Android：無法啓動活動java.lang.nullpointerexception

我創建了一個activity我在onCreate()函數中寫了一些函數。在運行應用程序時，我收到了一些錯誤消息無法啓動活動java.lang.nullpointerexception。我已包括在AndroidManifest.xmlAndroid：無法啓動活動java.lang.nullpointerexception

@Override 
    protected void onCreate(Bundle savedInstanceState) { 
     // TODO Auto-generated method stub 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.user_report_hr_full); 
     List<Employee> data = new ArrayList<Employee>(); 
      Employee eg=new Employee(); 
      ListView li=(ListView)findViewById(R.id.user_report_hr_list); 
      Intent myIntent = getIntent(); // this is just for example purpose 
      Bundle b=myIntent.getExtras(); 
      Log.i("User Report by Hours", b.toString()); 
      Toast.makeText(getApplicationContext(), "User ", Toast.LENGTH_LONG).show(); 
      if(b !=null) 
      { 
       String username = b.getString("username"); 
       String userid = b.getString("userid"); 
       String startdate = b.getString("startdate"); 
       String enddate = b.getString("enddate"); 
       String mode=b.getString("mode"); 
       Log.i("LOOP", userid+"-"+startdate+"-"+enddate+"-"+mode); 
       data=eg.getReports(username, userid, startdate, enddate,mode); 
       Log.i("Get Report",data.toString()); 
       li.setAdapter(new UserHoursByReportArrayadapter(getApplicationContext(),data)); 
      } 


    }

這個活動和我的日誌文件是

05-08 11:45:30.745: I/User Report by HoursActivity:mode(517): 1 
05-08 11:45:30.837: I/User Report by Hours(517): Bundle[mParcelledData.dataSize=236] 
05-08 11:45:30.845: I/LOOP(517): 1-2012-04-08-2012-05-08-1 
05-08 11:45:30.855: D/HTTP(517): Execute HTTP Post Request 
05-08 11:45:30.855: D/UserID(517): Userid in EmpGlobal [1] 
05-08 11:45:30.855: D/Start date(517): Start date in EmpGlobal [2012-04-08] 
05-08 11:45:30.855: D/End date(517): End date in EmpGlobal [2012-05-08] 
05-08 11:45:30.855: D/Mode(517): Mode in EmpGlobal [1] 
05-08 11:45:48.275: I/log_tag(517): Time: 2033755 
05-08 11:45:48.275: I/log_tag(517): project name: AndroidTimesheet 
05-08 11:45:48.285: I/log_tag(517): username: admin1 
05-08 11:45:48.285: I/log_tag(517): Time: 34692 
05-08 11:45:48.285: I/log_tag(517): project name: Google 
05-08 11:45:48.285: I/log_tag(517): username: admin1 
05-08 11:45:48.285: I/Get Report(517): [[email protected], [email protected]] 
05-08 11:45:48.285: I/User Report by HoursAdapter(517): Inside constructor 
05-08 11:45:48.285: D/AndroidRuntime(517): Shutting down VM 
05-08 11:45:48.285: W/dalvikvm(517): threadid=3: thread exiting with uncaught exception (group=0x4001b188) 
05-08 11:45:48.285: E/AndroidRuntime(517): Uncaught handler: thread main exiting due to uncaught exception 
05-08 11:45:48.295: E/AndroidRuntime(517): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.technogems.employeetimecard/com.technogems.employeetimecard.UserHoursByReport}: java.lang.NullPointerException 
05-08 11:45:48.295: E/AndroidRuntime(517): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496) 
05-08 11:45:48.295: E/AndroidRuntime(517): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512) 
05-08 11:45:48.295: E/AndroidRuntime(517): at android.app.ActivityThread.access$2200(ActivityThread.java:119) 
05-08 11:45:48.295: E/AndroidRuntime(517): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863) 
05-08 11:45:48.295: E/AndroidRuntime(517): at android.os.Handler.dispatchMessage(Handler.java:99) 
05-08 11:45:48.295: E/AndroidRuntime(517): at android.os.Looper.loop(Looper.java:123) 
05-08 11:45:48.295: E/AndroidRuntime(517): at android.app.ActivityThread.main(ActivityThread.java:4363) 
05-08 11:45:48.295: E/AndroidRuntime(517): at java.lang.reflect.Method.invokeNative(Native Method) 
05-08 11:45:48.295: E/AndroidRuntime(517): at java.lang.reflect.Method.invoke(Method.java:521) 
05-08 11:45:48.295: E/AndroidRuntime(517): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) 
05-08 11:45:48.295: E/AndroidRuntime(517): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 
05-08 11:45:48.295: E/AndroidRuntime(517): at dalvik.system.NativeStart.main(Native Method) 
05-08 11:45:48.295: E/AndroidRuntime(517): Caused by: java.lang.NullPointerException 
05-08 11:45:48.295: E/AndroidRuntime(517): at com.technogems.employeetimecard.UserHoursByReport.onCreate(UserHoursByReport.java:35) 
05-08 11:45:48.295: E/AndroidRuntime(517): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
05-08 11:45:48.295: E/AndroidRuntime(517): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459) 
05-08 11:45:48.295: E/AndroidRuntime(517): ... 11 more

請提供適當的方式來啓動該活動

來源

2012-05-08 Sridhar

你試過調試過嗎？ – MByD

它看起來像你的UserHoursByReport類造成的問題，你可以發佈該代碼？ – stevebot

這是你的第35行？ – dreamcoder

刪除此行： 日誌.i（「按用戶時間報告」，b.toString（））; 其中b爲null所以nullpointerException發生了

來源

2012-05-08 06:45:24 Krish

我相信這一行是正常的，請參閱日誌：05-08 11：45：30.837：I/User Hours by Hours（517）：Bundle [mParcelledData.dataSize = 236] – Tobold

@Tobold我已更改該活動的佈局，現在它的工作。我不知道如何解決這個問題 – Sridhar

Android：無法啓動活動java.lang.nullpointerexception

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