无法将java.lang.string类型的对象转换为-firebaseui类型

ru9i0ody  于 2021-07-09  发布在  Java
关注(0)|答案(1)|浏览(407)

我不明白问题是什么,据我所说,一切正常。
日志:
com.google.firebase.database.databaseexception:无法在com.google.firebase.database.core.utilities.encoding.customclassmapper.convertbean(customclassmapper)上将java.lang.string类型的对象转换为com.hamidmadarati.mobilsorgulari.home.dashboard.ui.passengerecyclermodel类型。java:436)在com.google.firebase.database.core.utilities.encoding.customclassmapper.deserializetoclass(customclassmapper。java:232)在com.google.firebase.database.core.utilities.encoding.customclassmapper.converttocustomclass(customclassmapper。java:80)在com.google.firebase.database.datasnapshot.getvalue(datasnapshot。java:203)
碎片:

public class PassengerFragment extends Fragment {
    private RecyclerView listVehiclesWeekDay;
    private FirebaseRecyclerOptions<PassengerRecyclerModel> options;
    private FirebaseRecyclerAdapter<PassengerRecyclerModel, PassengerMyViewHolderRecycler> adapter;
    private DatabaseReference databaseReference;

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

        listVehiclesWeekDay = view.findViewById(R.id.listVehiclesWeekDay);
        listVehiclesWeekDay.setHasFixedSize(true);
        listVehiclesWeekDay.setLayoutManager(new LinearLayoutManager(getActivity()));

        databaseReference = FirebaseDatabase.getInstance().getReference().child("Travels").child("DaysOfTheWeekSimple");
        options = new FirebaseRecyclerOptions.Builder<PassengerRecyclerModel>().setQuery(databaseReference, PassengerRecyclerModel.class).build();
        adapter = new FirebaseRecyclerAdapter<PassengerRecyclerModel, PassengerMyViewHolderRecycler>(options){
            @Override
            protected void onBindViewHolder(@NonNull PassengerMyViewHolderRecycler holder, int position, @NonNull PassengerRecyclerModel model) {
                if (model.getDay() != null){
                    holder.titleTextView.setText(model.getDay());
                }
            }
            @Override
            public PassengerMyViewHolderRecycler onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
                View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.recyclerow, parent, false);
                return new PassengerMyViewHolderRecycler(view);
            }
        };
        adapter.startListening();
        listVehiclesWeekDay.smoothScrollToPosition(0);
        listVehiclesWeekDay.setAdapter(adapter);
        adapter.notifyDataSetChanged();
        return view;
    }
}

班级:

public class PassengerRecyclerModel {
    private String day; //name

    public PassengerRecyclerModel() {
        //Empty - for Firebase Database
    }

    // model
    public PassengerRecyclerModel(String day) {
        this.day = day;
    }

    //Getter and Setter
    public String getDay() {
        return day;
    }
    public void setDay(String day) {
        this.day = day;
    }
}

twh00eeo

twh00eeo1#

传递以下引用时:

databaseReference = FirebaseDatabase.getInstance().getReference().child("Travels").child("DaysOfTheWeekSimple");

与firebaserecycleroptions.builder的“setquety()”方法的“passengerrecyclermodel”类一起,意味着您要使用firebase ui库来显示以下对象中存在的所有“passengerrecyclermodel”对象:

Travels -> DaysOfTheWeekSimple

这实际上是不可能的,因为在该引用下它只存在一个string类型的子级,因此出现以下错误:

com.google.firebase.database.DatabaseException: Can't convert object of type java.lang.String to type com.hamidmadarati.mobilsorgulari.Home.Dashboard.ui.PassengerRecyclerModel

要解决这个问题,您需要在“daysoftheweeksimple”节点下添加一个额外的级别。这可以使用databasereference的push()方法简单地实现。因此,当您在上述引用处添加对象时,请按如下方式添加:

databaseReference.push().setValue(passengerRecyclerModel);

这样,数据库架构应该如下所示:

Firebase-root
  |
  --- Travels
       |
       --- DaysOfTheWeekSimple
             |
             --- $pushedId
                   |
                   --- day: "Day 5: 22-4-2021"

获取数据的代码可能保持不变。
编辑:
根据您的意见:
不,事实上,我们不创建数据
如果您直接在firebase控制台中添加数据,您将无法使用push()。如果不希望以编程方式添加数据,则仍然需要额外的层级别。因此,在这种情况下,在“daysoftheweeksimple”节点和“day”属性之间,添加另一个至少带有日期或id的节点,如下所示:

Firebase-root
  |
  --- Travels
       |
       --- DaysOfTheWeekSimple
             |
             --- 22-4-2021 //Extra level added
                   |
                   --- day: "Day 5: 22-4-2021"

问题是当它被获取时,firebase认为它是一个对象而没有将它转换为字符串
如果不“think”,则对象的类型为“passengerrecyclermodel”,应该在适配器中相应地读取。

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