android 计算地图上两点距离的算法，android两点,android计算地图上

android 计算地图上两点距离的算法，android两点,android计算地图上

android计算地图上两点距离的算法接口：```java package com.computedistance;
public interface DistanceComputeInterface {

    double getDistance(double lat1, double lng1, double lat2, double lng2);    double getShortDistance(double lat1, double lon1, double lat2, double lon2);    double getLongDistance(double lat1, double lon1, double lat2, double lon2);    double getDistanceBySpeed(double speed, double timeSpace);    double getAccurancyDistance(double lat_a, double lng_a, double lat_b, double lng_b);}

实现类：```java    package com.computedistance.impl;      import java.security.InvalidParameterException;      import com.baidu.mapapi.utils.DistanceUtil;      import com.baidu.platform.comapi.basestruct.GeoPoint;      import com.computedistance.DistanceComputeInterface;      public class DistanceComputeImpl implements DistanceComputeInterface{          private final static double DEF_PI = 3.14159265359; // PI          private final static double DEF_2PI= 6.28318530712; // 2*PI          private final static double DEF_PI180= 0.01745329252; // PI/180.0          private final static double DEF_R =6370693.5; // radius of earth          private static DistanceComputeImpl instance = null;          public synchronized static DistanceComputeImpl getInstance(){              if (instance == null) {                  instance = new DistanceComputeImpl();              }              return instance;          }          private DistanceComputeImpl(){}          @Override          public double getDistance(double lat1, double lng1, double lat2, double lng2) {              GeoPoint p1LL = new GeoPoint((int) (lat1*1e6), (int) (lng1*1e6));              GeoPoint p2LL = new GeoPoint((int) (lat2*1e6), (int) (lng2*1e6));              double distance = DistanceUtil.getDistance(p1LL, p2LL);              return distance/1000;          }          @Override          public double getShortDistance(double lat1, double lon1, double lat2,double lon2) {              double ew1, ns1, ew2, ns2;              double dx, dy, dew;              double distance;              // 角度转换为弧度              ew1 = lon1 * DEF_PI180;              ns1 = lat1 * DEF_PI180;              ew2 = lon2 * DEF_PI180;              ns2 = lat2 * DEF_PI180;              // 经度差              dew = ew1 - ew2;              // 若跨东经和西经180 度，进行调整              if (dew > DEF_PI)                  dew = DEF_2PI - dew;              else if (dew < -DEF_PI)                  dew = DEF_2PI + dew;              dx = DEF_R * Math.cos(ns1) * dew; // 东西方向长度(在纬度圈上的投影长度)              dy = DEF_R * (ns1 - ns2); // 南北方向长度(在经度圈上的投影长度)              // 勾股定理求斜边长              distance = Math.sqrt(dx * dx + dy * dy);              return distance/1000;          }          @Override          public double getLongDistance(double lat1, double lon1, double lat2,double lon2) {              double ew1, ns1, ew2, ns2;              double distance;              // 角度转换为弧度              ew1 = lon1 * DEF_PI180;              ns1 = lat1 * DEF_PI180;              ew2 = lon2 * DEF_PI180;              ns2 = lat2 * DEF_PI180;              // 求大圆劣弧与球心所夹的角(弧度)              distance = Math.sin(ns1) * Math.sin(ns2) + Math.cos(ns1) * Math.cos(ns2) * Math.cos(ew1 - ew2);              // 调整到[-1..1]范围内，避免溢出              if (distance > 1.0){                  distance = 1.0;              } else if (distance < -1.0){                  distance = -1.0;              }              // 求大圆劣弧长度              distance = DEF_R * Math.acos(distance);              return distance/1000;          }          @Override          public double getDistanceBySpeed(double speed, double timeSpace) {              if (speed  < 0 || timeSpace <= 0) {                  throw new InvalidParameterException();              }              return speed * timeSpace;          }          @Override          public double getAccurancyDistance(double lat_a, double lng_a,double lat_b, double lng_b) {              double pk = (double) (180 / 3.14169);              double a1 = lat_a / pk;              double a2 = lng_a / pk;              double b1 = lat_b / pk;              double b2 = lng_b / pk;              double t1 = Math.cos(a1) * Math.cos(a2) * Math.cos(b1) * Math.cos(b2);              double t2 = Math.cos(a1) * Math.sin(a2) * Math.cos(b1) * Math.sin(b2);              double t3 = Math.sin(a1) * Math.sin(b1);              double tt = Math.acos(t1 + t2 + t3);              return 6366000 * tt / 1000;          }      }