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 listed way it takes time and not giving flow less output as I need.

My EditText contains

final EditText txtSearchCity = (EditText) findViewById(R.id.edtCity);
        txtSearchCity.addTextChangedListener(new TextWatcher() {
            @Override
            public void afterTextChanged(Editable s) {
            }

            @Override
            public void beforeTextChanged(CharSequence s, int start, int count,
                    int after) {
            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before,
                    int count) {
                aCountryIDTemp.clear();
                aCityStateTemp.clear();

                for (int i = 0; i < aCountryID.size(); i++) {
                    if (aCityState
                            .get(i)
                            .toLowerCase()
                            .contains(
                                    txtSearchCity.getText().toString()
                                            .toLowerCase())) {
                        aCountryIDTemp.add(aCountryID.get(i));
                        aCityStateTemp.add(aCityState.get(i));
                    }
                }

                BindList();
            }
        });
    }

BindList() method is setting the arraylist aCityStateTemp to adapter. Any Other way to Search and Create new ArrayList dynamically.

Answer 1

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.