Re: [android-developers] why is onDoubleTap being called before second tup's up action?
( will try responding at the bottom for a change ) 21 января 2012 г. 2:38 пользователь skink написал: > > > Kostya Vasilyev wrote: > > Have you tried using MotionEvent.ACTION_CANCEL in the double-tap > listener? > > > > GestureDetector has code to reset its internal state in response to this: > > > > > https://github.com/android/platform_frameworks_base/blob/master/core/java/android/view/GestureDetector.java#L594 > > > > I'm thinking you'd need post a handler message to self to get out of the > > current stack state when onDoubleTap is called, and then in response to > > that message, use ACTION_CANCEL to reset the gesture listener and then > > start the activity. > > > > -- Kostya > > > > Kostya, > > do you mean that in onDoubleTap (MotionEvent e) listener I should > modify "e" by: > > e.setAction(MotionEvent.ACTION_CANCEL) > > and then "feed" gesture detector with that modified event? > No, that won't get you out of the call chain that exists when your onDoubleTap is called: https://github.com/android/platform_frameworks_base/blob/master/core/java/android/view/GestureDetector.java#L488 There is code in GestureDetector's onTouchEvent after the call to onDoubleTap, and replacing the event's action will do nothing to skip it. The switch at line 468 won't go back to be re-evaluated, etc. > > but if it cancels internal state of detector why to use a Handler? > To return from your onDoubleTap listener to the gesture detector's onTouchEvent, let it execute the rest of its code, and only then send the cancel event to reset its state. > > btw I already tried in onDoubleTap to post Runnable that starts > activity and it worked well but I decided it's dirty workaround - > that's why I used onDoubleTapEvent > That's pretty similar to what I was suggesting, and also unwinds the call chain from the double-tap listener call. Perhaps the framework sends a cancel event in this case -- or perhaps your letting go after the double tap has time to register. I'd do a test to find out, keeping the finger down after the double-tap's second touch. If the gesture detector still works Ok after returning back to this activity (like your original email mentioned), good. If it doesn't, it would mean that you were just getting lucky with the timing of the second up event, and that sending a cancel is still necessary. Hope this makes sense. -- Kostya > > pskink > > -- > You received this message because you are subscribed to the Google > Groups "Android Developers" group. > To post to this group, send email to android-developers@googlegroups.com > To unsubscribe from this group, send email to > android-developers+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/android-developers?hl=en > -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
Re: [android-developers] why is onDoubleTap being called before second tup's up action?
Kostya Vasilyev wrote: > Have you tried using MotionEvent.ACTION_CANCEL in the double-tap listener? > > GestureDetector has code to reset its internal state in response to this: > > https://github.com/android/platform_frameworks_base/blob/master/core/java/android/view/GestureDetector.java#L594 > > I'm thinking you'd need post a handler message to self to get out of the > current stack state when onDoubleTap is called, and then in response to > that message, use ACTION_CANCEL to reset the gesture listener and then > start the activity. > > -- Kostya > Kostya, do you mean that in onDoubleTap (MotionEvent e) listener I should modify "e" by: e.setAction(MotionEvent.ACTION_CANCEL) and then "feed" gesture detector with that modified event? but if it cancels internal state of detector why to use a Handler? btw I already tried in onDoubleTap to post Runnable that starts activity and it worked well but I decided it's dirty workaround - that's why I used onDoubleTapEvent pskink -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
Re: [android-developers] why is onDoubleTap being called before second tup's up action?
Have you tried using MotionEvent.ACTION_CANCEL in the double-tap listener?
GestureDetector has code to reset its internal state in response to this:
https://github.com/android/platform_frameworks_base/blob/master/core/java/android/view/GestureDetector.java#L594
I'm thinking you'd need post a handler message to self to get out of the
current stack state when onDoubleTap is called, and then in response to
that message, use ACTION_CANCEL to reset the gesture listener and then
start the activity.
-- Kostya
20 января 2012 г. 17:37 пользователь skink написал:
> hi,
>
> i'm using GestureDetector to detect double tup actions and having a
> little problem when trying to startActivity() inside onDoubleTap
> listener.
>
> namely i have observed when onDoubleTap is empty i see the following:
>
> D/GestureActivity( 987): onTouchEvent action=0
> D/GestureActivity( 987): onTouchEvent action=1
> D/GestureActivity( 987): onTouchEvent action=0
> D/GestureActivity( 987): onDoubleTap
> D/GestureActivity( 987): onTouchEvent action=1
>
> here action == 0 for ACTION_DOWN, while action == 1 for ACTION_UP
>
> as you can see onDoubleTap is being called after second tups's
> ACTION_DOWN and before its ACTION_UP, strange but OK
>
> but when i call startActivity() in onDoubleTap listener i see:
>
> D/GestureActivity( 1019): onTouchEvent action=0
> D/GestureActivity( 1019): onTouchEvent action=1
> D/GestureActivity( 1019): onTouchEvent action=0
> D/GestureActivity( 1019): onDoubleTap
> D/GestureActivity( 1019): onPause
>
> as you can see there is missing second ACTION_UP (i think it's because
> my main activity is paused and doesn't handle touch events) and when i
> return back to my main activity GestureDetector is somehow mislead and
> behaves a bit strange
>
> in the end i used onDoubleTapEvent (instead of onDoubleTap) like this:
> public boolean onDoubleTapEvent(MotionEvent e) {
>if (e.getAction() == MotionEvent.ACTION_UP) {
>// start activity here
>}
> }
>
> and it works OK but i'm still not sure if it's a good solution
>
> any ideas how to use onDoubleTap in my scenario?
>
> pskink
>
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[android-developers] why is onDoubleTap being called before second tup's up action?
hi,
i'm using GestureDetector to detect double tup actions and having a
little problem when trying to startActivity() inside onDoubleTap
listener.
namely i have observed when onDoubleTap is empty i see the following:
D/GestureActivity( 987): onTouchEvent action=0
D/GestureActivity( 987): onTouchEvent action=1
D/GestureActivity( 987): onTouchEvent action=0
D/GestureActivity( 987): onDoubleTap
D/GestureActivity( 987): onTouchEvent action=1
here action == 0 for ACTION_DOWN, while action == 1 for ACTION_UP
as you can see onDoubleTap is being called after second tups's
ACTION_DOWN and before its ACTION_UP, strange but OK
but when i call startActivity() in onDoubleTap listener i see:
D/GestureActivity( 1019): onTouchEvent action=0
D/GestureActivity( 1019): onTouchEvent action=1
D/GestureActivity( 1019): onTouchEvent action=0
D/GestureActivity( 1019): onDoubleTap
D/GestureActivity( 1019): onPause
as you can see there is missing second ACTION_UP (i think it's because
my main activity is paused and doesn't handle touch events) and when i
return back to my main activity GestureDetector is somehow mislead and
behaves a bit strange
in the end i used onDoubleTapEvent (instead of onDoubleTap) like this:
public boolean onDoubleTapEvent(MotionEvent e) {
if (e.getAction() == MotionEvent.ACTION_UP) {
// start activity here
}
}
and it works OK but i'm still not sure if it's a good solution
any ideas how to use onDoubleTap in my scenario?
pskink
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