Draw.java

 @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        // get width and height of navigation bar
        // Navigation bar bounds (width & height)
         mNavigationBarWidth = getWidth();
         mNavigationBarHeight = getHeight();
        // the coordinates (x,y) of the start point before curve
        mFirstCurveStartPoint.set((mNavigationBarWidth / 2) - (CURVE_CIRCLE_RADIUS * 2) - (CURVE_CIRCLE_RADIUS / 3), 0);
        // the coordinates (x,y) of the end point after curve
        mFirstCurveEndPoint.set(mNavigationBarWidth / 2, CURVE_CIRCLE_RADIUS + (CURVE_CIRCLE_RADIUS / 4));
        // same thing for the second curve
        mSecondCurveStartPoint = mFirstCurveEndPoint;
        mSecondCurveEndPoint.set((mNavigationBarWidth / 2) + (CURVE_CIRCLE_RADIUS * 2) + (CURVE_CIRCLE_RADIUS / 3), 0);

        // the coordinates (x,y)  of the 1st control point on a cubic curve
        mFirstCurveControlPoint1.set(mFirstCurveStartPoint.x + CURVE_CIRCLE_RADIUS + (CURVE_CIRCLE_RADIUS / 4), mFirstCurveStartPoint.y);
        // the coordinates (x,y)  of the 2nd control point on a cubic curve
        mFirstCurveControlPoint2.set(mFirstCurveEndPoint.x - (CURVE_CIRCLE_RADIUS * 2) + CURVE_CIRCLE_RADIUS, mFirstCurveEndPoint.y);

        mSecondCurveControlPoint1.set(mSecondCurveStartPoint.x + (CURVE_CIRCLE_RADIUS * 2) - CURVE_CIRCLE_RADIUS, mSecondCurveStartPoint.y);
        mSecondCurveControlPoint2.set(mSecondCurveEndPoint.x - (CURVE_CIRCLE_RADIUS + (CURVE_CIRCLE_RADIUS / 4)), mSecondCurveEndPoint.y);
    }

Please keep practice to share variable initialization and declaration.