RecyclerView not updating dynamically on search

Question

I have a recycler view with flight information, and I am searching using the flight number on the search bar. When I search, the recyclerview is updated dynamically for which the logic is there in my filter function, however when I clear the search, the recycler view is completely empty. How can I fix this issue?

search filter function

private void filter(String text) {
     ArrayList<FlightItem> filteredList = new ArrayList<>();

     for(FlightItem item : flightItems) {
         if(item.getFlightNumber().toLowerCase().contains(text.toLowerCase())){
             filteredList.add(item);
          }
     }
     mAdapter.filterList(filteredList);
     flightItems.clear();
     flightItems.addAll(filteredList);
   }
}

Answer 1

keep a copy of flightItems, as you are clearing it before adding filtered items

ArrayList<FlightItem> flightItems = new ArrayList<>();
ArrayList<FlightItem> flightItemsCopy = new ArrayList<>();

private void filter(String text) {
     if(text.trim() == ""){
        clearSearch()
        return
     }
     ArrayList<FlightItem> filteredList = new ArrayList<>();

     for(FlightItem item : flightItems) {
         if(item.getFlightNumber().toLowerCase().contains(text.toLowerCase())){
             filteredList.add(item);
          }
     }
     flightItemsCopy.clear(); //clear copy
     flightItemsCopy.addAll(flightItems); // make a copy here
     mAdapter.filterList(filteredList);
     flightItems.clear();
     flightItems.addAll(filteredList);
   }
}

private void clearSearch(){
    flightItems.clear();
    flightItems.addAll(flightItemsCopy);
    mAdapter.notifyDataSetChanged();
}