| 9b278112467581e2b8d99f29cf48b9fbef9cc53f |
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04-Jan-2016 |
Anna Galusza <agalusza@google.com> |
Add API for IME control by Accessibility Services.
Change-Id: I3bb806cf420e0551a2c9ef97d95613f73e362df9
/frameworks/base/core/java/android/accessibilityservice/IAccessibilityServiceClient.aidl
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| a6b64f5099b7be6e8384958d8bcddb97bb06ec93 |
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05-Dec-2015 |
Phil Weaver <pweaver@google.com> |
Gesture dispatch from accessibility services.
Add public APIs to describe gestures and dispatch them from
an accessibility service. Added a new capability that
services must declare to have this capability.
Bug: 22514086
Change-Id: I9bff2d9335f0310115112d14b7ed033a6d6c2393
/frameworks/base/core/java/android/accessibilityservice/IAccessibilityServiceClient.aidl
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| 214fb68767502f5fede643a062c1dc5975d75b27 |
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17-Nov-2015 |
Alan Viverette <alanv@google.com> |
APIs for querying and controlling display magnification
Also separates magnification state and touch event handling. Moves
callbacks for window manager changes and display state changes into
the magnification controller.
Bug: 22718911
Change-Id: I3a8ba060a07d8f1f51856855a5f85601766fd45d
/frameworks/base/core/java/android/accessibilityservice/IAccessibilityServiceClient.aidl
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| 3a5c721072c60c7ed9c8a95d0a65d0e3cb4eb9bb |
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14-Oct-2014 |
Svetoslav <svetoslavganov@google.com> |
APIs for an accessibility service to put interaction tracking overlays.
An accessibility service may register to observe the interactive windows
on the primary display. These windows are the one that has input focus and
ones a sighted user can touch. It is sometimes beneficial for an
accessibility service to overlay a window to intercept user interaction
and based on that introspect and perform an action on the windows that
are on the screen. This is problematic as overlaying a full screen window
that is touchable prevents the accessibility service to introspect the
content under this window.
This change adds a special type of window that only an accessibility service
can place which does not affect what an accessibility service can "see" on
the screen. Hence, even putting such a window full screen the service will
be able to interact with the other interactive windows it covers.
Change-Id: I053ccc3a5c6360a98dc40bdb172b54dab35d8b31
/frameworks/base/core/java/android/accessibilityservice/IAccessibilityServiceClient.aidl
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| a4725efd0bfa52cbddf6ca587d37fc4ebcbfaf72 |
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24-Jul-2014 |
Svetoslav <svetoslavganov@google.com> |
Improve the window query API performamce.
We are caching the window data in the accessibility service process.
When windows change we were sending the dalta of the windows the
service knows about. To make this work when the app asked for all
windows we had to call into the system as new windows may have
appeared. This was slow.
Now we are telling the service some windows change and if it gets
the windows we cache them. We call into the system only on a cache
miss and evict all windows from the cache on window change event.
We do not evict the nodes of the window as the former may have
just moved. If views in a window change they fire accessibility
events that trigger the correct eviction.
Change-Id: I586a72a2497b0d44a75288fa758e7e88817f3300
/frameworks/base/core/java/android/accessibilityservice/IAccessibilityServiceClient.aidl
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| 8e3feb15c5aec2c72b0ef120a1da325e1e8f0dda |
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24-Feb-2014 |
Svetoslav <svetoslavganov@google.com> |
Added accessibility APIs for introspecting interactive windows.
1. The old introspection model was allowing querying only the active window
which is the one the user is touching or the focused one if no window is
touched. This was limiting as auto completion drop downs were not inspectable,
there was not way to know when the IME toggles, non-focusable windows were
not inspectable if the user taps them as until a screen-reader starts
introspecting the users finger is up, accessibility focus was limited to
only one window and the user couldn't use gestures to visit the whole UI,
and other things I can't remember right now.
The new APIs allow getting all interactive windows, i.e. ones that a
sighted user can interact with. This prevents an accessibility service
from interacting with content a sighter user cannot. The list of windows
can be obtained from an accessibility service or the host window from an
accessibility node info. Introspecting windows obey the same rules for
introspecting node, i.e. the service has to declare this capability
in its manifest.
When some windows change accessibility services receive a new type
of event. Initially the types of windows is very limited. We provide
the bounds in screen, layer, and some other properties which are
enough for a client to determined the spacial and hierarchical
relationship of the windows.
2. Update the documentation in AccessibilityService for newer event types.
3. LongArray was not removing elements properly.
4. Composite accessibility node ids were not properly constructed as they
are composed of two ints, each taking 32 bits. However, the values for
undefined were -1 so composing a 64 long from -1, -1 prevents from getting
back these values when unpacking.
5. Some apps were generating inconsistent AccessibilityNodeInfo tree. Added
a check that enforces such trees to be well formed on dev builds.
6. Removed an necessary code for piping the touch exploration state to
the policy as it should just use the AccessibilityManager from context.
7. When view's visibility changed it was not firing an event to notify
clients it disappeared/appeared. Also ViewGroup was sending accessibility
events for changes if the view is included for accessibility but this is
wrong as there may be a service that want all nodes, hence events from them.
The accessibility manager service takes care of delivering events from
not important for accessibility nodes only to services that want such.
8. Several places were asking for prefetching of sibling but not predecessor
nodes which resulted in prefetching of unconnected subtrees.
9. The local AccessibilityManager implementation was relying on the backing
service being ready when it is created but it can be fetched from a context
before that. If that happens the local manager was in a broken state forever.
Now it is more robust and starts working properly once the backing service
is up. Several places were lacking locking.
bug:13331285
Change-Id: Ie51166d4875d5f3def8d29d77973da4b9251f5c8
/frameworks/base/core/java/android/accessibilityservice/IAccessibilityServiceClient.aidl
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| c4fccd183f1bb47a027bb303af5e65bec2f68b1b |
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09-Apr-2013 |
Svetoslav <svetoslavganov@google.com> |
Adding APIs for an accessibility service to intercept key events.
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
/frameworks/base/core/java/android/accessibilityservice/IAccessibilityServiceClient.aidl
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| 152e9bb81aa5b2ab4637f4b2dae04b3ce89fa891 |
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13-Oct-2012 |
Svetoslav Ganov <svetoslavganov@google.com> |
Refactoring of the screen magnification feature.
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
/frameworks/base/core/java/android/accessibilityservice/IAccessibilityServiceClient.aidl
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| 7b1e0c7046abefc0b40884b36197c8a803d9cf6d |
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13-May-2012 |
Svetoslav Ganov <svetoslavganov@google.com> |
Removing default accessibility gesture handling.
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
/frameworks/base/core/java/android/accessibilityservice/IAccessibilityServiceClient.aidl
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| fefd20e927b7252d63acb7bb1852c5188e3c1b2e |
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20-Apr-2012 |
Svetoslav Ganov <svetoslavganov@google.com> |
Adding an opt-in mechanism for gesture detection in AccessibilityService.
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
/frameworks/base/core/java/android/accessibilityservice/IAccessibilityServiceClient.aidl
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| 4213804541a8b05cd0587b138a2fd9a3b7fd9350 |
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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/accessibilityservice/IAccessibilityServiceClient.aidl
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