SegmentView.java

    private void init() {
        paint = new Paint();
        paint.setColor(Color.BLUE);
        paint.setAntiAlias(true);
        paint.setStrokeWidth(50);
        paint.setStyle(Paint.Style.STROKE);

        paintFill = new Paint();
        paintFill.setColor(Color.RED);
        paint.setAntiAlias(true);
        paintFill.setStrokeWidth(50);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        float w = canvas.getWidth();
        float h = canvas.getHeight();
        float center_x = w/2f;
        float center_y = h/2f;
        float r = w * 0.4f;
        canvas.drawCircle(center_x, center_y, r + 25, paintFill);
        RectF rect = new RectF(center_x - r, center_y - r, center_x + r, center_y + r);
        canvas.drawArc(rect, 0, 90, false, paint);
    }