Drawing on canvas leaves behind old text

[joolzg]

Ok making progress.

Sub ShowChannelInfo
Dim rect1 As Rect

rect1.Initialize(5%x, 2%y, 5%x+64, 2%y+64)
canvas1.DrawBitmap( cCurrent.pIcon, Null, rect1)
'canvas1.DrawLine( 10,10,500,50,Colors.Blue,5dip)
canvas1.DrawText( cCurrent.cNumber, 5%x, 18%y, Typeface.DEFAULT_BOLD, 24, Colors.White, "LEFT")
canvas1.DrawText( cCurrent.cName, 5%x, 22%y, Typeface.DEFAULT_BOLD, 24, Colors.White, "LEFT")
canvas1.DrawText( DateTime.Time(DateTime.Now).SubString2(0,5), 97%x, 5%y, Typeface.DEFAULT_BOLD, 30, Colors.White, "RIGHT")
rect1.Initialize(30%x, 2%y, 90%x, 20%y)
canvas1.DrawRect( rect1, Colors.LightGray, True, 1dip)
channelInfo.Invalidate
End Sub

But the problem is that when i change channel the old information is still there and the new stuff adds on top of it.

Whats the correct wat of clearing the old text and bitmaps?

I tried this but i lose my transparency

canvas1.DrawColor( Colors.ARGB( 255, 128, 128, 128))

I tired this but no difference

canvas1.DrawColor( Colors.ARGB( 255, 128, 128, 128))
canvas1.DrawColor( Colors.ARGB( 127, 128, 128, 128))

Also a 2nd question, how do i make this code work on different sized displays, just tried on my Galaxy 3 and everything is too big, mostly in the right place, just too large

joolz

 

[COBRASoft]

You have to 'erase' the canvas by drawing a filled rectangle with Colors.Transparent. This will actually clear all the previous stuff you placed on it

 

[joolzg]

Thanks help out, working now.

So can you give me a pointer to how i get my drawing code to work on a phone and a tablet and chinese box, with everything scaled correctly?

joolz

 

[COBRASoft]

Sure, use % in your widths and heights for relative positioning. Use dip or diptocurrent to 'scale' an absolute value. Erel can explain this deeper .

 

[joolzg]

Thanks for the reply, ive used % on my x,y coords but how do i scale the bitmap and the fonts correctly

joolz

 

[Erel]

There are several approaches. Usually you will create your layout with the visual designer. Your layout can include multiple variants. With the designer script you can fine tune your layout to match all devices.