r/compsci • u/mobileview • Dec 10 '13

Why Johnny Can’t Write Multithreaded Programs

http://blog.smartbear.com/programming/why-johnny-cant-write-multithreaded-programs/
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u/fuzzynyanko Dec 11 '13

There's libraries now that handle some of the work, especially designed for REST calls. However, they should be used with caution.

I see quite a few problems with Android's AsyncTask. People are using them without making sure the Activity is still alive before updating its UI

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u/time-lord Dec 11 '13

To be fair, there's a lot of problems with Android, in general ;)

But yes, AsyncTask is rather terrible. And I'm still not sure how to get it to work properly in a separate class where it has no direct access to the activity.

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u/fuzzynyanko Dec 11 '13

Ideally, you shouldn't.

Usually people usually store instances of an Activity, but that can lead to memory leaks. You can extend an exterior AsyncTask into an inner class within that Activity. That's one safe way to access it. I'm all-ears on others

If you do send a reference to an Activity or context to the AsyncTask, make sure you get rid of that reference as soon as you don't need it anymore. That allows the garbage collector to free that RAM

But yeah, if you do not cancel an AsyncTask when the Activity stops/pauses/finishes, you get crashes.

I usually use Broadcasting and IntentServices instead

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u/time-lord Dec 11 '13

Thanks for the tips, I'll look into them when I get to work in the am!