Question

有人可以告诉那条特定行中的错误是什么。

以下是显示的错误消息。

package com.example.souravkumar.sqaurewallpapers;

import android.os.Bundle;
import android.os.PersistableBundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import com.firebase.ui.database.FirebaseRecyclerAdapter;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.squareup.picasso.Picasso;

/**
 * Created by Sourav Kumar on 11/3/2017.
 */

public class popular extends AppCompatActivity {

    private RecyclerView recyclerView;
    private DatabaseReference myRef;
    @Override
    public void onCreate(@Nullable Bundle savedInstanceState, @Nullable PersistableBundle persistentState) {
        super.onCreate(savedInstanceState, persistentState);
        recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        myRef = FirebaseDatabase.getInstance().getReference();
        FirebaseRecyclerAdapter<image_details, BlogViewHolder> adapter = new FirebaseRecyclerAdapter<image_details, BlogViewHolder>(
                image_details.class,
                R.layout.individual_row,

                myRef) {
            @Override
            protected void onBindViewHolder(BlogViewHolder holder, int position, image_details model) {
                holder.setDate(model.getDate());
                holder.setUrl(model.getUrl());
            }

            @Override
            public BlogViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
                return null;
            }
        };

        recyclerView.setAdapter(adapter);

    }

    public static  class BlogViewHolder extends RecyclerView.ViewHolder {
        TextView textView;
        ImageView imageView;
        public BlogViewHolder(View itemView) {
            super(itemView);
            textView = (TextView)itemView.findViewById(R.id.date);
            imageView = (ImageView)itemView.findViewById(R.id.imageView);
        }

        public void setDate(Long date) {
            textView.setText(date.toString());
        }

        public void setUrl(String url) {
            Picasso.with(itemView.getContext())
                    .load(url)
                    .resize(50, 50)
                    .centerCrop()
                    .into(imageView);
        }
    }
}

Link to the whole code

Answer 1

FirebaseUI的最新版本（3.x）实现了一种初始化FirebaseRecyclerAdapter的方法，而不是以前的版本。来自using the FirebaseRecyclerAdapter documentation：

首先，通过构建FirebaseRecyclerOptions来配置适配器。在在这种情况下，我们将继续我们的聊天示例：
 FirebaseRecyclerOptions<Chat> options =
                new FirebaseRecyclerOptions.Builder<Chat>()
                        .setQuery(query, Chat.class)
                        .build();
接下来创建FirebaseRecyclerAdapter对象。你应该已经有一个ViewHolder子类用于显示每个项目。

因此，对于您的示例，您需要执行与以下类似的操作：

FirebaseRecyclerOptions<image_details> options =
        new FirebaseRecyclerOptions.Builder<image_details>()
                .setQuery(myRef, image_details.class)
                .build();

FirebaseRecyclerAdapter adapter = new FirebaseRecyclerAdapter<image_details, BlogViewHolder>(options) {
    @Override
    public BlogViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.individual_row, parent, false);

        return new BlogViewHolder(view);
    }

    @Override
    protected void onBindViewHolder(BlogViewHolder holder, int position, image_details model) {
        // Bind the image_details object to the BlogViewHolder
        // ...
    }
};

最后，FirebaseRecyclerAdapter使用事件监听器来监控对Firebase查询的更改。要开始侦听数据，请调用adapter.startListening()和adapter.stopListening()以停止侦听器。建议分别在onStart()和onStop()中调用这些内容。有关详细信息，请参阅FirebaseRecyclerAdapter lifecycle documentation。

Answer 2

您错过了启动活动的方法。在onStart()方法中添加：

firebaseRecyclerAdapter.startListening();

Answer 3

你好你的错误是由于在这个

旁边的这些（）中缺少一个参数

<image_details, BlogViewHolder>

所以你错过了BlogViewHolder类的另一个参数，所以我将添加这段代码并通过以下注释引用你缺少的参数：

FirebaseRecyclerAdapter<image_details, BlogViewHolder> adapter = new FirebaseRecyclerAdapter<image_details, BlogViewHolder>(
            image_details.class,
            R.layout.individual_row,
            BlogViewHolder.class //see this is missing so you should add it       
            myRef) {

Answer 4

这是正确的方法：

FirebaseRecyclerOptions<image_details> options =
    new FirebaseRecyclerOptions.Builder<image_details>()
            .setQuery(myRef, image_details.class)
            .build();

FirebaseRecyclerAdapter adapter = new FirebaseRecyclerAdapter<image_details, BlogViewHolder>(options) {
    @Override
    public BlogViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.individual_row, parent, false);

        return new BlogViewHolder(view);
    }

    @Override
    protected void onBindViewHolder(BlogViewHolder holder, int position, image_details model) {
        // Bind the image_details object to the BlogViewHolder
        // ...
    }
};

Answer 5

我有同样的错误，这对我来说非常有效。希望对别人有帮助

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firebaserecycleradapter（）无法应用于FirebaseRecyclerAdapter

5 个答案: