Kotlin 过滤器在 RecyclerView 中搜索 EditText

Question

在我的带有 Kotlin 的 android 应用程序 Api 28 中，我创建了一个接口“listOfCountry.xml”，一个用于搜索的 editText 和一个包含所有国家/地区列表的回收器视图，如下代码：

           <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"/>

    <TextView
        android:id="@+id/cancelSearch"
        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" />

<androidx.recyclerview.widget.RecyclerView
    android:id="@+id/recyclerViewGovernmentOrSectionList"
    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" />

我想使用搜索过滤器从列表中获取一个国家/地区，以下代码是我的适配器的描述：

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

    private var selectedPos = -1
    var searchableList: MutableList<AddressesData> = arrayListOf()
    private var onNothingFound: (() -> Unit)? = null


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

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

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

    }

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

    interface OnItemClickListener {
        fun onItemClick(view: View, viewModel: AddressesData)
    }
    override fun getFilter(): Filter {
        return object : Filter() {
            private val filterResults = FilterResults()
            override fun performFiltering(constraint: CharSequence?): FilterResults {
                searchableList.clear()
                if (constraint.isNullOrBlank()) {
                    searchableList.addAll(countries)
                } else {
                    val filterPattern = constraint.toString().toLowerCase().trim { it <= ' ' }
                    for (item in 0..countries.size) {
                        if (countries[item].englishName!!.toLowerCase().contains(filterPattern)) {
                            searchableList.add(countries[item])
                        }
                    }}
                    return filterResults.also {
                        it.values = searchableList
                    }
                }

                override fun publishResults(constraint: CharSequence?, results: FilterResults?) {
                    if (searchableList.isNullOrEmpty())
                        onNothingFound?.invoke()
                    notifyDataSetChanged()

                }

我在我的活动中添加以下代码：

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) {}
        })

过滤器不起作用，我想知道我的代码中的问题出在哪里以及如何纠正它以使过滤器工作？

Answer 1

我认为您在适配器中丢失了getItemCount方法，它必须返回适配器中项目的实际大小。

Answer 2

它迟到了，但它可能会帮助某人，

您正在过滤searchableList列表中的数据，但您已将countries列表应用于适配器。 相应地改变它会起作用。