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我正在使用RecyclerView在Fragment中以ImageViews和TextViews的形式顯示信息。我給了ImageViews一個OnClickListener來獲取位置，並用這個可繪製的ID在更大的ImageView中顯示圖像。這對在片段開頭處顯示的所有RecyclerView行都適用，但是隻要我點擊一行ImageView，我需要滾動到的位置，就會得到一個NullPointerException與按摩：RecyclerView OnClick導致NullPointerException
java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.view.View.findViewById(int)' on a null object reference
java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.view.View.findViewById(int)' on a null object reference
顯示的信息根據預覽片段中的微調器而變化。該變量通過使用fragmentManager.region（d）的Activity被賦予Fragment。
的infromationFragment的代碼爲follwed：
public class Info_Material extends Fragment implements View.OnClickListener {
Button button_back;
Communicator communicator;
static ImageView image_large;
static private RecyclerView recyclerView;
private Information_List_Adapter adapter;
static ArrayList<String> holz_;
static ArrayList<String> land_;
static ArrayList<Integer> blatt_;
static ArrayList<Integer> baum_;
static ArrayList<Integer> frucht_;
String region_;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_info_material, container, false);
holz_ = new ArrayList<>();
land_ = new ArrayList<>();
blatt_ = new ArrayList<>();
baum_ = new ArrayList<>();
frucht_ = new ArrayList<>();
holz_.add(getString(R.string.));
land_.add("");
blatt_.add(R.drawable.);
baum_.add(R.drawable.);
frucht_.add(R.drawable.);
if (region_wahl.equals(getString(a))){
holz_.addAll(Arrays.asList());
land_.addAll(Arrays.asList());
blatt_.addAll(Arrays.asList());
baum_.addAll(Arrays.asList());
frucht_.addAll(Arrays.asList());
}
if (region_wahl.equals(getString(b))){
holz_.addAll(Arrays.asList());
land_.addAll(Arrays.asList());
blatt_.addAll(Arrays.asList());
baum_.addAll(Arrays.asList());
frucht_.addAll(Arrays.asList());
}
recyclerView= (RecyclerView) view.findViewById(R.id.materialInfoList);
adapter = new Information_List_Adapter(getActivity(),getData());
recyclerView.setAdapter(adapter);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
button_back = (Button) view.findViewById(R.id.back_I_M);
button_back.setOnClickListener(this);
image_large= (ImageView) view.findViewById(R.id.image_large);
image_large.setOnClickListener(this);
return view;
}
public static List<Information_List> getData() {
List<Information_List> data = new ArrayList<>();
for(int i=0;i<holz_.size() && i<blatt_.size() && i<baum_.size() && i<frucht_.size();i++) {
Information_List current = new Information_List();
current.blattID=blatt_.get(i);
current.baumID=baum_.get(i);
current.fruchtID=frucht_.get(i);
current.holz=holz_.get(i);
data.add(current);
}
return data;
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
public void setCommunicator (Communicator communicator) {
this.communicator = communicator;
}
@Override
public void onClick(View view) {
if(view.getId()==R.id.back_I_M){
String d;
d = "back";
communicator.finish_I_M(d);
}
if(view.getId()==R.id.image_large){
image_large.setImageDrawable(null);
}
}
public void region (String d) {
region_ = d;
}
static void enlarge (int position,String data){
ImageView imageView=null;
if(data.equals("blatt")){
imageView = (ImageView)recyclerView.getChildAt(position).findViewById(R.id.info_list_blatt);
}
if(data.equals("baum")){
imageView = (ImageView)recyclerView.getChildAt(position).findViewById(R.id.info_list_baum);
}
if(data.equals("frucht")){
imageView = (ImageView)recyclerView.getChildAt(position).findViewById(R.id.info_list_frucht);
}
BitmapDrawable drawable = (BitmapDrawable) imageView.getDrawable();
image_large.setImageDrawable(drawable);
}
public interface Communicator {
void finish_I_M (String data);
}
}
的AdapterClass：
public class Information_List_Adapter extends RecyclerView.Adapter <Information_List_Adapter.MyViewHolder> {
private Context context;
private LayoutInflater inflater;
List<Information_List> data = Collections.emptyList();
public Information_List_Adapter(Context context, List<Information_List> data) {
this.context=context;
inflater= LayoutInflater.from(context);
this.data=data;
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = inflater.inflate (R.layout.custom_info_material_row,parent,false);
MyViewHolder holder = new MyViewHolder(view);
return holder;
}
@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
holder.holz.setText(Info_Material.holz_.get(position));
holder.land.setText(Info_Material.land_.get(position));
holder.blattID.setImageResource(Info_Material.blatt_.get(position));
holder.baumID.setImageResource(Info_Material.baum_.get(position));
holder.fruchtID.setImageResource(Info_Material.frucht_.get(position));
}
@Override
public int getItemCount() {
return Info_Material.holz_.size();
}
class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
TextView holz;
TextView land;
ImageView blattID;
ImageView baumID;
ImageView fruchtID;
public MyViewHolder(View itemView) {
super(itemView);
holz= (TextView) itemView.findViewById(R.id.info_list_holz);
land = (TextView) itemView.findViewById(R.id.info_list_land);
blattID = (ImageView) itemView.findViewById(R.id.info_list_blatt);
baumID = (ImageView) itemView.findViewById(R.id.info_list_baum);
fruchtID = (ImageView) itemView.findViewById(R.id.info_list_frucht);
blattID.setOnClickListener(this);
baumID.setOnClickListener(this);
fruchtID.setOnClickListener(this);
}
@Override
public void onClick(View v) {
if(v.getId()==R.id.info_list_blatt){
Info_Material.enlarge(getAdapterPosition(),"blatt");
}
if(v.getId()==R.id.info_list_baum){
Info_Material.enlarge(getAdapterPosition(),"baum");
}
if(v.getId()==R.id.info_list_frucht){
Info_Material.enlarge(getAdapterPosition(),"frucht");
}
}
}
}
如上所述，這種方法工作正常的所有初始創建行，當啓動片段，但儘快，作爲一個新創建的行（不是最初顯示在屏幕上）點擊應用程序崩潰與NullPointerException。
因爲我對Java編程還很陌生，所以我真的不知道從哪裏可以開始尋找錯誤，所以我很感激任何有關錯誤發生的提示。
在此先感謝。
請向我們顯示它的錯誤行 – tyczj