android实现查询公交车还有几站的功能

 上一篇文章介绍了如何在Android平台上利用百度地图进行定位，接下来就介绍一下在获取的定位功能的基础上采用百度地图来获取周边的公交信息。

这里采用如上文同样的方式，单独写一个类，该类是对周边搜索功能的封装，NearbySearchHelper。该类向外部只暴露一个函数SearchNearby()接口;

实现的主要流程时,根据当前的定位获取周边的公交车的信息,并排除了冗余的公交车线路信息,根据搜索到的公交线路信息，继续搜索该公交车的uid（百度地图的唯一标示符）,再根据具体的uid来搜索详细的公交车信息，包括起始站点。具体代码如下：

创建周边公交搜索帮助类：NearbySearchHelper

import java.util.ArrayList; import java.util.List;  import com.baidu.mapapi.model.LatLng; import com.baidu.mapapi.search.busline.BusLineResult; import com.baidu.mapapi.search.busline.BusLineSearch; import com.baidu.mapapi.search.busline.OnGetBusLineSearchResultListener; import com.baidu.mapapi.search.core.PoiInfo; import com.baidu.mapapi.search.core.SearchResult; import com.baidu.mapapi.search.poi.OnGetPoiSearchResultListener; import com.baidu.mapapi.search.poi.PoiDetailResult; import com.baidu.mapapi.search.poi.PoiNearbySearchOption; import com.baidu.mapapi.search.poi.PoiResult; import com.baidu.mapapi.search.poi.PoiSearch; import com.baidu.mapapi.utils.DistanceUtil; import com.busleep.app.CustomApplication; import com.busleep.bean.MrNearbyBus; import com.busleep.config.Constant; import com.busleep.listener.MrNearbySearchListener; import com.busleep.utils.LogUtils;   public class NearbySearchHelper implements OnGetPoiSearchResultListener,    OnGetBusLineSearchResultListener{    public static final String TAG = "NearbySearchHelper";      private final int BUSSTATION=0;          // 先查询周边的公交站点信息;   private final int BUSLINE=1;              // 站点的公交信息;   private PoiSearch mSearch = null;         // Poi点搜索模块;     private BusLineSearch mBusLineSearch = null;  // 公交路线搜索模块;      private int mType;                  // 查询类型;   private int nodeIndex=-1;            // 查询的索引;      private MrNearbySearchListener nearBySearchListener; //查询结束监听对象,该对象是为了封装而重新的一个监听器;      private List<MrNearbyBus> nearbyBuses=null;     //查询的结果;      public NearbySearchHelper(){      }    public void setNearBySearchListener(MrNearbySearchListener nearBySearchListener) {     this.nearBySearchListener = nearBySearchListener;   }       public void init(){          if(mSearch==null||mBusLineSearch==null){              mSearch = PoiSearch.newInstance();       mSearch.setOnGetPoiSearchResultListener(this);       mBusLineSearch = BusLineSearch.newInstance();       mBusLineSearch.setOnGetBusLineSearchResultListener(this);              nearbyBuses=new ArrayList<MrNearbyBus>();            }else {       nearbyBuses.clear();     }   }         public void Destory(){          mSearch.destroy();     mBusLineSearch.destroy();   }         public void searchNearby(){         //设置当前的搜索类型是公交站点的搜索;         mType=BUSSTATION;      //获取当前位置的经度与纬度，该值是通过上文的定位方式来获取的;          double latitude=CustomApplication.mLastLocation.getLatitude();     double longtitude=CustomApplication.mLastLocation.getLongitude();          //查询周边公交线路;采用百度地图的周边搜索接口，并定义周边点搜索选项，其中Constant.nearbyRadius是周边搜索的半径;     mSearch.searchNearby(new PoiNearbySearchOption().keyword("公交站")         .location(new LatLng(latitude,longtitude)).radius(Constant.nearbyRadius));        }      @Override   public void onGetBusLineResult(BusLineResult arg0) {     // TODO Auto-generated method stub        }    @Override   public void onGetPoiDetailResult(PoiDetailResult arg0) {     // TODO Auto-generated method stub        }    //该函数是百度地图的周边兴趣点搜索回调函数；该函数在两处都进行了回调，所以需要根据当前的搜索类型来进行判断；    @Override   public void onGetPoiResult(PoiResult result) {          switch(mType)     {       case BUSSTATION:       {         //如果查询失败直接返回;         if (result == null || result.error != SearchResult.ERRORNO.NO_ERROR)         {           LogUtils.i(TAG, "查询站点失败！");           nearBySearchListener.onRefreshBusNearby(nearbyBuses);           return;         }         //处理公交站点的搜索结果；         ProcessBusStation(result);         break;       }       case BUSLINE:       {         //如果查询失败直接返回;         if (result == null || result.error != SearchResult.ERRORNO.NO_ERROR)         {           LogUtils.i(TAG, "查询线路失败！");           nearBySearchListener.onRefreshBusNearby(nearbyBuses);           return;         }         //处理公交线路的搜索结果;         ProcessBusLine(result);         break;       }     }   }        private boolean FindSameBus(MrNearbyBus nearbyBus){          String busName=nearbyBus.getBusName();          LatLng nowLocation=new LatLng(CustomApplication.mLastLocation.getLatitude(),         CustomApplication.mLastLocation.getLongitude());          LatLng newLocation=nearbyBus.getStationLaction();          double newDistance=DistanceUtil.getDistance(nowLocation, newLocation);     double oldDistance=0.0;          for(int i=0;i<nearbyBuses.size();i++)     {       //如果存在名称相同的公交线路;       if(nearbyBuses.get(i).getBusName().equals(busName))       {         LatLng oldLocation=nearbyBuses.get(i).getStationLaction();          //DistanceUtil是百度地图提供的计算两个经纬度坐标之间的距离工具类;                  oldDistance=DistanceUtil.getDistance(nowLocation, oldLocation);                  //如果当前的距离小于之前的距离,则更新该公交车的信息;         if(newDistance<oldDistance)         {           nearbyBuses.get(i).setStationLaction(newLocation);           nearbyBuses.get(i).setStationName(nearbyBus.getStationName());         }         return true;       }     }     return false;   }         private void ProcessBusStation(PoiResult result){          for (PoiInfo poi : result.getAllPoi())     {       if (poi.type == PoiInfo.POITYPE.BUS_STATION)       {           String busNames []=poi.address.split(";");                  for(int i=0;i<busNames.length;++i){                      MrNearbyBus nearbyBus=new MrNearbyBus();           nearbyBus.setBusName(busNames[i]);           nearbyBus.setStationName(poi.name);           nearbyBus.setStationLaction(poi.location);                      boolean bRes=FindSameBus(nearbyBus);                      if(!bRes)           {             nearbyBuses.add(nearbyBus);           }             }       }     }      //搜索完了公交站点后则根据公交站点来搜索公交路线，由于搜索时间有可能会挺长，故查询完站点后就调用周边搜索监听器      //来刷新数据，UI线程实现了该监听器,则可以直接刷新数据。      searchBusLine();     nearBySearchListener.onRefreshBusNearby(nearbyBuses);   }         private void searchBusLine(){     //nodeIndex表示当前周边站点的索引;          nodeIndex++;          mType=BUSLINE;          if(nearbyBuses.isEmpty()){       return;     }          //部分刷新;     if(nodeIndex%5==0){       nearBySearchListener.onRefreshBusNearby(nearbyBuses);     }          //如果此时返回表明查询完毕;     if(nodeIndex >= nearbyBuses.size()){       LogUtils.i(TAG, "查询完毕！");       nearBySearchListener.onRefreshBusNearby(nearbyBuses);       return;     }          //这里还是采用搜索周边的方式,效率会更高;     double latitude=CustomApplication.mLastLocation.getLatitude();     double longtitude=CustomApplication.mLastLocation.getLongitude();     //获取当前节点下的周边公交车的公交名称;          String busLineName=nearbyBuses.get(nodeIndex).getBusName();     mSearch.searchNearby(new PoiNearbySearchOption().keyword(busLineName+"公交")         .location(new LatLng(latitude,longtitude)).radius(Constant.nearbyRadius));   }         private void ProcessBusLine(PoiResult result)   {     for (PoiInfo poi : result.getAllPoi())     {       if (poi.type == PoiInfo.POITYPE.BUS_LINE)       {         MrNearbyBus nearbyBus=nearbyBuses.get(nodeIndex);                  //如果是第一次进来;         if(nearbyBus.getUid()==null){              nearbyBus.setUid(poi.uid);           String drection=poi.name;           int index=drection.indexOf("(");           int length=drection.length();                      drection=drection.substring(index+1,length-1);           nearbyBus.setBusDrection(drection);                    }else {  //否则是返程公交车;                      nearbyBus.setReverseUid(poi.uid);;         }       }     }     searchBusLine();   } }