データアダプターのヌルポインター例外

Question

マルチプル&異なるレイアウトのRecyclerViewが1つ必要ですが、このエラーを解決できません。

エラー：java.lang.NullPointerExceptionが：nullのオブジェクト参照

エラーコード

に '無効android.widget.ImageView.setImageResource（int型）' 仮想メソッドを呼び出すための試み（ （ViewHolder1）ホルダー）.mIdView.setImageResource（（（ViewHolder1）ホルダー）.mItem.id）

データアダプター

package krishidarshan; 

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

import java.util.List; 

import krishidarshan.dummy.DummyContent.DummyItem; 

/** 
* Created by Abhishek on 19-03-2017. 
*/ 

public class DataAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> { 
private final List<DummyItem> mValues; 
int type; 


public DataAdapter(List<DummyItem> items, int layoutType) { 
    mValues = items; 
    type = layoutType; 
} 

@Override 
public int getItemViewType(int position) { 
    return type; 
} 

@Override 
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { 
    if (viewType == 1) { 
     View view1 = LayoutInflater.from(parent.getContext()) 
       .inflate(R.layout.card_view, parent, false); 
     return new ViewHolder1(view1); 
    } else { 
     View view2 = LayoutInflater.from(parent.getContext()) 
       .inflate(R.layout.fragment_crops, parent, false); 
     return new ViewHolder2(view2); 
    } 
} 

@Override 
public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int position) { 
    if (holder instanceof ViewHolder1) { 
     ((ViewHolder1) holder).mItem = mValues.get(position); 
     ((ViewHolder1) holder).mIdView.setImageResource(((ViewHolder1) holder).mItem.id); 
     ((ViewHolder1) holder).mIdView.setImageResource(((ViewHolder1) holder).mItem.id); 
     ((ViewHolder1) holder).mContentView.setText(((ViewHolder1) holder).mItem.content); 

    } else if (holder instanceof ViewHolder2) { 
     ((ViewHolder2) holder).mItem = mValues.get(position); 
     ((ViewHolder2) holder).mIdView.setImageResource(((ViewHolder2) holder).mItem.id); 
     ((ViewHolder2) holder).mContentView.setText(((ViewHolder2) holder).mItem.content); 
     ((ViewHolder2) holder).mContentDetailView.setText(((ViewHolder2) holder).mItem.content_detail); 
    } 
} 

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


public class ViewHolder1 extends RecyclerView.ViewHolder { 
    public final View mView; 
    public final ImageView mIdView; 
    public final TextView mContentView; 
    public final Context mContext; 
    public DummyItem mItem; 

    public ViewHolder1(final View view) { 
     super(view); 
     mView = view; 
     mContext = view.getContext(); 
     mIdView = (ImageView) view.findViewById(R.id.id); 
     mContentView = (TextView) view.findViewById(R.id.content); 
     view.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       int position = getAdapterPosition(); 
       switch (position) { 
        case 0: 
         Intent i = new Intent(mContext, CropsActivity.class); 
         mContext.startActivity(i); 
         break; 
        case 1: 
         Intent i1 = new Intent(mContext, WeatherActivity.class); 
         mContext.startActivity(i1); 
       } 
      } 
     }); 

    } 

    @Override 
    public String toString() { 
     return super.toString() + " '" + mContentView.getText() + "'"; 
    } 

} 

public class ViewHolder2 extends RecyclerView.ViewHolder { 
    public final View mView; 
    public final ImageView mIdView; 
    public final TextView mContentView, mContentDetailView; 
    public final Context mContext; 
    public DummyItem mItem; 

    public ViewHolder2(final View view) { 
     super(view); 
     mView = view; 
     mContext = view.getContext(); 
     mIdView = (ImageView) view.findViewById(R.id.crops_image); 
     mContentView = (TextView) view.findViewById(R.id.crops_name); 
     mContentDetailView = (TextView) view.findViewById(R.id.crops_detail); 
    } 

    @Override 
    public String toString() { 
     return super.toString() + " '" + mContentView.getText() + "'"; 
    } 

} 

} 

DummyContent

package krishidarshan.dummy; 

/** 
* Created by Abhishek on 19-03-2017. 
*/ 

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

import krishidarshan.R; 

/** 
* Helper class for providing sample content for user interfaces created by 
* Android template wizards. 
* <p/> 
* TODO: Replace all uses of this class before publishing your app. 
*/ 
public class DummyContent { 

/** 
* An array of sample (dummy) items. 
*/ 
public static final List<DummyItem> ITEMS = new ArrayList<>(); 
public static final List<DummyItem> CROPS_ITEMS = new ArrayList<>(); 

private static String[] item_names = {"Crops", "Weather", "Market Price", "ABC"}; 
private static int[] item_list = {R.drawable.bg, R.drawable.bg, R.drawable.bg, R.drawable.bg}; 

private static String[] crops_names = {"Rice", "Wheat", "Jwar", "Bajra"}; 
private static int[] crops_images = {R.drawable.bg, R.drawable.bg, R.drawable.bg, R.drawable.bg}; 
private static String[] crops_content = {"They are useful", "They are useful", "They are useful", "They are useful"}; 

private static final int COUNT = 4; 

static { 
    // Add some sample items. 
    for (int i = 0; i < COUNT; i++) { 
     addItem(createDummyItem(i)); 
     addItemForCrop(createCropItem(i)); 
    } 
} 

private static void addItem(DummyItem item) { 
    ITEMS.add(item); 
} 

private static void addItemForCrop(DummyItem item) { 
    CROPS_ITEMS.add(item); 
} 

private static DummyItem createDummyItem(int position) { 
    return new DummyItem(item_list[position], item_names[position]); 
} 

private static DummyItem createCropItem(int position) { 
    return new DummyItem(crops_images[position], crops_names[position], crops_content[position]); 
} 

/** 
* A dummy item representing a piece of content. 
*/ 
public static class DummyItem { 
    public final int id; 
    public final String content; 
    public final String content_detail; 

    public DummyItem(int id, String content) { 
     this.id = id; 
     this.content = content; 
     this.content_detail = null; 
    } 
    @Override 
    public String toString() { 
     return content; 
    } 

    public DummyItem(int id, String content, String content_detail) { 
     this.id = id; 
     this.content = content; 
     this.content_detail = content_detail; 
    } 

} 
} 

card_view.xml

<?xml version="1.0" encoding="utf-8"?> 
<android.support.v7.widget.CardView  xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:card_view="http://schemas.android.com/apk/res-auto" 
android:id="@+id/card" 
android:layout_width="match_parent" 
android:layout_height="wrap_content" 
android:layout_margin="4dp" 
android:elevation="4dp" 
android:foreground="?selectableItemBackground" 
card_view:cardBackgroundColor="#ffffff" 
card_view:cardCornerRadius="6dp" 
card_view:contentPadding="0.2dp"> 

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

    <ImageView 
     android:id="@+id/id" 
     android:layout_width="match_parent" 
     android:layout_height="150dp" 
     android:adjustViewBounds="true" 
     android:scaleType="fitXY" /> 

    <TextView 
     android:id="@+id/content" 
     android:layout_width="match_parent" 
     android:layout_height="40dp" 
     android:layout_alignBottom="@+id/id" 
     android:alpha="0.8" 
     android:background="#757575" 
     android:gravity="center" 
     android:paddingLeft="@dimen/activity_horizontal_margin" 
     android:paddingRight="@dimen/activity_horizontal_margin" 
     android:text="Crops" 
     android:textSize="17dp" /> 

</RelativeLayout> 

Answer 1

はこれを試してみてください、それが必要な作品：

if (holder instanceof ViewHolder1) { 
    ((ViewHolder1) holder).bind(mValues.get(position)); 
} else { 
// more code here! ... 
}