从json添加多个标记

Question

我正在尝试从 json 在 google map v2 上添加多个标记 这是我迄今为止尝试过的，但无法在地图上找到单个标记。

我觉得我在添加标记时犯了错误， 我应该添加另一种添加标记的方法还是应该准备好地图 或者我应该使用两个单独的活动，一个用于谷歌地图，另一个用于 JSON，如果您可以在这里提出一些更正建议。

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
    HashMap<String, Double> resultp;
    private String TAG = MapsActivity.class.getSimpleName();
    private ProgressDialog pDialog;
    private static String url = "https://api.myjson.com/bins/1an69r";
    ArrayList<HashMap<String, String>> placeList;
    ArrayList<HashMap<String, Double>> Coordinate;
    private GoogleMap mMap;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        new GetPlace().execute();
       placeList = new ArrayList<>();
        Coordinate = new ArrayList<>();
         resultp = new HashMap<>();
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);

    }
    private class GetPlace extends AsyncTask<Void, Void, Void> {

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

                pDialog = new ProgressDialog(MapsActivity.this);
                pDialog.setMessage("wait bro");
                pDialog.setCancelable(false);
                pDialog.show();

            }

            @Override
            protected Void doInBackground(Void... arg0) {
                HttpHandler sh = new HttpHandler();


                String jsonStr = sh.makeServiceCall(url);

                Log.e(TAG, "Response from url: " + jsonStr);

                if (jsonStr != null) {
                    try {
                        JSONObject jsonObj = new JSONObject(jsonStr);

                        // Getting JSON Array node
                        JSONArray places = jsonObj.getJSONArray("places");

                        // looping through All places
                        for (int i = 0; i < places.length(); i++) {
                            JSONObject c = places.getJSONObject(i);

                            String id = c.getString("id");
                            String name = c.getString("name");
                            String city = c.getString("city");
                            String needle = c.getString("needle");
                            Double lat = c.getDouble("lat");
                            Double lng = c.getDouble("lng");
                            String rating = c.getString("rating");


                            // tmp hash map for single contact
                            HashMap<String, String> place = new HashMap<>();

                            // adding each child node to HashMap key => value
                            place.put("id", id);
                            place.put("name", name);
                            place.put("city", city);
                            place.put("needle", needle );
                            place.put("rating",rating);
                            placeList.add(place);
                            //adding to new hashmap 
                            HashMap<String, Double> lace = new HashMap<>();
                            lace.put("lat",lat);
                            lace.put("lng",lng);
                            // adding contact to place list
                            Coordinate.add(lace);

                        }
                    } catch (final JSONException e) {
                        Log.e(TAG, "Json parsing error: " + e.getMessage());
                        runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                Toast.makeText(getApplicationContext(),
                                        "Json parsing error: " + e.getMessage(),
                                        Toast.LENGTH_LONG)
                                        .show();
                            }
                        });

                    }
                } else {
                    Log.e(TAG, "Couldn't get json from server.");
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            Toast.makeText(getApplicationContext(),
                                    "Couldn't get json from server. Check LogCat for possible errors!",
                                    Toast.LENGTH_LONG)
                                    .show();
                        }
                    });

                }

                return null;
            }

            @Override
            protected void onPostExecute(Void result) {
                super.onPostExecute(result);
                // Dismiss the progress dialog
                if (pDialog.isShowing())
                    pDialog.dismiss();


            }

        }

    **@Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;
   for( int i=0;i<Coordinate.size();i++)
        {

           resultp = Coordinate.get(i);
          Double lAT = resultp.get("lat");
            Double lNG = resultp.get("lng");

            //Plot latitude and longitude in the map

            LatLng lk = new LatLng(lAT,lNG);

            googleMap.addMarker(new MarkerOptions().position(new    LatLng(lAT, lNG)));
            Log.e("PlaceLL",lAT+" "+lNG);

        }**
    }

}

Answer 1

请在 Mapready 而不是 onCreate 上调用 asynTask，并在 PostExe 而不是 onDoingBackground 上解析 JSON。在 Mapready 上，确保在你的 asyntask 完成之前地图已经准备好。如果 OnCreate 中的 asynTask 在加载地图之前完成，您将不会在地图上看到任何标记。和解析 JSON 代码一样，把它放在 onPostExe 中，确保你有来自服务器的结果。