如何在片段的数据持有者中设置值？

Question

我制作了第二个片段，其中我收到了第一个片段的值。但问题是我无法将接收到的设置为第二个片段的文本视图。

我用的是Log.d()；方法来检查，但我发现 databindholder 从未被调用过：

Issue 1: databindholder is not called

Issue 2: can't set the value to the textview of 2nd fragment

感谢您的关心！

public class ListTable extends Fragment {

    private RecyclerView recyclerView;

    public ListTable() {
//         Required empty public constructor
    }


    public static ListTable newInstance(String param1, String param2) {
        ListTable fragment = new ListTable();
        Bundle args = new Bundle();
        fragment.setArguments(args);
        return fragment;
    }


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


        View view = inflater.inflate(R.layout.fragment_list_table, container, false);


        recyclerView = (RecyclerView) view.findViewById(R.id.recycler_view);
        recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));

        MyAdapter a = new MyAdapter();
//        a.notifyDataSetChanged();
        recyclerView.setAdapter(a);
        return view;
    }

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

    }

    public void receiveValue(String value) {

        int result = Integer.parseInt(value);
        Bundle bundle = new Bundle();
        bundle.putInt("value", result);
        ListTable listTable = new ListTable();
        listTable.setArguments(bundle);
        MyAdapter b=new MyAdapter();
        b.notifyDataSetChanged();
//        a.notifiedatachanged

        Log.d("ashu", "value recived :" + value);

    }

    public class MyAdapter extends RecyclerView.Adapter<MyDataViewHolder> {

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

            LayoutInflater inflater = (LayoutInflater) parent.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            View view = inflater.inflate(R.layout.fragment_list_table, parent, false);

            return new MyDataViewHolder(view);
        }

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

            if (getArguments() != null) {

                int value1 = getArguments().getInt("value");
                Log.d("ashu", "the value received inthe bindholder is " + value1);
                holder.myEditText.setText("Table is: " + position * value1);
            }
        }

        @Override
        public int getItemCount() {
            return 10;
        }
    }

    public class MyDataViewHolder extends RecyclerView.ViewHolder {

        public TextView myEditText;

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

            myEditText = (TextView) itemView.findViewById(R.id.table_value);

        }
    }

}

Answer 1

您不必显式声明一个空的构造函数，如果您没有声明任何其他构造函数，Java 会为您做这件事。

你的整个结构是错误的，你正在接收 ListTable 中的值，但是你创建了一个新的 ListTable 实例！？

您应该做的是让您的 activity 从您的第一个片段（通过接口）接收值，如果您已经引用它，则从您的 activity 直接将值设置为 ListTable或使用 ListTable.newInstance();

添加新的 ListTable 片段

Answer 2

使用构造函数将数据列表传递给 MyAdapter 并使用该列表获取每个位置的值。像这样...

public class MyAdapter extends RecyclerView.Adapter<MyDataViewHolder> {

    private List<YourObject> items;

    public MyAdapter(List<YourObject> items) {
        this.items = items;
    }


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

        LayoutInflater inflater = (LayoutInflater) parent.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View view = inflater.inflate(R.layout.fragment_list_table, parent, false);

        return new MyDataViewHolder(view);
    }

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

        YourObject val = items.get(position);

        if(val!=null){

            //do something
        }
    }

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

然后在片段中，像这样调用...

List<YourObject> items = ..... (generate anyway you need)
MyAdapter a = new MyAdapter(items);
recyclerView.setAdapter(a);

Answer 3

由于未正确使用setArguments()，未调用Data Binder。对于您的情况，您可以简单地在适配器中创建一个方法并传递该值。

你应该像这样在 Fragments 中使用 setArguments

Fragment fragment2 = new FragmentB();
fragment2.setArguments(bundle);
getFragmentManager.beginTransaction().replace(R.id.holder, fragment2).commit();

像这样使用 getArguments

class FragmentB extends Fragment {
@Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
     View view = inflater.inflate(R.layout.fragment_view, container, false);
     Bundle data = getArguments();
     if (data != null) {
        //TODO - retrieve all your data
     }
     // Create view
     // Create your adapter 
     return view;
  }

}

Answer 4

只需添加以下代码：

getFragmentManager.beginTransaction().replace(R.id.holder, fragment2).commit();

它应该添加到你在 receiveValue 函数中创建第二个片段的对象的地方！

public void receiveValue(String value) {

    int result = Integer.parseInt(value);
    Bundle bundle = new Bundle();
    bundle.putInt("value", result);
    ListTable listTable = new ListTable();
    listTable.setArguments(bundle);

    getFragmentManager().beginTransaction().replace(R.id.table_value_container, listTable).commit();

}

如何在片段的数据持有者中设置值？

How to set value in the dataholder of fragment?

android

android-fragments

android-viewholder