0

查看我的代码：

import android.content.Context;
import android.content.Intent;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import org.w3c.dom.ls.LSException;

import java.util.ArrayList;
import java.util.Arrays;

/**
 * Created by Ankit on 3/25/2016.
 */
public class CustomAdapterRecyclerView extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
    Context context;
    private ArrayList<String> questionsList;
    LayoutInflater layoutInflater;

    public CustomAdapterRecyclerView(Context context, ArrayList<String> questionsList) {
        this.context = context;
        this.questionsList = questionsList;
        layoutInflater = LayoutInflater.from(context);
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        switch (viewType) {
            case 1:
                final View view = layoutInflater.inflate(R.layout.recycler_view_list, parent, false);
                MyViewHolder myViewHolder = new MyViewHolder(view, context);
                return myViewHolder;
        default:
            final View view1 = layoutInflater.inflate(R.layout.single_item_in_list, parent, false);
            MyExpandedViewHolder myExpandedViewHolder= new MyExpandedViewHolder(view1, context,new ArrayList<String>(Arrays.asList("A","Aa")));
            return myExpandedViewHolder;
        }
}

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        switch (holder.getItemViewType())
        {
            case 1:
                MyViewHolder vh = (MyViewHolder) holder;
                vh.questionTitle.setText(questionsList.get(position));
                break;
            default:
                MyExpandedViewHolder viewHolder= (MyExpandedViewHolder) holder;
                viewHolder.getListView();
        }
    }
/*
    @Override
    public void onBindViewHolder(RecyclerView.V holder, int position) {
        holder.questionTitle.setText(questionsList.get(position));
    }*/

    @Override
    public int getItemCount() {
        return questionsList.size();
    }

    @Override
    public int getItemViewType(int position) {
    if(position ==0|| position==1|| position==2)
    {
        return 0;
    }
        else
        return 1;
    }

    public class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
        TextView questionTitle;
        private Context context;

        public MyViewHolder(final View itemView, Context context) {
            super(itemView);
            this.context = context;
            itemView.setOnClickListener(this);
            questionTitle = (TextView) itemView.findViewById(R.id.question);
            questionTitle.setOnClickListener(this);
        }

        @Override
        public void onClick(View v) {
            Toast.makeText(context, "" + getAdapterPosition() + questionTitle.getText().toString(), Toast.LENGTH_LONG).show();
            Log.d("TAG", "" + getAdapterPosition());
            Intent intent = new Intent(context, ProgramViewer.class);
            intent.putExtra("titlePos",getAdapterPosition());
            intent.putExtra("title",questionTitle.getText().toString());
            context.startActivity(intent);
        }
    }
    public class MyExpandedViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener
    {
        private Context context;
        ListView listView;
        public MyExpandedViewHolder(View itemView, Context context,ArrayList<String> mobileArray) {
            super(itemView);
            this.context = context;
            ArrayAdapter adapter = new ArrayAdapter<String>(context, R.layout.expanded_list_inside_recycler_view, mobileArray);
            listView= (ListView) itemView.findViewById(R.id.list_view);
            listView.setAdapter(adapter);
        }
        public ListView getListView()
        {
            return this.listView;
        }
        @Override
        public void onClick(View v) {
        Toast.makeText(context,getAdapterPosition()+"",Toast.LENGTH_LONG).show();
        }
    }
}

我试图做的是在点击时展开RecyclerView项目，但首先我必须一起实现回收器视图和列表视图。我得到NullPointerException。请告诉我代码中的问题。答案将不胜感激。

日志文件：

 java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ListView.setAdapter(android.widget.ListAdapter)' on a null object reference
 at kole.technicalbird.CustomAdapterRecyclerView$MyExpandedViewHolder.<init>(CustomAdapterRecyclerView.java:113)
 at kole.technicalbird.CustomAdapterRecyclerView.onCreateViewHolder(CustomAdapterRecyclerView.java:43)
 at android.support.v7.widget.RecyclerView$Adapter.createViewHolder(RecyclerView.java:5476)
 at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4701)
 at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(

布局文件：single_item_in_list.xml

    <?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
                  android:orientation="vertical"
                  android:layout_width="match_parent"
                  android:layout_height="match_parent">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/textView"
        android:text="a"/>
    </LinearLayout>


**recycler_view_list**
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

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

        <android.support.v7.widget.CardView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:clickable="true"
            android:elevation="8dp">

            <RelativeLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content">

                <TextView
                    android:id="@+id/question"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_centerVertical="true"
                    android:fontFamily="sans-serif"
                    android:text="ques"
                    android:padding="8dp"
                    android:layout_marginRight="32dp"
                    android:textSize="16dp" />

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_alignParentRight="true"
                    android:layout_marginRight="8dp"
                    android:fontFamily="sans-serif"
                    android:layout_centerVertical="true"
                    android:padding="8dp"
                    android:text=">" />
            </RelativeLayout>

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

    </LinearLayout>
    <ImageView
        android:src="@android:drawable/divider_horizontal_dark"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:scaleType="fitXY"
        android:paddingLeft="5dp"
        android:paddingRight="5dp"
        android:paddingBottom="0.2dp"
        android:paddingTop="0.2dp" />
</LinearLayout>


<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
<ListView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/list_view">
</ListView>
</LinearLayout>

expand_list_inside_recycler_view

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
<ListView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/list_view">
</ListView>
</LinearLayout>
4

1 回答 1

0

您的 single_item_in_list.xml 中的列表视图在哪里。您的 single_item_in_list.xml 没有列表视图，所以当您使用 getListView() 时，列表视图为空。我想这就是原因！

于 2016-04-01T08:06:36.927 回答