javaandroidarraylistcollections

What is the Simplest Way to Reverse an ArrayList?


What is the simplest way to reverse this ArrayList?

ArrayList<Integer> aList = new ArrayList<>();

//Add elements to ArrayList object
aList.add("1");
aList.add("2");
aList.add("3");
aList.add("4");
aList.add("5");

while (aList.listIterator().hasPrevious())
  Log.d("reverse", "" + aList.listIterator().previous());

Solution

  • Collections.reverse(aList);
    

    Example (Reference):

    ArrayList aList = new ArrayList();
    //Add elements to ArrayList object
    aList.add("1");
    aList.add("2");
    aList.add("3");
    aList.add("4");
    aList.add("5");
    Collections.reverse(aList);
    System.out.println("After Reverse Order, ArrayList Contains : " + aList);