Real difference between AsyncTask and Thread

Question

I have been reading Android documentation (AsyncTask, Thread) and vogella tutorial about this matter, but I have doubts yet.

For example, I want to send a message from an Android app to a server. And I would like this process to be responsive. What should I use?

I have seen examples where they create a new Thread for not block UI, but this way we don't have the progress of process, also you have to process the response within the Thread because the run() method doesn't returning anything.

AsyncTask seems better option than Thread, but I don't know what are the consequences of using an AsyncTask instead of a Thread.

score 33 · Accepted Answer · answered Oct 05 '13 at 12:44

33

Please read this blog

http://crazyaboutandroid.blogspot.in/2011/12/difference-between-android.html

and Details are:

Difference between Android Service,Thread,IntentService and AsyncTask

When to use ?

Service

   Task with no UI, but shouldn't be too long. Use threads within service for long tasks.

Thread

- Long task in general.

- For tasks in parallel use Multiple threads (traditional mechanisms)

AsyncTask

- Small task having to communicate with main thread.

- For tasks in parallel use multiple instances OR Executor

answered Oct 05 '13 at 12:44

Ashish Dwivedi

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Where did you get that `AsyncTask` is for small tasks and `Thread` is for long tasks? Why shouldn't a person use `AsyncTask` for long tasks? – Bugs Happen Nov 15 '18 at 04:42
@BugsHappen Kindly check the following link and you will come to know why AsyncTask is recommended for small task. – Kanwarpreet Singh Jul 16 '19 at 12:06
Which link are you referring to? – Bugs Happen Jul 16 '19 at 12:12
@BugsHappen That is a very good question, technically there is no difference between an async task and a thread, only difference is that the async task can update the UI through its call back methods. So there should be no difference between an async task and a thread in terms of the length of operations that should be performed in them. – Sreekanth Karumanaghat Dec 13 '19 at 05:53
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Dead link, see [here](https://web.archive.org/web/20180102150725/http://www.onsandroid.com/2011/12/difference-between-android.html) for the blog table – dwb Jul 23 '20 at 12:45

score 21 · Answer 2 · edited Jun 26 '18 at 09:04

All other answers here are not complete, there is a big difference between AsyncTask and Thread, i.e.

Thread can be triggered from any thread, main(UI) or background; but AsyncTask must be triggered from main thread.

Also on lower API of Android(not sure, maybe API level < 11), one instance of AsyncTask can be executed only once.

For more information read Difference between Android Service, Thread, IntentService and AsyncTask

In general

Thread

Long task in general.
For tasks in parallel use Multiple threads (traditional mechanisms)

AsyncTask

Small task having to communicate with main thread.
For tasks in parallel use multiple instances OR Executor

Why should only short tasks be run in the AsyncTask? Since how the thread and async task operates are similar manner? — Sreekanth Karumanaghat, Dec 13 '19 at 05:53

score 4 · Answer 3 · answered Aug 01 '12 at 11:58

4

in general using of 2 this features are equivalent, but AsyncTask is more simple in terms of integration with GUI

answered Aug 01 '12 at 11:58

Alex Klimashevsky

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However the android documentation says 'AsyncTasks should ideally be used for short operations (a few seconds at the most.)' – Fran b Aug 01 '12 at 12:23
yeas, because of you work with GUI and user dont want to wait for a long period of time :) – Alex Klimashevsky Aug 01 '12 at 12:25
But AsynTask will run like an independent thread. His work shouldn't affect to main thread (GUI). Or am I wrong? – Fran b Aug 01 '12 at 12:30
yes, you have 2 points to synchonize: onreexecute and onpostexecute – Alex Klimashevsky Aug 01 '12 at 12:37

Tuna Karakasoglu · Answer 4 · 2014-03-03T12:05:36.593

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AsyncTask enables proper and easy use of the UI thread. This class allows to perform background operations and publish results on the UI thread without having to manipulate threads and/or handlers.

You can control its own functions

doInBackground(Params... params), onCancelled(), onPostExecute(Result result), onPreExecute(), nProgressUpdate(Progress... values), publishProgress(Progress... values)

edited Mar 03 '14 at 12:05

answered Aug 01 '12 at 11:59

Tuna Karakasoglu

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score 4 · Answer 5 · answered Aug 01 '12 at 12:00

I would prefer to Use Async Task as it will let you know when the background process gets started and over and when can I parse the response.
Async has methods like onPreExecute and onPostExecute which will allow us to do tasks before and after calling the background tasks.

score 3 · Answer 6 · answered Aug 01 '12 at 12:01

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AsyncTask enables proper and easy use of the UI thread. - from Developer.

The thing is - AsyncTask is a special kind of Thread - one which is a GUI thread, it works in the background and also let's you do something with the GUI - it is basically "pre-programmed" for you with functions onPreExecute(), do inBackground(), onPostExecute().

In order to make Thread work that way, you have to write a loooot of code.

answered Aug 01 '12 at 12:01

Michal

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loooot of code isn't needed.. Using handlers is very basic – Rahul May 29 '17 at 04:45

Real difference between AsyncTask and Thread

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