Stop Thread in Kotlin - multithreading

Question

First of all, I'm new in Kotlin, so please be nice :).
It's also my first time posting on StackOverflow
I want to literally STOP the current thread that I created but nothing works.
I tried quit(), quitSafely(), interrupt() but nothing works.
I created a class (Data.kt), in which I create and initialize a Handler and HandlerThread as follows :
class Dispatch(private val label: String = "main") {
var handler: Handler? = null
var handlerThread: HandlerThread? = null
init {
if (label == "main") {
handlerThread = null
handler = Handler(Looper.getMainLooper())
} else {
handlerThread = HandlerThread(label)
handlerThread!!.start()
handler = Handler(handlerThread!!.looper)
}
}
fun async(runnable: Runnable) = handler!!.post(runnable)
fun async(block: () -> (Unit)) = handler!!.post(block)
fun asyncAfter(milliseconds: Long, function: () -> (Unit)) {
handler!!.postDelayed(function, milliseconds)
}
fun asyncAfter(milliseconds: Long, runnable: Runnable) {
handler!!.postDelayed(runnable, milliseconds)
}
companion object {
val main = Dispatch()
private val global = Dispatch("global")
//fun global() = global
}
}
And now, in my DataManager, I use these to do asynchronous things :
fun getSomething(forceNetwork: Boolean ) {
val queue1 = Dispatch("thread1") // Create a thread called "thread1"
queue1.async {
for (i in 0..2_000_000) {
print("Hello World")
// Do everything i want in the current thread
}
// And on the main thread I call my callback
Dispatch.main.async {
//callback?.invoke(.........)
}
}
}
Now, in my MainActivity, I made 2 buttons :
One for running the function getSomething()
The other one is used for switching to another Controller View :
val button = findViewById<Button>(R.id.button)
button.setOnClickListener {
DataManager.getSomething(true)
}
val button2 = findViewById<Button>(R.id.button2)
button2.setOnClickListener {
val intent = Intent(this, Test::class.java) // Switch to my Test Controller
intent.setFlags(Intent.FLAG_ACTIVITY_NO_HISTORY)
startActivity(intent)
finish()
}
Is there a way to stop the thread, because when I switch to my second View, print("Hello World") is still triggered, unfortunately.
Thanks for helping me guys I hope that you understand !

Answer 1

A thread needs to periodically check a (global) flag and when it becomes true then the thread will break out from the loop. Java threads cannot be safely stopped without its consent.
Refer to page 252 here http://www.rjspm.com/PDF/JavaTheCompleteReference.pdf that describes the true story behind the legend.
I think that a truly interruptible thread is only possible through the support of the operating system kernel. The actual true lock is held deep down by the CPU hardware microprocessor.