Android Live数据观察器异常

我想实现新的android架构组件，并在片段和视图模型中使用了实时数据，但是当我向实时数据添加观察者时，应用程序崩溃引发此异常。Android Live数据观察器异常

Process: com.nrs.nsnik.architecturecomponents, PID: 3071 

java.lang.RuntimeException: Unable to start activity 
ComponentInfo{com.nrs.nsnik.architecturecomponents/com.nrs.nsnik.architecturec 
omponents.view.MainActivity}: java.lang.ClassCastException: android.arch.lifecycle.LiveData_LifecycleBoundObserver_LifecycleAdapter cannot be cast to android.arch.lifecycle.GeneratedAdapter 
. 
. 
. 
. 
Caused by: java.lang.ClassCastException: android.arch.lifecycle.LiveData_LifecycleBoundObserver_LifecycleAdapter cannot be cast to android.arch.lifecycle.GeneratedAdapter

名单片段：

public class ListFragment extends Fragment { 

    @BindView(R.id.listFragmentRecyclerView) 
    RecyclerView mRecyclerView; 
    @BindView(R.id.listFragmentAddItem) 
    FloatingActionButton mFloatingActionButton; 
    private Unbinder mUnbinder; 
    private CompositeDisposable mCompositeDisposable; 
    private ListViewModel mListViewModel; 
    private List<NoteEntity> mNoteEntityList; 
    private ListAdapter mListAdapter; 
    private NoteDatabase mNoteDatabase; 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
     View v = inflater.inflate(R.layout.fragment_list, container, false); 
     mUnbinder = ButterKnife.bind(this, v); 
     mListViewModel = ViewModelProviders.of(this).get(ListViewModel.class); 
     mNoteDatabase = ((MyApplication)getActivity().getApplication()).getNoteDatabaseInstance(); 
     initialize(); 
     listeners(); 
     return v; 
    } 

    private void initialize() { 
     mCompositeDisposable = new CompositeDisposable(); 
     mNoteEntityList = new ArrayList<>(); 
     mListAdapter = new ListAdapter(getActivity(), mNoteEntityList); 
     mListViewModel.getNoteList().observe(this, noteEntityList -> { 
      mListAdapter.swapList(noteEntityList); 
      mListAdapter.notifyDataSetChanged(); 
     }); 
    } 

    private void cleanUp() { 
     if (mUnbinder != null) { 
      mUnbinder.unbind(); 
     } 
     if (mCompositeDisposable != null) { 
      mCompositeDisposable.dispose(); 
     } 
    } 

    private void listeners() { 
     RxView.clicks(mFloatingActionButton).subscribe(o -> { 
     AlertDialog.Builder newNoteDialog = new AlertDialog.Builder(getActivity()); 
     View v = LayoutInflater.from(getActivity()).inflate(R.layout.fragment_add_note_dialog, null); 
     newNoteDialog.setView(v); 
     EditText editText = v.findViewById(R.id.addNoteEditText); 
     newNoteDialog.setNegativeButton(getActivity().getResources().getString(R.string.cancel), (dialogInterface, i) -> { 
     }).setPositiveButton(getActivity().getResources().getString(R.string.add), (dialogInterface, i) -> { 
      if (isValid(editText)) { 
       NoteEntity entity = new NoteEntity(); 
       entity.setNote(editText.getText().toString()); 
       entity.setDate(getCurrentDate()); 
       mNoteDatabase.getNoteDao().insertNote(entity); 
      } 
     }); 
     newNoteDialog.create().show(); 
     }); 
    } 

    private Date getCurrentDate() { 
     Date date = new Date(Calendar.getInstance().getTimeInMillis()); 
     SimpleDateFormat simpleDateFormat = new SimpleDateFormat("dd-MM-yyyy", Locale.ENGLISH); 
     simpleDateFormat.format(date); 
     return date; 
    } 

    private boolean isValid(EditText editText) { 
     return !(editText.getText().toString().length() <= 0 || editText.getText().toString().isEmpty()); 
    } 

    @Override 
    public void onDestroy() { 
     super.onDestroy(); 
     cleanUp(); 
     if (BuildConfig.DEBUG) { 
      RefWatcher refWatcher = MyApplication.getRefWatcher(getActivity()); 
      refWatcher.watch(this); 
     } 
    } 
}

视图模型：

public class ListViewModel extends AndroidViewModel { 

    private LiveData<List<NoteEntity>> mNoteList; 
    private final NoteDatabase mNoteDatabase; 

    ListViewModel(Application application) { 
     super(application); 
     mNoteDatabase = ((MyApplication)application).getNoteDatabaseInstance(); 
     mNoteList = mNoteDatabase.getNoteDao().getNoteList(); 
    } 

    public LiveData<List<NoteEntity>> getNoteList() { 
     return mNoteList; 
    } 
}

NoteDatabase：

@Database(entities = {NoteEntity.class}, version = 1) 
public abstract class NoteDatabase extends RoomDatabase { 
    public abstract NoteDao getNoteDao(); 
}

应用程序崩溃，如果增加对实时数据的正面。

我在我的应用程序类中使用“Room.databaseBuilder（....）”函数构建数据库的单个实例，并将它用于任何地方，我的NoteEntity类有三个字段，一个是id，它是一个主键自动生成。

来源

2017-10-09 Nsnik

任何人都可以帮忙吗？ – Nsnik

什么是片段和视图模型的超类？你还可以提供NoteDatabase的代码片段吗？ –

@LongRanger我已更新了帖子中的代码。 – Nsnik

我有类似的错误，在我的情况是由这种依赖于gradle.build文件引起的：

implementation "android.arch.lifecycle:common-java8:1.0.0-beta2"

来源

2017-10-11 12:50:46

的FirebaseUI尚未更新android.arch.lifecycle到1.0.0-β2。

使用1.0.0-beta1而不是1.0.0-beta2。
等到他们更新生命周期库。

来源

2017-10-13 03:36:05 Devofure

Android Live数据观察器异常

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