停止使用谷歌的Location.distancebetween＆安培; location.distanceto功能。他们没有始终如一地工作。

Stop using google's Location.distancebetween & location.distanceto functions. They don't work consistently.

而不是使用直接的公式来计算距离：

Instead use the direct formula to calculate the distance:

double distance_between(Location l1, Location l2)
{
    //float results[] = new float[1];
    /* Doesn't work. returns inconsistent results
    Location.distanceBetween(
            l1.getLatitude(),
            l1.getLongitude(),
            l2.getLatitude(),
            l2.getLongitude(),
            results);
            */
    double lat1=l1.getLatitude();
    double lon1=l1.getLongitude();
    double lat2=l2.getLatitude();
    double lon2=l2.getLongitude();
    double R = 6371; // km
    double dLat = (lat2-lat1)*Math.PI/180;
    double dLon = (lon2-lon1)*Math.PI/180;
    lat1 = lat1*Math.PI/180;
    lat2 = lat2*Math.PI/180;

    double a = Math.sin(dLat/2) * Math.sin(dLat/2) +
            Math.sin(dLon/2) * Math.sin(dLon/2) * Math.cos(lat1) * Math.cos(lat2);
    double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
    double d = R * c * 1000;

    log_write("dist betn "+
            d + " " +
            l1.getLatitude()+ " " +
            l1.getLongitude() + " " +
            l2.getLatitude() + " " +
            l2.getLongitude()
            );

    return d;
}