Android Plotten Marker null Zeiger auf postExecute

Question

Wie repariere ich eine java.lang.NullPointerException auf meiner for-Schleife. Ich schätze, ich bekomme keinen Wert bei list_location.size() und auch eine NPE auf sharePreferences onBackground. Was ich versuche, ist, alle Markierungen auf postExecute zu plotten und seine Daten auf gemeinsamen Voreinstellungen zu speichern, während es auf Background läuft.

Frage, wie bekomme ich den Wert von list_location, die hier list_location.add(new LocationHolder(lat, lng, location, remarks)); auf meinem onbackground und bekommen es bei OnPostExecute hinzugefügt wurde?

public class SnailTrailFragment extends Fragment implements OnMapReadyCallback { 

private ProgressDialog pDialog; 

ArrayList<LocationHolder> list_location; 

public static GoogleMap mMapSnailTrail; 

public static String baseUrl = "http://mark.journeytech.com.ph/mobile_api/"; 
public static NetworkAPI networkAPI; 

Context context; 
static Activity activity; 

public SnailTrailFragment(Context c, Activity a) { 
    context = c; 
    activity = a; 
} 

public interface NetworkAPI { 
    @POST("snailtrail.php") 
    @Headers({"Content-Type:application/json; charset=UTF-8"}) 
    Call<JsonElement> loginRequest(@Body SnailTrailPojo body); 
} 

public static class SnailTrailPojo { 
    String platenum; 
    String datetimefrom; 
    String datetimeto; 
    String client_table; 

    public SnailTrailPojo(String platenum, String datetimefrom, String datetimeto, String client_table) { 
     this.platenum = platenum; 
     this.datetimefrom = datetimefrom; 
     this.datetimeto = datetimeto; 
     this.client_table = client_table; 
    } 
} 

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, 
         Bundle savedInstanceState) { 

    // Inflate the layout for this fragment 
    View v = inflater.inflate(R.layout.fragment_contact_us, container, false); 

    return v; 
} 

@Override 
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) { 
    super.onViewCreated(view, savedInstanceState); 
    SupportMapFragment mapFragment = (SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.map1); 
    mapFragment.getMapAsync(this); 

} 

@Override 
public void onMapReady(GoogleMap googleMap) { 
    mMapSnailTrail = googleMap; 
    new GetSnailTrail().execute(); 
    mMapSnailTrail.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(12.405888, 123.273419), 6)); 
} 

class GetSnailTrail extends AsyncTask<Void, Void, Void> { 

    @Override 
    protected void onPreExecute() { 
     super.onPreExecute(); 
     // Showing progress dialog 
     pDialog = new ProgressDialog(getActivity()); 
     pDialog.setMessage("Please wait..."); 
     pDialog.setCancelable(false); 
     pDialog.show(); 
    } 

    @Override 
    protected Void doInBackground(Void... arg0) { 

     HttpLoggingInterceptor logging = new HttpLoggingInterceptor(); 

     logging.setLevel(HttpLoggingInterceptor.Level.BODY); 
     OkHttpClient.Builder httpClient = new OkHttpClient.Builder(); 

     httpClient.addInterceptor(logging); 
     Retrofit retrofit = new Retrofit.Builder() 
       .baseUrl(baseUrl) 
       .addConverterFactory(GsonConverterFactory.create()) 
       .client(httpClient.build()) 
       .build(); 

     networkAPI = retrofit.create(NetworkAPI.class); 

     SnailTrailPojo loginRequest = new SnailTrailPojo(vm.getPlate_num(), /*"08/03/2017 00:00:00"*/ BottomSheetModalFragment.dateFrom, "08/04/2017 23:59:59", client_table); 

     System.out.println(vm.getPlate_num() + client_table + BottomSheetModalFragment.dateFrom + " asdas"); 

     Call<JsonElement> call = networkAPI.loginRequest(loginRequest); 

     call.enqueue(new Callback<JsonElement>() { 
      @Override 
      public void onResponse(Call<JsonElement> call, Response<JsonElement> response) { 
       // success response 
       if (response.body().isJsonArray()) { 
        JsonArray objectWhichYouNeed = response.body().getAsJsonArray(); 
    //     System.out.println(response.body() + " "+ "Response"); 

        list_location = new ArrayList<>(); 
        for (int i = 0; i < response.body().getAsJsonArray().size(); i++) { 

         JsonElement location_array = response.body().getAsJsonArray().get(i); 
         JsonObject location_obj = location_array.getAsJsonObject(); 
         String location = location_obj.get("location").toString(); 

         JsonElement lat_array = response.body().getAsJsonArray().get(i); 
         JsonObject lat_obj = lat_array.getAsJsonObject(); 
         String lati = lat_obj.get("lat").toString(); 
         String latiString = lati; 
         latiString = latiString.replace("\"", ""); 
         String lat = String.valueOf(latiString); 

         JsonElement lng_array = response.body().getAsJsonArray().get(i); 
         JsonObject lng_obj = lng_array.getAsJsonObject(); 
         String longi = lng_obj.get("lng").toString(); 
         String longiString = longi; 
         longiString = longiString.replace("\"", ""); 
         String lng = String.valueOf(longiString); 

         JsonElement remarks_array = response.body().getAsJsonArray().get(i); 
         JsonObject remarks_obj = remarks_array.getAsJsonObject(); 
         String remarks = remarks_obj.get("remarks").toString(); 
         if (lat != null && !lat.equals("null") && (lng != null && !lng.equals("null"))) { 
          list_location.add(new LocationHolder(lat, lng, location, remarks)); 
         } 



         SharedPreferences preferences = context.getSharedPreferences("AppPrefs", MODE_PRIVATE); 
         SharedPreferences.Editor prefsEditor = preferences.edit(); 

         Gson gson = new Gson(); 

         String jsonText = gson.toJson(list_location); 
         prefsEditor.putString("key", jsonText); 
         prefsEditor.commit(); 
        } 

       } else { 
        System.out.println("Not a JSONArray."); 
       } 
      } 

      @Override 
      public void onFailure(Call<JsonElement> call, Throwable t) { 
       // failure response 
       System.out.println("Fail " + call.toString()); 
      } 

     }); 

     return null; 
    } 

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

final PolylineOptions polylineOptions = new PolylineOptions(); 
          for (int j = 0; j < list_location.size(); j++) { 

           // Setting the color of the polyline 
           polylineOptions.color(Color.RED); 

           // Setting the width of the polyline 
           polylineOptions.width(3); 

           Double d1 = Double.parseDouble(list_location.get(j).getLatitude()); 
           Double d2 = Double.parseDouble(list_location.get(j).getLongitude()); 

           Toast.makeText(getContext(), d1 + d2.toString(),Toast.LENGTH_LONG).show(); 
           // Setting points of polyline 
           polylineOptions.add(new LatLng(d1, d2)); 

           createMarker(j, d1, d2, list_location.get(j).getRemarks()); 

          } 
          // Adding the polyline to the map 
          mMapSnailTrail.addPolyline(polylineOptions); 

/*   Gson gson = new Gson(); 
     SharedPreferences myPrefs; 
     myPrefs = context.getSharedPreferences("AppPrefs", MODE_PRIVATE); 
     String jsonText = myPrefs.getString("key", null); 

     Type collectionType = new TypeToken<List<LocationHolder>>(){}.getType(); 
     List<LocationHolder> addArray= (List<LocationHolder>) new Gson() 
       .fromJson(jsonText , collectionType);*/ 

    } 
} 

public void createMarker(int index, Double latitude, Double longitude, String snippet) { 
    // Adding the taped point to the ArrayList 
    BitmapDescriptor image = BitmapDescriptorFactory.fromResource(R.drawable.bus); 

    mMapSnailTrail.addMarker(new MarkerOptions() 
      .position(new LatLng(latitude, longitude)) 
      .anchor(0.5f, 0.5f) 
      .title(snippet) 
      .snippet(snippet) 
      .icon(image)); 

    mMapSnailTrail.animateCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(latitude, longitude), 15.0f)); 

    mMapSnailTrail.setOnInfoWindowClickListener(new GoogleMap.OnInfoWindowClickListener() { 
     @Override 
     public void onInfoWindowClick(Marker marker) { 
      marker.hideInfoWindow(); 
     } 
    }); 
} 

public class MarkerInfoWindowAdapter implements GoogleMap.InfoWindowAdapter { 

    public MarkerInfoWindowAdapter() { 
    } 

    @Override 
    public View getInfoWindow(Marker marker) { 
     return null; 
    } 

    @Override 
    public View getInfoContents(final Marker marker) { 
     View v = getActivity().getLayoutInflater().inflate(R.layout.marker_popup, null); 
     Button b = (Button) v.findViewById(R.id.button2); 
     b.setOnClickListener(new Button.OnClickListener() { 

      @Override 
      public void onClick(View v) { 
       marker.hideInfoWindow(); 
      } 
     }); 
     TextView markerLabel = (TextView) v.findViewById(R.id.textView2); 
     markerLabel.setText(""); 

     return v; 
    } 
} 
} 

Logs

java.lang.NullPointerException 
                at com.journeytech.mark.mark.fragment.SnailTrailFragment$GetSnailTrail.onPostExecute(SnailTrailFragment.java:227) 
                at com.journeytech.mark.mark.fragment.SnailTrailFragment$GetSnailTrail.onPostExecute(SnailTrailFragment.java:122) 
                at android.os.AsyncTask.finish(AsyncTask.java:632) 
                at android.os.AsyncTask.access$600(AsyncTask.java:177) 
                at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645) 
                at android.os.Handler.dispatchMessage(Handler.java:102) 
                at android.os.Looper.loop(Looper.java:136) 
                at android.app.ActivityThread.main(ActivityThread.java:5021) 
                at java.lang.reflect.Method.invokeNative(Native Method) 
                at java.lang.reflect.Method.invoke(Method.java:515) 
                at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:827) 
                at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:643) 

Hier ist das zweite Protokoll

java.lang.NullPointerException bei com.journeytech.mark.mark.fragment.SnailTrailFragment $ GetSnailTrail $ 1.einResponse (SnailTrailFragment.java:212) bei retrofit2.ExecutorCallAdapterFactory $ ExecutorCallbackCall $ 1 $ 1.run (ExecutorCallAdapterFactory.java:68) bei android.os.Handler.handleCallback (Handler.java:733) bei android.os.Handler.dispatchMessage (Handler.java:95) bei android.os.Looper.loop (Looper.java:136) bei android.app.ActivityThread.main (ActivityThread.java:5021) bei java.lang.reflect.Method.invokeNative (native Methode) bei java.lang.reflect.Method.invoke (Method.java:515) bei com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run (ZygoteInit.java:827)

Answer 1

Problem:

Sie Retrofit verwenden reponse mit enqueue zu erhalten, die asynchron die Anforderung sendet.

Nein, was Sie tun, ruft enqueue asynchron, und es gibt keine Notwendigkeit dafür. Ihre AsyncTask endet, bevor Sie Ihre Antwort erhalten in onResponse und wenn Sie eine For-Schleife in Ihrem postExecute Sie Null Zeiger, weil die Liste noch nicht aktualisiert und Sie versuchen, darauf zuzugreifen.

@Override 
public void onMapReady(GoogleMap googleMap) { 
    mMapSnailTrail = googleMap; 
    // Remove asynctask since you are already using retrofit enqueue 
    // new GetSnailTrail().execute(); 
    //Create a new method to call api using retrofit 
    getDataFromServer(); 
    mMapSnailTrail.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(12.405888, 123.273419), 6)); 
} 

private void getDataFromServer() { 

    /** 
    *Show Progress dialog here  
    */ 

    HttpLoggingInterceptor logging = new HttpLoggingInterceptor(); 

    logging.setLevel(HttpLoggingInterceptor.Level.BODY); 
    OkHttpClient.Builder httpClient = new OkHttpClient.Builder(); 

    httpClient.addInterceptor(logging); 
    Retrofit retrofit = new Retrofit.Builder() 
      .baseUrl(baseUrl) 
      .addConverterFactory(GsonConverterFactory.create()) 
      .client(httpClient.build()) 
      .build(); 

    networkAPI = retrofit.create(NetworkAPI.class); 

    SnailTrailPojo loginRequest = new SnailTrailPojo(vm.getPlate_num(), /*"08/03/2017 00:00:00"*/ BottomSheetModalFragment.dateFrom, "08/04/2017 23:59:59", client_table); 

    System.out.println(vm.getPlate_num() + client_table + BottomSheetModalFragment.dateFrom + " asdas"); 

    Call<JsonElement> call = networkAPI.loginRequest(loginRequest); 

    call.enqueue(new Callback<JsonElement>() { 
     @Override 
     public void onResponse(Call<JsonElement> call, Response<JsonElement> response) { 
      // success response 

      /** 
      * Hide the progress dialog here 
      */ 

      if (response.body().isJsonArray()) { 
       JsonArray objectWhichYouNeed = response.body().getAsJsonArray(); 
       //     System.out.println(response.body() + " "+ "Response"); 

       list_location = new ArrayList<>(); 
       for (int i = 0; i < response.body().getAsJsonArray().size(); i++) { 

        JsonElement location_array = response.body().getAsJsonArray().get(i); 
        JsonObject location_obj = location_array.getAsJsonObject(); 
        String location = location_obj.get("location").toString(); 

        JsonElement lat_array = response.body().getAsJsonArray().get(i); 
        JsonObject lat_obj = lat_array.getAsJsonObject(); 
        String lati = lat_obj.get("lat").toString(); 
        String latiString = lati; 
        latiString = latiString.replace("\"", ""); 
        String lat = String.valueOf(latiString); 

        JsonElement lng_array = response.body().getAsJsonArray().get(i); 
        JsonObject lng_obj = lng_array.getAsJsonObject(); 
        String longi = lng_obj.get("lng").toString(); 
        String longiString = longi; 
        longiString = longiString.replace("\"", ""); 
        String lng = String.valueOf(longiString); 

        JsonElement remarks_array = response.body().getAsJsonArray().get(i); 
        JsonObject remarks_obj = remarks_array.getAsJsonObject(); 
        String remarks = remarks_obj.get("remarks").toString(); 
        if (lat != null && !lat.equals("null") && (lng != null && !lng.equals("null"))) { 
         list_location.add(new LocationHolder(lat, lng, location, remarks)); 
        } 



        SharedPreferences preferences = context.getSharedPreferences("AppPrefs", MODE_PRIVATE); 
        SharedPreferences.Editor prefsEditor = preferences.edit(); 

        Gson gson = new Gson(); 

        String jsonText = gson.toJson(list_location); 
        prefsEditor.putString("key", jsonText); 
        prefsEditor.commit(); 


        //Move the on postExecute code here 

        final PolylineOptions polylineOptions = new PolylineOptions(); 
        for (int j = 0; j < list_location.size(); j++) { 

         // Setting the color of the polyline 
         polylineOptions.color(Color.RED); 

         // Setting the width of the polyline 
         polylineOptions.width(3); 

         Double d1 = Double.parseDouble(list_location.get(j).getLatitude()); 
         Double d2 = Double.parseDouble(list_location.get(j).getLongitude()); 

         Toast.makeText(getContext(), d1 + d2.toString(),Toast.LENGTH_LONG).show(); 
         // Setting points of polyline 
         polylineOptions.add(new LatLng(d1, d2)); 

         createMarker(j, d1, d2, list_location.get(j).getRemarks()); 

        } 
        // Adding the polyline to the map 
        mMapSnailTrail.addPolyline(polylineOptions); 

       } 

      } else { 
       System.out.println("Not a JSONArray."); 
      } 
     } 

     @Override 
     public void onFailure(Call<JsonElement> call, Throwable t) { 
      // failure response 
      System.out.println("Fail " + call.toString()); 
     } 

    }); 
}