动态更改多个Android Google地图标记的图标

Question

我正在尝试根据我从网络服务器获取的网址更改多个Google地图标记图标。由于我之前只使用过网络应用程序，这对我来说是一个新手。

我已经阅读了其他主题，我必须创建一个新的线程，但如果我想获得多张照片不会成为一个问题？有没有人对我的问题有任何建议？

这是我的代码：

import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.support.v7.app.ActionBarActivity;
import android.view.View;

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
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;

import org.json.JSONArray;
import org.json.JSONException;

public class Mainmap extends ActionBarActivity implements View.OnClickListener {

private GoogleMap mMap; // Might be null if Google Play services APK is not available.
private LocationManager location;
private String provider;

private double lat;
private double lng;

private double pic_lat;
private double pic_lng;
private String image;
public static String LOG_TAG = "cn-quotes";


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_mainmap);
    location = (LocationManager) getSystemService(LOCATION_SERVICE);
    Criteria c = new Criteria();
    provider = location.getBestProvider(c, false);
    setUpMapIfNeeded();
    View newPhoto = findViewById(R.id.button_local_position);
    newPhoto.setOnClickListener(this);
    View popPhoto  =findViewById(R.id.button_popphoto);
    popPhoto.setOnClickListener(this);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
//            startActivity(new Intent(this, SettingsActivity.class));
        return true;
    }

    return super.onOptionsItemSelected(item);
}

@Override
protected void onResume() {
    super.onResume();

    location.requestLocationUpdates(provider, 300000, 1000, onLocationChange);
    setUpMapIfNeeded();
}

LocationListener onLocationChange=new LocationListener() {
    public void onLocationChanged(Location location) {
        lng = location.getLongitude();
        lat = location.getLatitude();
    }

    public void onProviderDisabled(String provider) {
        // required for interface, not used
    }

    public void onProviderEnabled(String provider) {
        // required for interface, not used
    }

    public void onStatusChanged(String provider, int status,
                                Bundle extras) {
        // required for interface, not used
    }
};

private void setUpMapIfNeeded() {
    // Do a null check to confirm that we have not already instantiated the map.
    if (mMap == null) {
        // Try to obtain the map from the SupportMapFragment.
        mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                .getMap();
        // Check if we were successful in obtaining the map.
        if (mMap != null) {
            setUpMap();
        }
    }
}

private void setUpMap() {
    mMap.setMapType(mMap.MAP_TYPE_HYBRID);
    mMap.setMyLocationEnabled(true);
    if (lat != 0) {
        LatLng latLng = new LatLng(lat, lng);
        mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
        mMap.animateCamera(CameraUpdateFactory.zoomTo(10));
        Log.d("DEBUG", "succes");
    } else {
        Log.d("DEBUG", "fail");
    }
}

private void downloadJSON(String downloadurl) {
    new JSONDownloader(this, downloadurl).execute();
}

public void updatephotos(JSONArray result) {
    Log.d("Debug arraylength", "" + result.length());
    for (int i = 0; i < result.length(); i++) {
        try {
            pic_lat = result.getJSONObject(i).getDouble("latitudes");
            pic_lng = result.getJSONObject(i).getDouble("longtitudes");
            image = result.getJSONObject(i).getString("images");
            mMap.addMarker(new MarkerOptions().position(new LatLng(lat, lng)));
        } catch (JSONException e) {
            Log.e(Mainmap.LOG_TAG, "JSONException", e);
        }
    }
}

@Override
public void onClick(View v) {
    String downloadurl = "";
    switch (v.getId())
    {
        case R.id.button_popphoto:
            downloadurl = "index.php";
            break;
        case R.id.button_local_position:
            downloadurl = "index.php?yourLat=" + lat + "&yourLng=" + lng;
            break;
    }

    downloadJSON(downloadurl);
}

}

JSONdownloader：

import android.os.AsyncTask;
import android.util.Log;

import org.json.JSONArray;
import org.json.JSONException;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;


public class JSONDownloader extends AsyncTask<Void, Void, JSONArray> {

private Mainmap mm;
private String downloadurl = "http://student.cmi.hro.nl/0876538/Jaar1/Kwartaal3/IMP03/huiswerk/week04/opdracht/libs/php/";

public JSONDownloader(Mainmap mm, String url) {
    this.mm = mm;
    this.downloadurl = downloadurl + url;
}

public JSONArray getPhotos() {
    JSONArray result = new JSONArray();

    HttpURLConnection con = null;
    Log.d(Mainmap.LOG_TAG, "Getting photos");
    try {
        Log.d(Mainmap.LOG_TAG, downloadurl);
        URL url = new URL(downloadurl);
        con = (HttpURLConnection) url.openConnection();
        con.setReadTimeout(10000);
        con.setConnectTimeout(15000);
        con.setRequestMethod("GET");
        con.setDoInput(true);
        con.connect();

        BufferedReader reader = new BufferedReader(
                new InputStreamReader(con.getInputStream(), "UTF-8"));
        String payload = reader.readLine();
        reader.close();
        result = new JSONArray(payload);

    } catch (IOException e) {
        Log.e(Mainmap.LOG_TAG, "IOException", e);
    } catch (JSONException e) {
        Log.e(Mainmap.LOG_TAG, "JSONException", e);
    } catch (Exception e) {
        Log.d(Mainmap.LOG_TAG, "Something went wrong....", e);
    } finally {
        if (con != null) {
            con.disconnect();
        }
    }
    Log.d(Mainmap.LOG_TAG, "-> returned: " + result);

    return result;
}

@Override
protected JSONArray doInBackground(Void... params) {
    JSONArray photos = getPhotos();
    return photos;
}

@Override
protected void onPostExecute(JSONArray result) {
    super.onPostExecute(result);

    mm.updatephotos(result);
}
}