地球赤道上环绕地球一周走一圈共40075.04公里,而@一圈分成360°,而每1°(度)有60,每一度一秒在赤道上的长度计算如下： 　　40075.04km/360°=111.31955km 　　

111.31955km/60=1.8553258km=1855.3m

任意两点距离计算公式见代码：

package org.wavefar.lib.utils;import android.content.Context;import com.baidu.location.BDAbstractLocationListener;
import com.baidu.location.LocationClient;
import com.baidu.location.LocationClientOption;
import com.baidu.mapapi.model.LatLng;
import com.baidu.mapapi.navi.BaiduMapAppNotSupportNaviException;
import com.baidu.mapapi.navi.BaiduMapNavigation;
import com.baidu.mapapi.navi.NaviParaOption;
import com.baidu.mapapi.utils.poi.BaiduMapPoiSearch;
import com.baidu.mapapi.utils.route.BaiduMapRoutePlan;
import com.baidu.mapsdkplatform.comapi.location.CoordinateType;import org.wavefar.lib.utils.LogUtil;
import org.wavefar.lib.utils.StringUtil;/*** 定位相关工具类* @author summer*/
public class LocationUtil {private LocationClient  mLocationClient;private BDAbstractLocationListener mlistener;private Context context;// 地球半径private final static double EARTH_RADIUS = 6378.137;public LocationUtil(Context context) {this.context = context;mLocationClient = new LocationClient(context.getApplicationContext());LocationClientOption option = initLocationOption();mLocationClient.setLocOption(option);LogUtil.d(LocationUtil.class.getSimpleName(), "当前定位库版本" + mLocationClient.getVersion());}private LocationClientOption initLocationOption() {LocationClientOption option = new LocationClientOption();// 设置定位模式option.setLocationMode(LocationClientOption.LocationMode.Hight_Accuracy);// 返回的定位结果是百度经纬度,默认值gcj02option.setCoorType(CoordinateType.BD09LL);// 设置发起定位请求的间隔时间为5000msoption.setScanSpan(5000);// 返回的定位结果包含地址信息option.setIsNeedAddress(true);//可选，默认false，设置是否需要POI结果，可以在BDLocation.getPoiList里得到option.setIsNeedLocationPoiList(true);// 返回的定位结果包含手机机头的方向option.setNeedDeviceDirect(true);//可选，默认false，设置是否需要位置语义化结果，可以在BDLocation.getLocationDescribe里得到，结果类似于“在北京天安门附近”option.setIsNeedLocationDescribe(true);option.setOpenGps(true);return option;}/*** 注册定位回调* @param listener*/public void registerLocationListener(BDAbstractLocationListener listener) {mlistener = listener;if (mlistener != null) {mLocationClient.registerLocationListener(mlistener);}}/*** 启动定位*/public void start() {if (mLocationClient.isStarted()) {return;}mLocationClient.start();}/*** 重新定位*/public void reStart() {if (mLocationClient.isStarted()) {return;}mLocationClient.restart();}/*** 停止定位*/public void stop() {if (mLocationClient.isStarted()) {mLocationClient.stop();}}/*** 销毁定位*/public void destroy() {if (mLocationClient != null) {mLocationClient.unRegisterLocationListener(mlistener);mLocationClient.stop();mLocationClient = null;}}/*** 启动百度地图导航(Native),如果本地没有安装百度地图，调用WEBAPP* @param pt1 起点* @param pt2 终点*/public void startNavi(LatLng pt1, LatLng pt2) {// 构建 导航参数NaviParaOption para = new NaviParaOption().startPoint(pt1).endPoint(pt2);try {BaiduMapNavigation.openBaiduMapNavi(para, context);} catch (BaiduMapAppNotSupportNaviException e) {BaiduMapNavigation.openWebBaiduMapNavi(para, context);e.printStackTrace();}}/*** 启动百度地图导航(Web)*/public void startWebNavi(LatLng pt1,LatLng pt2) {NaviParaOption para = new NaviParaOption().startPoint(pt1).endPoint(pt2);BaiduMapNavigation.openWebBaiduMapNavi(para, context);}/*** 用完导航后需要调用该函数销毁*/public void stopNavi() {try {BaiduMapNavigation.finish(context);BaiduMapRoutePlan.finish(context);BaiduMapPoiSearch.finish(context);} catch (Exception e) {e.printStackTrace();}}private static double rad(double d) {return d * Math.PI / 180.0;}/*** 计算距离 返回单位km* @param lat1* @param lng1* @param lat2* @param lng2* @return*/public static double getDistance(double lat1, double lng1, double lat2,double lng2) {LogUtil.d("LocationUtil", "lat1:" + lat1 + "lng1:" + lng1 + "lat2:" + lat2 + "lng2:" + lng2);double radLat1 = rad(lat1);double radLat2 = rad(lat2);// 如果有一方等于零，直接返回0if (radLat1 == 0 || radLat2 == 0) {return 0;}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;s = Math.round(s * 10000) / 10000;return s;}/*** 距离格式化** @param distance 以千米为单位* @return*/public static String distanceKMFormat(double distance) {return distance > 1 ? (distance + "KM") : (distance * 1000 + "M");}/*** 距离只保留两位小数* @param distance 以米为单位* @return*/public static String distanceFormat(double distance) {String str;double value = distance;if (distance >= 1000) {value = value / 1000;str = "KM";} else {str = "M";}return String.format("%s%s",StringUtil.formatDecimal(value,null),str);}}

以上代码定位依赖于百度定位API，所以粘贴以上代码之前，需要引入百度定位API，引入百度定位API不在这里介绍，自行去百度定位官方查看；