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问题：

如何在Android中设置lazyLoader？

公羊浩气
2023-03-14

我希望从服务器加载数据并显示到我的应用程序中（RecyclerView），对于此作业，当启动应用程序时，我显示10篇帖子，当滚动时，显示另一篇帖子<我写了下面的代码，但当得到10篇帖子时，不要加载其他帖子

我的Json：

{
    "status": "ok",
    "count": 9,
    "pages": 3,
    "category": {
        "id": 1,
        "slug": "%d8%b3%d8%b1%da%af%d8%b1%d9%85%db%8c",
        "title": "\u0633\u0631\u06af\u0631\u0645\u06cc",
        "description": "\u062a\u0648\u06cc \u0627\u06cc\u0646 \u06a9\u0644\u0648\u0646\u06cc \u0647\u0645\u0647 \u0686\u06cc\u0632 \u0648\u0627\u0633\u0647 \u0633\u0631\u06af\u0631\u0645 \u0628\u0648\u062f\u0646 \u0647\u0633\u062a. \u067e\u0633 \u0628\u062f\u0648 \u0628\u0631\u0648 \u062a\u0648\u0634",
        "parent": 0,
        "post_count": 29
    },
    "posts": [{
        "id": 85,
        "type": "post",
        "slug": "%d8%b9%d9%86%d9%88%d8%a7%d9%86-%d8%b3%d9%88%d9%85-%d8%a8%d8%b1%d8%a7%db%8c-%d8%b1%d9%81%d8%b1%d8%b4",
        "url": "http:\/\/tellfa.com\/tafrihgah\/?p=85",
        "status": "publish",
        "title": "\u0639\u0646\u0648\u0627\u0646 \u0633\u0648\u0645 \u0628\u0631\u0627\u06cc \u0631\u0641\u0631\u0634",
        "title_plain": "\u0639\u0646\u0648\u0627\u0646 \u0633\u0648\u0645 \u0628\u0631\u0627\u06cc \u0631\u0641\u0631\u0634",
        "content": "<p>\u062f\u06cc\u06af\u0647 \u0639\u0635\u0628\u0627\u0646\u06cc \u0634\u062f\u0645\u060c \u0686\u0631\u0627 \u0631\u0641\u0631\u0634 \u0646\u0645\u06cc\u06a9\u0646\u0647! :@<\/p>\n",
        "excerpt": "<p>\u062f\u06cc\u06af\u0647 \u0639\u0635\u0628\u0627\u0646\u06cc \u0634\u062f\u0645\u060c \u0686\u0631\u0627 \u0631\u0641\u0631\u0634 \u0646\u0645\u06cc\u06a9\u0646\u0647! :@<\/p>\n",
        "date": "2016-04-20 15:02:26",
        "modified": "2016-04-20 15:02:26",
        "categories": [{
            "id": 1,
            "slug": "%d8%b3%d8%b1%da%af%d8%b1%d9%85%db%8c",
            "title": "\u0633\u0631\u06af\u0631\u0645\u06cc",
            "description": "\u062a\u0648\u06cc \u0627\u06cc\u0646 \u06a9\u0644\u0648\u0646\u06cc \u0647\u0645\u0647 \u0686\u06cc\u0632 \u0648\u0627\u0633\u0647 \u0633\u0631\u06af\u0631\u0645 \u0628\u0648\u062f\u0646 \u0647\u0633\u062a. \u067e\u0633 \u0628\u062f\u0648 \u0628\u0631\u0648 \u062a\u0648\u0634",
            "parent": 0,
            "post_count": 29
        }],
        "tags": [],
        "author": {
            "id": 1,
            "slug": "tellfa",
            "name": "\u0645\u062d\u0645\u062f",
            "first_name": "",
            "last_name": "",
            "nickname": "\u0645\u062d\u0645\u062f",
            "url": "http:\/\/codesaz.com",
            "description": "\u0627\u06cc\u0646 \u0632\u0646\u062f\u06af\u06cc \u0646\u0627\u0645\u0647 \u0645\u0646 \u0627\u0633\u062a",
            "avatar": "76"
        },
        "comments": [],
        "attachments": [{
            "id": 86,
            "url": "http:\/\/tellfa.com\/tafrihgah\/wp-content\/uploads\/2016\/04\/WallpapersMania_vol119-024.jpg",
            "slug": "wallpapersmania_vol119-024",
            "title": "[WallpapersMania]_vol119-024",
            "description": "",
            "caption": "",
            "parent": 85,
            "mime_type": "image\/jpeg",
            "images": {
                "full": {
                    "url": "http:\/\/tellfa.com\/tafrihgah\/wp-content\/uploads\/2016\/04\/WallpapersMania_vol119-024.jpg",
                    "width": 1680,
                    "height": 1050
                },
                "thumbnail": {
                    "url": "http:\/\/tellfa.com\/tafrihgah\/wp-content\/uploads\/2016\/04\/WallpapersMania_vol119-024-150x150.jpg",
                    "width": 150,
                    "height": 150
                },
                "medium": {
                    "url": "http:\/\/tellfa.com\/tafrihgah\/wp-content\/uploads\/2016\/04\/WallpapersMania_vol119-024-300x188.jpg",
                    "width": 300,
                    "height": 188
                },
                "medium_large": {
                    "url": "http:\/\/tellfa.com\/tafrihgah\/wp-content\/uploads\/2016\/04\/WallpapersMania_vol119-024-768x480.jpg",
                    "width": 768,
                    "height": 480
                }
            }
        }],
        "comment_count": 0,
        "comment_status": "open",
        "thumbnail": "http:\/\/tellfa.com\/tafrihgah\/wp-content\/uploads\/2016\/04\/WallpapersMania_vol119-024-150x150.jpg",
        "custom_fields": {},
        "thumbnail_size": "thumbnail",
        "thumbnail_images": {
            "full": {
                "url": "http:\/\/tellfa.com\/tafrihgah\/wp-content\/uploads\/2016\/04\/WallpapersMania_vol119-024.jpg",
                "width": 1680,
                "height": 1050
            },
            "thumbnail": {
                "url": "http:\/\/tellfa.com\/tafrihgah\/wp-content\/uploads\/2016\/04\/WallpapersMania_vol119-024-150x150.jpg",
                "width": 150,
                "height": 150
            },
            "medium": {
                "url": "http:\/\/tellfa.com\/tafrihgah\/wp-content\/uploads\/2016\/04\/WallpapersMania_vol119-024-300x188.jpg",
                "width": 300,
                "height": 188
            },
            "medium_large": {
                "url": "http:\/\/tellfa.com\/tafrihgah\/wp-content\/uploads\/2016\/04\/WallpapersMania_vol119-024-768x480.jpg",
                "width": 768,
                "height": 480
            }
        }
    }

Api接口代码：

public interface Retrofit_ApiInterface {

    // For load more category
    @GET("?json=get_category_posts")
    Call<R_CatModelResponse> getCatMoreResponse(@Query("id") Integer id, @Query("page") Integer page);
}

适配器代码：

public class CategoryAdapter extends RecyclerView.Adapter {

    private List<R_CatModel> mDateSet;
    private Context mContext;

    private final int VIEW_ITEM = 1;
    private final int VIEW_PROG = 0;

    // The minimum amount of items to have below your current scroll position
    // before loading more.
    private int visibleThreshold = 10;
    private int lastVisibleItem, totalItemCount;
    private boolean loading;
    private OnLoadMoreListener onLoadMoreListener;

    public CategoryAdapter(Context context, RecyclerView recyclerView, List<R_CatModel> dataSet) {
        this.mContext = context;
        this.mDateSet = dataSet;

        if (recyclerView.getLayoutManager() instanceof LinearLayoutManager) {

            final LinearLayoutManager linearLayoutManager = (LinearLayoutManager) recyclerView
                    .getLayoutManager();
            recyclerView
                    .addOnScrollListener(new RecyclerView.OnScrollListener() {
                        @Override
                        public void onScrolled(RecyclerView recyclerView,
                                               int dx, int dy) {
                            super.onScrolled(recyclerView, dx, dy);
                            totalItemCount = linearLayoutManager.getItemCount();
                            lastVisibleItem = linearLayoutManager
                                    .findLastVisibleItemPosition();
                            if (!loading
                                    && totalItemCount <= (lastVisibleItem + visibleThreshold)) {
                                // End has been reached
                                // Do something
                                if (onLoadMoreListener != null) {
                                    onLoadMoreListener.onLoadMore();
                                }
                                loading = true;
                            }
                        }
                    });
        }
    }

    @Override
    public int getItemViewType(int position) {
        return mDateSet.get(position) != null ? VIEW_ITEM : VIEW_PROG;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        RecyclerView.ViewHolder vh;
        if (viewType == VIEW_ITEM) {
            View v = LayoutInflater.from(parent.getContext()).inflate(
                    R.layout.post_card_layout, parent, false);

            vh = new DataViewHolder(v);
        } else {
            View v = LayoutInflater.from(parent.getContext()).inflate(
                    R.layout.progressbar_item, parent, false);

            vh = new ProgressViewHolder(v);
        }
        return vh;
    }

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

        if (holder instanceof DataViewHolder) {
            ((DataViewHolder) holder).main_post_title.setText(Html.fromHtml(mDateSet.get(position).getTitle()));

            Glide.with(mContext)
                    .load(mDateSet.get(position).getThumbnail_images().getMedium().getUrl())
                    .placeholder(R.drawable.post_image)
                    .crossFade()
                    .override(600, 350)
                    .into(((DataViewHolder) holder).main_post_image);

            ((DataViewHolder) holder).main_post_content.setText(Html.fromHtml(mDateSet.get(position).getContent()));

            // Convert Date ////////
            String date = mDateSet.get(position).getDate();
            String[] parts = date.split(" ");
            String datePart = parts[0];
            String timePart = parts[1];

            int year;
            int month;
            int day;

            String[] dateParts = datePart.split("-");
            year = Integer.parseInt(dateParts[0]);
            month = Integer.parseInt(dateParts[1]);
            day = Integer.parseInt(dateParts[2]);

            JalaliCalendar.YearMonthDate georgianDate = new JalaliCalendar.YearMonthDate(year, month, day);
            JalaliCalendar.YearMonthDate JalaliDate = JalaliCalendar.gregorianToJalali(georgianDate);
            String jalaliDateTime = JalaliDate.toString();

            ((DataViewHolder) holder).main_dateTime.setText(jalaliDateTime);
            ////////////////////////

            ((DataViewHolder) holder).main_author.setText(Html.fromHtml(mDateSet.get(position).getCatAuthor().getAuthorName()));
            ((DataViewHolder) holder).main_author.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    R_CatModel model = mDateSet.get(position);
                    v.getContext().startActivity(new Intent(v.getContext(), Profile_page.class));
                    //.putExtra("author", model.getAuthor())
                    //.putExtra("authorID", model.getAuthorID())
                    //.putExtra("authorStatus", model.getAuthorStatus()));
                }
            });

            ((DataViewHolder) holder).main_category.setText(Html.fromHtml(String.valueOf(mDateSet.get(position).getCategories().get(0).getCatTitle())));
            ((DataViewHolder) holder).main_category.setTextColor(mContext.getResources().getColor(R.color.colorAccent));

            ((DataViewHolder) holder).main_post_image.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    int pos = holder.getPosition();
                    R_CatModel model = mDateSet.get(pos);
                    v.getContext().startActivity(new Intent(v.getContext(), PostShow_page.class)
                            .putExtra("title", model.getTitle())
                            .putExtra("image", model.getThumbnail())
                            .putExtra("content", model.getContent())
                            .putExtra("dateTime", model.getDate())
                            //.putExtra("author", model.getAuthor())
                            .putExtra("category", model.getTitle()));

                }
            });

        } else {
            ((ProgressViewHolder) holder).progressBar.setVisibility(View.VISIBLE);
        }
    }

    public void setLoaded() {
        loading = false;
    }

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

    public void setOnLoadMoreListener(OnLoadMoreListener onLoadMoreListener) {
        this.onLoadMoreListener = onLoadMoreListener;
    }

    public void remove(int position) {
        mDateSet.remove(position);
        notifyItemRemoved(position);
    }

    public void clear() {
        mDateSet.clear();
        notifyDataSetChanged();
    }


    public void add(List<R_CatModel> models) {
        mDateSet.addAll(models);
        notifyDataSetChanged();
    }

    public void update(List<R_CatModel> models) {
        mDateSet.clear();
        mDateSet.addAll(models);
        notifyDataSetChanged();
    }

    public class DataViewHolder extends RecyclerView.ViewHolder {

        private TextView main_post_title, main_post_content, main_dateTime, main_author, main_category;
        private ImageView main_post_image;

        public DataViewHolder(final View itemView) {
            super(itemView);

            main_post_title = (TextView) itemView.findViewById(R.id.post_content_title);
            main_post_image = (ImageView) itemView.findViewById(R.id.post_picture_image);
            main_post_content = (TextView) itemView.findViewById(R.id.post_content_text);
            main_dateTime = (TextView) itemView.findViewById(R.id.post_date_text);
            main_author = (TextView) itemView.findViewById(R.id.post_name_text);
            main_category = (TextView) itemView.findViewById(R.id.post_category_text);
        }
    }

    public static class ProgressViewHolder extends RecyclerView.ViewHolder {
        public AVLoadingIndicatorView progressBar;

        public ProgressViewHolder(View v) {
            super(v);
            progressBar = (AVLoadingIndicatorView) v.findViewById(R.id.avloadingIndicatorView);
        }
    }
}

活动和改装代码：

public class Category_page extends AppCompatActivity implements ConnectivityReceiver.ConnectivityReceiverListener {

    private static final long RIPPLE_DURATION = 250;
    private Toolbar toolbar;
    private TextView toolbar_title;
    private ImageView toolbar_menuImage;
    private Button categoryCheckNet_button;
    private RelativeLayout root;
    private CategoryAdapter mAdapter;
    private RecyclerView cat_recyclerView;
    private LinearLayoutManager mLayoutManager;
    private RelativeLayout loadLayout, checkNetLayout;
    private String catTitle = "";
    private Integer catID;
    private Bundle bundle;
    private int pageCount = 1;
    private Context context;

    private List<R_CatModel> models;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.category_page);

        // Hide StatusBar color
        getWindow().getDecorView().setSystemUiVisibility(
                View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);

        // Initializing
        context = Category_page.this;
        toolbar = (Toolbar) findViewById(R.id.category_toolbar);
        cat_recyclerView = (RecyclerView) findViewById(R.id.category_recycler);
        toolbar_title = (TextView) toolbar.findViewById(R.id.toolbar_pages_title);
        mLayoutManager = new LinearLayoutManager(this);
        root = (RelativeLayout) findViewById(R.id.category_root);
        loadLayout = (RelativeLayout) findViewById(R.id.category_empty_layout);
        checkNetLayout = (RelativeLayout) findViewById(R.id.category_checkInternet_layout);
        categoryCheckNet_button = (Button) checkNetLayout.findViewById(R.id.checkNet_button);
        // Toolbar
        setSupportActionBar(toolbar);
        if (toolbar != null) {
            getSupportActionBar().setTitle("");
        }

        // Receive Data
        bundle = getIntent().getExtras();
        catID = bundle.getInt("categoryID");
        if (bundle != null) {
            catTitle = bundle.getString("categoryTitle");
        }
        if (catTitle != null) {
            toolbar_title.setText(catTitle);
        }

        // Load Data
        loadData();

        // Load Progress
        loadLayout.setVisibility(View.VISIBLE);

        // Menu
        View guillotineMenu = LayoutInflater.from(this).inflate(R.layout.menu_layout, null);
        root.addView(guillotineMenu);
        toolbar_menuImage = (ImageView) toolbar.findViewById(R.id.toolbar_pages_logo);
        new GuillotineAnimation.GuillotineBuilder(guillotineMenu, guillotineMenu.findViewById(R.id.menu_layout_image), toolbar_menuImage)
                .setStartDelay(RIPPLE_DURATION)
                .setActionBarViewForAnimation(toolbar)
                .setClosedOnStart(true)
                .build();
        // RecyclerView
        cat_recyclerView.setLayoutManager(mLayoutManager);
        cat_recyclerView.setHasFixedSize(true);

        // Load More data
        if (mAdapter != null) {
            mAdapter.setOnLoadMoreListener(new OnLoadMoreListener() {
                @Override
                public void onLoadMore() {
                    models.add(null);
                    mAdapter.notifyItemInserted(models.size() - 1);
                    retrofitMoreData();
                }
            });
        }

    }

    private void loadData() {
        boolean isConnected = ConnectivityReceiver.isConnected();

        retrofitData(isConnected);
    }

    private void retrofitData(boolean isConnect) {

        if (isConnect) {
            Retrofit_ApiInterface apiInterface = Retrofit_ApiClient.getClient().create(Retrofit_ApiInterface.class);
            Call<R_CatModelResponse> call = apiInterface.getCatResponse(catID);

            call.enqueue(new Callback<R_CatModelResponse>() {
                @Override
                public void onResponse(Call<R_CatModelResponse> call, Response<R_CatModelResponse> response) {

                    if (response != null) {
                        models = response.body().getCat_posts();

                        mAdapter = new CategoryAdapter(context, cat_recyclerView, models);
                        cat_recyclerView.setAdapter(mAdapter);
                        loadLayout.setVisibility(View.GONE);

                    } else {
                        //loadLayout.setVisibility(View.VISIBLE);
                        Toast.makeText(Category_page.this, "Error 2", Toast.LENGTH_SHORT).show();
                        TastyToast.makeText(context, "خطایی رخ داده است", TastyToast.LENGTH_LONG, TastyToast.ERROR);
                    }

                    checkNetLayout.setVisibility(View.GONE);
                }

                @Override
                public void onFailure(Call<R_CatModelResponse> call, Throwable t) {

                    //loadLayout.setVisibility(View.VISIBLE);
                    //TastyToast.makeText(context, "لطفا برنامه را مجددا باز کنید", TastyToast.LENGTH_LONG, TastyToast.ERROR);
                    Toast.makeText(Category_page.this, "Error 2", Toast.LENGTH_SHORT).show();
                    //Cat_EmptyLayout.setVisibility(View.VISIBLE);
                    Log.e("CatResponseError", "Error : " + t);

                }
            });
        } else {
            //loadLayout.setVisibility(View.GONE);
            checkNetLayout.setVisibility(View.VISIBLE);
            if (mAdapter != null) {
                mAdapter.clear();
                cat_recyclerView.setAdapter(mAdapter);
            }
            categoryCheckNet_button.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    loadData();
                }
            });
        }
    }

    public void retrofitMoreData() {

        if (models.size() > 0) {
            mAdapter.remove(models.size() - 1);
            mAdapter.notifyItemRemoved(models.size());
            mAdapter.setLoaded();
        }

        mAdapter.add(models);
        mAdapter.notifyDataSetChanged();
        pageCount++;

        Retrofit_ApiInterface apiInterface = Retrofit_ApiClient.getClient().create(Retrofit_ApiInterface.class);
        Call<R_CatModelResponse> call = apiInterface.getCatMoreResponse(catID, pageCount);

        call.enqueue(new Callback<R_CatModelResponse>() {
            @Override
            public void onResponse(Call<R_CatModelResponse> call, Response<R_CatModelResponse> response) {

                if (response != null) {
                    models = response.body().getCat_posts();

                    mAdapter = new CategoryAdapter(context, cat_recyclerView, models);
                    cat_recyclerView.setAdapter(mAdapter);
                    //loadLayout.setVisibility(View.GONE);
                } else {
                    //loadLayout.setVisibility(View.VISIBLE);
                    Toast.makeText(Category_page.this, "Error 2", Toast.LENGTH_SHORT).show();
                    TastyToast.makeText(context, "خطایی رخ داده است", TastyToast.LENGTH_LONG, TastyToast.ERROR);
                }
            }

            @Override
            public void onFailure(Call<R_CatModelResponse> call, Throwable t) {

            }
        });
    }

我如何编辑我的上述代码设置lazyLoader？请帮帮我，我真的需要这个。谢谢大家

更新：为什么没有人帮我？：(


共有1个答案

班经亘
2023-03-14

对于改装中的逐页加载，以下结构将很有帮助：

1-首先，我建议使用它来使您的请求更干净。

2-与其在ScrollListener上实现，不如使用EndlessRecyclerView。

3-在onLoadMore（page）中（假设使用Endless RecyclView）调用您的webService，如下所示：

            @Override
            public void onLoadMore(int page) {
                callWebservice(page);
            }

4-在您的onResponse中，向适配器添加新项目：

            @Override
            public void onResponse(Call<YOUR_OBJECT> call, Response<YOUR_OBJECT> response) {
                adapter.addNewItem(response.body());
            }

5-您的适配器中的addNewItem将如下所示：

public void addNewItem(List<YOUR_OBJECT> newContent) {
    int start = this.contents.size();//contents is a List of your items initialize it your constructor
    int end = newContent.size();
    contents.addAll(newContent);
    notifyItemRangeInserted(start + 1, end);
}
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