将对象从一个片段发送到另一个片段

Question

我有两个片段，其中第一个片段（业务）有一个对象字符串列表需要传输到第二个片段（业务详细信息）。\

我想知道最好的练习方法是什么，我应该怎么做？

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);

            }

第二个片段：

在此片段中，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

如果 BusinessDetail 和 Business 是同一个 activity 的子级，您应该在两个片段和 activity 之间提供一个接口。在您的业务片段中，您可以进行此调用（在片段的 onAttach 中或之后）：

((MyActivity)getActivity()).showObjectOnBusiness(stringList);

在 MyActivity showObjectOnBusiness 方法中，您应该将对象传递给 BusinessDetail 片段：

Bundle bundle = new Bundle();
bundle.putParcelable(BusinessDetail.OBJECT_KEY, stringList);
new BusinessDetail().setArguments(bundle);

在您的 BusinessDetail 中，您可以通过参数获取您的对象：

Bundle bundle = getArguments();

if (bundle == null || !bundle.containsKey(OBJECT_KEY)) {
    throw new IllegalArgumentException("StringList should not be null");
}
StringList stringList = bundle.getParcelable(OBJECT_KEY);

StringList 应该实现 Parcelable。

Answer 2

在另一个片段中保存对片段的引用 - 不好的做法。您可以使用 this 方法，它工作正常。

Answer 3

碎片不应该相互了解。

不是从一个片段转移到另一个片段，而是在 activity 中声明对象列表并让每个片段从那里获取它：

要在 main activity 中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，可以得到列表：

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

您可以在 onResume() 中进行此调用以确保片段和 Activity 已准备就绪。

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

Answer 4

您可以通过以下代码实现此目的

Bundle bundle = new Bundle();
bundle.putParcelableArrayList("Key_List", businessNews);
fragmentInstance.setArguments(bundle);

您也可以使用 Serializable，但 serializable 比 parcelable 慢

 Bundle bundle = new Bundle();
bundles.putSerializable("Key_List", businessNews);
fragmentInstance.setArguments(bundle);

Answer 5

你可以使用 Event Bus图书馆

它将简化组件之间的通信，

适用于 publisher/subscriber 模式。

将对象从一个片段发送到另一个片段

Send Object from One Fragment to Another

android

object

android-fragments

android-fragmentactivity