Android 清除除我所在位置以外的地图标记

我正在寻找地图上我的位置附近的地方。当我更改地点类别时，我希望地图从上一次搜索的标记中清除，但我位置的标记始终存在。“mGoogleMap.clear（）；”清除所有标记，包括我所在位置的标记。我怎样才能改变这一点

这是我的主要活动：

package com.example.mobiletourismapp;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.HashMap;
import java.util.List;

import org.json.JSONObject;

import android.animation.ValueAnimator;
import android.app.Dialog;
import android.content.Intent;
import android.graphics.Color;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.Spinner;

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.GoogleMap.OnInfoWindowClickListener;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;




public class MainActivity extends FragmentActivity implements LocationListener{

    GoogleMap mGoogleMap;   
    Spinner mSprPlaceType;  

    String[] mPlaceType=null;
    String[] mPlaceTypeName=null;

    double mLatitude=0;
    double mLongitude=0;

    HashMap<String, String> mMarkerPlaceLink = new HashMap<String, String>();


    @Override
    protected void onCreate(Bundle savedInstanceState) {


        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);     

        // Array of place types
        mPlaceType = getResources().getStringArray(R.array.place_type);

        // Array of place type names
        mPlaceTypeName = getResources().getStringArray(R.array.place_type_name);

        // Creating an array adapter with an array of Place types
        // to populate the spinner
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_dropdown_item, mPlaceTypeName);

        // Getting reference to the Spinner 
        mSprPlaceType = (Spinner) findViewById(R.id.spr_place_type);

        // Setting adapter on Spinner to set place types
        mSprPlaceType.setAdapter(adapter);

        Button btnFind;

        // Getting reference to Find Button
        btnFind = ( Button ) findViewById(R.id.btn_find);


        // Getting Google Play availability status
        int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getBaseContext());


        if(status!=ConnectionResult.SUCCESS){ // Google Play Services are not available

            int requestCode = 10;
            Dialog dialog = GooglePlayServicesUtil.getErrorDialog(status, this, requestCode);
            dialog.show();

        }else { // Google Play Services are available

            // Getting reference to the SupportMapFragment
            SupportMapFragment fragment = ( SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);

            // Getting Google Map
            mGoogleMap = fragment.getMap();

            // Enabling MyLocation in Google Map
            mGoogleMap.setMyLocationEnabled(true);



            // Getting LocationManager object from System Service LOCATION_SERVICE
            LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

            // Creating a criteria object to retrieve provider
            Criteria criteria = new Criteria();

            // Getting the name of the best provider
            String provider = locationManager.getBestProvider(criteria, true);

            // Getting Current Location From GPS
            Location location = locationManager.getLastKnownLocation(provider);

            if(location!=null){
                    onLocationChanged(location);
            }

            locationManager.requestLocationUpdates(provider, 20000, 0, this);



            mGoogleMap.setOnInfoWindowClickListener(new OnInfoWindowClickListener() {

                @Override
                public void onInfoWindowClick(Marker arg0) {
                    Intent intent = new Intent(getBaseContext(), PlaceDetailsActivity.class);
                    String reference = mMarkerPlaceLink.get(arg0.getId());
                    intent.putExtra("reference", reference);

                    // Starting the Place Details Activity
                    startActivity(intent);
                }
            });



            // Setting click event lister for the find button
            btnFind.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {   


                    int selectedPosition = mSprPlaceType.getSelectedItemPosition();
                    String type = mPlaceType[selectedPosition];


                    StringBuilder sb = new StringBuilder("https://maps.googleapis.com/maps/api/place/nearbysearch/json?");
                    sb.append("location="+mLatitude+","+mLongitude);
                    sb.append("&radius=5000");
                    sb.append("&types="+type);
                    sb.append("&sensor=true");
                    sb.append("&key=AIzaSyB6f_n3Z9877pSGkV6XhHXsJtfCmetJqCM");


                    // Creating a new non-ui thread task to download Google place json data 
                    PlacesTask placesTask = new PlacesTask();                                   

                    // Invokes the "doInBackground()" method of the class PlaceTask
                    placesTask.execute(sb.toString());

                }
            });

        }       

    }

    /** A method to download json data from url */
    private String downloadUrl(String strUrl) throws IOException{
        String data = "";
        InputStream iStream = null;
        HttpURLConnection urlConnection = null;
        try{
                URL url = new URL(strUrl);                


                // Creating an http connection to communicate with url 
                urlConnection = (HttpURLConnection) url.openConnection();                

                // Connecting to url 
                urlConnection.connect();                

                // Reading data from url 
                iStream = urlConnection.getInputStream();

                BufferedReader br = new BufferedReader(new InputStreamReader(iStream));

                StringBuffer sb  = new StringBuffer();

                String line = "";
                while( ( line = br.readLine())  != null){
                        sb.append(line);
                }

                data = sb.toString();

                br.close();

        }catch(Exception e){
                Log.d("Exception while downloading url", e.toString());
        }finally{
                iStream.close();
                urlConnection.disconnect();
        }

        return data;
    }         


    /** A class, to download Google Places */
    private class PlacesTask extends AsyncTask<String, Integer, String>{

        String data = null;

        // Invoked by execute() method of this object
        @Override
        protected String doInBackground(String... url) {
            try{
                data = downloadUrl(url[0]);
            }catch(Exception e){
                 Log.d("Background Task",e.toString());
            }
            return data;
        }

        // Executed after the complete execution of doInBackground() method
        @Override
        protected void onPostExecute(String result){            
            ParserTask parserTask = new ParserTask();

            // Start parsing the Google places in JSON format
            // Invokes the "doInBackground()" method of the class ParseTask
            parserTask.execute(result);
        }

    }

    /** A class to parse the Google Places in JSON format */
    private class ParserTask extends AsyncTask<String, Integer, List<HashMap<String,String>>>{

        JSONObject jObject;

        // Invoked by execute() method of this object
        @Override
        protected List<HashMap<String,String>> doInBackground(String... jsonData) {

            List<HashMap<String, String>> places = null;            
            PlaceJSONParser placeJsonParser = new PlaceJSONParser();

            try{
                jObject = new JSONObject(jsonData[0]);

                /** Getting the parsed data as a List construct */
                places = placeJsonParser.parse(jObject);

            }catch(Exception e){
                    Log.d("Exception",e.toString());
            }
            return places;
        }

        // Executed after the complete execution of doInBackground() method
        @Override
        protected void onPostExecute(List<HashMap<String,String>> list){            

            // Clears all the existing markers 
            mGoogleMap.clear();

            for(int i=0;i<list.size();i++){

                // Creating a marker
                MarkerOptions markerOptions = new MarkerOptions()
                .icon(BitmapDescriptorFactory.fromResource(R.drawable.pin));

                // Getting a place from the places list
                HashMap<String, String> hmPlace = list.get(i);

                // Getting latitude of the place
                double lat = Double.parseDouble(hmPlace.get("lat"));                

                // Getting longitude of the place
                double lng = Double.parseDouble(hmPlace.get("lng"));

                // Getting name
                String name = hmPlace.get("place_name");

                // Getting vicinity
                String vicinity = hmPlace.get("vicinity");

                LatLng latLng = new LatLng(lat, lng);

                // Setting the position for the marker
                markerOptions.position(latLng);

                // Setting the title for the marker. 
                //This will be displayed on taping the marker
                markerOptions.title(name + " : " + vicinity);   
                markerOptions.snippet("Click here for more info...");

                // Placing a marker on the touched position
                Marker m = mGoogleMap.addMarker(markerOptions);             

              // mGoogleMap.setInfoWindowAdapter(new MyInfoWindowAdapter(name,
                      //  vicinity));

                // Linking Marker id and place reference
                mMarkerPlaceLink.put(m.getId(), hmPlace.get("reference"));              


            }       

        }

    }



    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public void onLocationChanged(Location location) {
        mLatitude = location.getLatitude();
        mLongitude = location.getLongitude();
        LatLng latLng = new LatLng(mLatitude, mLongitude);

        mGoogleMap.addMarker (new MarkerOptions()
        .title ("You are here")
        .snippet("Current location")
        .position(latLng)
        .icon(BitmapDescriptorFactory.fromResource(R.drawable.gps)
                        ));

        mGoogleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
        mGoogleMap.animateCamera(CameraUpdateFactory.zoomTo(12));


    }

    @Override
    public void onProviderDisabled(String provider) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onProviderEnabled(String provider) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
        // TODO Auto-generated method stub      
    }
}

package com.example.mobiletourismapp；
导入java.io.BufferedReader；
导入java.io.IOException；
导入java.io.InputStream；
导入java.io.InputStreamReader；
导入java.net.HttpURLConnection；
导入java.net.URL；
导入java.util.HashMap；
导入java.util.List；
导入org.json.JSONObject；
导入android.animation.ValueAnimator；
导入android.app.Dialog；
导入android.content.Intent；
导入android.graphics.Color；
导入android.location.Criteria；
导入android.location.location；
导入android.location.LocationListener；
导入android.location.LocationManager；
导入android.os.AsyncTask；
导入android.os.Bundle；
导入android.support.v4.app.FragmentActivity；
导入android.util.Log；
导入android.view.Menu；
导入android.view.view；
导入android.view.view.OnClickListener；
导入android.widget.ArrayAdapter；
导入android.widget.Button；
导入android.widget.Spinner；
导入com.google.android.gms.common.ConnectionResult；
导入com.google.android.gms.common.GooglePlayServicesUtil；
导入com.google.android.gms.maps.CameraUpdateFactory；
导入com.google.android.gms.maps.GoogleMap；
导入com.google.android.gms.maps.GoogleMap.OnInfoWindowClickListener；
导入com.google.android.gms.maps.SupportMapFragment；
导入com.google.android.gms.maps.model.BitmapDescriptorFactory；
导入com.google.android.gms.maps.model.LatLng；
导入com.google.android.gms.maps.model.Marker；
导入com.google.android.gms.maps.model.MarkerOptions；
公共类MainActivity扩展FragmentActivity实现LocationListener{
谷歌地图；
微调器mSprPlaceType；
字符串[]mPlaceType=null；
字符串[]mPlaceTypeName=null；
双梯度=0；
双倍长度=0；
HashMap mMarkerPlaceLink=新HashMap（）；
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity_main）；
//位置类型数组
mPlaceType=getResources（）.getStringArray（R.array.place\u类型）；
//地名类型名称数组
mPlaceTypeName=getResources（）.getStringArray（R.array.place\u type\u name）；
//使用位置类型数组创建数组适配器
//填充微调器的步骤
ArrayAdapter=新的ArrayAdapter（这是android.R.layout.simple\u spinner\u dropdown\u项，mPlaceTypeName）；
//获取对微调器的引用
mSprPlaceType=（微调器）findViewById（R.id.spr\u place\u type）；
//在微调器上设置适配器以设置放置类型
mSprPlaceType.setAdapter（适配器）；
按钮btnFind；
//获取“查找”按钮的引用
btnFind=（按钮）findviewbyd（R.id.btn\u find）；
//获取Google Play可用性状态
int status=GooglePlayServicesUtil.isGooglePlayServicesAvailable（getBaseContext（））；
如果（status！=ConnectionResult.SUCCESS）{//Google Play服务不可用
int requestCode=10；
Dialog Dialog=GooglePlayServicesUtil.getErrorDialog（状态、此、请求代码）；
dialog.show（）；
}其他{//Google Play服务可用
//获取对SupportMapFragment的引用
SupportMapFragment fragment=（SupportMapFragment）getSupportFragmentManager（）.findFragmentById（R.id.map）；
//获取谷歌地图
mGoogleMap=fragment.getMap（）；
//在Google地图中启用MyLocation
mGoogleMap.setMyLocationEnabled（true）；
//从系统服务位置\u服务获取LocationManager对象
LocationManager LocationManager=（LocationManager）getSystemService（LOCATION\u服务）；
//创建条件对象以检索提供程序
标准=新标准（）；
//获取最佳提供商的名称
字符串提供程序=locationManager.getBestProvider（条件为true）；
//从GPS获取当前位置
Location Location=locationManager.getLastKnownLocation（提供者）；
如果（位置！=null）{
onLocationChanged（位置）；
}
locationManager.RequestLocationUpdate（提供程序，20000，0，此）；
mGoogleMap.setOnInfoWindowClickListener（新的OnInfoWindowClickListener（）{
@凌驾
公用无效信息窗口单击（标记arg0）{
Intent Intent=new Intent（getBaseContext（），PlaceDetailsActivity.class）；
字符串引用=mMarkerPlaceLink.get（arg0.getId（））；
意向。额外（“参考”，参考）；
//正在启动“地点详细信息”活动
星触觉（意向）；
}
});
//设置“查找”按钮的单击事件列表器
setOnClickListener（新的OnClickListener（）{
@凌驾
公共void onClick（视图v）{
int selectedPosition=mSprPlaceType.getSelectedItemPosition（）；
字符串类型=mPlaceType[selectedPosition]；
StringBuilder sb=新的StringBuilder（“https://maps.googleapis.com/maps/api/place/nearbysearch/json?");
sb.追加（“位置=”+mLatitude+，“+mllongitude”）；
sb.追加（“&radius=5000”）；
sb.追加（“&types=“+type”）；
sb.追加（“&sensor=true”）；
sb.追加（“&key=AIzaSyB6f_n3Z9877pSGkV6XhHXsJtfCmetJqCM”）；
//创建新的非ui线程任务以下载Googl
mGoogleMap.clear();