History log of /frameworks/base/services/java/com/android/server/accessibility/AccessibilityInputFilter.java
Revision Date Author Comments (<<< Hide modified files) (Show modified files >>>)
3dc75ac65f7bb077fd6afa3a7ad35f5899adf445 27-Apr-2013 Svetoslav <svetoslavganov@google.com> The helper query bridge in AccessibilityServiceManager missing capability.

1. The helper query bridge service did not have the now capability
to query the screen content.

2. Fixing the build.

bug:8633951

Change-Id: Ief6a3387793710a83b83c18cc6c53b51dcda9bdf
/frameworks/base/services/java/com/android/server/accessibility/AccessibilityInputFilter.java
ca523d6e95061f99455589512100839118044d43 26-Apr-2013 Svetoslav <svetoslavganov@google.com> Deliver key events to the system if no accessibility service handles them.

We have APIs that allow an accessibility service to filter key events. The
service has to declare the capability to toggle event filtering in its
manifest and then it can set a flag to toggle the feature at runtime. The
problem was that even if no accessibility service was handling key events
these events were not fed back to the input system.

This change adds a new feature flag in the accessibility input filter that
is set only if at least one service can and wants to filter key events. If
the feature flag is set then the filter will deliver events to services and
,if they are not handled, to the system. This change also cleaned the logic
for updating the input filter.

bug:8713422

Change-Id: I4bc0c1348676569d1b76e9024708d1ed43ceb26a
/frameworks/base/services/java/com/android/server/accessibility/AccessibilityInputFilter.java
c4fccd183f1bb47a027bb303af5e65bec2f68b1b 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/services/java/com/android/server/accessibility/AccessibilityInputFilter.java
57bf88508e0491caced22c4c592d33aba6d88129 08-Feb-2013 Svetoslav <svetoslavganov@google.com> Refactoring of the Accessibility.

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
/frameworks/base/services/java/com/android/server/accessibility/AccessibilityInputFilter.java
213c13aadd5bd4fd3876528f17f179379ca1c1f6 04-Feb-2013 Svetoslav <svetoslavganov@google.com> Ensure touch explorer and magnifier get a well-formed event stream.

We use an input filter to manipulate the event stream in accessibility
mode. Some input events, i.e. touch and hover events, are delivered
to a touch explorer, if touch exploration is enabled, and to a magnifier,
if screen magnification is enabled. It is possible that at the moment
each of these features is enabled we are in the middle of a touch or
hover gesture. The touch explorer and screen magnifier expect to receive
an event stream that starts with an event that denotes the stream start.
This change ensures that hover or touch events are dispatched to the
touch explorer and the magnifier only after the start of the first
well-formed hover or touch sequence.

Change-Id: I8cd0ad8e1844c59fd55cf1dfacfb79af6a8916df
/frameworks/base/services/java/com/android/server/accessibility/AccessibilityInputFilter.java
545252f4fde6fbb70b07e97a120c7d1405758017 11-Dec-2012 Svetoslav Ganov <svetoslavganov@google.com> Refactoring of the screen magnification feature.

1. This patch takes care of the case where a magnified window is covering an unmagnigied
one. One example is a dialog that covers the IME window.

bug:7634430

2. Ensuring that the UI automator tool can connect and correctly dump the screen.

bug:7694696

3. Removed the partial implementation for multi display magnification. It adds
unnecessary complexity since it cannot be implemented without support for
input from multiple screens. We will revisit when necessary.

4. Moved the magnified border window as a surface in the window manager.

5. Moved the mediator APIs on the window manager and the policy methods on the
WindowManagerPolicy.

6. Implemented batch event processing for the accessibility input filter.

Change-Id: I4ebf68b94fb07201e124794f69611ece388ec116
/frameworks/base/services/java/com/android/server/accessibility/AccessibilityInputFilter.java
152e9bb81aa5b2ab4637f4b2dae04b3ce89fa891 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/services/java/com/android/server/accessibility/AccessibilityInputFilter.java
45af84a483165f06c04d74baba67f90da29c6ad2 02-Oct-2012 Svetoslav Ganov <svetoslavganov@google.com> Touch explorer and magnifier do not work well together.

1. If tocuh exploration and screen magnification are enabled and the screen
is currently magnified, gesture detection does not work well. The reason
is because we are transforming the events if the screen is magnified before
passing them to the touch explorer to compensate for the magnification so
the user can poke what he thinks he pokes. However, when doing gesture
detection/velocity computing this compensating shrinks the gestured shape/
decreases velocity leading to poor gesture reco/incorrect velocity.

This change adds a onRawMotionEvent method in the event transformation chain
which will process the raw touch events. In this method of the touch explorer
we are passing events to the gesture recognized and the velocity tracker.

2. Velocity tracker was not cleared on transitions out of touch exploring state
which is the only one that uses velocity.

bug:7266617

Change-Id: I7887fe5f3c3bb6cfa203b7866a145c7341098a02
/frameworks/base/services/java/com/android/server/accessibility/AccessibilityInputFilter.java
1cf70bbf96930662cab0e699d70b62865766ff52 06-Aug-2012 Svetoslav Ganov <svetoslavganov@google.com> Screen magnification - feature - framework.

This change is the initial check in of the screen magnification
feature. This feature enables magnification of the screen via
global gestures (assuming it has been enabled from settings)
to allow a low vision user to efficiently use an Android device.

Interaction model:

1. Triple tap toggles permanent screen magnification which is magnifying
the area around the location of the triple tap. One can think of the
location of the triple tap as the center of the magnified viewport.
For example, a triple tap when not magnified would magnify the screen
and leave it in a magnified state. A triple tapping when magnified would
clear magnification and leave the screen in a not magnified state.

2. Triple tap and hold would magnify the screen if not magnified and enable
viewport dragging mode until the finger goes up. One can think of this
mode as a way to move the magnified viewport since the area around the
moving finger will be magnified to fit the screen. For example, if the
screen was not magnified and the user triple taps and holds the screen
would magnify and the viewport will follow the user's finger. When the
finger goes up the screen will clear zoom out. If the same user interaction
is performed when the screen is magnified, the viewport movement will
be the same but when the finger goes up the screen will stay magnified.
In other words, the initial magnified state is sticky.

3. Pinching with any number of additional fingers when viewport dragging
is enabled, i.e. the user triple tapped and holds, would adjust the
magnification scale which will become the current default magnification
scale. The next time the user magnifies the same magnification scale
would be used.

4. When in a permanent magnified state the user can use two or more fingers
to pan the viewport. Note that in this mode the content is panned as
opposed to the viewport dragging mode in which the viewport is moved.

5. When in a permanent magnified state the user can use three or more
fingers to change the magnification scale which will become the current
default magnification scale. The next time the user magnifies the same
magnification scale would be used.

6. The magnification scale will be persisted in settings and in the cloud.

Note: Since two fingers are used to pan the content in a permanently magnified
state no other two finger gestures in touch exploration or applications
will work unless the uses zooms out to normal state where all gestures
works as expected. This is an intentional tradeoff to allow efficient
panning since in a permanently magnified state this would be the dominant
action to be performed.

Design:

1. The window manager exposes APIs for setting accessibility transformation
which is a scale and offsets for X and Y axis. The window manager queries
the window policy for which windows will not be magnified. For example,
the IME windows and the navigation bar are not magnified including windows
that are attached to them.

2. The accessibility features such a screen magnification and touch
exploration are now impemented as a sequence of transformations on the
event stream. The accessibility manager service may request each
of these features or both. The behavior of the features is not changed
based on the fact that another one is enabled.

3. The screen magnifier keeps a viewport of the content that is magnified
which is surrounded by a glow in a magnified state. Interactions outside
of the viewport are delegated directly to the application without
interpretation. For example, a triple tap on the letter 'a' of the IME
would type three letters instead of toggling magnified state. The viewport
is updated on screen rotation and on window transitions. For example,
when the IME pops up the viewport shrinks.

4. The glow around the viewport is implemented as a special type of window
that does not take input focus, cannot be touched, is laid out in the
screen coordiates with width and height matching these of the screen.
When the magnified region changes the root view of the window draws the
hightlight but the size of the window does not change - unless a rotation
happens. All changes in the viewport size or showing or hiding it are
animated.

5. The viewport is encapsulated in a class that knows how to show,
hide, and resize the viewport - potentially animating that.
This class uses the new animation framework for animations.

6. The magnification is handled by a magnification controller that
keeps track of the current trnasformation to be applied to the screen
content and the desired such. If these two are not the same it is
responsibility of the magnification controller to reconcile them by
potentially animating the transition from one to the other.

7. A dipslay content observer wathces for winodw transitions, screen
rotations, and when a rectange on the screen has been reqeusted. This
class is responsible for handling interesting state changes such
as changing the viewport bounds on IME pop up or screen rotation,
panning the content to make a requested rectangle visible on the
screen, etc.

8. To implement viewport updates the window manger was updated with APIs
to watch for window transitions and when a rectangle has been requested
on the screen. These APIs are protected by a signature level permission.
Also a parcelable and poolable window info class has been added with
APIs for getting the window info given the window token. This enables
getting some useful information about a window. There APIs are also
signature protected.

bug:6795382

Change-Id: Iec93da8bf6376beebbd4f5167ab7723dc7d9bd00
/frameworks/base/services/java/com/android/server/accessibility/AccessibilityInputFilter.java
c9c9a48e7bafae63cb35a9aa69255e80aba83988 16-Jul-2012 Svetoslav Ganov <svetoslavganov@google.com> Removing a workaround for incorrect window position on window move.

1. The window manager was not notifying a window when the latter
has been moved. This was causing incorrect coordinates of the
nodes reported to accessibility services. To workaround that
we have carried the correct window location when making a
call from the accessibility layer into a window. Now the
window manager notifies the window when it is moved and the
workaround is no longer needed. This change takes it out.

2. The left and right in the attach info were not updated properly
after a report that the window has moved.

3. The accessibility manager service was calling directly methods
on the window manager service without going through the interface
of the latter. This leads to unnecessary coupling and in the
long rung increases system complexity and reduces maintability.

bug:6623031

Change-Id: Iacb734b1bf337a47fad02c827ece45bb2f53a79d
/frameworks/base/services/java/com/android/server/accessibility/AccessibilityInputFilter.java
ee33ad24cdc31ed0d7f99e110e041b0a63c9b0f1 09-Jun-2012 Svetoslav Ganov <svetoslavganov@google.com> Settings crash after enabling TalkBack accessibility.

1. AccessibilityInput filter was not checking whether the touch
explorer instance is not null before passing it an accessibility
event. If the accessibility event is dispatched before the input
filter is installed but after it is created we runt into this
case.

2. Added a missing null check in accessibility node info.

bug:6635089

Change-Id: Ia389dc1f427427eb73794f6331ccb870e0b44c55
/frameworks/base/services/java/com/android/server/accessibility/AccessibilityInputFilter.java
86783474fdec98a22bc22e224462767eab13e273 07-Jun-2012 Svetoslav Ganov <svetoslavganov@google.com> Cannot interact with dialogs when IME is up and on not touch explored popups.

1. If the last touch explored location is within the active window we
used to click on exact location if it is within the accessibility
focus otherwise in the accessibility focus center. If the last touch
explored location is not within the active window we used to just
click there. This breaks in the case were one has touch explored
at a given place in the current window and now a dialog opens *not*
covering the touch explored location. If one uses swipes to move
accessibility focus i.e. to traverse the dialog without touching
it one cannot activate anything because the touch explorer is using
the last touch explored location that is outside of the active
window e.g the dialog.

The solution is to clear the last touch explored location when a
window opens or accessibility focus moves. If the last touch
explored location is null we are clicking in the accessibility
focus location.

bug:6620911

2. There is a bug in the window manager that does not notify a
window that its location has changed (bug:6623031). This breaks
accessibility interaction with dialogs that have input because
when the IME is up the dialog is moved but not notified. Now
the accessibility layer gets incorrect location for the
accessibility focus and the window bounds.

The soluion is when the accessibility manager service calls
into the remove thress to obtain some accessibility node infos
it passes the window left and top which it gets from the
window manager. These values are used to update the attach info
window left and top so all accessibility node infos emitted
from that window had correct bounds in screen coordinates.

bug:6620796

Change-Id: I18914f2095c55cfc826acf5277bd94b776bda0c8
/frameworks/base/services/java/com/android/server/accessibility/AccessibilityInputFilter.java
e15ccb93add99ebb9cd7aec03a04faa37f45b39d 17-May-2012 Svetoslav Ganov <svetoslavganov@google.com> Changing the interaction model of the touch explorer.

1. Now the user have to double tap to activate the last
item. If the last touched window is not active because
it does not take input focus the click on the last
touch explored location. Othewise the click is on the
accessibility focus location.

bug:5932640

Change-Id: Ibb7b97262a7c5f2f94abef429e02790fdc91a8dd
/frameworks/base/services/java/com/android/server/accessibility/AccessibilityInputFilter.java
d1ff736d01cebaee70b76f012b660ae549c252b9 15-May-2012 Svetoslav Ganov <svetoslavganov@google.com> Keeping the screen on during gesture detection.

1. During gesture detection we are not injecting the events we receive
since we do not want the accessibility focus to move as a result of
the hover event of the gesture. Because of that it was possible that
we consume all events since the user performs only gesture to navigate
resulting in the screen being off while the user is actively interacting
with the device. Now we are poking the user activity in the power
manager to keep the screen on.

bug:6485171

Change-Id: I06a09c5297f01bef5e20d471cee76fa7aae0c4fe
/frameworks/base/services/java/com/android/server/accessibility/AccessibilityInputFilter.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/services/java/com/android/server/accessibility/AccessibilityInputFilter.java
4532e6158474a263d9d26c2b42240bcf7ce9b172 05-Apr-2012 Jeff Brown <jeffbrown@google.com> Refactor input system into its own service.

Extracted the input system from the window manager service into
a new input manager service. This will make it easier to
offer new input-related features to applications.

Cleaned up the input manager service JNI layer somewhat to get rid
of all of the unnecessary checks for whether the input manager
had been initialized. Simplified the callback layer as well.

Change-Id: I3175d01307aed1420780d3c093d2694b41edf66e
/frameworks/base/services/java/com/android/server/accessibility/AccessibilityInputFilter.java
3e4e4af45216aee4d4b009fe842c0324610918eb 05-Aug-2011 Svetoslav Ganov <svetoslavganov@google.com> Turning off accessibility feature reboots the device

1. The touch explorer uses delayed injection of events
which can happen after its hosting accessibility
input filer has been unregistered, thus the explorer
was trying to inject events when this is not allowed.
Now upon unregistration of the accessibility explorer
it resets the state of the touch explorer it hosts.

bug:5105956

Change-Id: I720682abf93382aedf4f431eaac90fd2c781e442
/frameworks/base/services/java/com/android/server/accessibility/AccessibilityInputFilter.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/services/java/com/android/server/accessibility/AccessibilityInputFilter.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/services/java/com/android/server/accessibility/AccessibilityInputFilter.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/services/java/com/android/server/accessibility/AccessibilityInputFilter.java
0029c66203ab9ded4342976bf7a17bb63af8c44a 30-Mar-2011 Jeff Brown <jeffbrown@google.com> Add input filter mechanism for accessibility.

This patch adds a mechanism for capturing, filtering, transforming
and injecting input events at a very low level before the input
dispatcher attempts to deliver them to applications. At this time,
the mechanism is only intended to be used by the accessibility
system to implement built-in system-level accessibility affordances.

The accessibility input filter is currently just a stub.
It logs the input events receives and reinjects them unchanged,
except that it transforms KEYCODE_Q into KEYCODE_Z.

Currently, the accessibility input filter is installed whenever
accessibility is enabled. We'll probably want to change that
so it only enables the input filter when a screen reader is
installed and we want touch exploration.

Change-Id: I35764fdf75522b69d09ebd78c9766eb7593c1afe
/frameworks/base/services/java/com/android/server/accessibility/AccessibilityInputFilter.java