具有多个项目的recycleView上的Android SearchView 请尝试此（如果结果！=null）{items.addAll（（List）results.values）；} @Override public Filter getFilt

具有多个项目的recycleView上的Android SearchView 请尝试此

（如果结果！=null）{items.addAll（（List）results.values）；}

@Override
    public Filter getFilter() {
        return exampleFilter;
    }
    private Filter exampleFilter = new Filter() {
        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            List<Item> filteredlist = new ArrayList<>();
            if(constraint==null || constraint.length() == 0) {
                filteredlist.addAll(itemsfull);
            } else {
                String filterPattern = constraint.toString().toLowerCase().trim();
                for (Item item : itemsfull ) {
                    if (item.getCode().toLowerCase().contains(filterPattern)) {
                        filteredlist.add(item);
                    }
                }
                for (Item item : itemsfull ) {

                if (item.getDescription().toLowerCase().contains(filterPattern)) {
                    filteredlist.add(item);
                }
                }
                for (Item item : itemsfull ) {

                    if (item.getEmplacement().toLowerCase().contains(filterPattern)) {
                        filteredlist.add(item);
                    }
                }

            }
            FilterResults results = new FilterResults();
            results.values = filteredlist;
            return results;
        }

        @Override
        protected void publishResults(CharSequence constraint, FilterResults results) {
            items.clear();
            items.addAll((List) results.values);
            notifyDataSetChanged();
        }
    };

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.gestion_actif, PID: 5357
    java.lang.NullPointerException: Attempt to invoke interface method 'java.lang.Object[] java.util.Collection.toArray()' on a null object reference
        at java.util.ArrayList.addAll(ArrayList.java:588)
        at com.example.gestion_actif.Adapter.MyAdapter$5.publishResults(MyAdapter.java:264)