Java RecycleServiceAdapter中的空指针异常

适配器工作正常，直到我决定添加本机广告，为此我在适配器中做了6次更改

添加了新的视图类型（AD_视图_类型）

添加了新的ViewHolder（NativeExpressAdViewHolder）

更改了getItemViewType（使其每8个位置返回AD_视图_类型）

在onCreateViewHolder中添加了一个新案例

     switch (viewType){

        case AD_VIEW_TYPE:
        View nativeExpressLayoutView = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.native_express_ad_container, parent, false);
        return new NativeExpressAdViewHolder(nativeExpressLayoutView);

          switch (viewType){

          case AD_VIEW_TYPE:
          NativeExpressAdViewHolder nativeExpressHolder = (NativeExpressAdViewHolder)holder;
          NativeExpressAdView adView = (NativeExpressAdView)arrayList.get(position);

        ViewGroup adCardView = (ViewGroup)nativeExpressHolder.itemView;
        adCardView.removeAllViews();

        if(adView.getParent() != null){
            ((ViewGroup)adView.getParent()).removeView(adView);
        }

        adCardView.addView(adView);
        break;

向onBindViewHolder添加了一个新案例

     switch (viewType){

        case AD_VIEW_TYPE:
        View nativeExpressLayoutView = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.native_express_ad_container, parent, false);
        return new NativeExpressAdViewHolder(nativeExpressLayoutView);

          switch (viewType){

          case AD_VIEW_TYPE:
          NativeExpressAdViewHolder nativeExpressHolder = (NativeExpressAdViewHolder)holder;
          NativeExpressAdView adView = (NativeExpressAdView)arrayList.get(position);

        ViewGroup adCardView = (ViewGroup)nativeExpressHolder.itemView;
        adCardView.removeAllViews();

        if(adView.getParent() != null){
            ((ViewGroup)adView.getParent()).removeView(adView);
        }

        adCardView.addView(adView);
        break;

除了上述更改之外，我还在Activity and Adapter中将我的

ArrayList

更改为

ArrayList

现在的问题是，当我运行应用程序时，它会抛出

NullPointerException

logcat说

 java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.View.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
                                                                      at com.company.appname.adapters.RecyclerViewAdapter$RecyclerViewHolder.<init>(RecyclerViewAdapter.java:186)
                                                                      at com.company.appname.adapters.RecyclerViewAdapter$RecyclerViewHolder.<init>(RecyclerViewAdapter.java:165)
                                                                      at com.company.appname.adapters.RecyclerViewAdapter$NativeExpressAdViewHolder.<init>(RecyclerViewAdapter.java:150)
                                                                      at com.company.appname.adapters.RecyclerViewAdapter.onCreateViewHolder(RecyclerViewAdapter.java:84)
                                                                      at com.company.appname.adapters.RecyclerViewAdapter.onCreateViewHolder(RecyclerViewAdapter.java:48)

java.lang.NullPointerException:尝试对空对象引用调用虚拟方法“void android.view.view.setOnClickListener（android.view.view$OnClickListener）”
位于com.company.appname.adapters.RecycleServiceAdapter$RecycleServiceWholder。（RecycleServiceAdapter.java:186）
位于com.company.appname.adapters.RecycleServiceAdapter$RecycleServiceWholder。（RecycleServiceAdapter.java:165）
位于com.company.appname.adapters.RecycleServiceAdapter$NativeExpressAdViewHolder。（RecycleServiceAdapter.java:150）
位于com.company.appname.adapters.RecycleServiceAdapter.onCreateViewHolder（RecycleServiceAdapter.java:84）
位于com.company.appname.adapters.RecycleServiceAdapter.onCreateViewHolder（RecycleServiceAdapter.java:48）

这些是我的代码中logcat指向的部分

/*Line 48*/public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.RecyclerViewHolder> {
 public RecyclerViewAdapter(Context context, ArrayList<Object> arrayList, ArrayList<String> favouriteItemList, int totalCount {...}

 @Override
 public long getItemId(int position){...}

     @Override
     public RecyclerViewAdapter.RecyclerViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

         switch (viewType){

         case AD_VIEW_TYPE:
            View nativeExpressLayoutView = LayoutInflater.from(parent.getContext())
                    .inflate(R.layout.native_express_ad_container, parent, false);
 /*Line 84*/               return new NativeExpressAdViewHolder(nativeExpressLayoutView); 

         case MENU_ITEM_VIEW_TYPE:

         default:
            View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.cards, parent, false);
            return new RecyclerViewHolder(view);
        }
    }

     @Override
     public void onBindViewHolder(final RecyclerViewHolder holder, final int position){...}

         public class NativeExpressAdViewHolder extends RecyclerViewHolder{
                NativeExpressAdViewHolder(View view){
/*Line 150*/                    super(view);
                }
        }

     @Override
     public int getItemViewType(int position){...}

     @Override
     public int getItemCount(){...}


/*Line 165*/        public class RecyclerViewHolder extends RecyclerView.ViewHolder {

    TextView title;
    RelativeLayout relativeLayout;
    RelativeLayout cardDescription;
    SimpleDraweeView image;
    ImageView favourite_button;
    CardSetterGetter cardSetterGetter;
    ImageView share;


    private RecyclerViewHolder(View itemView) {
        super(itemView);
        title = (TextView) itemView.findViewById(R.id.image_title);
        relativeLayout = (RelativeLayout) itemView.findViewById(R.id.activity_dash_board);
        cardDescription = (RelativeLayout) itemView.findViewById(R.id.card_details);
        image = (SimpleDraweeView) itemView.findViewById(R.id.image);
        favourite_button = (ImageView) itemView.findViewById(R.id.favourite_button);
        share = (ImageView) itemView.findViewById(R.id.share);

 /*Line 186*/           image.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                Activity activity = (Activity) context;
                saveInfo(constants.SERVERIP.concat(cardSetterGetter.getImageurl()), cardSetterGetter.getImageId(), cardSetterGetter.getDescription(), cardSetterGetter.getImagetitle(), cardSetterGetter.getFavourite());
                Intent i = new Intent().setClass(context, DetailsImageviewActivity.class);
                i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_MULTIPLE_TASK);
                context.startActivity(i);
                activity.overridePendingTransition(R.anim.pull_from_right, R.anim.pull_out_to_right);
            }
        });

    }
}
}

/*第48行*/公共类RecycleServiceAdapter扩展了RecycleView.Adapter{
公共RecycleServiceAdapter（上下文上下文、ArrayList ArrayList、ArrayList FavoriteItemList、int totalCount{…}
@凌驾
公共长getItemId（int位置）{…}
@凌驾
public RecycleServiceAdapter.RecycleServiceWholder onCreateViewHolder（视图组父级，int-viewType）{
开关（视图类型）{
案例广告视图类型：
View nativeExpressLayoutView=LayoutFlater.from（parent.getContext（））
.充气（R.layout.native\u express\u ad\u container，父级，false）；
/*第84行*/返回新的NativeExpressAdViewHolder（nativeExpressLayoutView）；
案例菜单\项目\视图\类型：
违约：
View=LayoutInflater.from（parent.getContext（））.flate（R.layout.cards，parent，false）；
返回新的RecycleServiceWholder（视图）；
}
}
@凌驾
public void onBindViewHolder（最终RecyclerViewHolder持有者，最终int位置）{…}
公共类NativeExpressAdViewHolder扩展了RecycleServiceWholder{
NativeExpressAdViewHolder（视图）{
/*第150行*/super（视图）；
}
}
@凌驾
公共int getItemViewType（int位置）{…}
@凌驾
public int getItemCount（）{…}
/*第165行*/公共类RecyclerViewHolder扩展了RecyclerView.ViewHolder{
文本视图标题；
相对的相对的；
相对性描述；
简单回顾图像；
ImageView收藏夹按钮；
cardsettergeter cardsettergeter；
图像视图共享；
private RecycleServiceWholder（查看项目视图）{
超级（项目视图）；
title=（TextView）itemView.findViewById（R.id.image\u title）；
relativeLayout=（relativeLayout）itemView.findViewById（R.id.activity\u dash\u board）；
cardDescription=（RelativeLayout）itemView.findViewById（R.id.card\U详细信息）；
image=（simpledraweview）itemView.findviewbyd（R.id.image）；
Favorite_按钮=（ImageView）itemView.findViewById（R.id.Favorite_按钮）；
share=（ImageView）itemviewbyd（R.id.share）；
/*第186行*/image.setOnClickListener（新视图.OnClickListener（）{
@凌驾
公共void onClick（视图）{
活动=（活动）上下文；
saveInfo（constants.SERVERIP.concat（cardsetterget.getImageurl（）），cardsetterget.getImageId（），cardsetterget.getDescription（），cardsetterget.getImagetitle（），cardsetterget.getFavorite（））；
Intent i=new Intent（）.setClass（context，DetailsImageviewActivity.class）；
i、 setFlags（Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_MULTIPLE_TASK）；
背景。起始触觉（i）；
activity.overridePendingTransition（R.anim.pull_from_right，R.anim.pull_out_right）；
}
});
}
}
}

---

我知道什么是Null PoExtExchange，我知道解决这些问题的方法，但是在这种情况下，我很难找到问题的根源和解决办法。所以如果解决方案很简单，请不要把问题标记为复制品，请考虑帮助我解决这个问题。

< P>当2个不同视图类型膨胀时在recyclerView中，我们需要创建两个独立的

ViewHolder

类来包含每个布局中的不同元素

请尝试以下操作：

//make this a separate class,but not inside the onBindViewHolder
private class NativeExpressAdViewHolder extends RecyclerView.ViewHolder{
    NativeExpressAdViewHolder(View view){                            
    super(view);
    //find the view here
    adView = (NativeExpressAdView)view.findViewById(R.id.native_ad);
}

private class RecyclerViewHolder extends RecyclerView.ViewHolder{
   //this one as usual..
}



//change your onCreateViewHolder for this as well,
// cause now you have 2 view type,so you just override from universal 
//RecyclerView.ViewHolder,not need RecyclerViewAdapter.RecyclerViewHolder
   @Override
     public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { }




@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
    int viewType = getItemViewType(position);
    switch (viewType){
      case AD_VIEW_TYPE:
      final NativeExpressAdViewHolder adHolder (NativeExpressAdViewHolder)holder
       //here find your view and load the ad


     break;
     case MENU_ITEM_VIEW_TYPE:
     final  RecyclerViewHolder viewHolder = (RecyclerViewHolder)holder
     //do your thing here,find view,assign value to the layout

    }

还有一件事，请检查您的XML，您的XML应该如下所示

<com.google.android.gms.ads.NativeExpressAdView
        xmlns:ads="http://schemas.android.com/apk/res-auto"
        android:id="@+id/native_ad"
        android:layout_gravity="center_horizontal"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        ads:adSize="360x132"
        ads:adUnitId="@string/your_ads">

 </com.google.android.gms.ads.NativeExpressAdView>

我知道什么是NullPointerException以及如何修复它。只是我在这里找不到问题。这就是为什么我需要问题特定的解决方案，而不是一般的解决方案。为什么您的

公共类NativeExpressAdViewHolder扩展了RecycleServiceWholder{

在你的

onBindViewHolder中

？@ken因为演员阵容问题，我在这里问了一个关于StackOverflow的问题，有人建议我这样做，它解决了这个问题。谢谢你的回答，ken，但是NativeExpressAdViewHolder的onBindViewHolder已经用完了，你想让我在另一个java文件中使用它吗？如果它已经读过了