从NPE崩溃的Android片段onCreate

我被卡住了，一双新的眼睛将不胜感激。我的MainActivity拨打fragment，点击button。它正在拉动它，然后我在fragment中添加database呼叫，现在它正在崩溃。在我的logcat中，它说我的onCreate中得到一个空指针异常。这里是代码和logcat。从NPE崩溃的Android片段onCreate

片段代码

public class StatsFragment extends Fragment { 
    public static MySmokinDatabase mySmokinDatabase; 
    public static Model model; 
    View view; 

    public View onCreateView(LayoutInflater inflater, 
      ViewGroup container, 
      Bundle savedInstanceState) { 

     model = MainActivity.model; 
     mySmokinDatabase = new MySmokinDatabase(getActivity()); 

     TextView daysText = (TextView) getView().findViewById(R.id.days); 
     TextView totalText = (TextView) getView().findViewById(R.id.total); 
     TextView aveText = (TextView) getView().findViewById(R.id.ave); 
     try { 
      daysText.setText("" + (model.getDays())); 
      totalText.setText("" + mySmokinDatabase.getTotal()); 
      if (model.getDays() > 0) 
      aveText.setText("" + (float) mySmokinDatabase.getTotal()/(float) model.getDays()); 
     } 

     catch (Exception e) { 
      Log.v("*** DEBUG ***", "Error"); 
      System.out.print("error" + e); 
     } 

     // Create, or inflate the Fragment’s UI, and return it. 
     // If this Fragment has no UI then return null. 
     view = inflater.inflate(R.layout.stats_frag, container, false); 
     return view; 
    } 
}

按钮处理

public void statisticsHandler(View view) { 
    FragmentManager fm = getFragmentManager(); 
    FragmentTransaction ft = fm.beginTransaction(); 
    Log.v("*** DEBUG ***", "Statistics Handler"); 
    ft.replace(R.id.main_container_Id, new StatsFragment()); 
    ft.commit(); 
}

logcat的

03-27 15:40:03.767: W/dalvikvm(862): threadid=1: thread exiting with uncaught exception (group=0x40a13300) 
03-27 15:40:03.867: E/AndroidRuntime(862): FATAL EXCEPTION: main 
03-27 15:40:03.867: E/AndroidRuntime(862): java.lang.NullPointerException 
03-27 15:40:03.867: E/AndroidRuntime(862): at com.example.smokin4tomsullivan.StatsFragment.onCreateView(StatsFragment.java:24) 
03-27 15:40:03.867: E/AndroidRuntime(862): at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:829) 
03-27 15:40:03.867: E/AndroidRuntime(862): at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1035) 
03-27 15:40:03.867: E/AndroidRuntime(862): at android.app.BackStackRecord.run(BackStackRecord.java:635) 
03-27 15:40:03.867: E/AndroidRuntime(862): at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1397) 
03-27 15:40:03.867: E/AndroidRuntime(862): at android.app.FragmentManagerImpl$1.run(FragmentManager.java:426) 
03-27 15:40:03.867: E/AndroidRuntime(862): at android.os.Handler.handleCallback(Handler.java:615) 
03-27 15:40:03.867: E/AndroidRuntime(862): at android.os.Handler.dispatchMessage(Handler.java:92) 
03-27 15:40:03.867: E/AndroidRuntime(862): at android.os.Looper.loop(Looper.java:137) 
03-27 15:40:03.867: E/AndroidRuntime(862): at android.app.ActivityThread.main(ActivityThread.java:4745) 
03-27 15:40:03.867: E/AndroidRuntime(862): at java.lang.reflect.Method.invokeNative(Native Method) 
03-27 15:40:03.867: E/AndroidRuntime(862): at java.lang.reflect.Method.invoke(Method.java:511) 
03-27 15:40:03.867: E/AndroidRuntime(862): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 
03-27 15:40:03.867: E/AndroidRuntime(862): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
03-27 15:40:03.867: E/AndroidRuntime(862): at dalvik.system.NativeStart.main(Native Method)

来源

2013-03-27 IrishWhiskey

移动这个接近顶部，你抢前视图。你正在得到一个NPE，因为findViewById调用返回null。

// Create, or inflate the Fragment’s UI, and return it. 
// If this Fragment has no UI then return null. 
view = inflater.inflate(R.layout.stats_frag, container, false);

之前你抢视图。然后做

TextView daysText = (TextView) view.findViewById(R.id.days); 
TextView totalText = (TextView) view.findViewById(R.id.total); 
TextView aveText = (TextView) view.findViewById(R.id.ave);

来源

2013-03-27 19:59:11

谢谢，你的回答不仅修复了它显示值的崩溃。答案将尽快接受 – IrishWhiskey 2013-03-27 20:04:58

设置此view = inflater.inflate(R.layout.stats_frag, container, false);之前得到您的意见如下

使用getActivity()而不是getView()同时得到的意见。

即

TextView daysText = (TextView) getActivity().findViewById(R.id.days); 
    TextView totalText = (TextView) getActivity().findViewById(R.id.total); 
    TextView aveText = (TextView) getActivity().findViewById(R.id.ave);

来源

2013-03-27 19:54:37 Pragnani

非常感谢你，我的应用程序不再崩溃。但值不显示。下面的答案解决了这两个问题。你会得到upvote，但他会得到复选标记 – IrishWhiskey 2013-03-27 20:02:12

@IrishWhiskey是Textviews部分R.layout.stats_frag，然后在实际获取值之前设置上下文视图。即设置此视图= inflater.inflate（R.layout.stats_frag，容器，false）;在得到Textviews之前 – Pragnani 2013-03-27 20:05:41

@IrishWhiskey更新了答案...... – Pragnani 2013-03-27 20:08:57

从NPE崩溃的Android片段onCreate

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