Question

Basically, I have an arraylist declared like :

private ArrayList<HashMap<String, String>> songsList = 
                             new ArrayList<HashMap<String, String>>();

now what I want to do is that for each key I want to give two value fields. Can it be done??

Secondly I want to sort the key-value pair according to the value pair. So how can it be achieved?

Answer 1

That’s a lot of String objects. Have you considered encapsulating your data structure using an Object, rather than a complex collection of strings? For example, assuming your map key is a song:

public Song implements Comparable<Song> {
    private String title;
    private String artist;
    private String album;

    public Song(String title, String artist, String album) {
       ...
    }

    public int compareTo(Song s) {
        // sorting logic
    }

    ... // getters, setters, equals & hashCode
}

Then, create your list of songs:

List<Song> songs = new ArrayList<Song>();
songs.add(new Song("Dancing Queen", "Abba", "Arrival"); // I had to find this on Wikipedia
...

Then sort them:

Collections.sort(songs);