Doubletap + Storyboard

Games
#1

Hello folks,

I’ve got a small problem. Let me describe what I want to do. I am doing a picture book using storyboard API. I have a couple of arrows to navigate between pages. I don’t want to have a home button. Therefore I came up with an idea - if a user singel taps an arrow, next page is shown. But double tap would show the first page.

The issue is that there is no event “doubletap” only “tap”. There is of cause numTaps. But if a user double taps an object the tap even is called 2 times: first where numTaps = 1 and second with numTaps = 2.

I thought I could manage this as follows (please note this is not a complete code)

  
local numTaps  
local timerStash = {}  
  
local function goToScene()  
 if numTaps \> 1 then  
 timer.cancel(timerStash[1])  
 storyboard.gotoScene(true, "firstPage", effect, 500)  
 else  
 storyboard.gotoScene(true, nextPage, effect, 500)  
 end  
end  
  
local function turnPage(event)  
 numTaps = event.numTaps  
  
 table.insert(timerStash, timer.performWithDelay(350, goToScene, 1))  
end

But this thing just crashes.

Please help. Thanks in advance. [import]uid: 40334 topic_id: 20908 reply_id: 320908[/import]

#2

Try this:

 local previousTapTime = 0  
 tapAbsorber = display.newRect(0,0,display.contentWidth,display.contentHeight)  
  
 local function tapAbsorberHandler(event)  
 print("event.phase", event.phase)  
--  
-- in my app this is sitting on top of a scroll view (sv) and I want  
-- any movement gestures to go to the scroll view.  
-- the "ended" phase has the double tap code in it.  
--  
 if event.phase == "moved" then  
 if math.abs(event.xStart - event.x) \> 5 or math.abs(event.yStart - event.y) then   
 sv:takeFocus(event)  
 return true  
 end  
 elseif event.phase == "ended" then  
 print("e.time - ptt", event.time - previousTapTime)  
 if (event.time - previousTapTime) \< 300 then -- double tap so close  
 print("double tap")  
 storyboard.gotoScene(previousScene)  
 return true  
 end  
 previousTapTime = event.time  
 end  
 return true  
 end  
 tapAbsorber:setReferencePoint(display.TopLeftReferencePoint)  
 tapAbsorber.x = 0  
 tapAbsorber.y = 0  
 tapAbsorber.alpha = 0  
 tapAbsorber.isHitTestable = true  
 tapAbsorber:addEventListener("touch", tapAbsorberHandler)  
 group:insert(tapAbsorber)

You have to use a touch handler, not a tap handler since I don’t think the event.time is passed on tap. [import]uid: 19626 topic_id: 20908 reply_id: 82473[/import]

#3

Thank you. Unfortunately it’s the same issue here. Your code is handeling only double tap. My problem is that I need to handle both single and double-tap. What happens is that both events are caught. So I need somehow to cancel an action of the first event if double-tap is detected. I just can’r figure out how to do that. [import]uid: 40334 topic_id: 20908 reply_id: 84907[/import]

#4 
 local function tapAbsorberHandler(event)  
 print("event.phase", event.phase)  
--  
-- in my app this is sitting on top of a scroll view (sv) and I want  
-- any movement gestures to go to the scroll view.  
-- the "ended" phase has the double tap code in it.  
--  
 if event.phase == "moved" then  
 if math.abs(event.xStart - event.x) \> 5 or math.abs(event.yStart - event.y) then   
 sv:takeFocus(event)  
 return true  
 end  
 elseif event.phase == "ended" then  
 print("e.time - ptt", event.time - previousTapTime)  
 if (event.time - previousTapTime) \< 300 then -- double tap so close  
--  
-- do what you need to on a double tap for example  
--  
 print("double tap")  
 storyboard.gotoScene(previousScene)  
 return true  
--  
-- added this bit  
--   
 else  
--  
-- do whatever you want to do on a single tap  
--  
 end  
 previousTapTime = event.time  
 end  
 return true  
 end

[import]uid: 19626 topic_id: 20908 reply_id: 84961[/import]

#5

Well. I want to switch scenes both when i tap and double-tap. So this suggestion doesn’t work. The reason is that if a switch begins during first tap, the second one never registeres. But I finally solved it. Here’s how

[code]
local nextScene
local timer1, timer2
local gfp = false

– go to next scene cancel all timers
local function goToNextScen()
storyboard.gotoScene(true, nextScene, effect, 500)

if timer1 then
timer.cancel(timer1)
end
if timer2 then
timer.cancel(timer2)
end
return true
end

– turn page
local function turnPage(event)

if event.phase == “ended” then
– if double-tap
if event.time - previousTapTime < 300 then
– we can go to first page
gfp = true
– fix what needed to be done to go to first page
nextScene = “firstPage”
else
– do not go to first page
gfp = fale
– fix what needed to be done to go to next page
nextScene = …
end

– now this event will be called twice for each tap.
– so we start to actually change to new scene first after 300 ms
– if during that time double-tap happens, we cancel the first call
– now we can go to first page
if gfp then
timer.cancel(timer1)
timer2 = timer.performWithDelay(300, goToNextScen, 1)
else
timer1 = timer.performWithDelay(300, goToNextScen, 1)
end

previousTapTime = event.time
end

return true
end

[/code] [import]uid: 40334 topic_id: 20908 reply_id: 85001[/import]

#6

Yogamatta, does this incur a delay after the taps before there is a response (300 milliseconds)?

I’m trying to write a routine that detects doubletaps without a delay (that doesn’t also trigger single tap response), if possible.

Thanks,
Eric [import]uid: 128346 topic_id: 20908 reply_id: 95174[/import]

#7

Well, there is a delay of cause. But there was a major delay bug with storyboard and transitions. With Those 2 delays combining it was very noticible. But I haven’t had a chance to test with the latest fix and see how it looks like only with 300ms delay.

I don’t think there is a way to solve it without a delay. If you find one, please share the solution. Good luck. [import]uid: 40334 topic_id: 20908 reply_id: 95212[/import]

#8

It’s a dilemna (if you don’t want a delay for a tap), because you have to wait to see if a double tap happens before you respond to the single tap!

Besides using tachyons that tunnel backward through time, I don’t know what the solution would be. :slight_smile:

But maybe I’m just not seeing it …
I will keep you posted.

By the way, I used 200 milliseconds in my solution, and it seems fine. YMMV.

Thanks

Eric [import]uid: 128346 topic_id: 20908 reply_id: 95225[/import]