Array, ArrayList
-can change size one created? no, yes
-is a class? no, yes
-use methods to access and modify element? no, yes
-what can it store? primitive and objects, only objects
ArrayList
import java.util.*;
public class ArrayListExample {
public static void main(String args[]) {
/*Creation of ArrayList: I'm going to add String
*elements so I made it of string type */
ArrayList<String> obj = new ArrayList<String>();
/*This is how elements should be added to the array list*/
obj.add("Ajeet");
obj.add("Harry");
obj.add("Chaitanya");
obj.add("Steve");
obj.add("Anuj");
/* Displaying array list elements */
System.out.println("Currently the array list has following elements:"+obj);
/*Add element at the given index*/
obj.add(0, "Rahul");
obj.add(1, "Justin");
/*Remove elements from array list like this*/
obj.remove("Chaitanya");
obj.remove("Harry");
System.out.println("Current array list is:"+obj);
/*Remove element from the given index*/
obj.remove(1);
System.out.println("Current array list is:"+obj);
}
}
NumberActivity.java
/.../
package com.example.android.miwok;
public class NumbersActivity extends AppCompactActivity {
@Override
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_numbers);
// Create on array of words
ArrayList<String> words = new ArrayList<String>();
words.add("one");
words.add("two");
words.add("three");
words.add("four");
words.add("five");
words.add("six");
words.add("seven");
words.add("eight");
words.add("nine");
words.add("ten");
Log.v("NumbersActivity","Word at index 0: " + words.get(0));
Log.v("NumbersActivity","Word at index 1: " + words.get(1));
}
}