Recycler View Not Printing Given Data

问题

I'm trying to incorporate SlideNerd's instructions on how to create a recycler view into my CS project. He was teaching how to make a recycler view inside the navigation drawer and I'm trying to make one in the main activity.

Here's my current output

There's one recycler element that shows up, but the problem is that it is the example text and icon in the XML code that is initialized.The data in the ChooseItemRecyclerFragment is not being passed to the ItemViewholder and not displaying. Can someone help me find what I'm doing wrong?

UPDATE After debugging by putting test statements in the getData(), onBindViewHolder(), and getItemCount() methods, I've learned that my onBindViewHolder() method is NOT being called. I've looked at other questions related to my problem, and their solutions were with instantiating the LinearLayoutManager, which I already did. Does anybody know where/how onBindViewHolder() is being called or what I forgot to do to call it?

java files

ChooseItem.Java:

import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;

public class ChooseItem extends AppCompatActivity {

    private Toolbar toolbar;
    private ItemAdapter adapter;
    private RecyclerView recyclerView;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_choose_item);

        ChooseItemRecyclerFragment fragment = (ChooseItemRecyclerFragment) getSupportFragmentManager().findFragmentById(R.id.choose_item_list_fragment);
        fragment.setUp(R.id.choose_item_list_fragment, (DrawerLayout) findViewById(R.id.drawer_layout), toolbar);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_choose_item, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

ChooseItemRecyclerFragment.java:

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by michael on 11/17/2015.
 */
public class ChooseItemRecyclerFragment extends Fragment {

    private View containerView;
    private RecyclerView recyclerView;
    private ItemAdapter adapter;
    public ChooseItemRecyclerFragment() {
        // Required empty public constructor
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

    }

    public static List<Item> getData(){
        List<Item> data= new ArrayList<>();
        int[] iconId = {R.id.item_icon, R.id.item_icon, R.id.item_icon, R.id.item_icon, R.id.item_icon};
        String[] itemNames = {"Fajita", "Cahones", "Burger", "Bald Eagles", "Communism"};
        String[] itemPrice = {"$10.43", "$1.43", "$10.43", "$10.43", "$666.66"};
        for(int i = 0; i<iconId.length&&i<itemNames.length&&i<itemPrice.length;i++){
            Item current= new Item(itemNames[i], "description", itemPrice[i], iconId[i]);

            data.add(current);
        }
        return data;

    }
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View layout =inflater.inflate(R.layout.fragment_choose_item, container, false);
        recyclerView = (RecyclerView)layout.findViewById(R.id.choose_item_list);
        // use this setting to improve performance if you know that changes
        // in content do not change the layout size of the RecyclerView


        adapter=new ItemAdapter(getActivity(), getData());
        recyclerView.setAdapter(adapter);
        recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
        return  layout;  }


    public void setUp(int fragmentId, DrawerLayout drawerLayout, Toolbar toolbar) {
        containerView=getActivity().findViewById(fragmentId);

    }
}

ItemAdapter.java

package com.example.michael.othershit;

import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.Collections;
import java.util.List;

/**
 * Created by michael on 11/9/2015.
 */
public class ItemAdapter extends RecyclerView.Adapter<ItemAdapter.ItemViewHolder> {
    private LayoutInflater inflater;
    List<Item> data = Collections.EMPTY_LIST;
    /**
     * Created by michael on 11/9/2015.
     */
    public ItemAdapter(Context context,List<Item> list){
        inflater= LayoutInflater.from(context);
        data=list;
    }
    /**
     * Created by michael on 11/9/2015.
     */
    @Override
    public ItemViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view =inflater.inflate(R.layout.item_recycler_view_row, parent, false);
        ItemViewHolder holder = new ItemViewHolder(view);
        return holder;
    }

    /**
     * Created by michael on 11/9/2015.
     */
    @Override
    public void onBindViewHolder(ItemViewHolder holder, int position) {
        TextView title = holder.title;
        TextView price = holder.price;
        ImageView icon = holder.icon;

        title.setText(data.get(position).getName());
        price.setText(data.get(position).getItemPrice());
        icon.setImageResource(data.get(position).getIconId());
    }

    /**
     * Created by michael on 11/9/2015.
     */
    @Override
    public int getItemCount() {
        return data.size();
    }
    /**
     * Created by michael on 11/9/2015.
     */
    class ItemViewHolder extends RecyclerView.ViewHolder{
        TextView title;
        TextView price;
        ImageView icon;
        public ItemViewHolder(View itemView) {
            super(itemView);
            title= (TextView) itemView.findViewById(R.id.item_name);
            icon = (ImageView) itemView.findViewById(R.id.item_icon);
            price=(TextView) itemView.findViewById(R.id.item_price);
        }
    }
}

XML files:

activity_choose_items

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

<android.support.v4.widget.DrawerLayout  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" android:fitsSystemWindows="true"
    tools:context=".ChooseItemActivity"
    android:id="@+id/drawer_layout">



    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        >
        <include layout="@layout/item_recycler_view_row"/>

        <include layout="@layout/content_choose_item" />
        <fragment android:id="@+id/choose_item_list_fragment"

            android:layout_weight="1"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:name="com.example.michael.othershit.ChooseItemRecyclerFragment"
            tools:layout="@layout/fragment_choose_item" />

    </LinearLayout>

</android.support.v4.widget.DrawerLayout>

fragment_choose_item:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:id="@+id/rv_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <android.support.v7.widget.RecyclerView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/choose_item_list">

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

</RelativeLayout>

item_recycler_view_row

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal" android:layout_width="match_parent"
    android:layout_height="48dp"
    android:id="@+id/item_recycler_view"
    >

    <ImageView android:layout_height="wrap_content"
        android:layout_width="wrap_content"
        android:id="@+id/item_icon"
        android:layout_marginLeft="16dp"
       android:layout_marginRight="16dp"
        android:layout_gravity="center_vertical"
        android:src="@drawable/ic_local_restaurant">



    </ImageView>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        android:id="@+id/item_name"
       android:layout_marginLeft="72dp"
        android:text="Example Item Name"/>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        android:id="@+id/item_price"
        android:paddingLeft="32dp"
        android:text="$1.89"/>


</LinearLayout>

来源：https://stackoverflow.com/questions/33817295/recycler-view-not-printing-given-data

标签

java

android

android-recyclerview