c++builder 中的canvas指令怎么画圆弧?答:protected void onDraw(Canvas canvas) { Paint paint = new Paint();paint.setAntiAlias(true);paint.setColor(Color.argb(255, 255, 255, 255));RectF oval1 = new RectF(20.0f, 20.0f, 60.0f, 60.0f);canvas.drawArc(oval1, 0, 45, true, paint);RectF oval2 = new RectF(...