How to add new elements to an array?

Question

I have the following code:

String[] where;
where.append(ContactsContract.Contacts.HAS_PHONE_NUMBER + \"=1\");
where.append(ContactsContract.Contacts.IN_VISIB         


        

Answer 1

You need to use a Collection List. You cannot re-dimension an array.

Answer 2

There is no method append() on arrays. Instead as already suggested a List object can service the need for dynamically inserting elements eg.

List<String> where = new ArrayList<String>();
where.add(ContactsContract.Contacts.HAS_PHONE_NUMBER + "=1");
where.add(ContactsContract.Contacts.IN_VISIBLE_GROUP + "=1");

Or if you are really keen to use an array:

String[] where = new String[]{
    ContactsContract.Contacts.HAS_PHONE_NUMBER + "=1",
    ContactsContract.Contacts.IN_VISIBLE_GROUP + "=1"
};

but then this is a fixed size and no elements can be added.

Answer 3

I'm not that experienced in Java but I have always been told that arrays are static structures that have a predefined size. You have to use an ArrayList or a Vector or any other dynamic structure.

Answer 4

You can simply do this:

System.arraycopy(initialArray, 0, newArray, 0, initialArray.length);

Answer 5

Apache Commons Lang has

T[] t = ArrayUtils.add( initialArray, newitem );

it returns a new array, but if you're really working with arrays for some reason, this may be the ideal way to do this.

Answer 6

There is another option which i haven't seen here and which doesn't involve "complex" Objects or Collections.

String[] array1 = new String[]{"one", "two"};
String[] array2 = new String[]{"three"};
String[] array = new String[array1.length + array2.length];
System.arraycopy(array1, 0, array, 0, array1.length);
System.arraycopy(array2, 0, array, array1.length, array2.length);