HTTP Post with Android - 「println需要一條消息」錯誤

Question

這就是我的活動，我想要發送帶格式數據JSON的Post請求。

public class OrderActivity extends Activity { 


     List<Piatto> ordine = new ArrayList<Piatto>(); 
     Context context; 


     @Override 
     public void onCreate(Bundle savedInstanceState) { 
      super.onCreate(savedInstanceState); 
      setContentView(R.layout.order_layout); 




       TextView disptext = (TextView) findViewById(R.id.dispid); 


       ordine = getIntent().getParcelableArrayListExtra("ordinelist"); 

       context = getApplicationContext(); 




       String json = ""; 
       Integer contatore = 0; 
       for (Integer i = 0; i < ordine.size(); i++) { 
        if (ordine.get(i) != null){ 
         if (contatore > 0){ 
          json = json+", "; 
         } 
         json = json+ordine.get(i).getJSON(); 

        } 
       } 
       disptext.setText(json); 

       POST("http://some.altervista.org/order.php", json); 

       } 



     public static String POST(String url, String json){ 
      InputStream inputStream = null; 
      String result = ""; 
      try { 

       // 1. create HttpClient 
       HttpClient httpclient = new DefaultHttpClient(); 

       // 2. make POST request to the given URL 
       HttpPost httpPost = new HttpPost(url); 


       // 5. set json to StringEntity 
       StringEntity se = new StringEntity(json); 

       // 6. set httpPost Entity 
       httpPost.setEntity(se); 

       // 7. Set some headers to inform server about the type of the content 
       httpPost.setHeader("Accept", "application/json"); 
       httpPost.setHeader("Content-type", "application/json"); 

       // 8. Execute POST request to the given URL 
       HttpResponse httpResponse = httpclient.execute(httpPost); 


      } catch (Exception e) { 
       Log.d("InputStream", e.getLocalizedMessage()); 
      } 

      // 11. return result 
      return result; 
     } 


} 

那麼，這是錯誤我收到

07-23 16:09:21.450: E/AndroidRuntime(5806): FATAL EXCEPTION: main 
07-23 16:09:21.450: E/AndroidRuntime(5806): java.lang.RuntimeException: Unable to start activity ComponentInfo{it.sii.mywaiter/it.sii.mywaiter.OrderActivity}: java.lang.NullPointerException: println needs a message 
07-23 16:09:21.450: E/AndroidRuntime(5806):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2092) 
07-23 16:09:21.450: E/AndroidRuntime(5806):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2117) 
07-23 16:09:21.450: E/AndroidRuntime(5806):  at android.app.ActivityThread.access$700(ActivityThread.java:134) 
07-23 16:09:21.450: E/AndroidRuntime(5806):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1218) 
07-23 16:09:21.450: E/AndroidRuntime(5806):  at android.os.Handler.dispatchMessage(Handler.java:99) 
07-23 16:09:21.450: E/AndroidRuntime(5806):  at android.os.Looper.loop(Looper.java:137) 
07-23 16:09:21.450: E/AndroidRuntime(5806):  at android.app.ActivityThread.main(ActivityThread.java:4867) 
07-23 16:09:21.450: E/AndroidRuntime(5806):  at java.lang.reflect.Method.invokeNative(Native Method) 
07-23 16:09:21.450: E/AndroidRuntime(5806):  at java.lang.reflect.Method.invoke(Method.java:511) 
07-23 16:09:21.450: E/AndroidRuntime(5806):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1007) 
07-23 16:09:21.450: E/AndroidRuntime(5806):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:774) 
07-23 16:09:21.450: E/AndroidRuntime(5806):  at dalvik.system.NativeStart.main(Native Method) 
07-23 16:09:21.450: E/AndroidRuntime(5806): Caused by: java.lang.NullPointerException: println needs a message 
07-23 16:09:21.450: E/AndroidRuntime(5806):  at android.util.Log.println_native(Native Method) 
07-23 16:09:21.450: E/AndroidRuntime(5806):  at android.util.Log.d(Log.java:155) 
07-23 16:09:21.450: E/AndroidRuntime(5806):  at it.sii.mywaiter.OrderActivity.POST(OrderActivity.java:133) 
07-23 16:09:21.450: E/AndroidRuntime(5806):  at it.sii.mywaiter.OrderActivity.onCreate(OrderActivity.java:71) 
07-23 16:09:21.450: E/AndroidRuntime(5806):  at android.app.Activity.performCreate(Activity.java:5047) 
07-23 16:09:21.450: E/AndroidRuntime(5806):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094) 
07-23 16:09:21.450: E/AndroidRuntime(5806):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2056) 
07-23 16:09:21.450: E/AndroidRuntime(5806):  ... 11 more 

你有關於一些想法？我沒有關於println的直接代碼。 或者你有關於實現類似的東西的其他建議？

非常感謝

Answer 1

的問題還涉及到在內部調用的println Log類。舉例來說，你有

Log.d("InputStream", e.getLocalizedMessage()); 

如果e.getLocalizedMessage()回報，你的應用程序將與例外