Question

我正在尝试使用updateList（）中的notifyDataSetchanged（）更新myadapter。但不适用于recyclerview。我可以在updateList（）中看到列表大小并显示实际结果，但只有reclerview没有更新。这个类是用MVVM设计模式设计的。

   public class TasksAdapter extends RecyclerView.Adapter<TasksAdapter.TasksAdapterViewHolder> {
        private static final String TAG =  TasksAdapter.class.getSimpleName();
        static ArrayList<ItemModel> list;
        static Context mContext;
        private Fragment fragment;
        private int row_index = -1;
        private SessionManager session;
    //    SelectColorVM colorVM;

        public TasksAdapter(Fragment fragment, Context context, ArrayList<ItemModel> itemList) {
            this.mContext = context;
            this.list = itemList;
            this.fragment = fragment;
            session = new SessionManager(fragment.getContext());
        }

        public void updateList(ArrayList<ItemModel> itemList){
            list.clear();
            this.list = itemList;
            notifyDataSetChanged();
        }

        @Override
        public TasksAdapterViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            TasksItemBinding binding =
                    DataBindingUtil.inflate(LayoutInflater.from(parent.getContext()), R.layout.tasks_item,
                            parent, false);
            return new TasksAdapter.TasksAdapterViewHolder(binding);
        }

        @Override
        public void onBindViewHolder(TasksAdapterViewHolder holder, final int position) {
            holder.binding.setViewModel(list.get(position));
            if(position == 0 && list.get(position).btnText.get().toString().length() > 0)
                holder.binding.btnUpdate.setVisibility(View.VISIBLE);
            else
                holder.binding.btnUpdate.setVisibility(View.INVISIBLE);
            holder.binding.layoutItem.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
    //                row_index = position;
    //                notifyDataSetChanged();
                    Fragment fragment = new DetailFragment();
                    FragmentManager manager = ((FragmentActivity) mContext).getSupportFragmentManager();
                    FragmentTransaction fragmentTransaction = manager.beginTransaction();
                    Bundle bundle = new Bundle();
                    ItemModel item = list.get(position);
                    bundle.putSerializable("item", item);
                    fragment.setArguments(bundle);
                    fragmentTransaction.replace(R.id.id_frame, fragment, "details");
                    fragmentTransaction.addToBackStack("details");
                    fragmentTransaction.commit();
                }
            });
            holder.binding.btnUpdate.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    HashMap<String, String> user = session.getUserDetails();
                    if(list.get(position).btnText.get().equals("Task Start")){
                        LandingEngine.updateStatusAndSetStartTimeForRequest(fragment, user.get(SessionManager.KEY_CLEANER_ID), list.get(position).sid.get().toString());
                    } else if(list.get(position).btnText.get().equals("Task Complete")){
                        LandingEngine.updateStatusAndSetCompleteTimeForRequest(fragment, user.get(SessionManager.KEY_CLEANER_ID), list.get(position).sid.get().toString());
                    }
                }
            });
        }

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

        public static class TasksAdapterViewHolder extends RecyclerView.ViewHolder {
            TasksItemBinding binding;

            public TasksAdapterViewHolder(TasksItemBinding rowbinding) {
                super(rowbinding.getRoot());
                this.binding = rowbinding;
            }

        }
        @Override
        public long getItemId(int position) {
            return position;
        }

        @Override
        public int getItemViewType(int position) {
            return position;
        }


    }

我正在调用我的片段中的适配器，如下所示

if(list.size() > 0) {
            if(adapter == null) {
                view.setHasFixedSize(true);
                mLayoutManager = new LinearLayoutManager(fragment.getContext());
                view.setLayoutManager(mLayoutManager);
                adapter = new TasksAdapter(fragment, fragment.getContext(), list);
                view.setAdapter(adapter);
                view.addItemDecoration(new DividerItemDecoration(fragment.getContext()));
            } else {
                adapter.updateList(list);
//                view.getAdapter().notifyDataSetChanged();
//                view.invalidate();
            }
        }

请检查一下，让我知道我在哪里做错了。谢谢。

Answer 1

最后，它通过从排序类中调用此方法，一旦从排球库中获取API响应。

我在ViewModel类中编写了以下方法。

public void updateList(ArrayList<Class> list){
        if(adapter != null) {
            adapter.updateList(list);
        }
    }

从片段类调用此方法，如下所示。

ArrayList<StatisticsModel> list = (ArrayList) data;
        viewModel.updateList(list);

所以在适配器类中更新方法如下。

public void updateList(ArrayList<StatisticsModel> itemList){
        list.clear();
//        this.list = itemList;
//        list.addAll(itemList);
//        notifyItemInserted(list.size());
//        notifyDataSetChanged();
        this.list.addAll(itemList);
//        notifyItemInserted(list.size());
        notifyDataSetChanged();
    }

Answer 2

我遇到了同样的问题，你在这里犯了错误，将列表更改为itemList：

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

Answer 3

不要

 public void updateList(ArrayList<ItemModel> itemList)
        {
            list.clear();
            this.list = itemList;
            notifyDataSetChanged();
        }

每当调用此方法时 list.clear(); 清除所有值。

clear（）方法用于从列表中删除所有元素。

<强> DO

 public void updateList(ArrayList<ItemModel> itemList)
            {
               this.list.addAll(itemList);
               notifyDataSetChanged();
            }

Answer 4

尝试从您的 list.clear(); 方法移除 updateList

public void updateList(ArrayList<ItemModel> itemList){

            this.list.addAll(itemList);
            notifyItemInserted(list.size());
            notifyDataSetChanged();
        }

notifyItemInserted(int position)

通知任何已登记的观察员已经新插入了位置反映的项目。

也试试这个

        list.addAll(your new list);

        if (adapter == null) {
            view.setHasFixedSize(true);
            mLayoutManager = new LinearLayoutManager(fragment.getContext());
            view.setLayoutManager(mLayoutManager);
            adapter = new TasksAdapter(fragment, fragment.getContext(), list);
            view.setAdapter(adapter);
            view.addItemDecoration(new DividerItemDecoration(fragment.getContext()));
        } else {


            view.notifyItemInserted(list.size());
            view.notifyDataSetChanged();
        }

Answer 5

尝试在notifyDataSetChanged()课程中添加Fragment，例如......

adapter.notifyDataSetChanged();

Answer 6

试试这个

    getActivity().runOnUiThread(new Runnable() {
                @Override
                public void run() {
                       view.adapter.notifyDataSetChanged();
                }
            });

Answer 7

有一个相同的问题。就我而言，logcat RecyclerView中出现错误消息：未附加布局管理器；跳过布局

我已经用以下代码修复了

 drop(event) {
      event.preventDefault();
      var data = document.getElementById(event.dataTransfer.getData("Text"));
      data.style.position="relative";
     data.style.left = event.pageX - data.clientWidth / 2 + "px";
     data.style.top = event.pageY - data.clientHeight / 2 + "px";
    }

然后notifyDataSetChanged开始工作

recyclerview notifyDataSetChanged（）无法正常工作

7 个答案: