com.google.firebase.database.DatabaseException：无法将java.lang.Long类型的对象转换为com.realty.drake.kunuk.Property

Question

我需要一些帮助： - 我的代码中出现异常的原因是什么。它是关于反序列化的吗？ - 怎么修复这个bug？ - 替代方法实现这个？

基本上，代码假设在我的片段上显示一些cardview，其中包含recyclelerView。

这是包含大部分实现的片段

public class Tab1Buy extends Fragment {
private DatabaseReference mDatabase;
private RecyclerView mPropertyRecyclerView;
private FirebaseRecyclerAdapter<Property, Tab1Buy.PropertyViewHolder>     mPropertyAdapter;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.property_tab, container, false);
    Log.d("debbug", "onCreateView called in TAb1");
    return rootView;
}

@Override
public  void onViewCreated(View view, @Nullable Bundle savedInstanceState){
    super.onViewCreated(view, savedInstanceState);
    Log.d("debbug", "onViewCreated called in TAb");


    mDatabase =  FirebaseDatabase.getInstance().getReference().child("Property");
    mDatabase.keepSynced(true);
    //TODO might need to remove view from findBy...
    mPropertyRecyclerView = (RecyclerView) view.findViewById(R.id.property_recyclerView);
    //TODO check is this is necessary?
    DatabaseReference personRef = FirebaseDatabase.getInstance().getReference().child("Property");
    // keyQuery - the Firebase location containing the list of keys to be found in dataRef
    Query personQuery = personRef.orderByKey();
    mPropertyRecyclerView.hasFixedSize();
    mPropertyRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));



    FirebaseRecyclerOptions<Property> personsOptions =
            new FirebaseRecyclerOptions.Builder<Property>()
                    .setQuery(personQuery, Property.class)
                    .build();

    //FirebaseRecyclerOptions personsOptions = new  FirebaseRecyclerOptions.Builder<>().setQuery(personQuery, Property.class);

    mPropertyAdapter = new FirebaseRecyclerAdapter<Property, PropertyViewHolder>(personsOptions){
        @Override
        public Tab1Buy.PropertyViewHolder onCreateViewHolder(ViewGroup parent, int viewType){
            // Create a new instance of the ViewHolder, in this case we are using a custom
            // layout called R.layout.property_card for each item
            View view = LayoutInflater.from(parent.getContext())
                    .inflate(R.layout.property_card, parent, false);
            Log.d("debbug", "onCreateViewHolder called in Adapter");
            return new Tab1Buy.PropertyViewHolder(view);

        }

        @Override
        // Bind the Chat object to the ChatHolder
        public void onBindViewHolder(Tab1Buy.PropertyViewHolder holder, final int position, final Property model){
            holder.setPrice(model.getPrice());
            Log.d("debbug", "onBindViewHolder called in TAb1");

        }


    };
    mPropertyRecyclerView.setAdapter(mPropertyAdapter);
}

@Override
public void onStart(){
    super.onStart();
    mPropertyAdapter.startListening();
}

@Override
public void onStop(){
    super.onStop();
    mPropertyAdapter.stopListening();
}




public class PropertyViewHolder extends RecyclerView.ViewHolder {

    //TODO correct itemView parm name & mView

    View mView;

    public PropertyViewHolder(View itemView) {
        super(itemView);
        mView = itemView;
        Log.d("debbug", "PropertyViewHolder RecyclerView called in TAb1");

    }

    public void setPrice(long price) {
        Log.d("debbug", "SetPrice method called PropertyViewHolder  RecyclerView called in TAb1");

        //TODO implement all the object views
        TextView post_price = (TextView) mView.findViewById(R.id.post_price);
        post_price.setText((int) price);
    }
}

}

这是属性类

import android.util.Log;

/**
 * Created by drake on 5/1/18.
*/

// TODO generate setters and getters
public class Property {
private int price;
private String address;
private int numberOfbed;
private int numberOfCar;
private int numberOfbath;
private String image;

public Property(){} //Needed for Firebase

public Property (int price, String address,
                 int numberOfbed, int numberOfCar,
                 int numberOfbath, String image) {
    this.address = address;
    this.price= price;
    this.numberOfbath = numberOfbath;
    this.numberOfbed = numberOfbed;
    this.numberOfCar = numberOfCar;
    this.image = image;

}



public int getPrice() {
    Log.d("debbug", "GetPrice called in Property");

    return price;
}

public void setPrice(int price) {
    this.price = price;
}

public String getAddress() {
    return address;
}

public void setAddress(String address) {
    this.address = address;
}

public int getNumberOfbed() {
    return numberOfbed;
}

public void setNumberOfbed(int numberOfbed) {
    this.numberOfbed = numberOfbed;
}

public int getNumberOfCar() {
    return numberOfCar;
}

public void setNumberOfCar(int numberOfCar) {
    this.numberOfCar = numberOfCar;
}

public int getNumberOfbath() {
    return numberOfbath;
}

public void setNumberOfbath(int numberOfbath) {
    this.numberOfbath = numberOfbath;
}

public String getImage() {
    return image;
}

public void setImage(String image) {
    this.image = image;
}



}

这是cardview的xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#dfdfdf"
android:orientation="vertical">
<!-- TODO Add white icon -->
<android.support.v7.widget.CardView  xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:card_view="http://schemas.android.com/tools"
    android:id="@+id/property"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    app:cardUseCompatPadding="true"
    card_view:cardCornerRadius="4dp"
    card_view:cardElevation="4dp">

    <android.support.constraint.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="290dp"
        android:orientation="vertical">

        <ImageView
            android:id="@+id/post_image"
            android:contentDescription="@string/property"
            android:layout_width="0dp"
            android:layout_height="0dp"
            android:layout_marginBottom="71dp"
            android:scaleType="centerCrop"
            android:src="@drawable/house1"
            app:layout_constraintBottom_toTopOf="@+id/number_bedroom"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <TextView
            android:id="@+id/post_price"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="8dp"
            android:layout_marginStart="5dp"
            android:layout_marginTop="8dp"
            android:text="55,000$"
            android:textColor="@color/colorPrimary"
            android:textSize="20sp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.79" />

        <TextView
            android:id="@+id/post_address"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="10dp"
            android:layout_marginStart="5dp"
            android:layout_marginTop="1dp"
            android:text="23,Rue Duvivier-hall, Les Cayes, "
            android:textColor="#737373"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/post_price"
            app:layout_constraintVertical_bias="0.0" />

        <ImageView
            android:id="@+id/bathroom"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="5dp"
            android:layout_marginStart="100dp"
            android:layout_marginTop="2dp"
            android:background="#ff9100"
            android:src="@drawable/bathroom"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.976" />

        <ImageView
            android:id="@+id/bedroom"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="5dp"
            android:layout_marginStart="25dp"
            android:layout_marginTop="2dp"
            android:background="#ff9100"
            android:src="@drawable/bedroom"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.976" />

        <TextView
            android:id="@+id/number_bathroom"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginEnd="8dp"
            android:text="2"
            android:textColor="#ff9100"
            android:textStyle="bold"
            app:layout_constraintBottom_toBottomOf="@+id/bathroom"
            app:layout_constraintEnd_toStartOf="@+id/bathroom" />

        <TextView
            android:id="@+id/number_bedroom"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginEnd="8dp"
            android:text="3"
            android:textColor="#ff9100"
            android:textStyle="bold"
            app:layout_constraintBottom_toBottomOf="@+id/bedroom"
            app:layout_constraintEnd_toStartOf="@+id/bedroom" />

        <TextView
            android:id="@+id/number_garage"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginEnd="8dp"
            android:text="1"
            android:textColor="#ff9100"
            android:textStyle="bold"
            app:layout_constraintBottom_toBottomOf="@+id/garage"
            app:layout_constraintEnd_toStartOf="@+id/garage" />

        <ImageView
            android:id="@+id/garage"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="5dp"
            android:layout_marginStart="175dp"
            android:layout_marginTop="2dp"
            android:background="#ff9100"
            android:src="@drawable/garage"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintVertical_bias="0.976" />

    </android.support.constraint.ConstraintLayout>

</android.support.v7.widget.CardView>

</LinearLayout>

这里是logcat输出：

05-09 21:05:00.282 8391-8391/com.realty.drake.kunuk E/RecyclerView: No adapter attached; skipping layout
05-09 21:05:00.396 8391-8420/com.realty.drake.kunuk D/FA: Connected to remote service
05-09 21:05:00.397 8391-8420/com.realty.drake.kunuk V/FA: Processing queued    up service tasks: 4
05-09 21:05:00.401 8391-8391/com.realty.drake.kunuk E/RecyclerView: No adapter attached; skipping layout
05-09 21:05:05.601 8391-8391/com.realty.drake.kunuk D/debbug: onCreateViewHolder called in Adapter
05-09 21:05:05.602 8391-8391/com.realty.drake.kunuk D/debbug: PropertyViewHolder RecyclerView called in TAb1
05-09 21:05:05.605 8391-8391/com.realty.drake.kunuk D/AndroidRuntime:  Shutting down VM
05-09 21:05:05.608 8391-8391/com.realty.drake.kunuk E/AndroidRuntime: FATAL  EXCEPTION: main
 Process: com.realty.drake.kunuk, PID: 8391
 com.google.firebase.database.DatabaseException: Can't convert object of  type java.lang.Long to type com.realty.drake.kunuk.Property
    at com.google.android.gms.internal.firebase_database.zzkt.zzb(Unknown Source)
    at com.google.android.gms.internal.firebase_database.zzkt.zza(Unknown Source)
    at com.google.firebase.database.DataSnapshot.getValue(Unknown Source)
    at com.firebase.ui.database.ClassSnapshotParser.parseSnapshot(ClassSnapshotParser.java:29)
    at com.firebase.ui.database.ClassSnapshotParser.parseSnapshot(ClassSnapshotParser.java:15)
    at com.firebase.ui.common.BaseCachingSnapshotParser.parseSnapshot(BaseCachingSnapshotParser.java:35)
    at com.firebase.ui.common.BaseObservableSnapshotArray.get(BaseObservableSnapshotArray.java:52)
    at com.firebase.ui.database.FirebaseRecyclerAdapter.getItem(FirebaseRecyclerAdapter.java:106)
    at com.firebase.ui.database.FirebaseRecyclerAdapter.onBindViewHolder(FirebaseRecyclerAdapter.java:122)
    at android.support.v7.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:6482)
    at android.support.v7.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:6515)
    at android.support.v7.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline(RecyclerView.java:5458)
    at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5724)
    at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5563)
    at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5559)
    at android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2229)
    at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1556)
    at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1516)
    at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:608)
    at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3693)
    at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3410)
    at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:3962)
    at android.view.View.layout(View.java:16647)
    at android.view.ViewGroup.layout(ViewGroup.java:5438)
    at android.support.v4.view.ViewPager.onLayout(ViewPager.java:1767)
    at android.view.View.layout(View.java:16647)
    at android.view.ViewGroup.layout(ViewGroup.java:5438)
    at android.support.design.widget.HeaderScrollingViewBehavior.layoutChild(HeaderScrollingViewBehavior.java:132)
    at android.support.design.widget.ViewOffsetBehavior.onLayoutChild(ViewOffsetBehavior.java:42)
    at android.support.design.widget.AppBarLayout$ScrollingViewBehavior.onLayoutChild(AppBarLayout.java:1361)
    at android.support.design.widget.CoordinatorLayout.onLayout(CoordinatorLayout.java:869)
    at android.view.View.layout(View.java:16647)
    at android.view.ViewGroup.layout(ViewGroup.java:5438)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:336)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:273)
    at android.view.View.layout(View.java:16647)
    at android.view.ViewGroup.layout(ViewGroup.java:5438)
    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1743)
    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1586)
    at android.widget.LinearLayout.onLayout(LinearLayout.java:1495)
    at android.view.View.layout(View.java:16647)
    at android.view.ViewGroup.layout(ViewGroup.java:5438)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:336)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:273)
    at android.view.View.layout(View.java:16647)
    at android.view.ViewGroup.layout(ViewGroup.java:5438)
    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1743)
    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1586)
    at android.widget.LinearLayout.onLayout(LinearLayout.java:1495)
    at android.view.View.layout(View.java:16647)
    at android.view.ViewGroup.layout(ViewGroup.java`

更新了数据库结构

我修复了代码，这是完整的代码

package com.realty.drake.kunuk;

import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
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 android.widget.TextView;

import com.firebase.ui.database.FirebaseRecyclerAdapter;
import com.firebase.ui.database.FirebaseRecyclerOptions;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;


/**
 * Created by drake on 4/11/18
 */

public class Tab1Buy extends Fragment {
private DatabaseReference personRef;
private RecyclerView mPropertyRecyclerView;
FirebaseRecyclerAdapter<Property, PropertyViewHolder> mPropertyAdapter;

//*private FirebaseRecyclerAdapter<Property, PropertyViewHolder> mPropertyAdapter;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.property_tab, container, false);
    mPropertyRecyclerView = rootView.findViewById(R.id.property_recyclerView);
    return rootView;
}


@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    mPropertyRecyclerView.hasFixedSize();
    mPropertyRecyclerView.setLayoutManager(new   LinearLayoutManager(getActivity()));

    personRef = FirebaseDatabase.getInstance()
            .getReference()
            .child("Property");
    personRef.keepSynced(true);
    // keyQuery - the Firebase location containing the list of keys to be found in dataRef
    //Query personQuery = personRef.orderByKey();


    FirebaseRecyclerOptions<Property> options =
            new FirebaseRecyclerOptions.Builder<Property>()
                    .setQuery(personRef, Property.class)
                    .build();

    //FirebaseRecyclerOptions personsOptions = new   FirebaseRecyclerOptions.Builder<>().setQuery(personQuery, Property.class);

    mPropertyAdapter = new FirebaseRecyclerAdapter<Property,  PropertyViewHolder>(options) {


        @Override
        // Bind the Property object to the PropertyHolder
        public void onBindViewHolder(@NonNull PropertyViewHolder holder, final int position, @NonNull final Property model) {
            holder.setPrice(model.getPrice());
            holder.setAddress(model.getAddress());
            holder.setNumberOfBed(model.getNumberOfBed());
            holder.setNumberOfBath(model.getNumberOfBath());
            holder.setNumberOfCar(model.getNumberOfCar());


        }

        @Override
        public PropertyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            // Create a new instance of the ViewHolder, in this case we are using a custom
            // layout called R.layout.property_card for each item
            View view = LayoutInflater.from(parent.getContext())
                    .inflate(R.layout.property_card, parent, false);
            return new PropertyViewHolder(view);

        }

        // @Override
        // public void onDataChanged() {
        //     // Called each time there is a new data snapshot. You may want to use this method
        //     // to hide a loading spinner or check for the "no documents" state and update your UI.
        //     // ...
        // }

        //   @Override
        //   public void onError(DatabaseError e) {
        //       // Called when there is an error getting data. You may want to update
        //       // your UI to display an error message to the user.
        //       // ...
        //   }
    };
    mPropertyRecyclerView.setAdapter(mPropertyAdapter);



}

@Override
public void onStart() {
    super.onStart();
    mPropertyAdapter.startListening();
}

@Override
public void onStop() {
    super.onStop();
    mPropertyAdapter.stopListening();
}


public class PropertyViewHolder extends RecyclerView.ViewHolder {
    View mView;

    public PropertyViewHolder(View itemView) {
        super(itemView);
        mView = itemView;
    }

    public void setPrice(int price) {
        TextView Price = (TextView) mView.findViewById(R.id.post_price);

       Price.setText(String.valueOf(price));
    }

    public void setAddress(String address){
        TextView Address = (TextView) mView.findViewById(R.id.post_address);
        Address.setText(String.valueOf(address));
    }

    public void setNumberOfBed(int numberOfBed){
        TextView NumberOfBed = (TextView) mView.findViewById(R.id.post_bedroom);
        NumberOfBed.setText(String.valueOf(numberOfBed));
    }

    public void setNumberOfBath(int numberOfBath){
        TextView NumberOfBath = (TextView) mView.findViewById(R.id.post_bathroom);
        NumberOfBath.setText(String.valueOf(numberOfBath));
    }

    public  void  setNumberOfCar(int numberOfCar) {
        TextView NumberOfCar = (TextView) mView.findViewById(R.id.post_garage);
        NumberOfCar.setText(String.valueOf(numberOfCar));
    }


}

}

Answer 1

导致问题，因为数据库的结构不适合您的代码。您需要一个名为Property的中间级别。

尝试像这样更改数据库的结构：