如何在谷歌地图中移动标记以进行车辆跟踪应用程序

Question

在我的应用程序中，我想跟踪车辆，从 JSON 中获取多个纬度和经度标记上一个标记仍然存在。如何删除上一个位置的标记

private void setUpMapIfNeeded(View inflatedView) {
if (mMap == null) { 
            mMap = ((MapView) inflatedView.findViewById(R.id.mapView)).getMap(); 
            mMap.setMyLocationEnabled(true); 

            Location myLocation = mMap.getMyLocation(); 
            if (mMap != null) {  
                //mMap.clear();

                // setUpMap(); 
                mMap.setOnMyLocationChangeListener(new GoogleMap.OnMyLocationChangeListener() { 

                    @Override 
                    public void onMyLocationChange(Location arg0) { 

                        // TODO Auto-generated method stub 
                        final LatLngBounds.Builder builder = new LatLngBounds.Builder(); 
                     mMap.clear();
                        if (marker != null) {
                             marker.remove();
                         }
                        for (int i = 0; i < arraylist1.size(); i++) { 
                            final LatLng position = new LatLng(Double 
                                    .parseDouble(arraylist1.get(i).get("Latitude")), 
                                    Double.parseDouble(arraylist1.get(i).get( 
                                            "Longitude"))); 
                            String ime1 = arraylist1.get(i).get("IME");

                            final MarkerOptions options = new MarkerOptions() 
                            .position(position); 
                            //mMap.addMarker(options); 
                            //mMap.addMarker(options.icon(BitmapDescriptorFactory .fromResource(R.drawable.buspng)).title(ime1));

                              marker=mMap.addMarker(new MarkerOptions().position(position).icon(BitmapDescriptorFactory .fromResource(R.drawable.buspng)).title(ime1));

                            //options.title(ime1);
                            builder.include(position); 

                        } 
                        LatLng latLng = new LatLng(arg0.getLatitude(), arg0 
                                .getLongitude()); 
                        mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
                        mMap.setMyLocationEnabled(true); 

                        mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng)); 
                        // mMap.setOnMapClickListener(null); 
                        mMap.setOnMarkerClickListener(null); 

                        mMap.animateCamera(CameraUpdateFactory.zoomTo(9)); 
                    } 
                }); 

            } 
        } 
    } 

    /*  protected void retrieveAndAddCities() throws IOException { 
        HttpURLConnection conn = null; 
        final StringBuilder json = new StringBuilder(); 
        try { 

            URL url = new URL(SERVICE_URL); 
            conn = (HttpURLConnection) url.openConnection(); 
            InputStreamReader in = new InputStreamReader(conn.getInputStream()); 

            int read; 
            char[] buff = new char[1024]; 
            while ((read = in.read(buff)) != -1) { 
                json.append(buff, 0, read); 
            } 
        } catch (IOException e) { 
            Log.e(LOG_TAG, "Error connecting to service", e); 
            throw new IOException("Error connecting to service", e); 
        } finally { 
            if (conn != null) { 
                conn.disconnect(); 
            } 
        } 
        new DownloadJSON().execute(); 

    } */

    private class DownloadJSON extends AsyncTask<Void, Void, Void> { 
        String result=""; 
        @Override 
        protected void onPreExecute() { 
            super.onPreExecute(); 
        }

        @Override 
        protected Void doInBackground(Void... params) { 
            try { 
                arraylist1 = new ArrayList<HashMap<String, String>>(); 

                JSONParser jParser = new JSONParser(); 
                String result = ""; 

                json = jParser.getJSONFromUrl(SERVICE_URL); 

                try { 
                    //arraylist1.clear(); 

                    jsonarray = json.getJSONArray("SingleIMEs"); 
                    Log.d("Haaaaaaaaaaaa", "" + json); 

                    for (int i = 0; i < jsonarray.length(); i++) { 
                        Log.d("H11111111111111111111111111", 
                                "" + jsonarray.length()); 
                        map = new HashMap<String, String>(); 
                        json = jsonarray.getJSONObject(i); 

                        // pubname = json.getString("PubName"); 
                        latitude = json.getDouble("Latitude"); 
                        longitude = json.getDouble("Longitude"); 
                        ime = json.getString("IME");
                        //  map.put("PubName", json.getString("PubName")); 
                        //map.put("PubID", json.getString("PubID")); 
                        map.put("Latitude", json.getString("Latitude")); 
                        Log.e("CHECKLAT",""+json.getString("Latitude") );
                        map.put("Longitude", json.getString("Longitude")); 
                        Log.e("CHECKLONG",""+json.getString("Longitude") );

                        map.put("IME", json.getString("IME"));
                        arraylist1.add(map); 
                    } 

                } catch (JSONException e) { 
                    Log.e("log_tag", "Error parsing data " + e.toString()); 
                    result="Error"; 
                    e.printStackTrace(); 
                } 
            }catch(Exception e){ 
                result="Error"; 
            } 

            return null; 
        } 

        protected void onPostExecute(Void args) { 

            // mProgressDialog.dismiss(); 

        } 
    } 

    @Override 
    public void onResume() { 
        super.onResume(); 
        mMapView.onResume(); 
    } 

    @Override 
    public void onPause() { 
        super.onPause(); 
        mMapView.onPause(); 
    } 

    @Override 
    public void onDestroy() { 
        mMapView.onDestroy(); 
    super.onDestroy(); 
    }

    @Override
    public void onLocationChanged(Location location) {
        // TODO Auto-generated method stub

   /* Toast.makeText(getActivity(), "onLocationUpdated!!!", Toast.LENGTH_SHORT).show();
        Log.d("onLocationUpdated!!!","");
        new DownloadJSON().execute(); 
        setUpMapIfNeeded(rootView);*/

    }


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

    }

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

    }

    @Override
    public void onProviderDisabled(String provider) {

        // TODO Auto-generated method stub

    } 


}

Answer 1

if (marker != null) {
    marker.remove();
}

你真的有一个功能来删除这里的标记吗？如果没有，您必须从地图中删除标记并将其设置为 null 才能将其删除。

marker.setMap(null);

来源：marker API documentation