java - 如何通过hashmap向Google map API添加多个标记？ - (安卓)

Question

我将所有位置的纬度和经度存储在 MySQL 数据库中。我从数据库获取数据并用 JSON 解析它。我将所有解析的值存储在 HashMap 集合中。但是，当我迭代 HashMap 集合时，我只能获取最后一个键/值(而不是全部)。我需要做什么才能获取每个位置的所有键/值？这是我的代码:

package com.example.maptest;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.apache.http.NameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

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

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

public class ShowAllMarkers {

    JSONParser jParser = new JSONParser();

    private static String url_all_markers = "http://...............";

    JSONParser jsonParser = new JSONParser();

    JSONArray markers;
    GoogleMap map;

    // HashMap<String, String> markersList=new HashMap<String, String>();;

    Map<String, String> hMap = new HashMap<String, String>();

    public ShowAllMarkers(GoogleMap map) {
        this.map = map;
    }

    public void getAllMarkers() {
        new AsyncTask<String, String, String>() {

            @Override
            protected String doInBackground(String... args) {

                List<NameValuePair> params = new ArrayList<NameValuePair>();

                JSONObject json = jParser.makeHttpRequest(url_all_markers,
                        "GET", params);

                // in success;
                try {
                    int success = json.getInt("success");

                    if (success == 1) {
                        markers = json.getJSONArray("markers");

                        for (int i = 0; i < markers.length(); i++) {
                            JSONObject markersObject = markers.getJSONObject(i);

                            String lat = markersObject.getString("lat");
                            String longt = markersObject.getString("long");

                            hMap.put("Latitude", lat);
                            hMap.put("Longitude", longt);
                        }
                    }

                } catch (JSONException e) {

                    e.printStackTrace();
                }

                return null;
            }

            @Override
            protected void onPostExecute(String result) {

                // Outputs hashmap elements as key and value
                Set<Map.Entry<String, String>> set = hMap.entrySet();

                for (Map.Entry<String, String> me : set) {
                    Log.d("JWP", "Key is:" + me.getKey() + ", value is: " + me.getValue());

                }
            }

        }.execute();
    }

}

这是我的 json 输出:

{
   "markers":[
      {
         "lat":"40.4176083",
         "long":"49.9389495",
         "title":"Location",
         "description":""
      },
      {
         "lat":"40.4175711",
         "long":"49.9389274",
         "title":"Location",
         "description":""
      },
      {
         "lat":"40.4176178",
         "long":"49.9389621",
         "title":"Location",
         "description":""
      },
      {
         "lat":"40.4176178",
         "long":"49.9389621",
         "title":"Location",
         "description":""
      },
      {
         "lat":"40.4176178",
         "long":"49.9389621",
         "title":"Location",
         "description":""
      },
      {
         "lat":"40.4176178",
         "long":"49.9389621",
         "title":"Location",
         "description":""
      },
      {
         "lat":"40.4176178",
         "long":"49.9389621",
         "title":"Location",
         "description":""
      },
      {
         "lat":"40.4176126",
         "long":"49.9389561",
         "title":"Location",
         "description":""
      }
   ],
   "success":1
}

提前谢谢您。

Answer 1

我认为这是你使用 hashMap 的方式。

如果markers.length()给出的值大于1则意味着它正确加载了标记数组。

看看这些例子，希望对你有帮助 http://java67.blogspot.com.au/2013/02/10-examples-of-hashmap-in-java-programming-tutorial.html

根据接口(interface)，它接收的是key和value对。在您的代码中，您不断用相同的键替换新值。

此外，要检查这一点，您可以找出 hashMap 中有多少个元素，我假设您只有 1 个。

我希望有这样的事情

int key=0;
Loop{

   hMap.put("Latitude_key"+key, lat);
   hMap.put("Longitude_key"+key, longt);
   key++;
}

祝一切顺利