Kotlin RecyclerView filter search

[Maha Sakka]

I create an interface with edittext "Search" and "recyclerview" below

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/whiteFour"
    android:orientation="vertical">

    <LinearLayout
        android:id="@+id/lyt_search"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="60dp"
        android:orientation="horizontal"
        android:theme="@style/ThemeOverlay.AppCompat.Light"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <androidx.cardview.widget.CardView
            android:id="@+id/search_bar"
            android:layout_width="300dp"
            android:layout_height="wrap_content"
            android:clipToPadding="false"
            android:layout_marginStart="20dp"
            android:layout_marginTop="10dp"
            android:layout_marginBottom="10dp"
            app:cardBackgroundColor="@color/whiteTwo"
            app:cardCornerRadius="20dp"
            app:cardElevation="1dp">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:orientation="horizontal">

                <View
                    android:layout_width="@dimen/spacing_medium"
                    android:layout_height="0dp" />

                <ImageView
                    android:id="@+id/bt_mic"
                    android:layout_width="15dp"
                    android:layout_height="15dp"
                    android:layout_gravity="center"
                    android:layout_marginStart="10dp"
                    android:background="@android:color/transparent"
                    android:clickable="true"
                    android:tint="@color/greyishTwo"
                    app:srcCompat="@drawable/ic_search" />

                <EditText
                    android:id="@+id/search"
                    android:layout_width="0dp"
                    android:layout_height="wrap_content"
                    android:layout_marginStart="10dp"
                    android:padding="5dp"
                    android:layout_weight="1"
                    android:background="@android:color/transparent"
                    android:fontFamily="@font/cairo"
                    android:hint="Search..."
                    android:imeOptions="actionSearch"
                    android:maxLines="1"
                    android:singleLine="true"
                    android:textSize="14sp">

                </EditText>

                <View
                    android:layout_width="@dimen/spacing_medium"
                    android:layout_height="0dp" />


            </LinearLayout>

        </androidx.cardview.widget.CardView>

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:fontFamily="@font/cairo"
            android:layout_marginTop="15dp"
            android:layout_marginStart="20dp"
            android:text="@string/cancel_msg"
            android:textSize="14sp" />
    </LinearLayout>


    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerViewList"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_marginStart="20dp"
        android:layout_marginEnd="20dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/lyt_search" />


</androidx.constraintlayout.widget.ConstraintLayout>

I would like to search an item in the recycler view
In my adapter for recyclerview "ItemAdapter" I implement Filterable:

class ItemAdapter(var items: Array<AddressesData>, var mListener: OnItemClickListener) : RecyclerView.Adapter<ItemAdapter.ViewHolder>()
       , Filterable 

and I add the following code in my adapter :

override fun getFilter(): Filter {
        return filter
    }

    private val filter: Filter = object : Filter() {
        var filteredList: MutableList<AddressesData> = arrayListOf()
        override fun performFiltering(constraint: CharSequence): FilterResults {

            if (constraint.isEmpty()) {
                filteredList.addAll(governments)
            } else {
                val filterPattern = constraint.toString().toLowerCase().trim { it <= ' ' }
                for (item in 0..governments.size) {
                    if (governments[item].englishName!!.toLowerCase().contains(filterPattern)) {
                        filteredList.add(governments[item])
                    }
                }
            }
            val results = FilterResults()
            results.values = filteredList
            return results
        }

        override fun publishResults(charSequence: CharSequence?, filterResults: FilterResults) {
            filteredList = filterResults.values as MutableList<AddressesData>
            notifyDataSetChanged()
        }
    }

In my Activity, I add the following code,
what should I add to doing search in recycler view

[Randy Tong]

Use textChangedListener on your search editText.

[Maha Sakka]

As follows, what should I put as code here ?

        search.addTextChangedListener(object : TextWatcher {
            override fun beforeTextChanged(charSequence: CharSequence, i: Int, i1: Int, i2: Int) {}
            override fun onTextChanged(charSequence: CharSequence, i: Int, i1: Int, i2: Int) {

            }

            override fun afterTextChanged(editable: Editable) {}
        })

[Randy Tong]

Have you read  https://inducesmile.com/android-programming/how-to-filter-a-recyclerview-with-a-edittext-in-android/ ?

Call getFilter in onTextChanged.

[Maha Sakka]

I add the following code :
   

  search.addTextChangedListener(object : TextWatcher {
            override fun beforeTextChanged(charSequence: CharSequence, i: Int, i1: Int, i2: Int) {}
            override fun onTextChanged(charSequence: CharSequence, i: Int, i1: Int, i2: Int) {
                adapter.filter.filter(charSequence.toString())

            }

            override fun afterTextChanged(editable: Editable) {}
        })

And this is the adapter code :

class GovernmentSectionItemAdapter(var governments: Array<AddressesData>, var mListener: OnItemClickListener) : RecyclerView.Adapter<GovernmentSectionItemAdapter.ViewHolder>()
        , Filterable {

    private var selectedPos = -1

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        val view = LayoutInflater.from(parent.context).inflate(R.layout.item_government_section, parent, false)
        return ViewHolder(view)
    }

    override fun getItemCount() = governments.size

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        val item: AddressesData = governments[position]
        holder.tickImage.visibility = (if (selectedPos == position) View.VISIBLE else View.GONE)
        holder.government.text = item.englishName.toString()

        holder.itemView.setOnClickListener {
            selectedPos = position
            mListener.onItemClick(holder.itemView, item)
            notifyDataSetChanged()
        }

    }

    inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        val government: TextView = itemView.government
        val tickImage: ImageView = itemView.tickGovernment
    }

    interface OnItemClickListener {
        fun onItemClick(view: View, viewModel: AddressesData)
    }

    override fun getFilter(): Filter {
        return filter
    }

    private val filter: Filter = object : Filter() {
        override fun performFiltering(constraint: CharSequence): FilterResults {
            var filteredList: MutableList<AddressesData> = arrayListOf()

            if (constraint.isEmpty()) {
                filteredList.addAll(governments)
            } else {
                val filterPattern = constraint.toString().toLowerCase().trim { it <= ' ' }
                      for (item in 0..governments.size) {
                    if (governments[item].englishName!!.toLowerCase().contains(filterPattern)) {
                        filteredList.add(governments[item])
                    }
                }
            }
            val results = FilterResults()
            results.count = filteredList.size
            results.values = filteredList
            return results
        }

        override fun publishResults(charSequence: CharSequence, filterResults: FilterResults) {
            governments = filterResults.values as Array<AddressesData>
            notifyDataSetChanged()
         }
    }

But, the filter didn't work up to now

[Randy Tong]

Have you tried debug? Did it goes to the else part?

if (constraint.isEmpty()) {
                filteredList.addAll(governments)
            } else {
                val filterPattern = constraint.toString().toLowerCase().trim { it <= ' ' }
                      for (item in 0..governments.size) {
                    if (governments[item].englishName!!.toLowerCase().contains(filterPattern)) {
                        filteredList.add(governments[item])
                    }
                }
            }

[Maha Sakka]

I think that the problem is here

   override fun publishResults(constraint: CharSequence?, results: FilterResults?) {
            governments = results?.values as Array<AddressesData>
                notifyDataSetChanged()
         }

I tried the debug and it goes to the else part

[Randy Tong]

Any exceptions?
What you want to do with this line?

governments = filterResults.values as Array<AddressesData>

[Maha Sakka]

I remove this ligne :

governments = filterResults.values as Array<AddressesData>

The recycleview not be updated, always display all the government without filtre

[Maha Sakka]

I haven't found a solution so far, could you help me please

[Randy Tong]

I wish too.

Is it possible for you to upload your project to git so I can help?