android - 将对象从一个 fragment 发送到另一个 fragment

Question

我有两个 fragment ，其中第一个 fragment (Business)有一个对象字符串列表需要传输到第二个 fragment (Businessdetail)。\

我想知道什么是最好的练习方法以及应该如何做？

public class Business extends Fragment {

        public List<StringList> businessNews = new ArrayList<>();
        private RecyclerView recyclerView;
        StringList stringList; //object need to transfered to other fragment 
        public Business() {
        }

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

            View view = inflater.inflate(R.layout.fragment_business, container, false);
            recyclerView = (RecyclerView) view.findViewById(R.id.business_recycler_view);

            FetchLists f = new FetchLists();
            f.execute(10, 0);
            return view;
        }

        @Override
        public void onCreate(@Nullable Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
        }


        public class FetchLists extends AsyncTask<Integer, Void, List<StringList>> {

            @Override
            protected List<StringList> doInBackground(Integer... params) {

                int count = params[0];
                int offset = params[1];

                String urlString = "https://nei.org/v1/articlesbjkbknklnmlmerg&sortBy=top&apiKey=50e2bjkbbkba5a5f476ff528a8";
                urlString = urlString + "&count=" + count + "&offset=" + offset;

                try {
                    URL url = new URL(urlString);
                    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                    connection.setRequestMethod("GET");
                    InputStream stream = connection.getInputStream();
                    BufferedReader reader = new BufferedReader(new InputStreamReader(stream));
                    String line = reader.readLine();
                    String response = "";
                    while (line != null) {
                        response += line;
                        line = reader.readLine();
                    }

                    JSONObject object = new JSONObject(response);
                    JSONArray emailLists = object.getJSONArray("articles");

                    for (int i = 0; i < emailLists.length(); i++) {
                        JSONObject listData = (JSONObject) emailLists.get(i);

                         stringList = new StringList();
                        stringList.authorName = listData.getString("author");
                        stringList.headline = listData.getString("title");
                        stringList.publishedTime = listData.getString("publishedAt");
                        stringList.newsDetail = listData.getString("description");

                        businessNews.add(stringList);
                        Log.d("ashu", "authorname" + stringList.authorName);
                    }

                } catch (Exception e) {
                    e.printStackTrace();
                }
                return businessNews;
            }

        public class BusinessAdapter extends RecyclerView.Adapter<BusinessHolder> {



            @Override
            public BusinessHolder onCreateViewHolder(ViewGroup parent, int viewType) {

                Context context = parent.getContext();
                LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                View view = inflater.inflate(R.layout.layout_news, parent, false);
                return new BusinessHolder(view);
            }

            @Override
            public void onBindViewHolder(BusinessHolder holder, int position) {

                StringList m = c.get(position);
                holder.bindListName(m, position);
     }}

        public class BusinessHolder extends RecyclerView.ViewHolder {

            public TextView headlineTextview;
            public TextView authorTextview;
            public TextView timeTextview;

            public BusinessHolder(View itemView) {
                super(itemView);

                headlineTextview = (TextView) itemView.findViewById(R.id.id_headline);
                authorTextview = (TextView) itemView.findViewById(R.id.id_author);
                timeTextview = (TextView) itemView.findViewById(R.id.id_time);

            }

第二个 fragment :

在此 fragment 中，我想将对象数据设置为 Textview 参数

public class BusinessDetail extends Fragment {
 StringList mstringList;
    private TextView headlineSecond;
    public TextView authorSecond;
    private TextView detailsSecond;


    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_business_detail, container, false);
        return view;
    }


    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        headlineSecond = (TextView) view.findViewById(R.id.id_headline_second);
        authorSecond = (TextView) view.findViewById(R.id.id_author_second);
        detailsSecond = (TextView) view.findViewById(R.id.id_details_second);
   }}

Answer 1

fragment 不应该互相了解。

不要从一个 fragment 传输到另一个 fragment ，而是在 Activity 中声明对象列表并让每个 fragment 从那里获取它:

要在主 Activity 中执行此操作，请声明对象列表和列表的 getter:

public List<StringList> businessNews = new ArrayList<>();

public List<StringList> getObjectList(){
    return objectList;
}

然后在Fragments中，可以获取列表:

((MainActivity) getActivity()).getObjectList();

您可以在 onResume() 中进行此调用，以确保 Fragment 和 Activity 已准备就绪。

为了更正确的解决方案，这部分((MainActivity) getActivity())可以使用接口(interface)来实现，以避免强制转换。