Ошибка при отображении диалогового окна предупреждения

Question

Я получаю исключение NullPointerException, когда я показываю диалоговое окно с предупреждением, однако я понятия не имею, как его решить. Дело в том, что это сработало несколько раз, но теперь что-то случилось. вот LogCat:

05-10 10:59:34.937 16886-16886/com.android.tfl.traffidriveapp E/AndroidRuntime﹕ FATAL EXCEPTION: main 
    java.lang.NullPointerException 
      at com.android.tfl.traffidriveapp.ParameterAlert.onCreateDialog(ParameterAlert.java:62) 
      at android.app.DialogFragment.getLayoutInflater(DialogFragment.java:398) 
      at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:828) 
      at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1032) 
      at android.app.BackStackRecord.run(BackStackRecord.java:622) 
      at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1382) 
      at android.app.FragmentManagerImpl$1.run(FragmentManager.java:426) 
      at android.os.Handler.handleCallback(Handler.java:605) 
      at android.os.Handler.dispatchMessage(Handler.java:92) 
      at android.os.Looper.loop(Looper.java:137) 
      at android.app.ActivityThread.main(ActivityThread.java:4424) 
      at java.lang.reflect.Method.invokeNative(Native Method) 
      at java.lang.reflect.Method.invoke(Method.java:511) 
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 
      at dalvik.system.NativeStart.main(Native Method) 

Мой Основная деятельность:

package com.android.tfl.traffidriveapp; 



public class MainActivity extends Activity implements ServiceConnection{ 
    private IExtMessage binding=null; 
    private parseParametersTask task=null; 
    HashMap<Integer,List<String>> parameters; 
    ParameterAlert alert; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
     connectToService(); 
     task=new parseParametersTask(); 
     task.execute(); 
     parameters=ReadParams.params; 





    } 

    public void connectToService(){ 
     Intent implicit=new Intent(IExtMessage.class.getName()); 
     List<ResolveInfo> matches=getPackageManager().queryIntentServices(implicit, 0); 
     if(matches.size()==0){ 
      Toast.makeText(getApplicationContext(), "Cannot find a matching service!", Toast.LENGTH_LONG).show(); 
     } 
     else if (matches.size()>1){ 
      Toast.makeText(getApplicationContext(), "Found multiple matching services!", Toast.LENGTH_LONG).show(); 
     } 
     else{ 
      Toast.makeText(getApplicationContext(), "Found the Protocol Service", Toast.LENGTH_LONG).show(); 
      Intent explicit=new Intent(implicit); 
      ServiceInfo svcInfo=matches.get(0).serviceInfo; 
      ComponentName cn=new ComponentName(svcInfo.applicationInfo.packageName, svcInfo.name); 
      explicit.setComponent(cn); 
      bindService(explicit, this, Context.BIND_AUTO_CREATE); 



     } 
    } 

    public void buttonClick(View v) { 
     if (v.getId() == R.id.navigation) { 
      DialogFragment dialog = new navigationChooserFragment(); 
      dialog.show(getFragmentManager(), "navigation"); 
     } 
     if(v.getId()==R.id.ptt){ 
      PackageManager pm=getPackageManager(); 
      Intent i=pm.getLaunchIntentForPackage("com.loudtalks"); 
      i.addCategory(Intent.CATEGORY_LAUNCHER); 
      startActivity(i); 
     } 

    } 

    @Override 
    public void onServiceConnected(ComponentName name, IBinder service) { 
     Log.d("SERVICE", "Service Connected"); 
     binding=IExtMessage.Stub.asInterface(service); 
     try { 
      binding.getMessage(cb); 
     } catch (RemoteException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 
    } 

    @Override 
    public void onServiceDisconnected(ComponentName name) { 
     Log.d("SERVICE","Service disconnected :("); 
     binding=null; 

    } 

    ICallBackMessage.Stub cb=new ICallBackMessage.Stub() { 

     @Override 
     public void onMessageReceived(int parameter,int state) throws RemoteException { 
      Log.d("SERVICE","received parameter "+parameter); 
      Log.d("SERVICE", "received state " + state); 
      if(state==1){ 
       alert=new ParameterAlert(); 
       Bundle bundleParam=new Bundle(); 
       bundleParam.putInt("parameter",parameter); 
       alert.setArguments(bundleParam); 
       alert.show(getFragmentManager(),"alert"); 
      }else { 
       if (alert.isVisible()) { 
        alert.dismiss(); 
       } 
      } 
     } 
    }; 

    class parseParametersTask extends AsyncTask<Void,Void,Void>{ 

     @Override 
     protected Void doInBackground(Void... params) { 
      ReadParams readParams =new ReadParams(); 
      try { 
       readParams.setInputFile(getAssets().open("parameters.xls")); 
       readParams.read(); 
      } catch (IOException e) { 
       e.printStackTrace(); 
      } 

      return null; 
     } 
    } 

} 

My Dialog Фрагмент:

public class ParameterAlert extends DialogFragment implements DialogInterface.OnClickListener { 
    private View form=null; 
    TextView alertTitle; 
    TextView alertType; 
    TextView alertDetails; 
    private int parameter; 
    List<String> paramValues; 

    public ParameterAlert(){ 
     //blank 
    } 



    @Override 
    public void onResume() { 
     int width=600; 
     int height=400; 
     super.onResume(); 
     Window window=getDialog().getWindow(); 
     window.setLayout(width, height); 
     window.setGravity(Gravity.CENTER_HORIZONTAL); 
     window.setGravity(Gravity.CENTER_VERTICAL); 
    } 

    @Nullable 
    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
     getDialog().setCanceledOnTouchOutside(false); 

     return super.onCreateView(inflater, container, savedInstanceState); 
    } 

    @Override 
    public Dialog onCreateDialog(Bundle savedInstanceState) { 
     //form=getActivity().getLayoutInflater().inflate(R.layout.alerts,null); 
     AlertDialog.Builder builder=new AlertDialog.Builder(getActivity()); 
     LayoutInflater inflater=getActivity().getLayoutInflater(); 
     View form=inflater.inflate(R.layout.alerts,null); 
     builder.setView(form); 
     builder.setTitle(paramValues.get(0)); 
     builder.setNegativeButton(R.string.cancel_alert,this); 

     Bundle bundleParam=getArguments(); 
     int parameter=bundleParam.getInt("parameter"); 
     paramValues=ReadParams.params.get(parameter); 
     alertTitle= (TextView) form.findViewById(R.id.alert_title); 
     //alertType= (TextView) form.findViewById(R.id.alert_type); 
     alertDetails= (TextView) form.findViewById(R.id.alert_details); 
     //alertType.setText(paramValues.get(0)); 
     alertTitle.setText(paramValues.get(1)); 
     alertDetails.setText(paramValues.get(2)); 


     return builder.create(); 


    } 


    @Override 
    public void onDismiss(DialogInterface dialog) { 
     super.onDismiss(dialog); 
    } 

    @Override 
    public void onClick(DialogInterface dialog, int which) { 

    } 
} 

Answer 1

builder.setTitle(paramValues.get(0)); 

вы обращаетесь paramValues перед инициализацией его, что имеет место 5 ниже. Если бы я был в вас, я бы избегал статических ссылок, содержащих данные, которые вы хотите показать. Вы используете подкласс DialogFragment, и вы должны указать нам setArguments/getArguments для обработки нужных данных.