ArrayList, passing strings to fragment Android

Question

I have a server, from which i get the values that i need(name, date, city, picture_url). To get them are in getValues class. I'm using Json. All the values are saved in an ArrayList called array. I would use them in multiple classes. I would like to call the array in FragmentB. This is the code for the ArrayList

private ArrayList<String> array;
`array = new ArrayList<String>();
 array.add(finalresult.getString("picture"));
 array.add(finalresult.getString("name")); 
 array.add(finalresult.getString("date"));
 array.add(finalresult.getString("city"));`

Then i thought i needed some kind of function, so it can be called, from other classes. I wanted to name the function, then arguments are numbers, so you can select which element you want, then you just return the object you wanted.

public ArrayList<String> getEvent(int pos)
    {
        return array.get(pos);
    }

But here i get an error:

Required: java.util.ArrayList <java.lang.String>
Found: java.lang.String

In Fragment, i want the specific element of the array, and save it in one string, so i can call it later.

Something like this:

    public class FragmentB extends android.support.v4.app.ListFragment{
        private GetEvents getEvents = new GetEvents();

        private String picture1, name1, city1, date1;


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


            picture1 = getEvents.getArray(0);
            name1 = getEvents.getArray(1);
            city1 = getEvents.getArray(2);
            date1 = getEvents.getArray(3);
       }
}

I know that this is wrong. What is the correct way to pass the elements, and then call them in the fragment?

Yes, because you have to change type of getEvent method from ArrayList<> to String.. like public String getEvent(int pos) { return array.get(pos); } — user370305
– user370305, Commented Mar 25, 2015 at 21:08

vinitius · Accepted Answer · 2015-03-25 21:14:27Z

3

Change

  public ArrayList<String> getEvent(int pos)
{
    return array.get(pos);
}

to:

 public String getEvent(int pos)
{
    return array.get(pos);
}

But I think you should consider passing info to your fragments via arguments

edited Mar 25, 2015 at 21:14

answered Mar 25, 2015 at 21:07

vinitius

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Comments

T.Gounelle · Accepted Answer · 2015-03-25 21:40:38Z

0

For the error, it is just that getEvent(int pos) should return a String and not a List<String>.

If (name, city, date, picture) is an object of your application model (I understand that these are used in several places), you may take advantage to create a simple pojo class to hold these infos, e.g.

public class Event {
    String name, city, url;
    Date date;
    // +constructor
    // +getters
}

Then you can store, pass as parameter, filter, sort Events and access properties with specific methods without ambiguity.

Actually storing values with different meaning in an array is bad practice: an array should contain objects of the same nature, e.g. a list of Event, a list of city, etc. Think of what will happen if the order in the array changes. Does it make sense to have city at position 0 and name at 1?

answered Mar 25, 2015 at 21:40

T.Gounelle

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3 Comments

WinterChilly Over a year ago

Thanks, I'll try it, will tell you how it goes.

WinterChilly Over a year ago

Thanks a lot. It works, and it is easier to use. But I have one more problem. I need public class FragmentB extends ActionBarActivity . It has no errors, but when i try to call it in an adapter ` case 1: FragmentB b = new FragmentB(); return b; , it says that i need android.support.v4.app.Fragment, which i can't implement because i need ActionBarActivity. Tried to import it, but it's not used, soo no effect. Any ideas?

T.Gounelle Over a year ago

If FragmentB extends ListFragment that extends Fragment there is no need to implement it yourself. There is not enough context. You should post another specific question.

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