Question

我正在尝试使用标记在Google地图上的MySql中绘制经度纬度值。获取经度纬度值的代码是正确的，因为代码在使用Toast Message时显示这些值。问题是一切都很顺利，除了我在谷歌地图上看不到任何标记。这是我的源代码。

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {

private GoogleMap mMap;
private String JSON_STRING;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_maps);

    // Obtain the SupportMapFragment and get notified when the map is ready to be used.
    SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
            .findFragmentById(map);
    mapFragment.getMapAsync(this);


}


@Override
public void onMapReady(GoogleMap googleMap) {
    mMap = googleMap;
    getJSON();



   /* LatLng sydney = new LatLng(33, 88);
    mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
    mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
*/
}


private void showLongLat(){
    JSONObject jsonObject = null;

    try {
        jsonObject = new JSONObject(JSON_STRING);
        JSONArray result = jsonObject.getJSONArray(Config.TAG_JSON_ARRAY);

        for(int i = 0; i<result.length(); i++){
            JSONObject jo = result.getJSONObject(i);
            String id = jo.getString(Config.TAG_ID);
            String longitude = jo.getString(Config.TAG_LONG);
            String latitude = jo.getString(Config.TAG_LAT);
           Toast.makeText(getApplicationContext(),latitude+longitude,Toast.LENGTH_LONG).show();

           LatLng marker = new LatLng(Double.parseDouble(longitude),Double.parseDouble(latitude));

            //LatLng sydney = new LatLng(42+i,87-i);

            mMap.addMarker(new MarkerOptions().position(marker).title("Marker Somewhere"));
            mMap.moveCamera(CameraUpdateFactory.newLatLng(marker));

        }

    } catch (JSONException e) {
        e.printStackTrace();
    }


}




private void getJSON(){
    class GetJSON extends AsyncTask<Void,Void,String>{

        ProgressDialog loading;
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            loading = ProgressDialog.show(MapsActivity.this,"Fetching Data","Wait...",false,false);
        }

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            loading.dismiss();
            JSON_STRING = s;
            showLongLat();
        }

        @Override
        protected String doInBackground(Void... params) {
            RequestHandler rh = new RequestHandler();
            String s = rh.sendGetRequest(Config.URL_GET_ALL);
            return s;
        }
    }
    GetJSON gj = new GetJSON();
    gj.execute();
}


}

Answer 1

您正在更改纬度和经度的值。这一行：

LatLng marker = new LatLng(Double.parseDouble(longitude),Double.parseDouble(latitude));

必须：

LatLng marker = new LatLng(Double.parseDouble(latitude),Double.parseDouble(longitude));

没有从MySql获取的相应经度纬度值获取地图上的标记

1 个答案: