demo describing using handler in android to process runnables

CustomBackgroundThread.kt

class CustomBackgroundThread : Thread() {

    private var handler: Handler? = null

    override fun run() {
        super.run()
        Looper.prepare() // Prepare the looper and associate with current thread
        handler = Handler()
        Looper.loop() // Start the thread so that it can keep the thread active
    }

    /**
     *  Here we can add the runnable to the message queue
     */
    fun addTaskToMessageQueue(task: Runnable) {
        handler?.post(task)
    }

    fun stopTheThread() { interrupt() }

}

HandlerActivity.kt

class HandlerActivity : AppCompatActivity() {

    private lateinit var binding: ActivityHandlerBinding
    lateinit var bkgThread : CustomBackgroundThread

    lateinit var  runnableWorkOne : Runnable
    lateinit var  runnableWorkTwo : Runnable
    lateinit var  runnableWorkThree : Runnable

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityHandlerBinding.inflate(layoutInflater)
        setContentView(binding.root)
        startThread()

        binding.btnPublishOneId.setOnClickListener {
            runnableWorkOne = RunnableWorkOne()
            bkgThread.addTaskToMessageQueue(runnableWorkOne);
        }

        binding.btnPublishTwoId.setOnClickListener {
            runnableWorkTwo = RunnableWorkTwo()
            bkgThread.addTaskToMessageQueue(runnableWorkTwo);
        }

        binding.btnPublishThreeId.setOnClickListener {
            runnableWorkThree = RunnableWorkThree()
            bkgThread.addTaskToMessageQueue(runnableWorkThree);
        }

        binding.btnRestartThreadId.setOnClickListener {
            startThread()
        }

        binding.btnStopThreadId.setOnClickListener {
            stopThreads()
        }

    }

    private fun startThread() {
        bkgThread = CustomBackgroundThread()
        bkgThread.start() // Start a new thread
    }

    private fun stopThreads() {
        bkgThread.stopTheThread()
    }

}

RunnableWorkOne.kt

class RunnableWorkOne : Runnable {

    override fun run() {
        try {
            val TAG_ONE = "one"
            for (i in 0 until 5) {
                Thread.sleep(500L)
                println(TAG_SAKURA.plus("--$i--").plus("Current Runnable-->$TAG_ONE"))
            }
        }catch (ex:InterruptedException){
            println(
                TAG_SAKURA.plus("--")
                .plus("Runnable named")
                .plus("--")
                .plus(CustomRunnableOne::class.java.name)
                .plus("--")
                .plus("is interrupted"))
        }
    }

}

RunnableWorkThree.kt

class RunnableWorkThree  : Runnable {

    override fun run() {
        try {
            val TAG_THREE = "three"
            for (i in 0 until 5) {
                Thread.sleep(500L)
                println(TAG_SAKURA.plus("--$i--").plus("Current Runnable-->$TAG_THREE"))
            }
        }catch (ex:InterruptedException){
            println(
                TAG_SAKURA.plus("--")
                .plus("Runnable named")
                .plus("--")
                .plus(CustomRunnableThree::class.java.name)
                .plus("--")
                .plus("is interrupted"))
        }
    }

}

RunnableWorkTwo.kt

class RunnableWorkTwo   : Runnable {

    override fun run() {
        try {
            val TAG_TWO = "two"
            for (i in 0 until 5) {
                Thread.sleep(500L)
                println(TAG_SAKURA.plus("--$i--").plus("Current Runnable-->$TAG_TWO"))
            }
        }catch (ex:InterruptedException){
            println(
                TAG_SAKURA.plus("--")
                .plus("Runnable named")
                .plus("--")
                .plus(CustomRunnableTwo::class.java.name)
                .plus("--")
                .plus("is interrupted"))
        }
    }

}