如何修复“未连接适配器；跳过布局”

Question

我想在 RecycleView 中显示包含在片段中的 ArrayList，但是当我运行 apk 时，它没有显示 RV。当我在 logcat 上看到时，有注释“No Adapter Attached; skipping layout”。

我尝试了很多方法来更改片段和适配器，但最终都没有奏效。由于该站点上的其他问题基于API，我不明白，因为我是初学者。我试图找出一个基于 Arraylist 的问题，结果还是一样，没有一个解决方案是基于我的问题。

我将展示来自我的 Adapter、Fragment 和 mainActivity 的代码，它会很长，但我想知道问题所在，因为我迷路了而且一无所知。

片段：

public class FilmFragment extends Fragment {


    View view;
    ArrayList<Film> list = new ArrayList<>();
    RecyclerView rvCategory;
    FilmDatas filmDatas;


    public FilmFragment() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        // Inflate the layout for this fragment
        view = inflater.inflate(R.layout.fragment_movie,container,false);
        return view;}
    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState){
        rvCategory = view.findViewById(R.id.rvCategory);
        rvCategory.setHasFixedSize(true);
        list.addAll(filmDatas.getListData());
        showRecycleList();}
private void showRecycleList(){
        rvCategory.setLayoutManager(new LinearLayoutManager(getActivity()));
        FilmAdapter adapter = new FilmAdapter(getContext());
        adapter.setListMovie(list);
        rvCategory.setAdapter(adapter);}}

适配器：

public class FilmAdapter extends RecyclerView.Adapter<FilmAdapter.CategotyViewHolder> {
    Context context;
    private ArrayList<Film> listFilm;


    public ArrayList<Film> getList(){ 
        return listFilm; }

    public void setListMovie(ArrayList<Film> list) {
        this.listFilm = list;}

    public FilmAdapter(Context context
    ) {this.context = context;}


    @NonNull
    @Override
    public CategotyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_row_film,parent,false);
        return new CategotyViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull final CategotyViewHolder holder, int position) {
        final Film film = listFilm.get(position);

        Glide.with(holder.itemView.getContext()).load(film.getPhoto()).apply(new RequestOptions().override(100,100))
                .into(holder.imgPhoto);
        holder.tvName.setText(film.getName());
        holder.tvFrom.setText(film.getFrom());
        holder.tvDate.setText(film.getDate());


    }

    @Override
    public int getItemCount() {

        return getList().size();
    }

    public class CategotyViewHolder extends RecyclerView.ViewHolder {
       ImageView imgPhoto;
       TextView tvName,tvFrom,tvDate;

        public CategotyViewHolder(@NonNull View itemView) {
            super(itemView);
            imgPhoto = itemView.findViewById(R.id.img_item_photo);
            tvName = itemView.findViewById(R.id.tv_item_name);
            tvFrom = itemView.findViewById(R.id.tv_item_from);
            tvDate = itemView.findViewById(R.id.tv_date);}}

主要活动：

public class MainActivity extends AppCompatActivity {
    TabLayout tabLayout;
    FrameLayout frameLayout;
    ViewPager viewPager;




    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        frameLayout = findViewById(R.id.Frame);
        tabLayout = findViewById(R.id.simpelTab);
        viewPager = findViewById(R.id.viewPager);
        viewPager.setAdapter(new sliderAdapter(getSupportFragmentManager()));

        tabLayout.post(new Runnable() {
            @Override
            public void run() {
                tabLayout.setupWithViewPager(viewPager);
            }
        });

        tabLayout.addOnTabSelectedListener(new TabLayout.BaseOnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                viewPager.setCurrentItem(tab.getPosition());
            }

            @Override
            public void onTabUnselected(TabLayout.Tab tab) {

            }

            @Override
            public void onTabReselected(TabLayout.Tab tab) {

            }
        });
    }

    private class sliderAdapter extends FragmentPagerAdapter {
        String movie = "MOVIE";
        String tvShow = "TV SHOW";
        final String tabs[] = {movie, tvShow};

        public sliderAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            switch (position){
                case 0:
                    return new FilmFragment();
                case 1:
                    return new TvShowFragment();
            }
            return null;
        }

        @Override
        public int getCount() {
            return tabs.length; //count Tabs[] size: 2
        }

        @Override
        public CharSequence getPageTitle(int position) {
            return tabs[position];
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main_menu, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            if (item.getItemId() == R.id.action_settings) {
                Intent mIntent = new Intent(Settings.ACTION_LOCALE_SETTINGS);
                startActivity(mIntent);
            }
        }

        return super.onOptionsItemSelected(item);
    }


    }

电影数据：

public class FilmDatas { public static String [][] data = new String[][]{
        {
                "Venom (2018)","Investigative journalist Eddie Brock attempts a comeback following a scandal, but accidentally becomes the host of Venom, a violent, super powerful alien symbiote. Soon, he must rely on his newfound powers to protect the world from a shadowy organization looking for a symbiote of their own.","https://image.tmdb.org/t/p/w220_and_h330_face/2uNW4WbgBXL25BAbXGLnLqX71Sw.jpg","https://image.tmdb.org/t/p/w533_and_h300_bestv2/VuukZLgaCrho2Ar8Scl9HtV3yD.jpg","October 5, 2018"
        }

};
    public ArrayList<Film> getListData() {
        ArrayList<Film> list = new ArrayList<>();
        for (String[] aData : data) {
            Film film = new Film();
            film.setName(aData[0]);
            film.setFrom(aData[1]);
            film.setBackground(aData[2]);
            film.setPhoto(aData[3]);
            film.setDate(aData[4]);

            list.add(film);
        }
        return list;
    }
}

电影：（它包含 parcelable 和 set/get）

public class Film implements Parcelable {
    private String name,from,background,photo,date;

    public Film() {

    }


    public String getName() {return name;}
    public void setName (String name) {this.name = name;}
    public String getFrom() {return from;}
    public void setFrom (String from) {this.from = from;}
    public String getBackground() {return background;}
    public void setBackground (String background) {this.background = background;}
    public String getPhoto() {return photo;}
    public void setPhoto (String photo) {this.photo = photo;}
    public String getDate() {return date;}
    public void setDate (String date) {this.date = date;}

    protected Film(Parcel in) {
        name = in.readString();
        from = in.readString();
        background = in.readString();
        photo = in.readString();
        date = in.readString();
    }

    public static final Creator<Film> CREATOR = new Creator<Film>() {
        @Override
        public Film createFromParcel(Parcel in) {
            return new Film(in);
        }

        @Override
        public Film[] newArray(int size) {
            return new Film[size];
        }
    };

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel parcel, int i) {
        parcel.writeString(name);
        parcel.writeString(from);
        parcel.writeString(background);
        parcel.writeString(photo);
        parcel.writeString(date);
    }
}

Answer 1

您的问题取决于您的 Fragment。

你已经声明了

FilmDatas filmDatas;

但是你从来没有实例化它，甚至没有在这里填充它的任何对象

 @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState){
        rvCategory = view.findViewById(R.id.rvCategory);
        rvCategory.setHasFixedSize(true);
        list.addAll(filmDatas.getListData());
        showRecycleList();
}

因此，没有数据可以填充您的列表，并且您的 recyclerview 不会显示任何内容

尝试通过像这样向列表中添加元素来测试

list.add(new FilmDatas("param1","param2"...))

此外，您将列表声明为类型 Film，但您使用 FilmDatas 类型填充它

但我假设 filmData.getListData() 返回您要填充的 Film 类型的对象。

问题不在于 “No adapter attached; skipping layout” ，问题在于您没有向列表中添加任何元素，并且当您将列表设置为适配器时，它不会在每个 recyclerview 行中绑定任何数据， getItemCount() 返回 0，所以你的 recyclerview 什么也不显示。

Answer 2

您的问题似乎与此代码有关：

 public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState){
    rvCategory = view.findViewById(R.id.rvCategory);
    rvCategory.setHasFixedSize(true);
    list.addAll(filmDatas.getListData());
    showRecycleList();}

private void showRecycleList(){
        rvCategory.setLayoutManager(new LinearLayoutManager(getActivity()));
        FilmAdapter adapter = new FilmAdapter(getContext());
        adapter.setListMovie(list);
        rvCategory.setAdapter(adapter);}}

您在创建 RecyclerView 之后添加列表，而没有刷新您的视图。您可以通过以下两种方式之一来处理：更新您的方法以使用数据更新视图；或者，在创建适配器时传入数据。

如果您只想刷新列表，这对您在视图膨胀后可能收到的数据很有帮助（想想从 API 请求中获取数据），那么您只需添加notifyDataSetChanged()：

适配器：

  public void setListMovie(ArrayList<Film> list) {
    this.listFilm = list;
    notifyDataSetChanged();
  }

否则，您只需在创建适配器时传递数据：

适配器：

 public FilmAdapter(Context context, ArrayList<Film> list) {
      this.context = context;
      this.listFilm = list;
 }

然后在您的Fragment 中，您将执行以下操作：

 private void showRecycleList(){
    rvCategory.setLayoutManager(new LinearLayoutManager(getActivity()));
    if(list != null){
         FilmAdapter adapter = new FilmAdapter(getContext(), list);
         rvCategory.setAdapter(adapter);
    } else {
         //Handle error
    }

  }