How to stop AsyncTask being executed when switching between tabs while retaining previous

Question

Let me explain my problem .. say I have three tabs- FragmentTab1 / FragmentTab2 /FragmentTab3.

Now I have listview in FragmentTab1. Here I load data using AsyncTask

Answer 1

For this..first whenever you return back to the fragment again you have to check whether the Asynchtask already executed or not ..that means check with the loaded data ..if data null you have load data otherwise you no need to call Asynchtask againn..

In your fragment maintain one boolean flag..in onPostExecute set it to true..whenever you are moving one tab to another fragment will be removed and again added so in your onCreateView method if boolean flag is false execute asynchtask..ohterwise data is already loaded..

or maintain a one singleton class and set your loaded data again moving back to activity gat data from singleton class and if data is null load load it and set to the singleton class..

In your onDestroy() method of fragment stop the AsynchTask like this..

@Override
public void onDestroy() {
    super.onDestroy();
    if (applicationLoadTask != null) {
        if (!applicationLoadTask.isCancelled()) {
            applicationLoadTask.cancel(true);
        }
    }
}

Answer 2

You need to create a class that will store the data you just fetched from execution of AsyncTask. In onPostExecute() save the fetched data in this class's object, and in some other method(say A()) show the data from class's object to your views.

When you will navigate between tabs, check if that Object has data, If it has then call A() otherwise re-execute the Async-Task to fetch the data.

This seems more of design issue.

// cancelling asynck-task if it is running

 if(yourTask.getStatus() == AsyncTask.Running){
   yourTask.cancel();
}

Similarly you can check for other states of async-task as per your requirement. Refer : this