code: @Override
      public void onDraw(Canvas canvas) {
          if (animationOn) {
              if (angleRecalculate(new Date().getTime())) {
                  this.setRotation(angle1);
              }
          } else {
              this.setRotation(angle1);
          }
          super.onDraw(canvas);
          if (animationOn) {
              this.invalidate();
          }
      }
docs: onDraw override.
  If animation is "on", view is invalidated after each redraw,
  to perform recalculation on every loop of UI redraw