ArrayList Data not properly transferring to Array in Java

Question

When I log out the sectionList there are 20 items; for some reason, all but the last item is being entered into the section Array. Can someone see whats wrong here?

UPDATE: I posted the entire class in question; it's relatively short. It is from an Android app.

public class ItemAdapter extends ArrayAdapter<ItemObject> implements
        SectionIndexer {

    private HashMap<String, Integer> alphaIndexer;
    private String[] sections;
    private LayoutInflater inflater;

    public ItemAdapter(Context context, ItemObject[] objects) {
        super(context, R.layout.item_row_layout, objects);

        inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        alphaIndexer = new HashMap<String, Integer>();
        int size = objects.length;

        for (int i = 0; i < size; i++) {

            ItemObject it = objects[i];
            String name = it.name;
            String s = name.substring(0, 1);
            s = s.toUpperCase();

            if (!alphaIndexer.containsKey(s)) {
                alphaIndexer.put(s, i);
            }
        }

        Set<String> sectionLetters = alphaIndexer.keySet();
        ArrayList<String> sectionList = new ArrayList<String>(sectionLetters);
        Collections.sort(sectionList);
        sections = new String[sectionList.size()];

        sections = sectionList.toArray(new String[sectionList.size()]);


    }

@KickingLettuce you can use ArrayList.toArray. Also, if you want ordered keys, use a TreeMap. — obataku
– obataku, Commented Aug 28, 2012 at 1:54

obataku · Accepted Answer · 2012-08-28 02:00:58Z

3

    for (int i = 0; i < sectionList.size(); i++) {
        sections[i] = sectionList.get(i);
    }

    for (int i = 0; i < sections.length - 1; i++) {
        sections[i] = sectionList.get(i);
    }

Why are you copying the array twice here? Also, why not use an Iterator? Actually, what you should really use is ArrayList.toArray to convert to String[], e.g.

sections = sectionList.toArray(new String[sectionList.size()]);

Additionally, you can have your keys sorted by using a TreeMap as opposed to a HashMap, merely by doing TreeMap.keySet...

The set's iterator returns the keys in ascending order.

edited Aug 28, 2012 at 2:00

answered Aug 28, 2012 at 1:53

obataku

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6 Comments

TheLettuceMaster Over a year ago

I apologize, I had the wrong code in that for loop. I have updated up top and added more.

obataku Over a year ago

@KickingLettuce why are you looping twice to copy the array?

obataku Over a year ago

@KickingLettuce where are you logging to determine it's one short?

TheLettuceMaster Over a year ago

Thank you, that did what I needed! I also am using the more efficient 'toArray' as well. Thanks again!

obataku Over a year ago

@KickingLettuce what about using TreeMap?

|

Bhesh Gurung · Accepted Answer · 2012-08-28 01:57:42Z

1

I think the reason behind that is the condition in the for loop i < sections.length - 1;. You are probably logging sections[i] only in the for loop.

answered Aug 28, 2012 at 1:57

Bhesh Gurung

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4 Comments

obataku Over a year ago

You must remove the nextElement definition to prevent an ArrayIndexOutOfBoundsException.

TheLettuceMaster Over a year ago

I have updated code; that part you saw in the last for loop was incorrectly left in.

Bhesh Gurung Over a year ago

@veer: Correct changed my answer.

Bhesh Gurung Over a year ago

@KickingLettuce: But the last for loop you just added doesn't make sense at all.

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