Returning to an activity that was passed values in an intent

Question

I have an activity that was passed a value in an intent. I'll call it activity A. Activity A's job is to show a list. From A, I added a menu option to start activity B, whose job it is to hold the form to fill out a new list item. I use an intent to create activity B, which works just fine.

My issue is, when the user navigates back to activity A, I lose the value that was initially passed in via my intent.

[EDIT]: As I've come to learn, I didn't mean back in the previous sentence, I meant UP. See bottom of my post for more.

In activity A, I tried putting the following code, though savedinstanceState is null in onCreate when I navigate back from activity B.

To create activity B, I tried startActivity and startActivityForResult, and in activity B, I use the default back button on the top left to close the activity.

[EDIT]: As I've come to learn, I didn't mean back in the previous sentence, I meant UP. See bottom of my post for more.

How do I store the value of item ID in activity A when I need to come back from Activity B?

EDIT: Full code of Activity A:

public class ActivitiesActivity extends ActionBarActivity {

    public long item_id;

    public void onSaveInstanceState(Bundle savedInstanceState) {
        savedInstanceState.putLong(Global.itemIdKey, item_id);
        super.onSaveInstanceState(savedInstanceState);
    }

    @Override
    public void onRestoreInstanceState(Bundle savedInstanceState) {
        // Always call the superclass so it can restore the view hierarchy
        super.onRestoreInstanceState(savedInstanceState);

        item_id = savedInstanceState.getLong(Global.itemIdKey);

    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        if (savedInstanceState != null) {
            item_id = savedInstanceState.getLong(Global.itemIdKey);
        }
        else {
            item_id = getIntent().getLongExtra(Global.itemIdKey, item_id);
        }

        setContentView(R.layout.activity_activities);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

        ActivitiesActivityFragment frag =
                (ActivitiesActivityFragment) getFragmentManager().findFragmentById(R.id.activitiesFragment);

        frag.setSkillId(item_id);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_activities, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_addactivity)
        {

            Intent intent = new Intent(this, ActivityAdd.class);
            startActivityForResult(intent, 0);

            return true;
        }

        return super.onOptionsItemSelected(item);
    }

}

Full code of activity B - I use a fragment here that's empty. Right now I'm just using the native back button to navigate back up to activity A, but I've also tried calling finish() explicitly from a button.

public class ActivityAdd extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_activity_add);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    }

}

EDIT: Thanks for the answers below. Initially, I implemented shared preferences, though when reading further, I mistakenly said I was navigating BACK from activity B, which this was not the case - I was navigating UP from activity B, which behaves differently from BACK. UP was creating a new instance of Activity A rather than returning to the existing instance until I added

android:launchMode="singleTop"

in my activity declaration in my manifest. I found this in this answer.

Answer 1

If i am not wrong then you need to implement the onRestoreInstanceState() function in your activity

public void onRestoreInstanceState(Bundle savedInstanceState) {
 // Always call the superclass so it can restore the view hierarchy
 super.onRestoreInstanceState(savedInstanceState);

 // Restore state members from saved instance
 item_id = = savedInstanceState. getLong("ITEM_ID");
}

Reference Link

Answer 2

I recomend you to use SharedPreferences.

If I didn't missunderstood what you were trying to tell to us is you want to save the values of your ListView, it could be done very easy with SharedPerferences.

Store ListView data on SharedPreferences

SharedPreferences prefs=this.getSharedPreferences(0,Context.MODE_PRIVATE);
Editor edit=prefs.edit();
Set<String> SetString = new HashSet<String>();
SetString .addAll(ArrayListName);
edit.putStringSet("ListActivityA", SetString );
edit.commit();

Then when you go back to the Activity A you can retrieve the data doing this :

Set<String> SetString = prefs.getStringSet("ListActivityA", null);
List<String> ListA =new ArrayList<String>(SetString );

Other way to do it, could be done as Radix said, using the onRestoreInstanceState() function.

Test to add a finish() once you start the ActivityB as follows :

Intent intent = new Intent(this, ActivityAdd.class);
startActivityForResult(intent, 0);
finish();