ArrayList

Java ArrayList

 

// Creating an empty array list
ArrayList list = new ArrayList();

// Adding items to arrayList
list.add("Item1");
list.add("Item2");

// Display the contents of the array list
System.out.println("The arraylist contains the following elements: " + list);

// Checking index of an item
int pos = list.indexOf("Item2");
System.out.println("The index of Item2 is: " + pos);

// Checking if array list is empty
boolean check = list.isEmpty();
System.out.println("Checking if the arraylist is empty: " + check);

// Getting the size of the list
int size = list.size();
System.out.println("The size of the list is: " + size);

// Checking if an element is included to the list
boolean element = list.contains("Item5");
System.out.println("Checking if the arraylist contains the object Item5: "+ element);

// Getting the element in a specific position
String item = list.get(0);
System.out.println("The item is the index 0 is: " + item);

// Retrieve elements from the arraylist

// 1st way: loop using index and size list
System.out.println("Retrieving items with loop using index and size list");
for (int i = 0; i < list.size(); i++) {
    System.out.println("Index: " + i + " - Item: " + list.get(i));
}

// 2nd way:using foreach loop
System.out.println("Retrieving items using foreach loop");
for (String str : list) {
    System.out.println("Item is: " + str);
}

// 3rd way:using iterator
// hasNext(): returns true if there are more elements
// next(): returns the next element
System.out.println("Retrieving items using iterator");
for (Iterator it = list.iterator(); it.hasNext();) {
    System.out.println("Item is: " + it.next());
}

// Replacing an element
list.set(1, "NewItem");
System.out.println("The arraylist after the replacement is: " + list);

// Removing items
// removing the item in index 0
list.remove(0);

// removing the first occurrence of item "Item3"
list.remove("Item3");

System.out.println("The final contents of the arraylist are: " + list);

// Converting ArrayList to Array
String[] simpleArray = list.toArray(new String[list.size()]);
System.out.println("The array created after the conversion of our arraylist is: "+ Arrays.toString(simpleArray));

 

 

http://examples.javacodegeeks.com/core-java/util/arraylist/arraylist-in-java-example-how-to-use-arraylist/

By bm on May 26, 2015 | Android, ArrayList | A comment?

Android Copy ArrayList variable to another

newObject = new ArrayList(oldObject);

OR

newObject = (ArrayList)oldObject.clone();

 

By bm on | Android, ArrayList | A comment?