds and position of the infos describing views in a magnified
window such that the info bounds are equivalent to what the user sees.
To improve performance we keep accessibility node info caches in the client process.
However, when magnification state changes we have to clear these caches since the
bounds of the cached infos no longer reflect the screen content which just got smaller
or larger.
This patch propagates not only the window scale as before but also the X/Y pan and the
bounds of the magnified portion of the screen to the introspected app. This information
is used to adjust the bounds of the node infos coming from this window such that the
reported bounds are the same as the user sees not as the app thinks they are. Note that
if magnification is enabled we zoom the content and pan it along the X and Y axis. Also
recomputed is the isVisibleToUser property of the reported info since in a magnified
state the user sees a subset of the window content and the views not in the magnified
viewport should be reported as not visible to the user.
bug:7344059
Change-Id: I6f7832c7a6a65c5368b390eb1f1518d0c7afd7d2
1. Added APIs for opening the quick settings to the StatusBarManagerService
and the local StatausBarManager. The new APIs are protected by the old
EXPAND_STATUS_BAR permission.
Renamed the expand* and collapse* non-public APIs that are expanding
the notifications to expandNotifications* collapseNotifications* to
better convey what they do given that this change adds
expandQuickSettings* and collapseQuickSettings*.
Added a global action to the accessibility layer to expand the quick
settings which is calling into the new status bar manager APIs.
bug:7030487
Change-Id: Ic7b46e1a132f1c0d71355f18e7c5a9a2424171c3
1. The feedback type provided by braille devices differs from all
already predefined types and this change defines braille
feedback type. Braille does not fit in the already predefined
categories.
bug:6998945
Change-Id: Ide6043bed03fdecd6d2ee45a08762f5bd07a2118
Okay this isn't entirely docs. I have un-hidden the new permission
for binding to accessibility services; we were going to go out with
it hidden since it didn't go into factory ROM, but now that we are
doing other things we might as well expose it.
Also changed a log from E to W, since it is not an error.
Change-Id: I9226c95e3b63e12218fe41dc3f4290d9824a9e5c
1. Every accessibility services targeting JellyBean or higher has
to request a special permission for the system to bind to it.
Change-Id: I6e579326bdf3597f148d6c67317455701ec8af68
1. The initial design was to have some accessibility gestures
being handled by the system if the gesture handling access
service does not consume the gesture. However, we are not
sure what a good default is and once we add a default handler
we cannot remove it since people may rely on it. Thus, we
take the simples approach and let the accessibility service
handle the gestures. If no gestures are handled the system
will work in explore by touch as before.
bug:5932640
Change-Id: I865a83549fa03b0141d27ce9713e9b7bb45a57b4
1. Delegating activation gestures has several issues that we should
decide how to handle if possible before allowing an accessibility
service to take over them:
A) It is needed that every view than can be clicked or long pressed on
reacts to such as a response to calling performClick and performLongPress
which is not necessary true since the view may watch the touch
events and do its own click long click detection. As a result it may
be possible that there are view a user cannot interact with in
touch exploration mode but can if not in that mode.
B) Clicking or long pressing on a different location in a view may yield
different results, for example NumberPicker. Ideally such views have
to implement AccessibilityNodeProvide which provider handles correctly
the request for click long press on virtual nodes. Some apps however
just fire different hover accessibility events when the user is over
a specific semantic portion of the view but do not provide virtual
nodes. Hence, a user will not be able to interact with such semantic
regions but the system can achieve that by sending the click/long click
at the precise location in the view that was last touch explored.
2. Adding a flag on accessibility service info to request explore by touch
mode. There is no need to put the device in this mode if node of the currently
enabled accessibility services supports it. Now the problem is inverted and
the service has to explicitly state its capability.
3. Fixing a bug where includeImportantViews was ignored for automation
services.
Change-Id: I3b29a19f24ab5e26ee29f974bbac2197614c9e2a
This problem was introduced in I74df9c24. The intention of the
change was still let UiTestAutomationBridge see the
non-important views, but there were bugs in the implementation:
1. AccessibilityManagerService was not really updating
mIncludeNotImportantViews when mIsAutomation is true
2. Wrong constant is used to set the flag
Change-Id: Ia0a2e9ed9720bd0ea3a563e0b492e870a6ec1586
1. Since we are using a stateless proxy accessibility service to
perform default accessibility gesture handling it shuld not
operate against not important views.
bug:6422069
Change-Id: I74df9c2415ab3b164d9ac5873f7004c0459e2bfa
1. The clockwise and counter clockwise circle gestures are difficult to
perform for a blind user. Some user studies have shown that so nuke them.
bug:6435260
Change-Id: I81d23bd3c450239fe17b4b8c60bafab00daa480a
1. A view that creates an accessibility node info may add to the info
a list of granularity labels. These are granularities by which the
source view can iterate over its content. For example a text view
may support character, word link while a web view may additionally
support buttons, tables, etc. There are actions on accessibility
node info to go to the next/previous at a given granularity which
is passesed as an argument.
2. Added Bundle argument to the APIs for performing accessibility
actions. This is generic and extensible.
bug:5932640
Change-Id: I328cbbb4cddfdee082ab2a8b7ff1bd7477d8d6f9
1. An accessibility service has to explicitly opt in to be notified
for gestures by the system. There is only one accessibility service
that handles gestures and in case it does not handle a gesture
the system performs default handling. This default handling ensures
that we have gesture navigation even if no accessibility service
would like to participate/customize the interaction model.
bug:5932640
Change-Id: Id8194293bd94097b455e9388b68134a45dc3b8fa
1. This APIs is useful for accessibility services since very often
they want to get access to the root node in the current window
to determine where accessibility focus is and subsequently find
a next view to take accessibility focus.
Change-Id: Ide5231f832d9ce2e9b14dc411dfd675f753a4edb
1. Added more gesture for accessibility. After a meeting
with the access-eng team we have decided that the current
set of gestures may be smaller than needed considering
that we will use four gestures for home, back, recents,
and notifications.
2. Adding actions for going back, home, opening the recents,
and opening the notifications.
3. Added preliminary mapping from some of the new gestures
to the new actions.
4. Fixed a bug in the accessibility interaction controller
which was trying to create a handled on the main looper
thread which may be null if the queried UI is in the
system process. Now the context looper of the root view
is used.
5. Fixed a bug of using an incorrect constant.
6. Added a missing locking in a couple of places.
7. Fixed view comparison for accessibilityt since it was
not anisymmetric.
bug:5932640
bug:5605641
Change-Id: Icc983bf4eafefa42b65920b3782ed8a25518e94f
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
1. When the feedback type is set to TYPES_ALL_MASK the method
feedbackTypeToString was not generating a string with all
feedback types. Also the generated string sometimes could
have a comma appended after the last feedback type name
- this happens if the feedback type contains unknown type
flag.
Change-Id: I848c520cf7dae16dcd882f68275869c7ab656dd7
1. Now the thread is terminated in the disconnect() method
and also it is made demon since it has no pupose outside
the context of the bridge client.
bug:6053108
Change-Id: Idc25373fddf501eda4f875fea3e944367e4f04bf
1. Before there were two caches one in the app process that
kept track only the ids of infos that were given to a
querying client and one in the querying client that
holds the infos. This design requires precise sync
between the caches. Doing that is somehow complicated
since the app has cache for each window and it has
to intercept all accessibility events from that window
to manage the cache. Each app has to have a cache for
each querying client. This approach would guarantee that
no infos are fetched twice but due to its stateful nature
and the two caches is tricky to implement and adds
unnecessary complexity. Now there is only one cache in
the client and the apps are stateless. The client is
passing flags to the app that are a clue what nodes to
prefetch. This approach may occasionally fetch a node
twice but it is considerably simpler and stateless
from the app perspective - there is only one cache.
Fetching a node more than once does not cause much
overhead compared to the IPC.
Change-Id: Ia02f6fe4f82cff9a9c2e21f4a36747de0f414c6f
1. UiTestAutomationBridge was accessing the root node in the
active window by tracking the accessibility event stream
and keeping the last active window changing event. Now
the bridge is stateless and the root node is fetched by
passing special window and view id with the request to
the system.
2. AccessibilityNodeInfos that are cached were not finished,
i.e. not sealed, causing exception when trying to access
their children or rpedecessors.
3. AccessibilityManagerService was not properly restoring its
state after the UI automation bridge disconnects from it.
I particular the devices was still in explore by touch mode
event if no services are enabled and the sutomation bridge
is disconnected.
4. ViewRootImpl for the focused window now fires accessibility
events when accessibility is enabled to allow accessibility
services to determine the current user location.
5. Several missing null checks in ViewRootImpl are fixed since
there were scenraios in which a NPE can occur.
6. Update the internal window content querying tests.
7. ViewRootImpl was firing one extra focus event.
bug:6009813
bug:6026952
Change-Id: Ib2e058d64538ecc268f9ef7a8f36ead047868a05
1. Now when an interrogating client requires an AccessibilibtyNodeInfo
we aggressively prefetch all the predecessors of that node and its
descendants. The number of fetched nodes in one call is limited to
keep the APIs responsive. The prefetched nodes infos are cached in
the client process. The node info cache is invalidated partially or
completely based on the fired accessibility events. For example,
TYPE_WINDOW_STATE_CHANGED event clears the cache while
TYPE_VIEW_FOCUSED removed the focused node from the cache, etc.
Note that the cache is only for the currently active window.
The ViewRootImple also keeps track of only the ids of the node
infos it has sent to each querying process to avoid duplicating
work. Usually only one process will query the screen content
but we support the general case. Also all the caches are
automatically invalidated so not additional bookkeeping is
required. This simple strategy leads to 10X improving the
speed of the querying APIs.
2. The Monkey and UI test automation framework were registering a
raw event listener for accessibility events and hence perform
connection and cache management in similar way to an AccessibilityService.
This is fragile and requires the implementer to know internal framework
stuff. Now the functionality required by the Monkey and the UI automation
is encapsulated in a new UiTestAutomationBridge class. To enable this
was requited some refactoring of AccessibilityService.
3. Removed the *doSomethiong*InActiveWindow methods from the
AccessibilityInteractionClient and the AccessibilityInteractionConnection.
The function of these methods is implemented by the not *InActiveWindow
version while passing appropriate constants.
4. Updated the internal window Querying tests to use the new
UiTestAutomationBridge.
5. If the ViewRootImple was not initialized the querying APIs of
the IAccessibilityInteractionConnection implementation were
returning immediately without calling the callback with null.
This was causing the client side to wait until it times out. Now
the client is notified as soon as the call fails.
6. Added a check to guarantee that Views with AccessibilityNodeProvider
do not have children.
bug:5879530
Change-Id: I3ee43718748fec6e570992c7073c8f6f1fc269b3
1. AccessibilityServiceInfo loading the description string on
creation and using this value. Hence, changing the locale
results in reporting incorrectly localized string. Added a
new loadDescription method to return the localized version.
2. Deprecated the old method.
bug:5807616
Change-Id: Id82bda3c6a90fa6681b035d20da0b8688ed68da3
1. AccessibilityInteractionConnections were removed from the
AccessiiblityManagerService but their DeathRecipents were
not unregistered, thus every removed interaction connection
was essentially leaking. Such connection is registered in
the system for every ViewRootImpl when accessiiblity is
enabled and inregistered when disabled.
2. Every AccessibilityEvent and AccessiilbityEventInfo obtained
from a widnow content querying accessibility service had a
handle to a binder proxy over which to make queries. Hoewever,
holding a proxy to a remote binder prevents the latter from
being garbage collected. Therefore, now the events and infos
have a connection id insteand and the hindden singleton
AccessiiblityInteaction client via which queries are made
has a registry with the connections. This class looks up
the connection given its id before making an IPC. Now the
connection is stored in one place and when an accessibility
service is disconnected the system sets the connection to
null so the binder object in the system process can be GCed.
Note that before this change a bad implemented accessibility
service could cache events or infos causing a leak in the
system process. This should never happen.
3. SparseArray was not clearing the reference to the last moved
element while garbage collecting thus causing a leak.
bug:5664337
Change-Id: Id397f614b026d43bd7b57bb7f8186bca5cdfcff9
Added an interface that is the contract for a client to expose a virtual
view hierarchy to accessibility services. Clients impement this interface
and set it in the View that is the root of the virtual sub-tree. Adding
this finctionality via compostion as opposed to inheritance enables apps
to maintain backwards compatibility by setting the accessibility virtual
hierarchy provider on the View only if the API version is high enough.
bug:5382859
Change-Id: I7e3927b71a5517943c6cb071be2e87fba23132bf
