CODEWITHSUNDEEP
javaandroidarraylist
Joffrey B.
Joffrey B.

Reputation: 7

Remove duplicate from custom ArrayList by parameter

I'm facing a problem that I don't arrive to resolve:

I read an ArrayList from the phone:

ArrayList<Game> gameResult = writeRead.getArrayList(this);

I put the object gamer from each game in a new ArrayList:

ArrayList<Gamer> gamerList = new ArrayList<>();
for (int i = 0; i < gameResult.size(); i++) {
    gamerList.add(gameResult.get(i).getWinnerGamer());
}

now, what I would like is to:

It's about a leaderboard activity with a custom ArrayList, but I don't arrive to do it.

All my code:

private void setGamerList() {

    ArrayList<Game> gameResult = writeRead.getArrayList(this);
    ArrayList<Gamer> gamerList = new ArrayList<>();
    ArrayList<Gamer> gamerNoDuplicate = new ArrayList<>();

    if (gameResult != null) {

        for (int i = 0; i < gameResult.size(); i++) {
            gamerList.add(gameResult.get(i).getWinnerGamer());
        }
    }

    Log.i(TAG, "--------------------------------");

    Collections.sort(mGamerList, (o1, o2) ->
        o2.getLeaderboardScore().compareTo(o1.getLeaderboardScore()));
}

Upvotes: 0

Views: 87

Answers (4)

Joffrey B.
Joffrey B.

Reputation: 7

Finally i did it like this :

and it work perfectly Thanks !

if (gameResult != null) {


        for (int i = 0; i < gameResult.size(); i++) {
            gamerList.add(gameResult.get(i).getWinnerGamer());
        }

        /* --------- */


        for (int i = 0; i < gamerList.size(); i++) {
            Gamer gamer = gamerList.get(i);
            gamer.setLeaderboardScore(1);
            boolean isInArray = false;

            if (!gamerNoDuplicate.isEmpty()) {
                for (int j = 0; j < gamerNoDuplicate.size(); j++) {
                    if (gamer.getName().equals(gamerNoDuplicate.get(j).getName())) {
                        gamerNoDuplicate.get(j).addLeaderscorePoint();
                        isInArray = true;
                    }
                }

                if (!isInArray) {
                    gamerNoDuplicate.add(gamer);
                }

            } else gamerNoDuplicate.add(gamer);
        }
    }

Upvotes: 0

Vladyslav Diachenko
Vladyslav Diachenko

Reputation: 785

writeRead.getArrayList(this).stream()
            .map(Game::getWinnerGamer)
            .collect(Collectors.groupingBy(Gamer::getName, Collectors.summingInt(Gamer::getLeaderboardScore)))
            .entrySet()
            .stream()
            .sorted(Comparator.comparing(Map.Entry<String, Integer>::getValue).reversed())
            .map(entry -> new Gamer(entry.getKey(), entry.getValue()))
            .collect(Collectors.toList());

Steps:

  1. extract winner
  2. group winners by name and sum their scores. As result you will get Map
  3. get entrySet of this Map
  4. open stream on this entySet
  5. sort by scores in DESC direction
  6. map entry to Gamer (create new gamer instance for each entry)
  7. collect to list

My answer based on assumption that you have such structure :

class Game {
    private Gamer winnerGamer;
    // getter & setter
}

class Gamer {
    private String name;
    private Integer leaderboardScore;
    // getters & setters && AllArgsContructor
}

BTW: if you override equals and hash code in class Gamer you can avoid Gamer recreation with this:

writeRead.getArrayList(this).stream()
            .map(Game::getWinnerGamer)
            .collect(Collectors.groupingBy(Function.identity(), Collectors.summingInt(Gamer::getLeaderboardScore)))
            .entrySet()
            .stream()
            .sorted(Comparator.comparing(Map.Entry<Gamer, Integer>::getValue).reversed())
            .map(Map.Entry::getKey)
            .collect(Collectors.toList());

Upvotes: 0

user8553611
user8553611

Reputation:

you can use Set Instead of ArrayList for unique value.

override HashCode and Equal Method.

Set<Gamer> gamerNoDuplicate=new HashSet();
if (gameResult != null) {
    for (int i = 0; i < gameResult.size(); i++) {
        if(gamerNoDuplicate.contains(gameResult.get(i).getWinnerGamer()){
            Gamer alreadyExist = gamerNoDuplicate.indexOf(gameResult.get(i).getWinnerGamer());
            alreadyExist.setLeaderPoints(alreadyExist.getLeaderPoints()+ gameResult.get(i).getWinnerGamer().getLeaderPoints());
        }else{
            gamerNoDuplicate.add(gameResult.get(i).getWinnerGamer());
        }
    }
}

Upvotes: 0

Rajen Raiyarela
Rajen Raiyarela

Reputation: 5636

Override equals and hashCode methods of your Gamer object class.

Then before adding object to ArrayList, check Arraylist.contains(), if yes then you can either call ArrayList.indexOf() method to get that object instance in ArrayList, increment the value of LeaderPoints and call ArrayList.set() to set back the instance at the same position.

Upvotes: 1

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