Android Recyclerview插入过多数据就会导致item重复，乱序

Question

item数量超过6条就会出现item重复，乱序

代码如下

fragment布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    tools:context="invinciblejoe.com.lightingbuy.main.LightingFragment">

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

recyclerview item布局

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/invinciblejoe.com.lightingbuy"
    android:layout_width="match_parent"
    android:layout_height="150dp"
    android:layout_marginTop="10dp"
    android:layout_marginBottom="10dp"
    android:layout_marginLeft="10dp"
    android:layout_marginRight="10dp"
    app:cardBackgroundColor="@color/orange"
    app:cardCornerRadius="20dp">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
        
        <TextView
            android:id="@+id/pic"
            android:layout_width="match_parent"
            android:layout_height="120dp"
            android:gravity="center"
            android:textSize="50sp"
            />

        <TextView
            android:clickable="true"
            android:id="@+id/name"
            android:layout_width="match_parent"
            android:layout_height="60dp"
            android:background="@color/orange"
            android:textColor="@android:color/white" />

    </LinearLayout>

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

recycerview adapter

public class LightingRVAdapter extends RecyclerView.Adapter {

    private List<Commodity> mlist;
    private Context mContext;
    private LightingViewHolder viewHolder;

    public LightingRVAdapter(Context mContext, List<Commodity> mlist) {
        this.mContext = mContext;
        this.mlist = mlist;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.cardview_lighting, parent, false);
        viewHolder = new LightingViewHolder(v);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {

        Commodity c = mlist.get(position);
        viewHolder.mImageView.setText(c.getName());
        viewHolder.mTextView.setText(String.valueOf(c.getPrice_discont()));
    }

    @Override
    public int getItemCount() {
        return mlist == null ? 0 : mlist.size();
    }

    private class LightingViewHolder extends RecyclerView.ViewHolder
        implements View.OnClickListener
    {
        public TextView mTextView;

        public TextView mImageView;

        public LightingViewHolder(View v )
        {
            super(v);
            mTextView = (TextView) v.findViewById(R.id.name);
            mImageView = (TextView) v.findViewById(R.id.pic);
            mImageView.setOnClickListener(this);
        }

        @Override
        public void onClick(View view) {
            switch (view.getId()) {
                case R.id.pic :
                    mTextView.setText("OnChlic");
                    break;
            }
        }
    }

}

Answer 1

Yes, it is a strange thing to be confused. Your view holder usage is wrong...
OnCreateViewHolder directly creates a new instance and returns it. This method will be called when a new item is needed.
The way you write it, the same holder is used in the entire adapter. Because the display is cached, the second item will not be confused.
OnBind will provide the holder instance you created and operate your data there.
At the same time, the return type of the above methods should be your custom holder.

Answer 2

What does "repeating out of order" mean? It is position 7, and the data displayed is the one that has been displayed before?
It is recommended that you debug in the onBindViewHolder() method to see the values ​​of related variables.

Looking at the code, there seems to be no problem. Is there any other code, such as the "insert" you mentioned

Answer 3

This line is the key
This is the correct way to write it

public class LightingRVAdapter extends RecyclerView.Adapter<LightingRVAdapter.LightingViewHolder> 

The implemented interface looks like this after correction

@Override
    public LightingViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.cardview_lighting, parent, false);
        return new LightingViewHolder(v);

    }

@Override
public void onBindViewHolder(final LightingViewHolder holder, int position)

Then operate the data directly in onBindViewHolder

Thanks to Original Wenhai for the correction, thank you