安卓端根据2点的经纬度计算距离

private static double EARTH_RADIUS = 6378.137;//地球半径private static double rad(double d) {    return d * Math.PI / 180.0;}public static double GetDistance(double lat1, double lng1, double lat2, double lng2) {    double radLat1 = rad(lat1);    double radLat2 = rad(lat2);    double a = radLat1 - radLat2;    double b = rad(lng1) - rad(lng2);    double s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a / 2), 2) +            Math.cos(radLat1) * Math.cos(radLat2) * Math.pow(Math.sin(b / 2), 2)));    s = s * EARTH_RADIUS;//单位千米    Log.e("s", "s=" + s);    return s;}