添加值后，arraylist为空

时间：2016-01-16 11:17:41

标签： android arraylist

当我执行程序时，它显示一个空白屏幕，在logcat中它显示没有连接适配器;跳过布局。当我调试代码时，ArrayList没有得到值（返回0）。 

public class MainActivity extends AppCompatActivity implements Constants, NetworkOperation, URL {

    LinearLayoutManager manager;
    ArrayList<OfferModal> bestoffers;
    RecyclerViewAdapter adapter;
    RecyclerView rv;
    FetchData fetchData;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        rv = (RecyclerView) findViewById(R.id.recyclerview1);

        fetchData = new FetchData(this, this, CLOUD_SECTION);
        fetchData.fromServer();
        manager = new LinearLayoutManager(getApplicationContext(), LinearLayoutManager.VERTICAL, false);
        rv.setLayoutManager(new LinearLayoutManager(this));

    }

    @Override
    public void started() {

    }

    @Override
    public void doingBackground() {

    }

    @Override
    public void completed(JSONObject jsonObject) {

        bestoffers = new ArrayList<OfferModal>();

        try {

            JSONArray array_item = new JSONArray();
            for (int i = 0; i < array_item.length(); i++) {

                JSONObject itemobj = array_item.getJSONObject(i);
                String id = itemobj.getString(ID);
                String le_id = itemobj.getString(LE_ID);
                String title = itemobj.getString(TITLE);
                String description = itemobj.getString(DESCRIPTION);
                String wid = itemobj.getString(WID);
                String hgt = itemobj.getString(HGT);
                String tn_path = itemobj.getString(TN_PATH);
                String create_time = itemobj.getString(CREATE_TIME);
                String update_time = itemobj.getString(UPDATE_TIME);
                String view_count = itemobj.getString(VIEW_COUNT);
                String slide_count = itemobj.getString(SLIDE_COUNT);
                String shared = itemobj.getString(SHARED);
                String publish_ver = itemobj.getString(PUBLISH_VER);
                String publish_time = itemobj.getString(PUBLISH_TIME);
                String user_name = itemobj.getString(USER_NAME);
                String avatar_path = itemobj.getString(AVATAR_PATH);
                String comment_count = itemobj.getString(COMMENT_COUNT);
                String fav = itemobj.getString(FAV);
                String fav_count = itemobj.getString(FAV_COUNT);

                OfferModal off = new OfferModal(id, le_id, title, description, wid, hgt, tn_path, create_time, update_time, view_count, slide_count, shared, publish_ver, publish_time, user_name, avatar_path, comment_count, fav, fav_count);

                off.setId(id);
                off.setId(le_id);
                off.setTitle(title);
                off.setDescription(description);
                off.setHgt(hgt);
                off.setTn_path(tn_path);
                off.setCreate_time(create_time);
                off.setUpdate_time(update_time);
                off.setView_count(view_count);
                off.setSlide_count(slide_count);
                off.setShared(shared);
                off.setPublish_ver(publish_ver);
                off.setPublish_time(publish_time);
                off.setUser_name(user_name);
                off.setAvatar_path(avatar_path);
                off.setComment_count(comment_count);
                off.setFav(fav);
                off.setFav_count(fav_count);
                bestoffers.add(off);

            }

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

        adapter = new RecyclerViewAdapter(getApplicationContext(), bestoffers);
        rv.setAdapter(adapter);

    }

}

这是我的json数据：

[
  {
    "id": "42057",
    "le_id": "568fb0d29a5eb",
    "title": "Bag the Big Deal Lulu Hypermarket",
    "description": "",
    "wid": "0",
    "hgt": "0",
    "tn_path": "",
    "create_time": "1452257490",
    "update_time": "1452332748",
    "view_count": "00000000669",
    "slide_count": "9",
    "shared": "F",
    "publish_ver": "11",
    "publish_time": "1452332761",
    "user_name": " Lulu Retail",
    "avatar_path": null,
    "comment_count": "0",
    "fav": "F",
    "fav_count": 0
  },
  {
    "id": "42019",
    "le_id": "568f9e45625da",
    "title": "Bag the Big Deal Lulu Fashion Store",
    "description": "",
    "wid": "0",
    "hgt": "0",
    "tn_path": "",
    "create_time": "1452252741",
    "update_time": "1452584969",
    "view_count": "00000000659",
    "slide_count": "1",
    "shared": "F",
    "publish_ver": "5",
    "publish_time": "1452584972",
    "user_name": " Lulu Retail",
    "avatar_path": null,
    "comment_count": "0",
    "fav": "F",
    "fav_count": 0
  },
  {
    "id": "42017",
    "le_id": "568f9e30df0da",
    "title": "Bag the Big Deal Lulu Connect",
    "description": "",
    "wid": "0",
    "hgt": "0",
    "tn_path": "",
    "create_time": "1452252720",
    "update_time": "1452585162",
    "view_count": "00000000726",
    "slide_count": "7",
    "shared": "F",
    "publish_ver": "7",
    "publish_time": "1452275301",
    "user_name": " Lulu Retail",
    "avatar_path": null,
    "comment_count": "0",
    "fav": "F",
    "fav_count": 0
  }
]

这是我的适配器类：

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewHolder> {

    ArrayList<OfferModal> mBestoffers;
    Context context;
    //  List<Offers>card_items;

    RequestQueue mRequestQueue;
    ImageLoader mImageLoader;

    public RecyclerViewAdapter(Context context, ArrayList<OfferModal> mBestoffers) {
        this.context = context;
        // this.card_items = card_items;
        this.mBestoffers = mBestoffers;

        mRequestQueue = Volley.newRequestQueue(context);
        mImageLoader = new ImageLoader(mRequestQueue, new ImageLoader.ImageCache() {
            private final LruCache<String, Bitmap> mCache = new LruCache<String, Bitmap>(10);

            public void putBitmap(String url, Bitmap bitmap) {
                mCache.put(url, bitmap);
            }

            public Bitmap getBitmap(String url) {
                return mCache.get(url);
            }
        });

    }

    @Override
    public RecyclerViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.cardlayout, null);
        RecyclerViewHolder rvh = new RecyclerViewHolder(view);

        return rvh;
    }

    @Override
    public void onBindViewHolder(RecyclerViewHolder holder, int position) {
       //      holder.imageView.setImageUrl(mBestoffers.get(position).getAvatar_path(), mImageLoader);
       holder.tv1.setText(mBestoffers.get(position).getTitle());
       //write code to download image and data from server and set here

    }

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

请帮我解决这个问题，任何帮助都会非常贴切。

3 个答案:

答案 0 :(得分：1)

请在完成（）中粘贴jsonObject.toString（）。

数组空的原因在这里。

       JSONArray array_item = new JSONArray();
        for (int i = 0; i < array_item.length(); i++) {

答案 1 :(得分：0)

请使用此代码，它会对您有所帮助。

公共类MainActivity扩展AppCompatActivity实现常量，NetworkOperation，URL {

LinearLayoutManager manager;
ArrayList<OfferModal> bestoffers;
RecyclerViewAdapter adapter;
RecyclerView rv;
FetchData fetchData;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    rv = (RecyclerView) findViewById(R.id.recyclerview1);

    fetchData = new FetchData(this, this, CLOUD_SECTION);
    fetchData.fromServer();
    manager = new LinearLayoutManager(getApplicationContext(), LinearLayoutManager.VERTICAL, false);
    rv.setLayoutManager(new LinearLayoutManager(this));

}

@Override
public void started() {

}

@Override
public void doingBackground() {

}

@Override
public void completed(JSONObject jsonObject) {

    bestoffers = new ArrayList<OfferModal>();

    try {

        JSONArray array_item = new JSONArray();
        for (int i = 0; i < array_item.length(); i++) {

            JSONObject itemobj = array_item.getJSONObject(i);
            String id = itemobj.getString(ID);
            String le_id = itemobj.getString(LE_ID);
            String title = itemobj.getString(TITLE);
            String description = itemobj.getString(DESCRIPTION);
            String wid = itemobj.getString(WID);
            String hgt = itemobj.getString(HGT);
            String tn_path = itemobj.getString(TN_PATH);
            String create_time = itemobj.getString(CREATE_TIME);
            String update_time = itemobj.getString(UPDATE_TIME);
            String view_count = itemobj.getString(VIEW_COUNT);
            String slide_count = itemobj.getString(SLIDE_COUNT);
            String shared = itemobj.getString(SHARED);
            String publish_ver = itemobj.getString(PUBLISH_VER);
            String publish_time = itemobj.getString(PUBLISH_TIME);
            String user_name = itemobj.getString(USER_NAME);
            String avatar_path = itemobj.getString(AVATAR_PATH);
            String comment_count = itemobj.getString(COMMENT_COUNT);
            String fav = itemobj.getString(FAV);
            String fav_count = itemobj.getString(FAV_COUNT);

            OfferModal off = new OfferModal(id, le_id, title, description, wid, hgt, tn_path, create_time, update_time, view_count, slide_count, shared, publish_ver, publish_time, user_name, avatar_path, comment_count, fav, fav_count);

            off.setId(id);
            off.setId(le_id);
            off.setTitle(title);
            off.setDescription(description);
            off.setHgt(hgt);
            off.setTn_path(tn_path);
            off.setCreate_time(create_time);
            off.setUpdate_time(update_time);
            off.setView_count(view_count);
            off.setSlide_count(slide_count);
            off.setShared(shared);
            off.setPublish_ver(publish_ver);
            off.setPublish_time(publish_time);
            off.setUser_name(user_name);
            off.setAvatar_path(avatar_path);
            off.setComment_count(comment_count);
            off.setFav(fav);
            off.setFav_count(fav_count);
            bestoffers.add(off);

        }

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

    adapter = new RecyclerViewAdapter(MainActivity.this,R.layout.cardlayout, bestoffers);
    rv.setAdapter(adapter);

adapter.notifyDataSetChanged（）

}

}

答案 2 :(得分：0)

你的主要问题在于JSONArray，你正在初始化为一个新的JSONArray，它是空的，请检查jsonArray.length（）中数组的大小;我确定它是0.这就是为什么你的arraylist也是空的。

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