Populating ListView from array in Kotlin

Question

I'm trying to display an array in a ListView but the final two lines of my MainActivity throwing up an Expecting member declaration message. Any idea why?

MainActivity.kt

package com.example.apple.stories

import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.widget.ArrayAdapter
import android.widget.ListView
import org.jetbrains.anko.db.MapRowParser

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
    }

    val authors = arrayOf("Conan Doyle, Arthur", "Christie, Agatha", "Collins, Wilkie");

    val listView = ListView(this);

    val adapter = ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, authors);

    listView.adapter = adapter;

    activity_main.addView(listView);

}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
    tools:context="com.example.apple.stories.MainActivity">

    <ListView
        android:fillViewport="true"
        android:id="@+id/listView" />

</android.support.constraint.ConstraintLayout>

GuilhermeFGL · Accepted Answer · 2017-10-27 19:57:16Z

There is an example here.

Basically, the code is very similar in Java:

class ListExampleAdapter(context: Context) : BaseAdapter() {
        internal var sList = arrayOf("One", "Two", "Three", "Four", "Five", "Six", "Seven",
                "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen")
        private val mInflator: LayoutInflater

        init {
            this.mInflator = LayoutInflater.from(context)
        }

        override fun getCount(): Int {
            return sList.size
        }

        override fun getItem(position: Int): Any {
            return sList[position]
        }

        override fun getItemId(position: Int): Long {
            return position.toLong()
        }

        override fun getView(position: Int, convertView: View?, parent: ViewGroup): View? {
            val view: View?
            val vh: ListRowHolder
            if (convertView == null) {
                view = this.mInflator.inflate(R.layout.list_row, parent, false)
                vh = ListRowHolder(view)
                view.tag = vh
            } else {
                view = convertView
                vh = view.tag as ListRowHolder
            }

            vh.label.text = sList[position]
            return view
        }
    }

    private class ListRowHolder(row: View?) {
        public val label: TextView

        init {
            this.label = row?.findViewById(R.id.label) as TextView
        }

}

Then, to include the adapter to your ListView:

val lv = findViewById(R.id.list) as ListView
lv.adapter = ListExampleAdapter(this)

Sangeet Suresh · Accepted Answer · 2017-10-28 08:08:28Z

Below adapter will suite your need

class MyArrayAdapter(val contexts: Context, val array: ArrayList<String>)
: ArrayAdapter<String>(contexts, android.R.layout.simple_list_item_1, array) {
companion object {
    class Holder {
        var textView: TextView? = null
    }
}

override fun getView(position: Int, convertView: View?, parent: ViewGroup?): View {
    var holder: Holder;
    if (convertView == null) {
        val view = LayoutInflater.from(context).inflate(android.R.layout.simple_list_item_1, parent, false)
        holder = Holder()
        holder.textView = view.findViewById(android.R.id.text1)
        holder.textView?.text = array[position]
        view.tag = holder
        return view;
    } else {
        holder = convertView.tag as Holder
        holder.textView?.text=array[position]
        return convertView
    }
}


}

Then set adapter

val adapter = MyArrayAdapter<String>(this authors);

    listView.adapter = adapter;

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