android - 如何计算行进距离

Question

我正在开发一个需要计算行进距离的应用程序。我在计算距离时遇到问题。这是我的代码:

 locationmanager.requestLocationUpdates(bestProvider,0,0,new Listener());

 public class Listener implements LocationListener{

@Override
public void onLocationChanged(Location location) {
    if(location!=null) {
        if(loc1==null) {
            loc1=new Location(location);
        }

        speed=location.getSpeed()*3.6;
        loc2=new Location(location);
        dist+=loc1.distanceTo(loc2);
        loc1=loc2;
        breaktv.setText(""+dist/1000);

我的 Intent 是计算汽车或其他东西行驶的总距离。但是 distanceTo() 方法对我来说效果不佳。

Answer 1

从技术上讲，它应该可以工作。

我有一些建议:

• dist 必须是 float(如果还没有的话)
• dist += loc2.distanceTo(location)，不需要创建loc1

---

这是我用过的代码

                if(lastLoc != null)
                {
                    ttf = (location.getTime() - lastLoc.getTime()) / 1000;
                    int R = 6371;
                    double lat1 = Math.PI / 180.0 *lastLoc.getLatitude();
                    double lon1 = Math.PI / 180.0 *lastLoc.getLongitude();
                    double lat2 = Math.PI / 180.0 *location.getLatitude();
                    double lon2 = Math.PI / 180.0 *location.getLongitude();
                    //  double dLon = Math.PI / 180.0 * (location.getLongitude() - lastLoc.getLongitude());
                    double dLat = (lat2-lat1);
                    double dLon = (lon2-lon1);
                    double a = Math.sin(dLat/2) * Math.sin(dLat/2) +
                    Math.cos(lat1) * Math.cos(lat2) * 
                    Math.sin(dLon/2) * Math.sin(dLon/2); 
                    double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); 
                    double d = R * c;
                   totalDistance += d;

                }

                lastLoc = location;