Sometimes quickly touching the screen with two fingers will result
in the firmware thinking one finger moved very quickly. This code
tries to identify the difference between the two based on velocity
of the last N points versus the velocity of the last M points and
figure out if there was mostly acceleration or a sudden deceleration.
It's still not perfect and very dependent on the touch hardware.
This takes care of allowing us to cancel the back button. The
back button is a bear because it is strewn all over the place --
everywhere you can close something, there is some code looking
for the back button that now needs to deal with being canceled.
The main things changed are activity (of course), dialog,
input method, search dialog. There are some other misc places
in the framework (and some I missed here that I will get in a
second pass).
To facility all of this, the key dispatching APIs now provide
a lot more support for dealing with looking for cancelled keys,
and incidentally also provide an actual API for catching long
key presses. This also helped clean up the code in PhoneWindow
where it deals with all of the combinations of key pressed and
releases. (And also allows people to override
Activity.onKeyLongPress() to provide a different long press
action for a standard key like search.)
And while I was doing this, I reworked how we detect long
presses by having this be part of the key event delivered by
the window manager. This should greatly reduce (hopefully
outright eliminate) the problems with long presses being
mis-detected when an application is being slow.
Change-Id: Ia19066b8d588d573df3eee6d96e1c90fdc19f57d
* Keyboard should use DisplayMetrics from Resource rather than getting it from WindowManager as
the display metrics can differ under compatibility mode.
