CODEWITHSUNDEEP
javaandroidmethodsarraylist
user4814802
user4814802

Reputation:

When this method ends, the ArrayList is emptied

I have this method which is used to store a list of Applications. 

public void storeApplication(String name, String item){
    peopleAttending.add(new Application(name, item));
}

It does what it's supposed to do, however when the method finishes, the data contained within the ArrayList also gets destroyed.

I've declared and instantiated the ArrayList globally:

private ArrayList<Application> peopleAttending = new ArrayList<>();

So I would have thought that once the object is added to the ArrayList, it would be safely stored until the program terminates.

Any help would be greatly appreciated.

Class that calls storeApplication:

    public void saveBookingInfo(View view) {

        GuestsAttending sendApplication = new GuestsAttending();

        EditText applicantNameText = (EditText) findViewById(R.id.applicantNameTextField);
        EditText itemToBurnText = (EditText) findViewById(R.id.itemToBurnTextField);

        String appName = applicantNameText.getText().toString();
        String appItemToBurn = itemToBurnText.getText().toString();

        if (appItemToBurn.isEmpty() || appName.isEmpty()) {
            Toast.makeText(BookingScreen.this, "Please fill in all fields.", Toast.LENGTH_SHORT).show();
        }
        else {
            sendApplication.storeApplication(appName, appItemToBurn);
        }
    }

Edit - Entire class:

public class GuestsAttending extends Activity {

    private ArrayList<Application> peopleAttending = new ArrayList<>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_guests_attending);
    }

    public void storeApplication(String name, String item){
        peopleAttending.add(new Application(name, item));
    }
}

Upvotes: 0

Views: 95

Answers (3)

Saurabh Jhunjhunwala
Saurabh Jhunjhunwala

Reputation: 2922

try to modify your code, a bit.

  1. private ArrayList peopleAttending;
  2. have getters and setters
  3. before adding to list check if(peopleAttending==null) peopleAttending = new ArrayList<>();
  4. in the calling method, create and obj of GuestsAttending and then try getting the list using the getter.

As per your request, will elaborate my point:

in GuestsAttending you are using 

private ArrayList<Application> peopleAttending = new ArrayList<>();

I want you to break this line and have 

private ArrayList<Application> peopleAttending;

public ArrayList getPeopleAttending(){ 
    return peopleAttending;
}

public void setPeopleAttending(ArrayList<Application> peopleAttending){ 
    this.peopleAttending=peopleAttending;
}


public void storeApplication(String name, String item){
    if(peopleAttending==null) 
        peopleAttending = new ArrayList<>();

    peopleAttending.add(new Application(name, item));
}

Assuming you are going to use the peopleAttending list in saveBookingInfo class, you should use

ArrayList<Application> peopleAttendingLst = sendApplication.getPeopleAttending();

You should be able to get the objects in the list.

Upvotes: 0

Daniel S. Fowler
Daniel S. Fowler

Reputation: 2033

I would have thought that once the object is added to the ArrayList, it would be safely stored until the program terminates

Nope. Looking at the posted code saveBookingInfo instantiates GuestsAttending which declares peopleAttending. When saveBookingInfo completes GuestsAttending is destroyed hence peopleAttending is destroyed.

Declare peopleAttending in your first activity and use intents to pass around other screens. Don't forget to use onSaveInstanceState to deal with App closures by the OS.

Upvotes: 0

Melquiades
Melquiades

Reputation: 8598

Your GuestsAttending extends Activity class, hence DO NOT THIS:

GuestsAttending sendApplication = new GuestsAttending();  //remove this line

Let the system deal with creating activity.

I'm guessing saveBookingInfo() could also be a member of GuestsAttending activity, which get's wired eg. to a button.

Upvotes: 0

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