HandlerThread's handleMessage() is not called

Question

I just came through a strange problem when using HandlerThread and Handlers (By Handlers i mean android.os.handler). I am trying to pass message from my Fragment to a separate Handler Thread. I just setup a handleMessage to handle message. But it is not called. I have got the looper for the handler thread after starting the thread using start()(after the looper is prepared).I have also checked that the handler got the message using hasMessage(). everything is fine. I am confused. kindly help me.My codes are below.

Fragment Code:

   package com.example.raaja.handlerone;

import android.app.Fragment;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;





/**
 * Created by Raaja on 08-12-2015.
 */
public class LoaderFragment extends Fragment {
    Button loaderButton;
    LoaderThread loadThread;
    Handler loaderThreadHandler;
    Handler loaderHandler;
    String[] queArray;


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        loaderHandler = new Handler();
        loadThread = new LoaderThread("LoaderThread",loaderHandler);
         queArray = new String[]{"http://www.paynekillers.com/downloads/screens/17_screen05.jpg",
                "http://www.hdwallpapers.in/walls/jacob_frye_assassins_creed_syndicate-wide.jpg",
        "http://www.percivalconstantine.com/wp-content/uploads/2015/03/Tomb-Raider-Lara-Croft-Summit-2013.jpg",
        "http://orig00.deviantart.net/f904/f/2014/155/e/a/batman_arkham_knight_hd_wallpaper_1_by_rajivcr7-d7l19pt.jpg",
        "http://static5.gamespot.com/uploads/original/536/5360430/2753139-15774024117_9026e0a43c_o.jpg"};
    }

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View loaderView = inflater.inflate(R.layout.loader_layout, container, false);
        this.loaderButton = (Button) loaderView.findViewById(R.id.proc_button);
        return loaderView;
    }

    @Override
    public void onResume() {
        super.onResume();



        loaderButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                loadThread.start();
                Looper loop = loadThread.requestLooper();
                loaderThreadHandler = new Handler(loop);
                Message msg = Message.obtain(loaderThreadHandler, 1, queArray);
                msg.sendToTarget();


            }
        });
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        loadThread.quit();
    }
}

HandlerThread

 package com.example.raaja.handlerone;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.Looper;
import android.os.Message;
import android.util.Log;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;

/**
 * Created by Raaja on 08-12-2015.
 */
public class LoaderThread extends HandlerThread implements Handler.Callback{
    Handler imageHandler;
    Map<Integer,String> queMap;
    HandlerActivity activity;

    public LoaderThread(String name, Handler handler) {
        super(name);
        imageHandler= handler;
        Log.d("inside : ", name);
    }

    Looper requestLooper(){

        Looper loop = this.getLooper();
        Log.d("In Thread : ", String.valueOf(loop.getThread().getName()));
        return loop.myLooper();
    }


    @Override
    public boolean handleMessage(Message msg) {
        String[] que = (String[]) msg.obj;
        queMap = new HashMap<Integer,String>();
        if(que != null){Log.d("",que[3]);}
        for (int i=0;i<=4; i++){
            String url = que[i];

            queMap.put(i,url);
            Log.d("1",url);
        }
        Random rand = new Random();
       String link = queMap.get(rand.nextInt(5));

        loadImages(link);
        return true;
    }

    void loadImages(final String url){
        Log.d("inside Load :","Inside Load");
        try {
            HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection();
            final Bitmap image = BitmapFactory.decodeStream(connection.getInputStream());
            imageHandler.post(new Runnable() {
                @Override
                public void run() {
                    activity.loadImage(image, url);
                }
            });

        } catch (IOException e) {
            e.printStackTrace();
        }
    }


}

Answer 1

ANSWER TO MY QUESTION:

I am able to send messages and I can receive message to my handleMessage() from the other thread. I have already extended the HandlerThread class and implemented Handler.Callback for my Thread class. So I just used the below version to instantiate a Handler passing the thread as Callback(as it implements the Handler.Callback it was accepted as callback). I hope it helps. If you are confused, read the code carefully. Thank you.

Handler myHandler = new Handler(myThread.getLooper(),myThread);