Question

我尝试使用RecyclerView从firebase检索数据但遗憾的是它没有向我显示任何内容，也没有任何错误。我不知道问题出在哪里。

这是我的第一堂课

package com.example.median1.helper;

import android.provider.ContactsContract;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.text.TextUtils;
import android.view.View;
import android.widget.TextView;

import com.firebase.ui.database.FirebaseRecyclerAdapter;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.iid.FirebaseInstanceIdReceiver;

import org.w3c.dom.Text;

public class recyclerview extends AppCompatActivity {

    private RecyclerView mbloglist;
    private DatabaseReference mDatabase;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_recyclerview);
        mDatabase= FirebaseDatabase.getInstance().getReference().child("Request");

        mbloglist=(RecyclerView)findViewById(R.id.blog_List);
        mbloglist.setHasFixedSize(true);

        mbloglist.setLayoutManager(new LinearLayoutManager(this));

    }

    @Override
    protected void onStart() {
        super.onStart();
        FirebaseRecyclerAdapter<blog,blogviewholder>firebaseRecyclerAdapter=new FirebaseRecyclerAdapter<blog, blogviewholder>(


                 blog.class,R.layout.blog_row,blogviewholder.class,mDatabase
        ) {
            @Override
            protected void populateViewHolder(blogviewholder viewHolder, blog model, int position) {
                viewHolder.settitle(model.getPosttitle());
                viewHolder.setemail(model.getPostemail());
                viewHolder.settmain(model.getPostmain());



            }
        };

    }
    public static class blogviewholder extends RecyclerView.ViewHolder {


        View mView;


        public blogviewholder(View itemView) {
            super(itemView);

            mView=itemView;

        }
        public void setemail(String postemail){
            TextView post_email=(TextView)mView.findViewById(R.id.blogemail);
            post_email.setText(postemail);


        }

        public void settitle(String  posttitle){

            TextView post_title=(TextView)mView.findViewById(R.id.blogtitle);
            post_title.setText(posttitle);
        }

        public void settmain(String  postmain){

            TextView post_main=(TextView)mView.findViewById(R.id.blogmain);
            post_main.setText(postmain);
        }



    }
}

这是它的xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.median1.helper.recyclerview">

    <android.support.v7.widget.RecyclerView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/blog_List"></android.support.v7.widget.RecyclerView>

</android.support.constraint.ConstraintLayout>

这是我称之为博客的课程，它假定要完成电子邮件标题和主要

package com.example.median1.helper;

/**
 * Created by median1 on 1/10/2018.
 */

public class blog
{

    private String postemail;
    private String postmain;
    private String posttitle;



    public blog(){

    }

    public blog(String postemail, String postmain, String posttitle) {
        this.postemail = postemail;
        this.postmain = postmain;
        this.posttitle = posttitle;
    }

    public String getPostemail() {
        return postemail;
    }

    public void setPostemail(String postemail) {
        this.postemail = postemail;
    }

    public String getPostmain() {
        return postmain;
    }

    public void setPostmain(String postmain) {
        this.postmain = postmain;
    }

    public String getPosttitle() {
        return posttitle;
    }

    public void setPosttitle(String posttitle) {
        this.posttitle = posttitle;
    }
}

这是我创建的用于在第一个类

中显示firebase内容的xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent" android:layout_height="wrap_content"
    android:layout_margin="20dp">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        >

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/blogemail"
            android:text="email"/>

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/blogtitle"
            android:text="title"/>

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/blogmain"
            android:text="main"/>




    </LinearLayout>

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

Answer 1

问题是您没有将适配器设置为RecyclerView。我建议将适配器声明移动到onCreate()方法。并在初始化适配器后设置适配器：

mbloglist.setHasFixedSize(true);

mbloglist.setLayoutManager(new LinearLayoutManager(this));

FirebaseRecyclerAdapter<blog,blogviewholder>firebaseRecyclerAdapter=new FirebaseRecyclerAdapter<blog, blogviewholder>(


                 blog.class,R.layout.blog_row,blogviewholder.class,mDatabase
        ) {
            @Override
            protected void populateViewHolder(blogviewholder viewHolder, blog model, int position) {
                viewHolder.settitle(model.getPosttitle());
                viewHolder.setemail(model.getPostemail());
                viewHolder.settmain(model.getPostmain());

            }
        };

mbloglist.setAdapter(firebaseRecyclerAdapter);

RecyclerView视图没有显示我的任何东西

1 个答案: