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I was trying to update the recycler view content from a background thread in Kotlin. I am not using AsyncTask.

Here is my code, i want to know if there is any better way than this:

In my MainActivity, i have progressThread as a member variable.

 var progressThread = Thread()

Then in my method where i want to run the thread first i am defining it...like

        progressThread = Thread (
    Runnable {
        kotlin.run {
            try {
            while (i <= 100 && !progressThread.isInterrupted) {
                Thread.sleep(200)
                //Some Logic
                runOnUiThread {
                    //this runs in ui thread

                }
                i++
            }
            }catch (e:InterruptedException){
                progressThread.interrupt()
            }
        }
    })

after that i am starting it in the same method as

 progressThread.start()

and for stopping it, i have a listener to cancel the progress and in the callback of that listener, i have written:

 progressThread.interrupt()
Samrat
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1 Answers1

12

Updated

Coroutines are stable now,: https://kotlinlang.org/docs/reference/coroutines-overview.html

Old Answer

Yes, you can do this using doAsync from kotlin anko library that is fairly simple and easy to use.

add following line in module level gradle file:

compile "org.jetbrains.anko:anko-commons:0.10.0"

Code example:

val future = doAsync {
    // do your background thread task
    result = someTask()

    uiThread {
        // use result here if you want to update ui
        updateUI(result)
    }
}

code block written in uiThread will only be executed if your Activity or Fragment is in foreground mode (It is lifecycle aware). So if you are trying to stop thread because you don't want your ui code to execute when Activity is in background, then this is an ideal case for you.

As you can check doAsync returns a Future object so you can cancel the background task, by cancel() function: 

future.cancel(true)

pass true if you want to stop the thread even when it has started executing.

If you have more specialised case to handle stopping case then you can do the same thing as in your example.

You can use Kotlin Coroutines also but its in Experimental phase, still you can try it out: https://kotlinlang.org/docs/reference/coroutines.html

Sachin Chandil
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  • I understood that doAsync is fairly simple to use... Ok so doAsync will be better here, than the current thread logic that i wrote??? .... is that what you mean?... My current code is working fine...but i don't know if its the correct/good way... – Samrat Feb 06 '18 at 06:11
  • I have updated the answer with more details, you will find answer of this question there. – Sachin Chandil Feb 06 '18 at 06:12
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    Although experimental, coroutines are in production-ready state, as explained [here](https://stackoverflow.com/questions/46240236/can-experimental-kotlin-coroutines-be-used-in-production). I use them in my Android project and have never experienced any issues. I would warmly recommend using them over this callback-based API. – Marko Topolnik Feb 06 '18 at 12:08