閱讀JSON從網址到Android

我在的Java/Android現在開始，我有這樣的錯誤...閱讀JSON從網址到Android

繼this教程（修改，以我的需求OFC），我想連接到rumonet.pt /feeder/index_android.php輸出一個json數組。

但這些代碼讓我在

button = (Button) findViewById(R.id.btnFetch); 
     buttonClear = (Button) findViewById(R.id.btnClear); 
     textView = (TextView) findViewById(R.id.txtView); 
     button.setOnClickListener(new Button.OnClickListener() 
     { 
      public void onClick(View v) 
      { 
       // examineJSONFile(); 
      } 
     }); 
     buttonClear.setOnClickListener(new Button.OnClickListener() 
     { 
      public void onClick(View v) 
      { 
       //textView.setText(""); 
      } 
     });

一個錯誤的更多specificly按鈕和buttonclear SetOnClickListener，因爲如果我評論的線條和空隙，它的工作原理...只是沒有做什麼..

Any1知道爲什麼，或者有更好的教程？ =）感謝=）

編輯

11-09 14:16:31.836: D/AndroidRuntime(9939): Shutting down VM 
11-09 14:16:31.836: W/dalvikvm(9939): threadid=1: thread exiting with uncaught exception (group=0x2b542210) 
11-09 14:16:31.836: E/AndroidRuntime(9939): FATAL EXCEPTION: main 
11-09 14:16:31.836: E/AndroidRuntime(9939): java.lang.RuntimeException: Unable to start activity ComponentInfo{noticias.rumonet.pt/noticias.rumonet.pt.MainActivity}: java.lang.NullPointerException 
11-09 14:16:31.836: E/AndroidRuntime(9939):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1967) 
11-09 14:16:31.836: E/AndroidRuntime(9939):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1992) 
11-09 14:16:31.836: E/AndroidRuntime(9939):  at android.app.ActivityThread.access$600(ActivityThread.java:127) 
11-09 14:16:31.836: E/AndroidRuntime(9939):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1158) 
11-09 14:16:31.836: E/AndroidRuntime(9939):  at android.os.Handler.dispatchMessage(Handler.java:99) 
11-09 14:16:31.836: E/AndroidRuntime(9939):  at android.os.Looper.loop(Looper.java:137) 
11-09 14:16:31.836: E/AndroidRuntime(9939):  at android.app.ActivityThread.main(ActivityThread.java:4441) 
11-09 14:16:31.836: E/AndroidRuntime(9939):  at java.lang.reflect.Method.invokeNative(Native Method) 
11-09 14:16:31.836: E/AndroidRuntime(9939):  at java.lang.reflect.Method.invoke(Method.java:511) 
11-09 14:16:31.836: E/AndroidRuntime(9939):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 
11-09 14:16:31.836: E/AndroidRuntime(9939):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 
11-09 14:16:31.836: E/AndroidRuntime(9939):  at dalvik.system.NativeStart.main(Native Method) 
11-09 14:16:31.836: E/AndroidRuntime(9939): Caused by: java.lang.NullPointerException 
11-09 14:16:31.836: E/AndroidRuntime(9939):  at noticias.rumonet.pt.MainActivity.onCreate(MainActivity.java:85) 
11-09 14:16:31.836: E/AndroidRuntime(9939):  at android.app.Activity.performCreate(Activity.java:4465) 
11-09 14:16:31.836: E/AndroidRuntime(9939):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049) 
11-09 14:16:31.836: E/AndroidRuntime(9939):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1931) 
11-09 14:16:31.836: E/AndroidRuntime(9939):  ... 11 more 







    button.setOnClickListener(new Button.OnClickListener() 
       { 
        public void onClick(View v) 
        { 
         // examineJSONFile(); 
        } 
       });

來源

2012-11-09 nunong21

您收到的錯誤是什麼？你可以發佈嗎？ – Grambot

發佈錯誤信息 –

如何獲取錯誤？：s我使用eclipse，並在我的手機只是說它停止工作 – nunong21

檢查XML佈局。它真的叫做btnClear？

在我看來，一旦您嘗試對onClickListener進行分析，因爲它沒有在佈局上找到視圖，您就有空指針。

來源

2012-11-09 14:32:23 nsemeniuk

謝謝，解決它感謝你=） – nunong21

Put setContentView（R.layout.categorias）;加載其他內容視圖 – nunong21

閱讀JSON從網址到Android

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