Android Listview - Load each row on thread

package com.example.examplelist;

import java.text.DateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.concurrent.TimeUnit;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ListView;

public class ActivityElemsExample extends Activity implements OnClickListener {
    ArrayList<Elem> myList;
    Button btn;
    ListView lv;
    AdapterA adapterA;
    AdapterB adapterB;
    boolean running = false;
    Thread thread;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        btn = (Button)findViewById(R.id.button_loading);
        btn.setOnClickListener(this);
        lv = (ListView)findViewById(R.id.lv);

        myList = new ArrayList<Elem>();

        adapterA = new AdapterA(this, myList);
        adapterB = new AdapterB(this, myList);

    }

    public void onClick(View button){
        if(!running){
            running = true;
            Log.d("MyLogs", "LOADING");

            thread = new Thread(new Runnable(){
            public void run(){
                myList.clear();

                for(int i=0; i < 3000; i++){
                    myList.add(new Elem(i, System.currentTimeMillis(), "Elem "+i));
                }
                handler.sendEmptyMessage(1);
            }
            });
            thread.start();
        }
    }

    public void onDestroy(){
        super.onDestroy();
        if(thread != null){
            while(true){
                try{
                    thread.join();
                    break;
                }
                catch (InterruptedException e){}
            }
        }
    }

    public Handler handler = new Handler() {
        public void handleMessage(android.os.Message msg) {

            lv.setAdapter(adapterA);

            running = false;
        }
    };
}

FromTableAdapter.setSelectedPosition(0); 
FromTableAdapter.notifyDataSetChanged();

<?xml version="1.0" encoding="utf-8" ?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item 
        android:state_selected="true"
        android:drawable="@color/pressed_color"/>
    <item
        android:drawable="@color/default_color" />
</selector> 

lv_FromTable.setItemChecked(0,true);

<ListView
    android:id="@android:id/list"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:listSelector="@drawable/list_selector_background" />  

private static Map<String, Image> images = new HashMap<>();

...

Image image;
if ((image = images.get(item.getOwnerId())) == null) {
    img.setImage(null);
    new Thread(() -> {
        Image image1 = new Image(item.getOwnerProfilePicUrl());
        images.put(item.getOwnerId(), image1);
        Platform.runLater(() -> img.setImage(image1));
    }).start();
} else {
    img.setImage(image);
}

...

import java.awt.Desktop; // importing more classes from awt than neccessary could result in problems
...

public class DischargeComment extends ListCell<Comment> {

    ...

    /**
     * Constructor to pass external cache
     * @param cache 
     */
    public DischargeComment(Map<String, SoftReference<Image>> cache) {
        if (cache == null) {
            throw new IllegalArgumentException();
        }
        this.cache = cache;
    }

    /**
     * constructor using the default cache
     */
    public DischargeComment() {
        this(getDefaultCache());
    }

    private final Map<String, SoftReference<Image>> cache;

    private static Map<String, SoftReference<Image>> defaultCache;

    private static final URL FXML_URL = DischargeComment.class.getResource("cell/discharge_comment.fxml");

    public static Map<String, SoftReference<Image>> getDefaultCache() {
        if (defaultCache == null) {
            defaultCache = new HashMap<>();
        }
        return defaultCache;
    }

    public static String search = "";
    private boolean loaded = false; // no need for a reference to fxmlloader here

    @Override
    protected void updateItem(Comment item, boolean empty) {
        super.updateItem(item, empty);

        if (empty || item == null) {
            setText(null);
            setGraphic(null);
        } else {
            if (!loaded) {
                FXMLLoader mLLoader = new FXMLLoader(FXML_URL);
                mLLoader.setController(this);

                try {
                    mLLoader.load();
                    img.setClip(new Circle(25, 25, 25));
                    loaded = true;
                } catch (IOException e) {
                    e.printStackTrace();
                }

            }

            ...

            // use single access here
            // also use url as key
            cache.compute(item.getOwnerProfilePicUrl(), (key, value) -> {
                Image image = null;
                if (value != null) {
                    image = value.get();
                }
                if (image == null) {
                    image = new Image(key, true); // load image in background
                    value = new SoftReference<>(image);
                }
                img.setImage(image);
                return value;
            });

            lblUsername.setOnMouseClicked(e->{
                try {
                    Desktop.getDesktop().browse(new URI("https://www.instagram.com/" + item.getOwnerUsername()));
                } catch (IOException | URISyntaxException exception) {
                    exception.printStackTrace();
                }
            });

            setText(null);
            setGraphic(pane);
            setPrefHeight(Region.USE_COMPUTED_SIZE); // don't set height to -1
        }
    }
}