android - Can we have two canvases in an activity ? (OR) Having a canvas outside the onDraw() is not working -

@override         protected void ondraw(canvas canvas) {         // draw graphic objects          .....              }           public void displaycalc(){             //do calculation & display results near these graphic objects             string result = string.valueof(value);               //do calculation                //display calculated values              canvas c =new canvas();              paint paint = new paint();              paint.setstyle(paint.style.fill);              paint.setantialias(true);              paint.setcolor(color.white);              c.drawtext(result,200,300,paint);                      } 

but if have same thing in function ondraw works fine. i know why or changes have make working

   @override     protected void ondraw(canvas canvas) {      // draw graphic objects      //do calculation & display results near these graphic objects      .....      string result = string.valueof(value);          //display calculated values          paint paint = new paint();          paint.setstyle(paint.style.fill);          paint.setantialias(true);          paint.setcolor(color.white);          canvas.drawtext(result,200,300,paint); } 

if you're trying implement kind of double buffering, might want take @ this

i think problem need create bitmap, attach canvas it, like:

bitmap bitmap = bitmap.createbitmap(width, height, config.rgb_565); canvas c = new canvas(bitmap);  // draw canvas.. // , when you're happy, draw bitmap onto canvas supplied ondraw. 

just creating canvas, doesn't make appear on screen.

you may want take at: this tutorial

if have surfaceview, can (don't have compiler, gist):

surfaceview view = (surfaceview)findviewbyid(r.id.view);  surfaceholder holder = view.getholder(); // save can accessed function  canvas c  try  {     c = holder.lockcanvas();     // draw stuff } {     if(null != c) {         holder.unlockcanvasandpost(c);     } }