Android : Search from Large Arraylist

Question

I have a recordset of about 29,000 records. My Screen contains EditText Box for Search Criteria and Listview containing all 29,000 records.

By searching with the lis

Answer 1

I would assume that you have passed aCityStateTemp to you Adapter as ArrayList while initializing the Adapter

Now after changing the contents of aCityStateTemp, you just need to call adapter.notifyDataSetChanged(). you don't need to set the aCityStateTemp to adapter as new ArrayList.

Answer 2

You can use HashSet or LinkedHashSet(keeps insertion order) for fast searching. With contains() method of that classes.

Answer 3

I would insist to use Lambdaj Library which is mostly used in such cases where you want to restrict loops for sorting and filtering Collections.

Here is a small example for using lambdaj for filtering ArrayList.

ArrayList<String> sortedArrayList = select(arrList, having(on(String.class),
                                                   Matchers.containsString("a");

This will return a complete filtered ArrayList with which you want to populate your ListView.

You can also filter Custom Classes - Java: What is the best way to filter a Collection?

UPDATE:

Above solution was case-sensitive so to work around you can add Multiple Matchers.

Like this you can add Multiple Matchers,

ArrayList<String> sortedArrayList = select(arrList, having(on(String.class),
   (Matchers.anyOf(Matchers.containsString("a"),Matchers.containsString("A")))));

UPDATE:

Even better way is to use filter(Matcher<?> matcher, T...array)

Here is how you can do that,

ArrayList<String> sortedArrayList = filter(Matchers.anyOf(
           Matchers.containsString("a"),Matchers.containsString("A")), arrList);

Also, if you are interested in using some of the methods/features of lambdaj, you can extract the source and get it working. I am adding the same for filter()

You can just download hamcrest-all-1.0.jar(63 kb) and add below code to get the filter() working

public static <T> List<T> filter(Matcher<?> matcher, Iterable<T> iterable) {
    if (iterable == null)
        return new LinkedList<T>();
    else{
        List<T> collected = new LinkedList<T>();
        Iterator<T> iterator = iterable.iterator();
        if (iterator == null)
            return collected;
        while (iterator.hasNext()) {
            T item = iterator.next();
            if (matcher.matches(item))
                collected.add(item);
        }
        return collected;
    }
}

So, you can just sort out the least from lambdaj source and integrate in your source.

Answer 4

You can store all data in a sqlite database and retrieve the searched item using like query.