是否在带有卡片的RecyclerView上添加搜索筛选器？

Question

我分别在ListView和RecyclerView上找到了筛选器的解决方案，但我希望将它们结合起来。有可能吗？

Answer 1

是的，您的recyclerview.adapter可能可以实现filterable。之后，您必须重写filter getFilter()方法。

您必须定义您自己的筛选器，如下面的代码所示：

@Override
public Filter getFilter() {
    return new YourFilterClass();
}

YourFilterClass

class YourFilterClass extends Filter {

        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            //Here you have to implement filtering way
            final FilterResults results = new FilterResults();
            //logic to filtering
            results.values = ...
            results.count = ...
            return results;
        }

        @Override
        protected void publishResults(CharSequence constraint, FilterResults results) {
            // here you can use result - (f.e. set in in adapter list)
        }
}

public class UserListAdapter extends RecyclerView.Adapter<UserListAdapter.ViewHolder> implements Filterable {

    private final List<User> userList;

    private final List<User> filteredUserList;

    private UserFilter userFilter;

    public UserListAdapter(Context context) {
        this.userList =new ArrayList<>();
        this.filteredUserList = new ArrayList<>();
    }


    ///... other methods

    @Override
    public Filter getFilter() {
       if(userFilter == null)
             userFilter = new UserFilter(this, userList);
        return userFilter;
    }

    private static class UserFilter extends Filter {

        private final UserListAdapter adapter;

        private final List<User> originalList;

        private final List<User> filteredList;

        private UserFilter(UserListAdapter adapter, List<User> originalList) {
            super();
            this.adapter = adapter;
            this.originalList = new LinkedList<>(originalList);
            this.filteredList = new ArrayList<>();
        }

        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            filteredList.clear();
            final FilterResults results = new FilterResults();

            if (constraint.length() == 0) {
                filteredList.addAll(originalList);
            } else {
                final String filterPattern = constraint.toString().toLowerCase().trim();

                for (final User user : originalList) {
                    if (user.getName().contains(filterPattern)) {
                        filteredList.add(user);
                    }
                }
            }
            results.values = filteredList;
            results.count = filteredList.size();
            return results;
        }

        @Override
        protected void publishResults(CharSequence constraint, FilterResults results) {
            adapter.filteredUserList.clear();
            adapter.filteredUserList.addAll((ArrayList<User>) results.values);
            adapter.notifyDataSetChanged();
        }
    }
}

之后在你想要过滤的地方叫：

userListAdapter.getFilter().filter(text)