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Thread.Sleep issue android methods and asynctask

I am working on app that updates data for every 8 secs and the update was done using Async task. I am using loops to achieve this condition
while(const_val > update_val) {
new Asynctask().execute();
Thread.sleep(8000);
}
const_val will be constant and will be not be changed by any other methods.lets say this value will be 5.update_val will be updated and decremented when Asynctask is called and let's the value will be 10. So , the while loop executes until the condition is true and asynctask ,sleep are called .
When I use above while loop in a general method then UI gets locked and if I use the same loop in another asynctask there was an error saying "Only original thread that created a view hierarchy can touch its view "

You need to change your code to start the AsyncTask and have it provide an update via its onPostExecute() method. By calling Thread.sleep() you are sleeping the main thread (or UI thread) of your app, which is not good. You do not ever want to block the main thread. This article may help you better understand AsyncTask and threading in Android: http://po.st/Cei3m2

I don't think you should use a surrounding loop. Look at this example:
http://javatechig.com/android/progress-notification-in-android-example
the AsyncTask is a private inner class
the onPostExecute updates the UI with a message/cancels the load bar
This way you don't have to loop and the onCreate() can return instantly.

Logging in Activity, postOnExecute, Resume

I need to implement auto-login process from an activity. Also I need to show ProgressDialog while logging in. I use AsyncTask for login process, because I haven't succeeded to show ProgressDialog in other way, and I execute the mentioned AsyncTask in onCreate. I read that all the code which is executed after doInBackground must be written in onPostExecute, but I have code in onResume. The onResume is launched when AsyncTask hasn't finished its execution yet. Is it possible to launch onResume only after AsyncTask is finished? Or is it possible to execute other functions after AsyncTask is finished (in general)?

Is it possible to launch onResume only after AsyncTask is finished?
No, you need to follow the Activity Lifecycle. And the AsyncTask is asynchronous so that it can run while your UI can still do other things. What you can do is put the code that is in onResume() that you want to run after the task has finished in your onPostExecute() method. There are other options but without seeing the code you are trying to run, this would be my suggestion.
Or is it possible to execute other functions after AsyncTask is finished (in general)?
Yes. You can put that code in another Activity method and call that from onPostExecute()
You also can use getStatus() method of AsyncTask to run code based on the Status of your AsyncTask

Short Answer: No.
If you check the developer android website or this image, you'll check that OnResume() after the Activity is loaded, either after created, paused or restarted. In my case, I have that verification done in OnResume().

Updating UI of Android activity from some other class running on different thread

I have a activity with a Listview and a adapter attached to it. I have a class which syncs data and hold it. (I think we should not care about from where data is coming) and it runs on a different thread. Now I want to know the clean way to update adapter but We should not call any function of activity from that class as it runs on different thread.
One way I know is to create handler in activity and pass it to other class and use it from there. But I want to know if activity is in background then activity's function can be called by UI thread or only when activity come in foreground.
I do not want to miss any update and want to update activity when it is in foreground.

If you want to update your listView from another class you can have a few ways to do that.
Send broadcastIntent from your worker class and add BroadcastReceiver to your activity and when you receive the right message, update your listview.
Second way is to create private or public class in your Activity which extends AsyncTask and in your doInBackground() do your work and in onPostExecute(result) update your listview.
Third way which I can imagine, but I don't think it's the best way create a static method is your activity which you can use from any other class for updatiogn your UI.
The best thing which you can use here at least in my opinion is AsyncTask.

this code will do what you want:
runOnUiThread(new Runnable() {
#Override
public void run() {
//your actions
}
});

We should not call any function of activity from that class as it runs on different thread.
That's wrong. (in java an object is not running in a thread. What you can say is that a method is running in the thread from which the method was called)
In Androïd (and in most UI frameworks) the rule is this:
You can only call a method updating UI from the UI thread.
If you have some code running on a thread (not the ui thread) and if that code need to update the UI : you can use the Handler of the UI-thread to post UI update code to the UI-thread. If the activity is not in the foreground when you post something to update it's UI : nevermind! the code you just post will be executed at some point in the future.

You should use AsyncTask, take a look at http://developer.android.com/reference/android/os/AsyncTask.html

Android progressbar thread exception

Question arising from my first attempt at using an Async object.
I have a main activity in which some TextViews have been created programmatically and added to a LinearLayout. Also a button, when this is clicked, an AsyncTask object is instantiated and results are obtained in the doInBackGround method. How should the result strings be transferred to the TextViews?
a) by calling the SetText methods of these TextViews from the onPostExecute method,
b) using intents and an onActivityResult method in the main activity
c) some other way (a clue would be nice!)
Thanks!

I would go for the AsyncTask option. I'm guessing that as you already have one in place, the obtaining results part that happens when you click the button takes time, so it's good design to have that in the doInBackground method of the AsyncTask.
Then you can call each TextView's setText(...) method in the onPostExecute method in your AsyncTask. Or, it's more suitable, you can update each view as you get the result by using the publishProgress(...) and onProgressUpdate(...) methods (see the AsyncTask documentation) during the background calculations, instead of having to wait until the end.
Just bear in mind that you can only call setText(...) from the onPreExecute, onProgressUpdate and onPostExecute methods, as (at least it seems this way from your explanation) the views have been created on the UI thread, so they can only be modified from that same thread, which those methods run on.

When using an AsyncTask, you can use the doInBackground method for processing, and the onPostExecute to update any UI changes. So, if you need to use an AsyncTask, I'd go for option A.

Make the TextViews private and define them in doInBackground, then you can just call the setText method in onPostExecute or as the last thing in doInBackground, but i would recommend onPostExecute.

Problems with AsyncTask and updating UI with ProgressUpdate and Listeners

I am getting a "CalledFromWrongThreadException" error when I try to update a TextView (via a listener) from an AsyncTask onProgressUpdate.
If I try to update the same TextView from onPostExecute everything works.
I have been testing using code based on
https://github.com/commonsguy/cw-android/tree/master/Service/WeatherAPI
(with a small mod that does an onProgressUpdate in the doInBackgroundMethod, and adds the onProgressUpdate override)
Any suggestion to fixes would be most appreciated.

Are you calling onProgressUpdate() from your code? You shouldn't do it. Use publishProgress() method.

onProgressUpdate doesn't run on UI thread, so you can't access views from this method. If you want to update progress, you should find a way to synchronize your AsyncTask with your activity. A way that I'm using is to create an interface with methods like onBegin, onUpdate and onFinish. You should implement this interface in your main activity class. Then you should have an instance of your activity inside your AsyncTask. In the onProgressUpdate method you just call the onUpdate method in your activity and update the layout. Hope I've explained it clear enough.