Невозможно использовать JSON, чтобы получить данные из URL (NullPointerException)

Я пытаюсь получить данные из формата Json из http://projectxapp.herokuapp.com/dashboard/ads/api/v1/ads/Невозможно использовать JSON, чтобы получить данные из URL (NullPointerException)

Это проявляется NullPointerException, и я попытался переменные пути ее решения. Но у меня до сих пор нет идей! Похоже, что objectList пуст.

public class ImagePagerActivity extends Activity { 
// url to make request 
private static String url =   
    "http://projectxapp.herokuapp.com/dashboard/ads/api/v1/ads/"; 

// JSON Node names 
static final String TAG_META = "meta"; 
static final String TAG_META_LIMIT = "limit"; 
private static final String TAG_META_NEXT = "next"; 
private static final String TAG_META_total_count = "count"; 
private static final String TAG_OBJECTS = "objects"; 
private static final String TAG_OBJECTS_END_TIME = "endTime"; 
private static final String TAG_OBJECTS_ID = "id"; 
private static final String TAG_OBJECTS_LINK = "link"; 
private static final String TAG_OBJECTS_PHOTO = "photo"; 
private static final String TAG_OBJECTS_PHOTO_HEIGHT = "height"; 
static final String TAG_OBJECTS_PHOTO_RESOURCE_URI = "resourceUri"; 
private static final String TAG_OBJECTS_PHOTO_SOURCE = "source"; 
private static final String TAG_OBJECTS_PHOTO_WIDTH = "width"; 
private static final String TAG_OBJECTS_RESOURCE_URI = "OResourceUri"; 
private static final String TAG_OBJECTS_START_TIME = "startTime"; 
// contacts JSONArray 
JSONArray meta = null; 
JSONArray objects = null; 

// 
private static final String TEST_FILE_NAME = "Universal Image Loader @#&=+-_.,!()~'%20.png"; 
private static final String STATE_POSITION = "STATE_POSITION"; 
ImageLoader imageLoader = ImageLoader.getInstance(); 
DisplayImageOptions options; 

ViewPager pager; 

@SuppressWarnings("null") 
@SuppressLint("NewApi") 
public void onCreate(Bundle savedInstanceState) { 
    // 
    StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder() 
      .detectDiskReads().detectDiskWrites().detectNetwork() 
      .penaltyLog().build()); 
    StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder() 
      .detectLeakedSqlLiteObjects().detectLeakedClosableObjects() 
      .penaltyLog().penaltyDeath().build()); 
    super.onCreate(savedInstanceState); 
    requestWindowFeature(Window.FEATURE_NO_TITLE); 
    ; 
    setContentView(R.layout.mos); 

    File testImageOnSdCard = new File("/mnt/sdcard", TEST_FILE_NAME); 
    if (!testImageOnSdCard.exists()) { 
     copyTestImageToSdCard(testImageOnSdCard); 
    } 

    ArrayList<HashMap<String, String>> objectsList = new  
              ArrayList<HashMap<String, String>>(); 
    JSONParser jParser = new JSONParser(); 
    JSONObject json = null; 
    try { 

     json = jParser.getStringContent(url); 
    } catch (Exception e1) { 
     // TODO Auto-generated catch block 
     e1.printStackTrace(); 
    } 

    try { 
     // Getting Array of Contacts 
     objects = json.getJSONArray(TAG_OBJECTS); 

     // looping through All Contacts 
     for (int i = 0; i < objects.length(); i++) { 
      JSONObject c = objects.getJSONObject(i); 
      String link = c.getString(TAG_OBJECTS_LINK); 
      JSONObject photo = c.getJSONObject(TAG_OBJECTS_PHOTO); 
      String source = photo.getString(TAG_OBJECTS_PHOTO_SOURCE); 
     HashMap<String, String> map = new HashMap<String, String>(); 
      map.put(TAG_OBJECTS_LINK, link); 
      map.put(TAG_OBJECTS_PHOTO_SOURCE, source); 
      // adding HashList to ArrayList 
      objectsList.add(map); 
     } 

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

    String[] imageUrls = null; 
    if(objectsList.isEmpty()); 
    Toast.makeText(this, "No Data", Toast.LENGTH_LONG).show(); 
    Log.i("getData1", "!!!!!!!!!!!"); 
      // 
      for(int i=0; i<objects.length(); i++) 
    { 
     Log.i("getData2", "!!!!!!!!!!!"); 
     imageUrls[i]=objectsList.get(i).get(TAG_OBJECTS_PHOTO_RESOURCE_URI); 
     Log.i("getData3", "!!!!!!!!!!!"); 
    } 
      // 
     private void copyTestImageToSdCard(final File testImageOnSdCard) { 
    new Thread(new Runnable() { 
     @Override 
     public void run() { 
      try { 
       InputStream is = getAssets().open(TEST_FILE_NAME); 
       FileOutputStream fos = new FileOutputStream(
         testImageOnSdCard); 
       byte[] buffer = new byte[8192]; 
       int read; 
       try { 
        while ((read = is.read(buffer)) != -1) { 
         fos.write(buffer, 0, read); 
        } 
       } finally { 
        fos.flush(); 
        fos.close(); 
        is.close(); 
       } 
      } catch (IOException e) { 
       L.w("Can't copy test image onto SD card"); 
      } 
     } 
    }).start(); 
}

Существует JSONParser().

public class JSONParser { 

static InputStream is = null; 
static JSONObject jObj = null; 
static String json = ""; 

// constructor 
public JSONParser() { 

} 
public static JSONObject getStringContent(String uri) throws Exception { 

    try { 
     HttpClient client = new DefaultHttpClient(); 
     HttpGet request = new HttpGet(); 
     request.setURI(new URI(uri)); 
     HttpResponse response = client.execute(request); 
     InputStream ips = response.getEntity().getContent(); 
     BufferedReader buf = new BufferedReader(new InputStreamReader(ips,"UTF-8")); 

     StringBuilder sb = new StringBuilder(); 
     String s; 
     while(true) 
     { 
      s = buf.readLine(); 
      if(s==null || s.length()==0) 
       break; 
      sb.append(s); 

     } 
     buf.close(); 
     ips.close(); 
     jObj = new JSONObject(sb.toString()); 
     return jObj; 

     } 



}

Это logcat сообщения ниже!

04-05 07:25:17.889: E/StrictMode(630): at 
    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573) 
    04-05 07:25:17.889: E/StrictMode(630): at java.lang.Thread.run(Thread.java:856) 
    04-05 07:25:21.831: E/AndroidRuntime(3285): FATAL EXCEPTION: main 
    04-05 07:25:21.831: E/AndroidRuntime(3285): java.lang.RuntimeException: Unable to   
    start activity ComponentInfo{com.sai.mosorder/com.sai.mosorder.ImagePagerActivity}: 
    java.lang.NullPointerException 
    04-05 07:25:21.831: E/AndroidRuntime(3285): at  
    android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 
    04-05 07:25:21.831: E/AndroidRuntime(3285): at 
    android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 
    04-05 07:25:21.831: E/AndroidRuntime(3285): at 
    android.app.ActivityThread.access$600(ActivityThread.java:141) 
    04-05 07:25:21.831: E/AndroidRuntime(3285): at 
    android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 
    04-05 07:25:21.831: E/AndroidRuntime(3285): at  
    android.os.Handler.dispatchMessage(Handler.java:99) 
    04-05 07:25:21.831: E/AndroidRuntime(3285): at  
    android.os.Looper.loop(Looper.java:137) 
    04-05 07:25:21.831: E/AndroidRuntime(3285): at 
    android.app.ActivityThread.main(ActivityThread.java:5041) 
    04-05 07:25:21.831: E/AndroidRuntime(3285): at 
    java.lang.reflect.Method.invokeNative(Native Method) 
    04-05 07:25:21.831: E/AndroidRuntime(3285): at 
    java.lang.reflect.Method.invoke(Method.java:511) 
    04-05 07:25:21.831: E/AndroidRuntime(3285): at 
    com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
    04-05 07:25:21.831: E/AndroidRuntime(3285): at  
    com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 
    04-05 07:25:21.831: E/AndroidRuntime(3285): at  
    dalvik.system.NativeStart.main(Native Method) 
    04-05 07:25:21.831: E/AndroidRuntime(3285): Caused by:  
    java.lang.NullPointerException 
    04-05 07:25:21.831: E/AndroidRuntime(3285): at  
    com.sai.mosorder.ImagePagerActivity.onCreate(ImagePagerActivity.java:132) 
    04-05 07:25:21.831: E/AndroidRuntime(3285): at 
    android.app.Activity.performCreate(Activity.java:5104) 
    04-05 07:25:21.831: E/AndroidRuntime(3285): at  
    android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 
    04-05 07:25:21.831: E/AndroidRuntime(3285): at 
    android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 
    04-05 07:25:21.831: E/AndroidRuntime(3285): ... 11 more 
    04-05 07:25:22.200: E/SurfaceFlinger(37): ro.sf.lcd_density must be defined as a  
    build property 
    04-05 07:25:22.560: E/SurfaceFlinger(37): ro.sf.lcd_density must be defined as a  
    build property 
    04-05 07:26:07.869: E/ActivityThread(630): at  
    com.android.exchange.ExchangeService$7.run(ExchangeService.java:1856)

источник

2013-04-05 苗仁愷

вывесить ошибку в LogCat –

Что код в 'ImagePagerActivity.java: 132'? –

>> imageUrls [i] = objectsList.get (i) .get (TAG_OBJECTS_PHOTO_RESOURCE_URI); Проблема в том, что objectList пуст. Фактически, он должен содержать данные из данных URL-адреса. Я не знаю почему. –

Я нашел ответ !!!! Если вы сбиваете с толку использование Json на Android. Вы должны проверить этот сайт.

http://mobiforge.com/developing/story/consuming-json-services-android-apps

источник

2013-04-06 12:25:58

Невозможно использовать JSON, чтобы получить данные из URL (NullPointerException)

ответ

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