Question

I start AsyncTask and put Context in constructor of the Task.

On onPostExecute I want to know is my activity active now and was not recreated. How it’s better to do?

For this I can:

• create randomNumber in onCreate Activity and then put it in Application class;

• onPause/onDestroy set randomNumber to 0 and in onResume restore randomNumber;

• in onPreExecute() get randomNumber and in onPostExecute compare randomNumber with Application randomNumber.

May be I can use Context for making decision … ?

Answer 1

There are many approaches to check if the activity is still there.

I usually create a SkeletonActivity with the following structure:

public class SkeletonActivity extends FragmentActivity {
    private boolean paused = false;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        paused = false;
    }
    @Override
    public void onPause() {
        super.onPause();
        paused = true;
    }
    @Override
    public void onResume() {
        super.onResume();
        paused = false;
    }
    @Override
    public void onStart() {
        super.onStart();
        paused = false;
    }
    public boolean isPaused() {
        return paused;
    }
}

Now let all your activities extend this SkeletonActivity. Finally change this Base Class to change the paused flag as you wish (For example update it in onDestroy()

---

Another way would be to have a Context instance inside your SkeletonActivity:

public class SkeletonActivity extends FragmentActivity {
    private Context mContext;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mContext = this;
    }
    @Override
    protected void onDestroy() {
        mContext = null;
        super.onDestroy();
    }
    public boolean isPaused() {
        return mContext==null;
    }
}