GoogleMap.addMarkerエラーNullPointerException

Question

GoogleMapにNullPointerExceptionを追加しました。を追加しました。
この問題を解決するのを手伝ってください。

エラー：

08-10 12:49:20.787 6670-6670/com.example.taxiproject E/AndroidRuntime: FATAL EXCEPTION: main 
Process: com.example.taxiproject, PID: 6670 
java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.android.gms.maps.model.Marker com.google.android.gms.maps.GoogleMap.addMarker(com.google.android.gms.maps.model.MarkerOptions)' on a null object reference 
at com.example.taxiproject.DriverPositionActivity$GetLocations.onPostExecute(DriverPositionActivity.java:523) 
at com.example.taxiproject.DriverPositionActivity$GetLocations.onPostExecute(DriverPositionActivity.java:437) 

これでDriverPositionActivity.java:523ラインコード：

markers=new HashMap<Marker, Driver>(); 
       removeMarkers(); 

       for (int i = 0; i < drivers.size(); i++) { 
        MarkerOptions mark=new MarkerOptions(); 
        mark.position(new LatLng(Double.parseDouble(drivers.get(i).getLatitude()),Double.parseDouble(drivers.get(i).getLongitude()))); 
        mark.title(drivers.get(i).getName()); 
        mark.icon(BitmapDescriptorFactory.fromResource(R.drawable.taxi)); 
        //mark.snippet(drivers.get(i).getInfo()+","+drivers.get(i).getCost()+" Rs.pKm, Ph. "+drivers.get(i).getNumber()); 
     -----------------> Marker m=googleMap.addMarker(mark); 
        mapMarker.add(m); 
        markers.put(m, drivers.get(i)); 
} 

これでDriverPositionActivity.java:437ラインコード：あなたはgoogleMapオブジェクトを宣言していなかった

class GetLocations extends AsyncTask<String, String, String> { 

    ProgressDialog pDialog; 
    String toastText="Internet Problem"; 
    String regiresult=""; 
    int success=0; 
    int error=0; 
    String errmsg="Server is down"; 

    @Override 
    protected void onPreExecute() { 
     super.onPreExecute(); 
     pDialog=new ProgressDialog(con); 
     pDialog.setMessage("Updating drivers locations. Please wait..."); 
     pDialog.setIndeterminate(false); 
     pDialog.setCancelable(true); 
     pDialog.show(); 
    } 

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

     List<NameValuePair> params=new ArrayList<NameValuePair>(); 
     JSONObject json=jparser.makeHttpRequest(getDataUrl, "POST", params); 

     try { 
      success=json.getInt("success"); 
      if(success==1){ 

       drivers=new ArrayList<Driver>(); 

       JSONArray sounds=json.getJSONArray("location"); 
       for (int i = 0; i < sounds.length(); i++) { 
        JSONObject jobj=sounds.getJSONObject(i); 
        Driver d=new Driver(); 
        d.setId(jobj.getString("id")); 
        d.setName(jobj.getString("name")); 
        d.setEmail(jobj.getString("email")); 
        d.setNumber(jobj.getString("number")); 
        d.setLatitude(jobj.getString("latitude")); 
        d.setLongitude(jobj.getString("longitude")); 
        d.setInfo(jobj.getString("info")); 
        d.setCost(jobj.getString("cost")); 


        drivers.add(d); 
       } 
      } 

     } catch (JSONException e) { 
      e.printStackTrace(); 
      error=1; 
     }catch (Exception e) { 
      error=1; 
     } 
     return null; 
    } 

    @Override 
    protected void onPostExecute(String result) { 
     super.onPostExecute(result); 
     //Toast.makeText(MainActivity.this, s+" "+result, Toast.LENGTH_SHORT).show(); 
     pDialog.dismiss(); 

     if(error==1){ 
      if(Util.isConnectingToInternet(con)){ 
       Toast.makeText(con,"Server is down. Please try again", Toast.LENGTH_SHORT).show(); 
      }else{ 
       Util.showNoInternetDialog(con); 
      } 
      return; 
     } 

     if(success==0){ 
      Toast.makeText(con,"Data loading failed", Toast.LENGTH_SHORT).show(); 
     }else if (success==1){ 

      markers=new HashMap<Marker, Driver>(); 
      removeMarkers(); 

      for (int i = 0; i < drivers.size(); i++) { 
       MarkerOptions mark=new MarkerOptions(); 
       mark.position(new LatLng(Double.parseDouble(drivers.get(i).getLatitude()),Double.parseDouble(drivers.get(i).getLongitude()))); 
       mark.title(drivers.get(i).getName()); 
       mark.icon(BitmapDescriptorFactory.fromResource(R.drawable.taxi)); 
       //mark.snippet(drivers.get(i).getInfo()+","+drivers.get(i).getCost()+" Rs.pKm, Ph. "+drivers.get(i).getNumber()); 
       Marker m=googleMap.addMarker(mark); 
       mapMarker.add(m); 
       markers.put(m, drivers.get(i)); 
      } 
      scheduleThread(); 
     } 
    } 
} 

Answer 1

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