java - RecyclerView 搜索过滤器不起作用

Question

我想通过搜索过滤一些 ArrayList 的数据，

在我的 Activity 的 onCreate 中:

        arrayList = getListItemData();
        filteredArrayList = new ArrayList<>();
        filteredArrayList.addAll(arrayList);

        adapter = new NameAdapter(filteredArrayList);
        itemList.setAdapter(adapter);

        searchBox.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {

                adapter.getFilter().filter(s.toString());

            }

            @Override
            public void afterTextChanged(Editable s) {

            }
        });

我的可过滤适配器:

public class NameAdapter extends RecyclerView.Adapter<NameAdapter.ViewHolder> implements Filterable {
        private ArrayList<Name> arrayList;
        private CustomFilter filter;

        public NameAdapter(ArrayList<Branch> items) {
            arrayList = items;
            filter = new CustomFilter(NameAdapter.this);
        }

        @Override
        public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_name, parent, false);
            return new ViewHolder(view);
        }

        @Override
        public void onBindViewHolder(final ViewHolder holder, int position) {
            holder.data = arrayList.get(position);


        }

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

        @Override
        public Filter getFilter() {
            return filter;
        }

        public class ViewHolder extends RecyclerView.ViewHolder {
            public final View view;
            public final TextView branch;
            public Name data;

            public ViewHolder(View view) {
                super(view);
                this.view = view;
                branch = view.findViewById(R.id.textView_name);

            }

        }

        public class CustomFilter extends Filter {
            private NameAdapter adapter;

            private CustomFilter(NameAdapter adapter) {
                super();
                this.adapter = adapter;
            }

            @Override
            protected FilterResults performFiltering(CharSequence constraint) {
                filteredArrayList.clear();
                final FilterResults results = new FilterResults();
                if (constraint.length() == 0) {
                    filteredArrayList.addAll(arrayList);
                } else {
                    final String filterPattern = constraint.toString().toLowerCase().trim();
                    for (final Name name : arrayList) {
                        if (name.getName().toLowerCase().startsWith(filterPattern)) {
                            filteredBranchArrayList.add(name);
                        }
                    }
                }
                results.values = filteredArrayList;
                results.count = filteredArrayList.size();
                return results;
            }

            @Override
            protected void publishResults(CharSequence constraint, FilterResults results) {

                this.adapter.notifyDataSetChanged();
            }
        }
    }

过滤器由于某种原因不起作用，当我输入内容时它会清除 recyclerview

Answer 1

1st 在构造函数中复制 branchArrayList。像这样:-

 private ArrayList<Branch> branchCopy = new ArrayList<>;
 public BranchAdapter(ArrayList<Branch> items) {
        branchArrayList = items;
        branchCopy.addAll(items);
        filter = new CustomFilter(BranchAdapter.this);
    }

你的performingFilter

  @Override
  protected FilterResults performFiltering(CharSequence constraint) {
        ArrayList<Branch> branchFilter = new ArrayList<>;
        final FilterResults results = new FilterResults();
            if (constraint.length() == 0) {
                branchFilter.addAll(branchArrayList);
            } else {
                final String filterPattern = constraint.toString().toLowerCase().trim();
                for (final Branch branch : branchCopy) {
                    if (branch.getBranchName().toLowerCase().startsWith(filterPattern)) {
                        branchFilter.add(branch);
                    }
                }
            }
            results.values = branchFilter ;
            results.count = branchFilter.size();
            return results;
        }

您的publishResults

  @Override
  protected void publishResults(CharSequence constraint, FilterResults results) {
      branchArrayList = (ArrayList<Branch>) results.values; // you have done nothing with the filter results 
      notifyDataSetChanged();
  }

在通知更改 mainList 之前 !!

 branchArrayList = (ArrayList<Branch>) results.values;

将此行添加到publishResults

You have done NOTHING with the filter results