Trouble getting x and y position, on a canvas

SlavaVB · Nov 4, 2011

Hi, i wrote an app recently that tells you the x and y of the place where you touch the screen, however it doesn't work if there's a canvas on top of it. Any ideas or suggestions?

Thanks!

klaus · Nov 4, 2011

... however it doesn't work if there's a canvas on top of it.

What do you mean with this? A canvas cannot hide anything directly.
A canvas has a target view, and it's this view that could hide something. But what target view do you have?
You must be much more precise on the conditions, on what you expect and what really doesn't work. The best way would be to post your project as a zip file with more detailed explanations.

Best regards.

SlavaVB · Nov 4, 2011

The source code and a screen capture...

Sub Process_Globals

End Sub

Sub Globals
Dim Canvas1 As Canvas

End Sub

Sub Activity_Create(FirstTime As Boolean)
canvas1.Initialize(Activity)
Globe
End Sub

Sub Globe

Dim xx(100) As Double
Dim yy(100) As Double
Dim vx(100) As Double
Dim vy(100) As Double
Dim ax(100) As Double
Dim ay(100) As Double
Dim r(100) As Double
Dim dt As Double

Dim w As Double
Dim h As Double
Dim diffx As Double
Dim diffy As Double
Dim dist1 As Double
Dim dist2 As Double

Dim xval As Double
Dim yval As Double

w = Canvas1.Bitmap.Width
h = Canvas1.Bitmap.Height

xx(0) = w/2
yy(0) = h/2
vx(0) = Rnd(-5,5)
vy(0) = Rnd(-5,5)
ax(0) = 0
ay(0) = 0
r(0) = 100

For i = 1 To 99
xx(i) = Rnd(0,w)
yy(i) = Rnd(0,h)
vx(i) = Rnd(-20,20)
vy(i) = Rnd(-20,20)
ax(0) = 0
ay(0) = 0
r(i) = Rnd(10,15)
Next

dt = .1

For a = 1 To 1000000

For i = 0 To 99

For j = 0 To 99
ax(j) = 0.0;
ay(j) = 0.0;
Next

For j = 0 To 99

If i <> j Then
diffx = xx(i) - xx(j)
diffy = yy(i) - yy(j)
dist1 = Sqrt(Power(diffx,2)+Power(diffy,2))
dist2 = r(i) + r(j)

If dist1 < dist2 Then
deltaDistance = (dist2 - dist1)

xval = (((deltaDistance * 10.0) / dist2) * diffx)
yval = (((deltaDistance * 10.0) / dist2) * diffy)

ax(i) = ax(i) + xval
ay(i) = ay(i) + yval

End If

End If
Next

vx(i) = (vx(i) + (ax(i) * dt)) *.999
vy(i) = (vy(i) + (ay(i) * dt)) *.999
xx(i) = xx(i) + (vx(i) * dt)
yy(i) = yy(i) + (vy(i) * dt)

If xx(i)-r(i) < 0 Then
vx(i) = -vx(i)
xx(i) = 0 + r(i)
End If
If yy(i)-r(i) < 0 Then
vy(i) = -vy(i)
yy(i) = 0 + r(i)
End If
If xx(i)+r(i) > w Then
vx(i) = -vx(i)
xx(i) = w - r(i)
End If
If yy(i)+r(i) > h Then
vy(i) = -vy(i)
yy(i) = h - r(i)
End If

Next

Canvas1.DrawColor(Colors.Black)

Canvas1.DrawCircle(xx(0),yy(0),r(0),Colors.Red,True,5)
For i = 1 To 99
Canvas1.DrawCircle(xx(i),yy(i),r(i),Colors.Green,True,5)
Next
Activity.Invalidate
DoEvents

Next

End Sub

screen capture on youtube... /watch?v=XpvudNE_82E

SlavaVB · Nov 4, 2011

I tried...

Sub Activity_Touch (Action As Int, X As Float, Y As Float)
Msgbox("it works!","")
End Sub

but it doesnt get called when i touch the screen

SlavaVB · Nov 4, 2011

Another question... do you know how to make infinite loops?

i tried do while true ... loop

but it couldn't see the end sub, because of it, so instead i used..

For a = 1 To 1000000 ... next

is there another way to loop infinitly?

Thanks

thedesolatesoul · Nov 4, 2011

SlavaVB said:
Another question... do you know how to make infinite loops?

i tried do while true ... loop

but it couldn't see the end sub, because of it, so instead i used..

For a = 1 To 1000000 ... next

is there another way to loop infinitly?

Thanks

Use a Timer.

SlavaVB · Nov 4, 2011

Do you know how to handle the touch event?

SlavaVB · Nov 4, 2011

I just redid my app to run off a timer, but now i cant get it to compile, i moved the declarations up to the top, so that they are non volatile. heres my code now....

Sub Process_Globals
Dim Timer1 As Timer

Dim xx(100) As Double
Dim yy(100) As Double
Dim vx(100) As Double
Dim vy(100) As Double
Dim ax(100) As Double
Dim ay(100) As Double
Dim r(100) As Double
Dim dt As Double

Dim w As Double
Dim h As Double
Dim diffx As Double
Dim diffy As Double
Dim dist1 As Double
Dim dist2 As Double

Dim xval As Double
Dim yval As Double

End Sub

Sub Globals
Dim Canvas1 As Canvas

End Sub

Sub Activity_Create(FirstTime As Boolean)
canvas1.Initialize(Activity)

Globe
End Sub

Sub Globe

w = Canvas1.Bitmap.Width
h = Canvas1.Bitmap.Height

xx(0) = w/2
yy(0) = h/2
vx(0) = Rnd(-5,5)
vy(0) = Rnd(-5,5)
ax(0) = 0
ay(0) = 0
r(0) = 100

For i = 1 To 99
xx(i) = Rnd(0,w)
yy(i) = Rnd(0,h)
vx(i) = Rnd(-20,20)
vy(i) = Rnd(-20,20)
ax(0) = 0
ay(0) = 0
r(i) = Rnd(10,15)
Next

dt = .1

'For a = 1 To 1000000

'Next

Timer1.Initialize("MainEvent", 10)
Timer1.Enabled = True

End Sub

Sub MainEvent

For i = 0 To 99

For j = 0 To 99
ax(j) = 0.0;
ay(j) = 0.0;
Next

For j = 0 To 99

If i <> j Then
diffx = xx(i) - xx(j)
diffy = yy(i) - yy(j)
dist1 = Sqrt(Power(diffx,2)+Power(diffy,2))
dist2 = r(i) + r(j)

If dist1 < dist2 Then
deltaDistance = (dist2 - dist1)

xval = (((deltaDistance * 10.0) / dist2) * diffx)
yval = (((deltaDistance * 10.0) / dist2) * diffy)

ax(i) = ax(i) + xval
ay(i) = ay(i) + yval

End If

End If
Next

vx(i) = (vx(i) + (ax(i) * dt)) *.999
vy(i) = (vy(i) + (ay(i) * dt)) *.999
xx(i) = xx(i) + (vx(i) * dt)
yy(i) = yy(i) + (vy(i) * dt)

If xx(i)-r(i) < 0 Then
vx(i) = -vx(i)
xx(i) = 0 + r(i)
End If
If yy(i)-r(i) < 0 Then
vy(i) = -vy(i)
yy(i) = 0 + r(i)
End If
If xx(i)+r(i) > w Then
vx(i) = -vx(i)
xx(i) = w - r(i)
End If
If yy(i)+r(i) > h Then
vy(i) = -vy(i)
yy(i) = h - r(i)
End If

Next

Canvas1.DrawColor(Colors.Black)

Canvas1.DrawCircle(xx(0),yy(0),r(0),Colors.Red,True,5)
For i = 1 To 99
Canvas1.DrawCircle(xx(i),yy(i),r(i),Colors.Green,True,5)
Next
Activity.Invalidate
DoEvents

End Sub

When i complile the code i get an error: "Signing package file (debug key). Error"

thedesolatesoul · Nov 4, 2011

Use the Activity_Touch event.
I have used it several times.

B4X:

Sub Activity_Touch (Action As Int, X As Float, Y As Float)
Log("(x,y)=" & X & "," & Y)
End Sub

thedesolatesoul · Nov 4, 2011

Can you use the Code Tags when you post the code. It makes reading code easier.
What is the settings in the IDE menu: Tools=>Private Sign Key ?
I have never had this error.

SlavaVB · Nov 4, 2011

PHP:

Sub Process_Globals
   Dim Timer1 As Timer
   
   Dim xx(100) As Double
   Dim yy(100) As Double
   Dim vx(100) As Double
   Dim vy(100) As Double
   Dim ax(100) As Double
   Dim ay(100) As Double
   Dim r(100) As Double
   Dim dt As Double
   
   Dim w As Double
   Dim h As Double
   Dim diffx As Double
   Dim diffy As Double
   Dim dist1 As Double
   Dim dist2 As Double
   
   Dim xval As Double
   Dim yval As Double

   
End Sub

Sub Globals
   Dim Canvas1 As Canvas
   

   
End Sub

Sub Activity_Create(FirstTime As Boolean)
   canvas1.Initialize(Activity)
   
   
   
   
   
   Globe
End Sub


Sub Globe
   



   
   w = Canvas1.Bitmap.Width 
   h = Canvas1.Bitmap.Height
   
   xx(0) = w/2
   yy(0) = h/2
   vx(0) = Rnd(-5,5)
   vy(0) = Rnd(-5,5)
   ax(0) = 0
   ay(0) = 0
   r(0) = 100
   
   For i = 1 To 99
      xx(i) = Rnd(0,w)
      yy(i) = Rnd(0,h)
      vx(i) = Rnd(-20,20)   
      vy(i) = Rnd(-20,20)
      ax(0) = 0
      ay(0) = 0
      r(i) = Rnd(10,15)
   Next 
   
   dt = .1
   
   
   'For a = 1 To 1000000
         
   'Next

  
     Timer1.Initialize("MainEvent", 10)
   Timer1.Enabled = True

  
  
End Sub

Sub MainEvent
      
      For i = 0 To 99
      
         For j = 0 To 99
            ax(j) = 0.0;
            ay(j) = 0.0;
         Next
            
         For j = 0 To 99
         
            If i <> j Then
               diffx = xx(i) - xx(j)
               diffy = yy(i) - yy(j)
               dist1 = Sqrt(Power(diffx,2)+Power(diffy,2))
               dist2 = r(i) + r(j)
               
               If dist1 < dist2 Then
                  deltaDistance = (dist2 - dist1)
               
                  xval = (((deltaDistance * 10.0) / dist2) * diffx)
                  yval = (((deltaDistance * 10.0) / dist2) * diffy)
                  
                  ax(i) = ax(i) + xval
                       ay(i) = ay(i) + yval
 
               End If
            
            End If
         Next
      
         vx(i) = (vx(i) + (ax(i) * dt)) *.999
         vy(i) = (vy(i) + (ay(i) * dt)) *.999
           xx(i) = xx(i) + (vx(i) * dt)
         yy(i) = yy(i) + (vy(i) * dt)
       
         If xx(i)-r(i) < 0 Then
            vx(i) = -vx(i)
            xx(i) = 0 + r(i)
         End If
         If yy(i)-r(i) < 0 Then
            vy(i) = -vy(i)
            yy(i) = 0 + r(i)
         End If
         If xx(i)+r(i) > w Then
            vx(i) = -vx(i)
            xx(i) = w - r(i)
         End If
         If yy(i)+r(i) > h Then
            vy(i) = -vy(i)
            yy(i) = h - r(i)
         End If
         
         
      Next 
      
        Canvas1.DrawColor(Colors.Black)
      
      Canvas1.DrawCircle(xx(0),yy(0),r(0),Colors.Red,True,5)
      For i = 1 To 99
         Canvas1.DrawCircle(xx(i),yy(i),r(i),Colors.Green,True,5)
      Next 
        Activity.Invalidate
      DoEvents 

End Sub

I cant change that setting because i dont have a full version of basic4android

SlavaVB · Nov 4, 2011

I have an unregistered version, so i cant change the Private Sign Key... could the be the issue? All i changed was putting my variable declarations into global... then it started giving the error.

B4X:

Sub Process_Globals
   Dim Timer1 As Timer
   
   Dim xx(100) As Double
   Dim yy(100) As Double
   Dim vx(100) As Double
   Dim vy(100) As Double
   Dim ax(100) As Double
   Dim ay(100) As Double
   Dim r(100) As Double
   Dim dt As Double
   
   Dim w As Double
   Dim h As Double
   Dim diffx As Double
   Dim diffy As Double
   Dim dist1 As Double
   Dim dist2 As Double
   
   Dim xval As Double
   Dim yval As Double

   
End Sub

Sub Globals
   Dim Canvas1 As Canvas
   

   
End Sub

Sub Activity_Create(FirstTime As Boolean)
   canvas1.Initialize(Activity)
   
   
   
   
   
   Globe
End Sub


Sub Globe
   



   
   w = Canvas1.Bitmap.Width 
   h = Canvas1.Bitmap.Height
   
   xx(0) = w/2
   yy(0) = h/2
   vx(0) = Rnd(-5,5)
   vy(0) = Rnd(-5,5)
   ax(0) = 0
   ay(0) = 0
   r(0) = 100
   
   For i = 1 To 99
      xx(i) = Rnd(0,w)
      yy(i) = Rnd(0,h)
      vx(i) = Rnd(-20,20)   
      vy(i) = Rnd(-20,20)
      ax(0) = 0
      ay(0) = 0
      r(i) = Rnd(10,15)
   Next 
   
   dt = .1
   
   
   'For a = 1 To 1000000
         
   'Next

  
     Timer1.Initialize("MainEvent", 10)
   Timer1.Enabled = True

  
  
End Sub

Sub MainEvent
      
      For i = 0 To 99
      
         For j = 0 To 99
            ax(j) = 0.0;
            ay(j) = 0.0;
         Next
            
         For j = 0 To 99
         
            If i <> j Then
               diffx = xx(i) - xx(j)
               diffy = yy(i) - yy(j)
               dist1 = Sqrt(Power(diffx,2)+Power(diffy,2))
               dist2 = r(i) + r(j)
               
               If dist1 < dist2 Then
                  deltaDistance = (dist2 - dist1)
               
                  xval = (((deltaDistance * 10.0) / dist2) * diffx)
                  yval = (((deltaDistance * 10.0) / dist2) * diffy)
                  
                  ax(i) = ax(i) + xval
                       ay(i) = ay(i) + yval
 
               End If
            
            End If
         Next
      
         vx(i) = (vx(i) + (ax(i) * dt)) *.999
         vy(i) = (vy(i) + (ay(i) * dt)) *.999
           xx(i) = xx(i) + (vx(i) * dt)
         yy(i) = yy(i) + (vy(i) * dt)
       
         If xx(i)-r(i) < 0 Then
            vx(i) = -vx(i)
            xx(i) = 0 + r(i)
         End If
         If yy(i)-r(i) < 0 Then
            vy(i) = -vy(i)
            yy(i) = 0 + r(i)
         End If
         If xx(i)+r(i) > w Then
            vx(i) = -vx(i)
            xx(i) = w - r(i)
         End If
         If yy(i)+r(i) > h Then
            vy(i) = -vy(i)
            yy(i) = h - r(i)
         End If
         
         
      Next 
      
        Canvas1.DrawColor(Colors.Black)
      
      Canvas1.DrawCircle(xx(0),yy(0),r(0),Colors.Red,True,5)
      For i = 1 To 99
         Canvas1.DrawCircle(xx(i),yy(i),r(i),Colors.Green,True,5)
      Next 
        Activity.Invalidate
      DoEvents 

End Sub

SlavaVB · Nov 4, 2011

If i can get the timer working, i think the touch event will work also.

SlavaVB · Nov 4, 2011

Does the following code compile on your machine? I added the Touch event handler....

B4X:

Sub Process_Globals
   Dim Timer1 As Timer
   
   Dim xx(100) As Double
   Dim yy(100) As Double
   Dim vx(100) As Double
   Dim vy(100) As Double
   Dim ax(100) As Double
   Dim ay(100) As Double
   Dim r(100) As Double
   Dim dt As Double
   
   Dim w As Double
   Dim h As Double
   Dim diffx As Double
   Dim diffy As Double
   Dim dist1 As Double
   Dim dist2 As Double
   
   Dim xval As Double
   Dim yval As Double

   
End Sub

Sub Globals
   Dim Canvas1 As Canvas
   

   
End Sub

Sub Activity_Create(FirstTime As Boolean)
   canvas1.Initialize(Activity)
   
   
   
   
   
   Globe
End Sub


Sub Globe
   



   
   w = Canvas1.Bitmap.Width 
   h = Canvas1.Bitmap.Height
   
   xx(0) = w/2
   yy(0) = h/2
   vx(0) = Rnd(-5,5)
   vy(0) = Rnd(-5,5)
   ax(0) = 0
   ay(0) = 0
   r(0) = 100
   
   For i = 1 To 99
      xx(i) = Rnd(0,w)
      yy(i) = Rnd(0,h)
      vx(i) = Rnd(-20,20)   
      vy(i) = Rnd(-20,20)
      ax(0) = 0
      ay(0) = 0
      r(i) = Rnd(10,15)
   Next 
   
   dt = .1
   
   
   'For a = 1 To 1000000
         
   'Next

  
     Timer1.Initialize("MainEvent", 10)
   Timer1.Enabled = True

  
  
End Sub

Sub MainEvent
      
      For i = 0 To 99
      
         For j = 0 To 99
            ax(j) = 0.0;
            ay(j) = 0.0;
         Next
            
         For j = 0 To 99
         
            If i <> j Then
               diffx = xx(i) - xx(j)
               diffy = yy(i) - yy(j)
               dist1 = Sqrt(Power(diffx,2)+Power(diffy,2))
               dist2 = r(i) + r(j)
               
               If dist1 < dist2 Then
                  deltaDistance = (dist2 - dist1)
               
                  xval = (((deltaDistance * 10.0) / dist2) * diffx)
                  yval = (((deltaDistance * 10.0) / dist2) * diffy)
                  
                  ax(i) = ax(i) + xval
                       ay(i) = ay(i) + yval
 
               End If
            
            End If
         Next
      
         vx(i) = (vx(i) + (ax(i) * dt)) *.999
         vy(i) = (vy(i) + (ay(i) * dt)) *.999
           xx(i) = xx(i) + (vx(i) * dt)
         yy(i) = yy(i) + (vy(i) * dt)
       
         If xx(i)-r(i) < 0 Then
            vx(i) = -vx(i)
            xx(i) = 0 + r(i)
         End If
         If yy(i)-r(i) < 0 Then
            vy(i) = -vy(i)
            yy(i) = 0 + r(i)
         End If
         If xx(i)+r(i) > w Then
            vx(i) = -vx(i)
            xx(i) = w - r(i)
         End If
         If yy(i)+r(i) > h Then
            vy(i) = -vy(i)
            yy(i) = h - r(i)
         End If
         
         
      Next 
      
        Canvas1.DrawColor(Colors.Black)
      
      Canvas1.DrawCircle(xx(0),yy(0),r(0),Colors.Red,True,5)
      For i = 1 To 99
         Canvas1.DrawCircle(xx(i),yy(i),r(i),Colors.Green,True,5)
      Next 
        Activity.Invalidate
      DoEvents 

End Sub
Sub Activity_Touch (Action As Int, X As Float, Y As Float)
   xx(0) = x
   yy(0) = y
End Sub

thedesolatesoul · Nov 5, 2011

Yes, it does.
What error do you get?

thedesolatesoul · Nov 5, 2011

B4X:

Sub MainEvent

should be

B4X:

Sub MainEvent_Tick

thedesolatesoul · Nov 5, 2011

I see a big red circle and lots of small green circles moving around.

SlavaVB · Nov 5, 2011

Signing package file (debug key). Error

Do you have the full version of the compiler?

Should both have the word Tick in them?

ie. "Timer1.Initialize("MainEvent_Tick", 10)" ?

SlavaVB · Nov 5, 2011

Compiling code. 0.03
Generating R file. 0.00
Compiling generated Java code. 0.91
Convert byte code - optimized dex. 0.52
Packaging files. 0.47
Signing package file (debug key). Error

Are you able to manipulate the large ball by touching the screen?

thedesolatesoul · Nov 5, 2011

SlavaVB said:
Signing package file (debug key). Error

Do you have the full version of the compiler?

I have the full version. But I think it should still work for you, afterall you were able to compile before?

Should both have the word Tick in them?
ie. "Timer1.Initialize("MainEvent_Tick", 10)" ?

No. Just the Sub name.

Trouble getting x and y position, on a canvas

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