Realm 实例已经关闭，无法使用

Question

函数fetchData在片段中。 dataRepository class 包含我用来从磁盘获取数据的函数：

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    final View view = inflater.inflate(R.layout.fragment_user, container, false);

    realm = Realm.getDefaultInstance();

    Log.i("realm", "oncreateView");

    items = new ArrayList<>();

    try {
        Log.i("realm", "check" + (realm == null));
    } catch (Exception e) {
        e.printStackTrace();
    }

    fetchData();

    return view;
}

@Override
public void onDestroy() {
    super.onDestroy();
    if (realm != null && !realm.isClosed())
        realm.close();
    Log.i("realm", "ondestroy");
}

    private void fetchData() {

    abcDataRepository = DataRepository.getInstance(realm);

    Observable<List<User>> observable = bcDataRepository.getUser_List();

    observable.subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(Users-> {
                Log.i("data", Users.size() + "");

                for (int i = 0; i < Users.size(); i++) {
                    items.add(Users.get(i));
                }
            });
}

DataRepository class:

public class DataRepository {

    private Realm realm;

private static PoliticoDataRepository dataRepository = null;

private PoliticoDataRepository(Realm realm) {
    this.realm = realm;
}

public static PoliticoDataRepository getInstance(Realm realm) {
    if (dataRepository == null)
        dataRepository = new PoliticoDataRepository(realm);

    return dataRepository;
}

@Override
public Observable<List<User>> getUser_List() {

    final UserDiskData diskData = new UserDiskData(realm);

    if (diskData.User_Size() > 0) {
        return diskData.getUser_List();
    } else {
        final UserCloudData cloudData = new UserCloudData(realm);
        return cloudData.getUser_List();
    }
}
}

UserDiskDataclass:

class  UserDiskData {

private Realm realm;

UserDiskData(Realm realm) {
    this.realm = realm;
}

int User_Size() {
    final RealmResults<User> results = realm.where(User.class).findAll();
    Log.i("disk", "pulledData" + results.size());
    return results.size();
}

@Override
public Observable<List<User>> getUser_List() {

    Log.i("disk", "called");

    final RealmResults<User> results = realm.where(User.class).findAll();
    ArrayList<User> list = new ArrayList<>();
    for (int i = 0; i < results.size(); i++)
        list.add(results.get(i));

    return Observable.just(list);
}

}

该应用程序第一次运行良好，但当我退出该应用程序并再次打开它时，它崩溃并给出错误提示 This Realm instance has already been closed，使其无法使用。如果我在最后跳过 realm.close ，它会工作得很好。我应该手动关闭领域对象吗？如果是的话如何？出于某种原因 realm==null returns true 当我关闭应用程序并再次打开它时，为什么会这样，特别是考虑到 realm.getdefaultinstance 就在它之前被调用。

Answer 1

我的同事@zaki50 指出：

DataRepository 保留对 PoliticoDataRepository 的 static 引用。这意味着 DataRepository.getInstance(Realm realm) 可以 return 包含已关闭 Realm 实例的 PoliticoDataRepository 的旧实例。

您必须删除静态字段并确保 DataRepository.getInstance(Realm realm) 始终 return 是引用传递的 Realm 实例的实例。

Realm 实例已经关闭，无法使用

Realm instance has already been closed, making it unusable

java

android

realm

observable

rx-java2