如何显示在Android的GMAP V2图距文本 [英] How to show map distance text in android GMap v2

问题描述

我想显示距离图（公里数）我applicatin。我实现了code从这个链接<一个href=\"http://stackoverflow.com/questions/14394366/find-distance-between-two-points-on-map-using-google-map-api-v2\">Find使用谷歌地图API V2 在地图上两点之间的距离 - 作者Abhijit仓根

 公共双CalculiationByDistance（经纬度StartP，经纬度ENDP）{
    INT半径= 6371;
    双LAT1 = StartP.latitude;
    双LAT2 = EndP.latitude;
    双lon1 = StartP.longitude;
    双lon2 = EndP.longitude;
    双DLAT = Math.toRadians（LAT2  -  LAT1）;
    双dLon = Math.toRadians（lon2  -  lon1）;
    双A = Math.sin（DLAT / 2）* Math.sin（DLAT / 2）
            + Math.cos（Math.toRadians（LAT1））
            * Math.cos（Math.toRadians（LAT2））* Math.sin（dLon / 2）
            * Math.sin（dLon / 2）;
    双C = 2 * Math.asin（的Math.sqrt（一））;
    双valueResult =半径* C;
    双公里= valueResult / 1;
    DecimalFormat的newFormat =新的DecimalFormat（####）;
    INT kmInDec = Integer.valueOf（newFormat.format（公里））;
    双米= valueResult％1000;
    INT meterInDec = Integer.valueOf（newFormat.format（米））;
    Log.i（半径值，+ valueResult +KM+ kmInDec
            +表+ meterInDec）;    返回半径* C;
}
 

但我只得到了错误的距离，给人logcat中只有0.2公里的距离。
我应该怎么办？

在此先感谢..

解决方案

 公共静态双distFrom（双LAT1，双lng1，双LAT2，
            双lng2）{
        双earthRadius = 3958.75;
        双DLAT = Math.toRadians（LAT2  -  LAT1）;
        双DLNG = Math.toRadians（lng2  -  lng1）;
        双sindLat = Math.sin（DLAT / 2）;
        双sindLng = Math.sin（DLNG / 2）;
        双一= Math.pow（sindLat，2）+ Math.pow（sindLng，2）
                * Math.cos（Math.toRadians（LAT1））
                * Math.cos（Math.toRadians（LAT2））;
        双C = 2 * Math.atan2（的Math.sqrt（一）的Math.sqrt（1  -  a）条）;
        双DIST = earthRadius * C;        返回DIST;
    }
用作KM像::  - ＆GT;距离= distFrom（纬度，经度，lat_array.get（ⅰ），
                            long_array.get（ⅰ））;
双公里=距离/ 0.62137;
 

I'm trying to show distance map in (in km) my applicatin. I implemented the code from this link Find distance between two points on map using Google Map API V2 - Abhijit Kurane

public double CalculiationByDistance(LatLng StartP, LatLng EndP) {
    int Radius = 6371;
    double lat1 = StartP.latitude;
    double lat2 = EndP.latitude;
    double lon1 = StartP.longitude;
    double lon2 = EndP.longitude;
    double dLat = Math.toRadians(lat2 - lat1);
    double dLon = Math.toRadians(lon2 - lon1);
    double a = Math.sin(dLat / 2) * Math.sin(dLat / 2)
            + Math.cos(Math.toRadians(lat1))
            * Math.cos(Math.toRadians(lat2)) * Math.sin(dLon / 2)
            * Math.sin(dLon / 2);
    double c = 2 * Math.asin(Math.sqrt(a));
    double valueResult = Radius * c;
    double km = valueResult / 1;
    DecimalFormat newFormat = new DecimalFormat("####");
    int kmInDec = Integer.valueOf(newFormat.format(km));
    double meter = valueResult % 1000;
    int meterInDec = Integer.valueOf(newFormat.format(meter));
    Log.i("Radius Value", "" + valueResult + "   KM  " + kmInDec
            + " Meter   " + meterInDec);

    return Radius * c;
}

but I only got the wrong distance, the logcat gives only 0.2 km distance. What should I do?

Thanks in advance..

解决方案

public static double distFrom(double lat1, double lng1, double lat2,
            double lng2) {
        double earthRadius = 3958.75;
        double dLat = Math.toRadians(lat2 - lat1);
        double dLng = Math.toRadians(lng2 - lng1);
        double sindLat = Math.sin(dLat / 2);
        double sindLng = Math.sin(dLng / 2);
        double a = Math.pow(sindLat, 2) + Math.pow(sindLng, 2)
                * Math.cos(Math.toRadians(lat1))
                * Math.cos(Math.toRadians(lat2));
        double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
        double dist = earthRadius * c;

        return dist;
    }


use as in KM like ::-->

distance = distFrom(latitude, longitude, lat_array.get(i),
                            long_array.get(i));
double km = distance / 0.62137;

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