Search filter in recyclerView android

 1. Adapter for filter search data 

 class CountryAdapter : RecyclerView.Adapter<CountryAdapter.CountryViewHolder>() {  
   private val items: ArrayList<CountryNameItem> = arrayListOf()  
   var onItemClick: ((CountryNameItem) -> Unit)? = null  
   private val itemsCopies: ArrayList<CountryNameItem> = arrayListOf()  
   fun addItems(newItems: List<CountryNameItem>) {  
     items.addAll(newItems)  
     itemsCopies.addAll(newItems)  
     notifyDataSetChanged()  
   }  
   override fun onCreateViewHolder(  
     parent: ViewGroup,  
     viewType: Int  
   ): CountryAdapter.CountryViewHolder {  
     val binding =  
       AdapterCountryItemLayoutBinding.inflate(  
         LayoutInflater.from(parent.context),  
         parent,  
         false  
       )  
     return CountryViewHolder(binding)  
   }  
   inner class CountryViewHolder(val binding: AdapterCountryItemLayoutBinding) :  
     RecyclerView.ViewHolder(binding.root) {  
     fun bind(item: CountryNameItem) {  
       binding.country = item  
       itemView.setOnClickListener {  
         onItemClick?.invoke(item)  
       }  
     }  
   }  
   override fun onBindViewHolder(holder: CountryAdapter.CountryViewHolder, position: Int) {  
     val item = items[position]  
     return holder.bind(item)  
   }  
   override fun getItemCount() = items.size  
   fun filter(sequence: CharSequence?) {  
     val temp: ArrayList<CountryNameItem> = arrayListOf()  
     if (sequence.isNullOrEmpty().not()) {  
       for (s in itemsCopies) {  
         if (s.name.toLowerCase().contains(sequence!!)) {  
           temp.add(s)  
         } else {  
           for (code in s.callingCodes) {  
             if (code.contains(sequence!!)) {  
               temp.add(s)  
             }  
           }  
         }  
       }  
     } else {  
       temp.addAll(itemsCopies)  
     }  
     items.clear()  
     items.addAll(temp)  
     notifyDataSetChanged()  
     temp.clear()  
   }  
 }  

 1. Use case of adapter in the search field 

 binding.countryFilter.doOnTextChanged { text, _, _, _ ->  
         countryAdapter.filter(text.toString())  
         text?.let {  
           if (it.isNotEmpty()) cancel.show() else cancel.hide()  
         }  
       }  
 binding.cancel.setOnClickListener {  
       binding.countryFilter.text?.clear()  
     }