マップ上に位置を表示するためのJSON配列の呼び出しに失敗しました

-2

私はマップ上にJSONを使用してマップ上にいくつかのマーカーを表示しようとしました。マップ上に位置を表示するためのJSON配列の呼び出しに失敗しました

route_activity.java

import java.util.ArrayList; 

import org.json.JSONObject; 

import com.google.android.gms.common.ConnectionResult; 
import com.google.android.gms.common.GooglePlayServicesUtil; 
import com.google.android.gms.maps.CameraUpdateFactory; 
import com.google.android.gms.maps.GoogleMap; 
import com.google.android.gms.maps.SupportMapFragment; 
import com.google.android.gms.maps.model.LatLng; 
import com.google.android.gms.maps.model.MarkerOptions; 

import android.app.ProgressDialog; 
import android.content.Context; 
import android.location.Criteria; 
import android.location.Location; 
import android.location.LocationManager; 
import android.os.AsyncTask; 
import android.os.Bundle; 
import android.support.v4.app.FragmentActivity; 
import android.support.v4.app.FragmentManager; 
import android.view.Menu; 

public class route_activity extends FragmentActivity { 
    private GoogleMap    map; 
    private JSONHelper    json; 
    private ProgressDialog   pDialog; 

    private ArrayList<route_list> listHalte; 
    private final String   URL_API = "http://nfcworld.web.id/wibisono/retrieve.php"; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) 
    { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.map_route); 
     json = new JSONHelper(); 

     new AsynTaskMain().execute(); 

     setupMapIfNeeded(); 
    } 

    @Override 
    public void onPause(){ 

     super.onPause(); 
     if(pDialog != null) 
      pDialog.dismiss(); 
    } 

    private void setupMapIfNeeded() 
    { 
     if (map == null) 
     { 
      FragmentManager fragmentManager = getSupportFragmentManager(); 
      SupportMapFragment supportMapFragment = (SupportMapFragment) fragmentManager.findFragmentById(R.id.map); 
      map = supportMapFragment.getMap(); 

      if (map != null) 
      { 
       setupMap(); 
      } 
     } 

    } 

    private void setupMap() 
    { 
     map.setMyLocationEnabled(true); 
     moveToMyLocation(); 
    } 

    private void moveToMyLocation() 
    { 
     LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE); 
     Criteria criteria = new Criteria(); 

     Location location = locationManager.getLastKnownLocation(locationManager.getBestProvider(criteria, false)); 
     if (location != null) 
     { 
      map.animateCamera(CameraUpdateFactory.newLatLngZoom(
        new LatLng(location.getLatitude(), location.getLongitude()), 17)); 
     } 
    } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) 
    { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.support_map, menu); 
     return true; 
    } 

    @Override 
    protected void onResume() 
    { 
     // TODO Auto-generated method stub 
     super.onResume(); 
//line 102 
     int resCode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getApplicationContext()); 
     if (resCode != ConnectionResult.SUCCESS) 
     { 
      GooglePlayServicesUtil.getErrorDialog(resCode, this, 1); 
     } 
    } 

    private class AsynTaskMain extends AsyncTask<Void, Void, Void> 
    { 

     @Override 
     protected void onPostExecute(Void result) 
     { 
      // TODO Auto-generated method stub 
      pDialog.dismiss(); 
      runOnUiThread(new Runnable() 
      { 

       @Override 
       public void run() 
       { 
        // TODO Auto-generated method stub 
        for (int i = 0; i < listHalte.size(); i++) 
        { 
         map.addMarker(new MarkerOptions() 
           .position(new LatLng(listHalte.get(i).getLat(), listHalte.get(i).getLng())) 
           .title(listHalte.get(i).getNama())); 

        } 
       } 
      }); 

      super.onPostExecute(result); 
     } 

     @Override 
     protected void onPreExecute() 
     { 
      // TODO Auto-generated method stub 
      super.onPreExecute(); 
      pDialog = new ProgressDialog(route_activity.this); 
      pDialog.setMessage("Loading...."); 
      pDialog.setCancelable(true); 
      pDialog.show(); 
     } //line 147 

     @Override 
     protected Void doInBackground(Void... params) 
     { 
      // TODO Auto-generated method stub 

      JSONObject jObject = json.getJSONFromURL(URL_API); 
      listHalte = json.gethalteAll(jObject); 
      return null; 
     } 
    } 

}

JSONHelper.java

import android.util.Log; 

import com.google.android.gms.maps.model.LatLng; 
/** 
* Created by wibisono on 10/19/2016. 
*/ 

public class JSONHelper { 

    private InputStream  is    = null; 
    private JSONObject  jsonObject  = null; 
    private String   json   = ""; 

    private final String TAG_HALTE  = "halte"; 
    private final String TAG_ID   = "id"; 
    private final String TAG_NAMA  = "nama"; 
    private final String TAG_LAT   = "lat"; 
    private final String TAG_LNG   = "lng"; 

    public JSONObject getJSONFromURL(String url) 
    { 
     try 
     { 
      DefaultHttpClient httpClient = new DefaultHttpClient(); 
      HttpGet httpGet = new HttpGet(url); 

      HttpResponse httpResponse = httpClient.execute(httpGet); 
      HttpEntity httpEntity = httpResponse.getEntity(); 
      is = httpEntity.getContent(); 
     } catch (UnsupportedEncodingException e) 
     { 
      e.printStackTrace(); 
     } catch (ClientProtocolException e) 
     { 
      e.printStackTrace(); 
     } catch (IOException e) 
     { 
      e.printStackTrace(); 
     } 

     try 
     { 
      BufferedReader reader = new BufferedReader(new InputStreamReader(
        is, "iso-8859-1"), 8); 

      StringBuilder sb = new StringBuilder(); 
      String line = null; 

      while ((line = reader.readLine()) != null) 
      { 
       sb.append(line + "\n"); 
      } 

      is.close(); 
      json = sb.toString(); 
     } catch (Exception e) 
     { 
      // TODO: handle exception 
     } 

     try 
     { 
      jsonObject = new JSONObject(json); 

     } catch (JSONException e) 
     { 
      // TODO: handle exception 
     } 

     return jsonObject; 
    } 

    public ArrayList<route_list> gethalteAll(JSONObject jobj) 
    { 
     ArrayList<route_list> listhalte = new ArrayList<route_list>(); 

     try 
     { 
      JSONArray arrayhalte = jobj.getJSONArray(TAG_HALTE); //line 99 

      for (int i = 0; i < arrayhalte.length(); i++) 
      { 
       JSONObject jobject = arrayhalte.getJSONObject(i); 

       Log.d("log", "muter ke " + i); 
       listhalte.add(new route_list(jobject.getInt(TAG_ID), jobject.getString(TAG_NAMA), jobject 
         .getDouble(TAG_LAT), jobject.getDouble(TAG_LNG))); 

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

route_list.java

import android.app.Fragment; 
import android.os.Bundle; 
import android.support.annotation.Nullable; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
/** 
* Created by wibisono on 10/8/2016. 
*/ 
public class route_list { 
    private int id; 
    private String nama; 
    private double lat; 
    private double lng; 

    public route_list() 
    { 
     // TODO Auto-generated constructor stub 
    } 

    public route_list(int id, String nama, double lat, double lng) 
    { 
     super(); 
     this.id = id; 
     this.nama = nama; 
     this.lat = lat; 
     this.lng = lng; 
    } 

    public String getNama() 
    { 
     return nama; 
    } 

    public void setNama(String nama) 
    { 
     this.nama = nama; 
    } 

    public double getLat() 
    { 
     return lat; 
    } 

    public void setLat(double lat) 
    { 
     this.lat = lat; 
    } 

    public double getLng() 
    { 
     return lng; 
    } 

    public void setLng(double lng) 
    { 
     this.lng = lng; 
    } 

}

LogCat

11-22 23:30:57.355 15576-15767/? E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1 
                Process: com.example.wibisono.tryhard_1, PID: 15576 
                java.lang.RuntimeException: An error occured while executing doInBackground() 
                 at android.os.AsyncTask$3.done(AsyncTask.java:304) 
                 at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355) 
                 at java.util.concurrent.FutureTask.setException(FutureTask.java:222) 
                 at java.util.concurrent.FutureTask.run(FutureTask.java:242) 
                 at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231) 
                 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) 
                 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) 
                 at java.lang.Thread.run(Thread.java:818) 
                Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'org.json.JSONArray org.json.JSONObject.getJSONArray(java.lang.String)' on a null object reference 
                 at com.example.wibisono.tryhard_1.JSONHelper.gethalteAll(JSONHelper.java:99) 
                 at com.example.wibisono.tryhard_1.route_activity$AsynTaskMain.doInBackground(route_activity.java:147) 
                 at com.example.wibisono.tryhard_1.route_activity$AsynTaskMain.doInBackground(route_activity.java:102) 
                 at android.os.AsyncTask$2.call(AsyncTask.java:292) 
                 at java.util.concurrent.FutureTask.run(FutureTask.java:237) 
                 at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)  
                 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)  
                 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)  
                 at java.lang.Thread.run(Thread.java:818)

map_route.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:paddingBottom="@dimen/activity_vertical_margin" 
    android:paddingLeft="@dimen/activity_horizontal_margin" 
    android:paddingRight="@dimen/activity_horizontal_margin" 
    android:paddingTop="@dimen/activity_vertical_margin" 
    tools:context=".route_activity" > 

    <fragment 
     android:id="@+id/map" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     class="com.google.android.gms.maps.SupportMapFragment" /> 

</RelativeLayout>

retrieve.php

<?php 

if($_SERVER['REQUEST_METHOD']=='GET'){ 

    define('HOST','localhost'); 
    define('USER','my_username'); 
    define('PASS','my_password'); 
    define('DB','my_database'); 
    $konek = mysqli_connect(HOST,USER,PASS,DB); 

$query = "SELECT * FROM halte"; 
$sql = mysqli_query($konek,$query); 

$response = array(); 

    while($row = mysqli_fetch_array($sql)){ 
     array_push($response,array(
     "id" => $row['id']; 
     "nama" => $row['nama']; 
     "lat" => $row['lat']; 
     "lng" => $row['lng']; 
     )); 
     } 

    echo json_encode(array('halte'=>$response)); 
    mysqli_close($konek); 

} 
?>

出典

2016-11-22 wibisono indiarto

[NullPointerExceptionとは何か、それを修正する方法は？]（http://stackoverflow.com/questions/218384/what-is-a-nullpointerexception-and-how -do-i-fix-it） – Selvin

原因：java.lang.NullPointerException：nullオブジェクトリファレンスで仮想メソッド 'org.json.JSONArray org.json.JSONObject.getJSONArray（java.lang.String）'を呼び出そうとしています何が間違っているかを判断するためにブレークポイントを使用しますが、doInBackgroundでjsonオブジェクトを呼び出すときにjsonオブジェクトが初期化されていないように見えます。初期化する必要があります：private JSONHelper json; 次のようなものがあります：private JSONHelper json = new JSONHelper（）; – Nyranith

@Nyranith私はまだ試したが、同じエラー、他の可能性がありますか？ –

が、私はエラーが私のretrieve.phpにタイプミスをした考え出した、私はすでに現れて代わりmysqli_query マップのmysql_queryを入力したが、マーカーの避難所それは大丈夫です。アドバイスありがとう:)

出典

2016-11-24 05:46:20

マップ上に位置を表示するためのJSON配列の呼び出しに失敗しました

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