如何使用下一页“10 项”填充标题和网格布局

Question

在我的应用程序中，我有四种布局，“卡片列表”，“卡片杂志”，“标题”和“网格”，我制作了选项菜单以允许用户从“更改布局”选项菜单中更改它，问题发生了这是第一次运行应用程序时选择标题或网格布局，它显示唯一的第一页“10 项”结果来自改造调用

要相关，请参阅此问题

在这个应用程序的旧版本“当我使用活动时”我用标题和网格视图持有者的这行代码解决了这个问题

if(position == getItemCount() -1)

if(context instanceof MainActivity){
 ((MainActivity)context).getMainPagePosts();

}

但是在这个版本中我使用了片段，所以当我试图解决它时，我创建了一个名为“WhichFragmentCalled”的接口，并将片段和 viewHolder 作为参数

public interface WhichFragmentCalled {

     void whichFragmentAndViewModel(Fragment fragment, PostViewModel postViewModel);
}

然后我在适配器和片段中使用它，就像这样

 @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        WhichFragmentCalled whichFragmentCalled = adapter;

        whichFragmentCalled.whichFragmentAndViewModel(this,postViewModel);
    }

并使适配器实现此接口，这是完整的PostAdapter代码

public class PostAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> implements WhichFragmentCalled{
    private Context context;
    private List<Item> items;

    private static final int CARD = 0;
    private static final int CARD_MAGAZINE = 1;
    private static final int TITLE = 2;
    private static final int GRID = 3;
    private static final int SDK_VERSION = Build.VERSION.SDK_INT;
    public static final String TAG = "POST ADAPTER";

    private int viewType;
    private int position;
    private Fragment fragment;
    private PostViewModel postViewModel;

    public PostAdapter(Context context, List<Item> items) {
        this.context = context;
        this.items = items;
    }

    public void setViewType(int viewType) {
        this.viewType = viewType;
        notifyDataSetChanged();
    }

    public int getViewType() {
        return this.viewType;
    }


    @NonNull
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        LayoutInflater inflater = LayoutInflater.from(context);
        View view;

        if (this.viewType == CARD) {
            view = inflater.inflate(R.layout.card, parent, false);
            return new CardViewHolder(view);
        } else if (this.viewType == CARD_MAGAZINE) {
            view = inflater.inflate(R.layout.card_magazine, parent, false);
            return new CardMagazineViewHolder(view);
        } else if (this.viewType == TITLE) {
            if(SDK_VERSION < Build.VERSION_CODES.LOLLIPOP){
                view = inflater.inflate(R.layout.title_layout_v15,parent,false);
            }else {
                view = inflater.inflate(R.layout.title_layout, parent, false);
            }
            return new TitleViewHolder(view);
        } else {
            if(SDK_VERSION < Build.VERSION_CODES.LOLLIPOP){
                view = inflater.inflate(R.layout.grid_layout_v15,parent,false);
            }else {
                view = inflater.inflate(R.layout.grid_layout, parent, false);
            }
            return new GridViewHolder(view);
        }

    }


    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {


        this.position = position;


        int itemType = getViewType();
        Item item = items.get(holder.getAdapterPosition());
        final Document document = Jsoup.parse(item.getContent());
        final Elements elements = document.select("img");

//        Log.e("IMAGE", document.getAllElements().select("img").get(0).attr("src"));

        Date date = new Date();
        SimpleDateFormat format = new SimpleDateFormat
                ("yyyy-MM-dd'T'HH:mm:ssZ", Locale.getDefault());
        Intent intent = new Intent(context, DetailsActivity.class);

        switch (itemType) {
            case CARD:
                if (holder instanceof CardViewHolder) {
                    CardViewHolder cardViewHolder = (CardViewHolder) holder;
                    cardViewHolder.postTitle.setText(item.getTitle());

                    try {
                        Log.e("IMAGE", elements.get(0).attr("src"));
                        Glide.with(context).load(elements.get(0).attr("src"))
                                .into(cardViewHolder.postImage);
                    }catch (IndexOutOfBoundsException e){
                        cardViewHolder.postImage.setImageResource(R.mipmap.ic_launcher);
                        Log.e(TAG,e.toString());
                    }


                    cardViewHolder.postDescription.setText(document.text());
                    try {
                        date = format.parse(items.get(position).getPublished());

                    } catch (ParseException e) {
                        e.printStackTrace();
                    }

                    PrettyTime prettyTime = new PrettyTime();

                    cardViewHolder.postDate.setText(prettyTime.format(date));

                    cardViewHolder.itemView.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View view) {


                            intent.putExtra("url", item.getUrl());
                            intent.putExtra("title", item.getTitle());
                            intent.putExtra("content", item.getContent());
                            int youtubeThumbnailImagesetVisibility = 0;

                            Element element = document.body();

                            String youtubeThumbnailImageSrc = "";
                            String youTubeLink = "";
                            for (Element e : element.getElementsByClass
                                    ("YOUTUBE-iframe-video")) {
                                youtubeThumbnailImageSrc = e.attr("data-thumbnail-src");
                                youTubeLink = e.attr("src");
                                Log.e("YouTube thumbnail", youtubeThumbnailImageSrc);
                                Log.e("Youtube link", youTubeLink);
                            }

                            if (youtubeThumbnailImageSrc.isEmpty()) {
                                youtubeThumbnailImagesetVisibility = 8;
                                intent.putExtra("youtubeThumbnailImagesetVisibility",
                                        youtubeThumbnailImagesetVisibility);
                            } else {
                                intent.putExtra("youtubeThumbnailImageSrc", youtubeThumbnailImageSrc);
                                intent.putExtra("youTubeLink", youTubeLink);
                            }

//             String imageSrc = elements.get(0).attr("src");
//             intent.putExtra("blogImage",imageSrc);

                            view.getContext().startActivity(intent);
                        }
                    });
                }
                break;

            case CARD_MAGAZINE:
                if (holder instanceof CardMagazineViewHolder) {
                    CardMagazineViewHolder cardMagazineViewHolder = (CardMagazineViewHolder) holder;
                    cardMagazineViewHolder.postTitle.setText(item.getTitle());


                    try {
                        Log.e("IMAGE", elements.get(0).attr("src"));
                        Glide.with(context).load(elements.get(0).attr("src"))
                                .into(cardMagazineViewHolder.postImage);
                    }catch (IndexOutOfBoundsException e){
                        cardMagazineViewHolder.postImage.setImageResource(R.mipmap.ic_launcher);
                        Log.e(TAG,e.toString());
                    }

                    try {
                        date = format.parse(items.get(position).getPublished());

                    } catch (ParseException e) {
                        e.printStackTrace();
                    }
                    PrettyTime prettyTime = new PrettyTime();

                    cardMagazineViewHolder.postDate.setText(prettyTime.format(date));

                    cardMagazineViewHolder.itemView.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View view) {
                            intent.putExtra("url", item.getUrl());
                            intent.putExtra("title", item.getTitle());
                            intent.putExtra("content", item.getContent());
                            int youtubeThumbnailImagesetVisibility = 0;

                            Element element = document.body();

                            String youtubeThumbnailImageSrc = "";
                            String youTubeLink = "";
                            for (Element e : element.getElementsByClass
                                    ("YOUTUBE-iframe-video")) {
                                youtubeThumbnailImageSrc = e.attr("data-thumbnail-src");
                                youTubeLink = e.attr("src");
                                Log.e("YouTube thumbnail", youtubeThumbnailImageSrc);
                                Log.e("Youtube link", youTubeLink);
                            }

                            if (youtubeThumbnailImageSrc.isEmpty()) {
                                youtubeThumbnailImagesetVisibility = 8;
                                intent.putExtra("youtubeThumbnailImagesetVisibility",
                                        youtubeThumbnailImagesetVisibility);
                            } else {
                                intent.putExtra("youtubeThumbnailImageSrc", youtubeThumbnailImageSrc);
                                intent.putExtra("youTubeLink", youTubeLink);
                            }

//             String imageSrc = elements.get(0).attr("src");
//             intent.putExtra("blogImage",imageSrc);

                            view.getContext().startActivity(intent);
                        }
                    });
                }
                break;
            case TITLE:
                if (holder instanceof TitleViewHolder) {
                    TitleViewHolder titleViewHolder = (TitleViewHolder) holder;
                    titleViewHolder.postTitle.setText(item.getTitle());

                    Log.d("TITLE", "title layout called");


                    try {
                        Log.e("IMAGE", elements.get(0).attr("src"));
                        Glide.with(context).load(elements.get(0).attr("src"))
                                .into(titleViewHolder.postImage);
                    }catch (IndexOutOfBoundsException e){
                        titleViewHolder.postImage.setImageResource(R.mipmap.ic_launcher);
                        Log.e(TAG,e.toString());
                    }


                    titleViewHolder.itemView.setOnClickListener(view -> {
                        intent.putExtra("url", item.getUrl());
                        intent.putExtra("title", item.getTitle());
                        intent.putExtra("content", item.getContent());
                        int youtubeThumbnailImagesetVisibility = 0;

                        Element element = document.body();

                        String youtubeThumbnailImageSrc = "";
                        String youTubeLink = "";
                        for (Element e : element.getElementsByClass
                                ("YOUTUBE-iframe-video")) {
                            youtubeThumbnailImageSrc = e.attr("data-thumbnail-src");
                            youTubeLink = e.attr("src");
                            Log.e("YouTube thumbnail", youtubeThumbnailImageSrc);
                            Log.e("Youtube link", youTubeLink);
                        }

                        if (youtubeThumbnailImageSrc.isEmpty()) {
                            youtubeThumbnailImagesetVisibility = 8;
                            intent.putExtra("youtubeThumbnailImagesetVisibility",
                                    youtubeThumbnailImagesetVisibility);
                        } else {
                            intent.putExtra("youtubeThumbnailImageSrc", youtubeThumbnailImageSrc);
                            intent.putExtra("youTubeLink", youTubeLink);
                        }

//             String imageSrc = elements.get(0).attr("src");
//             intent.putExtra("blogImage",imageSrc);

                        view.getContext().startActivity(intent);
                    });

                }
                break;
            case GRID:
                if (holder instanceof GridViewHolder) {
                    GridViewHolder gridViewHolder = (GridViewHolder) holder;
                    gridViewHolder.postTitle.setText(item.getTitle());


                    try {
                        Log.e("IMAGE", elements.get(0).attr("src"));
                        Glide.with(context).load(elements.get(0).attr("src"))
                                .into(gridViewHolder.postImage);
                    }catch (IndexOutOfBoundsException e){
                        gridViewHolder.postImage.setImageResource(R.mipmap.ic_launcher);
                        Log.e(TAG,e.toString());
                    }



                    gridViewHolder.itemView.setOnClickListener(view -> {
                        intent.putExtra("url", item.getUrl());
                        intent.putExtra("title", item.getTitle());
                        intent.putExtra("content", item.getContent());
                        int youtubeThumbnailImagesetVisibility;

                        Element element = document.body();

                        String youtubeThumbnailImageSrc = "";
                        String youTubeLink = "";
                        for (Element e : element.getElementsByClass
                                ("YOUTUBE-iframe-video")) {
                            youtubeThumbnailImageSrc = e.attr("data-thumbnail-src");
                            youTubeLink = e.attr("src");
                            Log.e("YouTube thumbnail", youtubeThumbnailImageSrc);
                            Log.e("Youtube link", youTubeLink);
                        }

                        if (youtubeThumbnailImageSrc.isEmpty()) {
                            youtubeThumbnailImagesetVisibility = 8;
                            intent.putExtra("youtubeThumbnailImagesetVisibility",
                                    youtubeThumbnailImagesetVisibility);
                        } else {
                            intent.putExtra("youtubeThumbnailImageSrc", youtubeThumbnailImageSrc);
                            intent.putExtra("youTubeLink", youTubeLink);
                        }

//             String imageSrc = elements.get(0).attr("src");
//             intent.putExtra("blogImage",imageSrc);

                        view.getContext().startActivity(intent);
                    });
                }
        }
    }


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

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public void whichFragmentAndViewModel(Fragment fragment, PostViewModel postViewModel) {
        this.fragment = fragment;
        this.postViewModel = postViewModel;

        if(position == getItemCount() -1) {
           postViewModel.getPosts();
           notifyDataSetChanged();
        }
    }


    public class CardViewHolder extends RecyclerView.ViewHolder {

        ImageView postImage;
        TextView postTitle,postDescription, postDate;

        private CardViewHolder(View itemView) {
            super(itemView);
            postImage = itemView.findViewById(R.id.postImage);
            postTitle = itemView.findViewById(R.id.postTitle);
            postDescription = itemView.findViewById(R.id.postDescription);
            postDate = itemView.findViewById(R.id.postDate);

        }
    }

    public class CardMagazineViewHolder extends RecyclerView.ViewHolder {

        ImageView postImage;
        TextView postTitle, postDate;

        private CardMagazineViewHolder(View itemView) {
            super(itemView);
            postImage = itemView.findViewById(R.id.postImage);
            postTitle = itemView.findViewById(R.id.postTitle);
            postDate = itemView.findViewById(R.id.postDate);

        }
    }

    public class TitleViewHolder extends RecyclerView.ViewHolder {
        TextView postTitle;
        MyImageview postImage;


        private TitleViewHolder(@NonNull View itemView) {
            super(itemView);
            postTitle = itemView.findViewById(R.id.postTitle);
            postImage = itemView.findViewById(R.id.postImage);
        }
    }


    public class GridViewHolder extends RecyclerView.ViewHolder {
        TextView postTitle;
        MyImageview postImage;


        private GridViewHolder(@NonNull View itemView) {
            super(itemView);
            postTitle = itemView.findViewById(R.id.postTitle);
            postImage = itemView.findViewById(R.id.postImage);
        }
    }
}

现在这段代码只有当我从标题或网格布局切换到其他布局然后再回到它时才起作用，我认为onBindViewHolder第一次没有检测到这个接口的实现，所以挑战是如何移动这个接口的实现插入onBindViewHolder方法

 @Override
    public void whichFragmentAndViewModel(Fragment fragment, PostViewModel postViewModel) {
        this.fragment = fragment;
        this.postViewModel = postViewModel;

        if(position == getItemCount() -1) {
           postViewModel.getPosts();
           notifyDataSetChanged();
        }
    }

这是我在片段中使用更改布局的方式，我删除了与问题代码无关的内容

HomeFragment 类

private PostViewModel postViewModel;
    public static final String TAG = "HomeFragment";
    private RecyclerView recyclerView;
    private PostAdapter adapter;
    private List<Item> itemArrayList;

    private boolean isScrolling = false;
    private int currentItems, totalItems, scrollOutItems;
    private GridLayoutManager titleLayoutManager, gridLayoutManager;
    WrapContentLinearLayoutManager layoutManager;


    private SharedPreferences sharedPreferences;

    public ItemsDatabase itemsDatabase;

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

        postViewModel = new ViewModelProvider(this).get(PostViewModel.class);

        itemsDatabase = ItemsDatabase.getINSTANCE(getContext());

        postViewModel.finalURL.setValue(PostsClient.getBaseUrl() + "?key=" + PostsClient.getKEY() );

        postViewModel.getPosts();

        View root = inflater.inflate(R.layout.fragment_home, container, false);

        setHasOptionsMenu(true);

        itemArrayList = new ArrayList<>();

        recyclerView = root.findViewById(R.id.homeRecyclerView);
        adapter = new PostAdapter(getContext(),itemArrayList);


        layoutManager = new WrapContentLinearLayoutManager(getContext(),
                LinearLayoutManager.VERTICAL, false);
        titleLayoutManager = new GridLayoutManager(getContext(), 2);
        gridLayoutManager = new GridLayoutManager(getContext(), 3);

        sharedPreferences =  getContext().getSharedPreferences("settings", Context.MODE_PRIVATE);
        String layout = sharedPreferences.getString("recyclerViewLayout", "cardLayout");
        switch (layout) {
            case "cardLayout":
                recyclerView.setLayoutManager(layoutManager);
                adapter.setViewType(0);
                recyclerView.setAdapter(adapter);
                break;
            case "cardMagazineLayout":
                recyc