Other Strange behaviour on panel touch event

udg

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Hi all,

I am experiencing what seems a strange or unexpected behaviour on my Samsung Galaxy Tab 2 (GT-P5100) tablet.
Executing the following code it results always in whole values (both X and Y).
Only placing-moving-lifting a finger on the panel leads to decimal values on the UP action (Down stays integer). What happens on your devices and, most important, how do you explain this case?
B4X:
Sub Process_Globals
End Sub

Sub Globals
   Dim pnlTest As Panel
End Sub

Sub Activity_Create(FirstTime As Boolean)
   pnlTest.Initialize("test")
   Activity.AddView(pnlTest,10dip,10dip,200dip,200dip)
   pnlTest.Color = Colors.Red
End Sub

Sub Activity_Resume
End Sub

Sub Activity_Pause (UserClosed As Boolean)
End Sub

Sub test_Touch (Action As Int, X As Float, Y As Float)
  Select Action
  Case pnlTest.ACTION_DOWN
     Log("Down -> X: "&X&" Y: "&Y)
  Case pnlTest.ACTION_UP
     Log("UP -> X: "&X&" Y: "&Y)
  Case pnlTest.ACTION_MOVE
     Log("Moving -> X: "&X&" Y: "&Y)
  Case Else
     Log("other action")
  End Select
  Return True
End Sub

After a few touches here and there, my log results in:

B4X:
Down -> X: 97 Y: 74
UP -> X: 97 Y: 74
Down -> X: 170 Y: 169
UP -> X: 170 Y: 169
Down -> X: 50 Y: 159
UP -> X: 50 Y: 159
Down -> X: 133 Y: 197
Moving -> X: 138.03152465820313 Y: 183.91806030273438
Moving -> X: 143.3489227294922 Y: 171.96493530273438
Moving -> X: 147.5701141357422 Y: 166.64483642578125
Moving -> X: 148.5677032470703 Y: 163.8645782470703
Moving -> X: 149.5 Y: 162
Moving -> X: 150.2666778564453 Y: 160.46664428710938
UP -> X: 150.2666778564453 Y: 160.46664428710938
Down -> X: 154 Y: 52
UP -> X: 154 Y: 52
** Activity (main) Pause, UserClosed = true **

TIA for your help and comments.

udg

ps: btw, Panel documentation doesn't show "boolean" as the returning type for Touch function; should it be added in any case?
 
Last edited:

LucaMs

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This is really strange, it probably just depends on the model of your device.
If so, you have no other solution than to cast the variables.

I want to add a strange behavior of my smartphone, both in this case and in other.

In this case, if I use your example maintaining the smartphone connected via USB, both in release and debug mode, I get even values 261 or 262 for Action! This does not happen when my smartphone is not connected to the PC.

I have not found an optimally USB driver for my device and this is the reason.
 
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Erel

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ps: btw, Panel documentation doesn't show "boolean" as the returning type for Touch function; should it be added in any case?
No. There is no return value (there was in the past).

About the whole numbers. I don't have a good explanation for that however the numbers come from the native API directly.

I also recommend you to see this thread to understand how the touch event is delivered: http://www.b4x.com/android/forum/th...touchevent-and-panel_touch.44711/#post-273217
 
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udg

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Hi Luca,

thank you for your feedback.
Our findings seem to lead to an unpredictable numeric type for the coordinates served by the Touch function.
Maybe it is a problem/bug in Android itself while converting the X,Y values to whole numbers right after entering the function at least makes them consistent on all the devices.
Now my fear is: is this platform so unreliable not to be able to stay with consistent results even in its own coordinate system?

Edit: I just saw Erel's post and I'm going to study it.
 
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udg

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Hi Erel,

I was aware of the Reflection trick about the Touch event and used it with success before.
Do you recommend to stick with it and forget about panel_Touch?

For those who don't know what I'm talking about, it is:
B4X:
Dim r AsReflector
 r.Target = panel1
 r.SetOnTouchListener("Panel1_Touch") 'why reflection instead of the regular Panel_Touch event? Good question which deserves a forum thread of its own (not related to classes)...

Please have a more complete example here.

Umberto
 
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udg

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does it matter if it is not rounded?

I guess it depends on its uses.
I discovered this issue while using my dgActionBar library to serve iconized options for a simple game. On my device everything worked as expected but others reported the "touch" event not working (so no options for them..).
The reason they found a not working event was that I required DOWN and UP values to be identical, and where decimals are served this is uncommon.

I understand that I could (and probably should) simply allow for a minimum difference between Down and Up values and still interpret it as a click on the icon, but the whole case surprised me. That's it.

Umberto
 
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sorex

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is this the same issue that makes dragging an object the "normal" way shocky? like it loses contact due to the movement.
 
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udg

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You forget that my hand is as still as the one of a neurosurgeon :)
And since we live in a tech society I could add as still as that of a robotic arm!
That means my Down and Up values will always be the same..no need for any "distance" factor yet.. eh eh

Seriously now, thanks for your support.
 
Last edited:
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LucaMs

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You should definitely check for the distance and not rely on the same exact value.

B4X:
Dim Dist As Float = sqrt(Power(x - prevX, 2) + Power(y - prevY, 2))
If Dist < 10dip Then
Log("click")
End If


Yes, this was my first thought: it is not reasonable to think of touch a single pixel using a finger.

But using an emulator and a mouse, for example, you can (or simply those little pen of plastic we used in the past).

But the main point is really strange: receive INTs instead of FLOATs as parameters!!!

I think this is a problem of that tablet
 
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Beja

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I I am not sure, but since you have initialized pnltest by just test, then how would you use a combination of both later?
 
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udg

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Hi Beja,

I'm not sure to understand your question.
Pnltest is the only object involved and it is a panel.
test is the name I gave to its event in order to catch the touch event like test_Touch.
Naming that event "myevent", it would result in myevent_touch raised when a touch action is sensed on pnltest.

But I'm sure you know all this, so I definitely must have missed your point.

Umberto
 
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