Question

我创建了一个recyclerView并处理了被单击的项目。现在，我需要更改单击一项时显示的文本。首先它说“天”，然后单击它应该说“完成”。它起作用了，但是当我关闭并重新打开活动后，它又说“天”。那么，我该怎么做才能使项目文本保持不变？

  private OnFragmentInteractionListener mListener;
    List<String> list;
    MyListAdapter adapter;
    RecyclerView recyclerView;
    String pressed="finished";
 public MainFragment() {
        // Required empty public constructor
    }

@Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View rootView= inflater.inflate(R.layout.fragment_main, container, false);

        recyclerView=(RecyclerView)rootView.findViewById(R.id.item_list);
        recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));

        list=new ArrayList<>();
        for(int i=1;i<50;i++){
            list.add("Day"+ i);
        }

        adapter =new MyListAdapter(getActivity(),list,this);
        recyclerView.setAdapter(adapter);


        return rootView;

    }

    @Override
    public void onDetach() {
        super.onDetach();
        mListener = null;
    }

    @Override
    public void onNoteClick(int position) {
        if (position == 0) {
            Log.d(TAG, "onNoteClick: ");
            list.set(0, "finished");
            adapter.getItemId(0);


            adapter.notifyItemChanged(0);
            adapter.notifyDataSetChanged();







            Fragment fr = new Day1();
            FragmentManager fm = getFragmentManager();
            FragmentTransaction fragmentTransaction = fm.beginTransaction();
            fragmentTransaction.replace(R.id.Mainfragment1, fr,null).addToBackStack(null);
            fragmentTransaction.commit();

        }

    }

和适配器代码

 Context context;
List<String>list;
public TextView textView;
public String finished="finished";
private MyViewHolder.OnNoteClickListener mOnNoteClickListener;

public MyListAdapter(Context context, List<String>list, MyViewHolder.OnNoteClickListener onNoteClickListener) {
    this.list=list;
    this.context=context;
    this.mOnNoteClickListener=onNoteClickListener;
}

public static class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
    Button textView;


    OnNoteClickListener onNoteClickListener;

    public MyViewHolder(View itemView,OnNoteClickListener onNoteClickListener) {
        super(itemView);
        textView=(Button) itemView.findViewById(R.id.textView);
        itemView.setOnClickListener(this);
        textView.setOnClickListener(this);
        this.onNoteClickListener=onNoteClickListener;


        itemView.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        onNoteClickListener.onNoteClick(getAdapterPosition());





    }



    public interface OnNoteClickListener{
        void onNoteClick(int position);

    }
}

@NonNull
@Override
public MyViewHolder onCreateViewHolder(@NonNull final ViewGroup parent, final int viewType) {
    View view= LayoutInflater.from(context).inflate(R.layout.layout_list_item,parent,false);
    final MyViewHolder vHolder=new MyViewHolder(view,mOnNoteClickListener);

    return vHolder;

}

@Override
public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {
    holder.textView.setText(list.get(position));




}

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

}

Answer 1

实际上，您所做的只是更改View，换句话说，适配器从数据存储时（即数据库）获取数据并将其显示在recyclerView中，因此此处更改的是上一次显示的值在回收站视图中，要永久更改值，您应该从recyclerView中获取数据，并在视图和数据库中设置数据。

@Override
public void onNoteClick(int position) {
    if (position == 0) {
        Log.d(TAG, "onNoteClick: ");
        list.set(0, "Finished");
        adapter.getItemId(0);
        // Here make the change in the source of data
        adapter.notifyDataSetChanged();
}

Answer 2

您可以在arrayList中设置您单击的项目，并将该数组列表保存在sharedPreference中，当您再次访问时，可以从sharedPrefrence检索arrayList并从arrayList中检查选中项的ID，而在设置适配器时，可以设置签入您的适配器onBindViewHolder（其ID包含arrayList）然后更改“完成”中的文本，否则将文本设置为“天”。

您可以创建一个AppPreference类：-

import emoji # Needs 'pip install emoji'

s['icons'] = s['emoji'].apply(lambda x: emoji.emojize(x))

或者您可以从项目中的任何地方调用此方法：-

保存您的列表：-

public class AppPreference {
    private static SharedPreferences mPreferences;
    private static SharedPreferences.Editor mPreferencesEditor;

    public static Set<String> getCamEval(Context ctx) {
            mPreferences = PreferenceManager.getDefaultSharedPreferences(ctx);
            return mPreferences.getStringSet("sdk_camEval", null);
        }

        public static void setCamEval(Context ctx, ArrayList<String> value) {
            mPreferences = PreferenceManager.getDefaultSharedPreferences(ctx);
            mPreferencesEditor = mPreferences.edit();
            Set<String> set = new HashSet<>();
            set.addAll(value);
            mPreferencesEditor.putStringSet("sdk_camEval", set);
            mPreferencesEditor.commit();
        }
}

或获取此列表：-

SdkPreferences.setCamEval(activity, yourList);

Answer 3

我找到了问题并使用gSon进行了解决，并为我的listview.bcs创建了新的Java类，在这种情况下，它一直都在创建，这就是问题

在Android回收器中单击项目时如何保存状态

3 个答案: