Adding accessibility events for touch and gesture detection states.
1. Currently the system fires accessibility events to announce the
start and end of a touch exploration gesture. However, such a
gesture starts after we have decided that the user is not
performing a gesture which is achieved by measuring speed of
movement during a threshold distance. This allows an accessibility
service to provide some feedback to the user so he knows that
he is touch exploring.
This change adds event types for the first and last touches
of the user. Note that the first touch does not conincide with
the start of a touch exploration gesture since we need a time
or distance to pass before we know whether the user explores
or gestures. However, it is very useful for an accessibility
service to know when the user starts to interact with the
touch screen so it can turn the speech off, to name one
compelling use case.
This change also provides event types for the start and end
of gesture detection. If the user has moved over the threshold
with a speed greater than X, then the system detects gestures.
It is useful for an accessibility service to know the begin
and end of gesture detection so it can provide given feedback
type for such a gesture, say it may produce haptic feedback
or sound that differs for the one for touch exploration.
The main benefit of announcing these new events is that an
accessibility service can provide feedback for each touch
state allowing the user to always know what he is doing.
bug:7166935
Change-Id: I26270d774cc059cb921d6a4254bc0aab0530c1dd
4 files changed