获取“ com.google.firebase.database.DatabaseException：无法将类型为java.lang.Long的值转换为String”

Question

当我想显示我的通知区域并且不知道问题出在哪里时，我遇到了异常。

NotificationFragment

package com.developer.fireone.finga.Fragment;

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.developer.fireone.finga.Adapter.NotificationAdapter;
import com.developer.fireone.finga.Model.Chat;
import com.developer.fireone.finga.Model.Notification;
import com.developer.fireone.finga.R;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;

import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;


public class NotificationFragment extends Fragment {

    private RecyclerView recyclerView;
    private NotificationAdapter notificationAdapter;
    private List<Notification> notificationList;

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

        recyclerView = view.findViewById(R.id.recycler_view);
        recyclerView.setHasFixedSize(true);
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getContext());
        recyclerView.setLayoutManager(linearLayoutManager);

        notificationList= new ArrayList<>();
        notificationAdapter = new NotificationAdapter(getContext(), notificationList);
        recyclerView.setAdapter(notificationAdapter);

        readNotifications();

        return view;
    }

    private void readNotifications() {

        FirebaseUser firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
        DatabaseReference reference = FirebaseDatabase.getInstance().getReference("Notifications").child(firebaseUser.getUid());
        reference.keepSynced(true);
        reference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                notificationList.clear();
                for(DataSnapshot snapshot:dataSnapshot.getChildren()){
       Notification notif=snapshot.getValue(Notification.class); //exception
                    notificationList.add(notif);
                }

                Collections.reverse(notificationList);
                notificationAdapter.notifyDataSetChanged();
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });
    }

}

通知（型号）

package com.developer.fireone.finga.Model;

/**
 * Created by user on 20/12/2018.
 */

public class Notification {

    private String userid;
    private String text;
    private String postid;
    private boolean ispost;

    public Notification() {
    }

    public Notification(String userid, String text, String postid, boolean ispost) {
        this.userid = userid;
        this.text = text;
        this.postid = postid;
        this.ispost = ispost;
    }


    public String getUserid() {
        return userid;
    }

    public void setUserid(String userid) {
        this.userid = userid;
    }

    public String getText() {
        return text;
    }

    public void setText(String text) {
        this.text = text;
    }

    public String getPostid() {
        return postid;
    }

    public void setPostid(String postid) {
        this.postid = postid;
    }

    public boolean isIspost() {
        return ispost;
    }

    public void setIspost(boolean ispost) {
        this.ispost = ispost;
    }

}

这是Firebase中的通知：

Answer 1

可能在通知模型中，您的变量之一很长，但是您将其声明为String 例如

    private String userid;
    private String text;
    private String postid;