CODEWITHSUNDEEP
androidsortingcomparator
sarahsdev
sarahsdev

Reputation: 177

android, Comparator sort wrong

I have a Comparator to sort by 3 values:

  1. ORDER_BY_Points
  2. ORDER_BY_Gdif // goals difference
  3. ORDER_BY_Goals

First I get a array from a json string. I send the array to StandingsSort.ORDER_BY_RULES

Arrays.sort(addressArray, StandingsSort.ORDER_BY_RULES);

Here is my code:

static final Comparator<Standings> ORDER_BY_Points = new Comparator<Standings>() {
    public int compare(Standings a1, Standings a2) {
        return a1.points.compareTo(a2.points);
    }
};
static final Comparator<Standings> ORDER_BY_Gdif = new Comparator<Standings>() {
    public int compare(Standings a1, Standings a2) {
        return a1.Gdif.compareTo(a2.Gdif);
    }
};
static final Comparator<Standings> ORDER_BY_Goals = new Comparator<Standings>() {
    public int compare(Standings a1, Standings a2) {
        return a1.goalsP.compareTo(a2.goalsP);
    }
};

static final Comparator<Standings> ORDER_BY_RULES = new Comparator<Standings>() {
    public int compare(Standings a1, Standings a2) {
        int i = ORDER_BY_Points.compare(a1,a2);
        if(i == 0){
            i = ORDER_BY_Gdif.compare(a1,a2);
            if(i == 0){
                i = ORDER_BY_Goals.compare(a1,a2);
            }
        }
        return i;
    }
};

class Standings {

    String teamName;
    String goalsP;
    String goalsM;
    String Gdif;
    String points;
    @Override
    public String toString() {
        return "" + teamName + ","  + goalsP + ":" + goalsM + "," + Gdif + "," + points + "";
    }
    public Standings(String teamName, String goalsP,
                String goalsM, String Gdif, String points) {
        super();
        this.teamName = teamName;
        this.goalsP = goalsP;
        this.goalsM = goalsM;
        this.Gdif = Gdif;
        this.points = points;
    }
}

But the result is not OK! Here is the result

Name, Goals, GDif, Points
Team,11:9,2,10
Team,5:3,2,10
Team,9:2,7,11
Team,0:6,-6,2
Team,3:9,-6,2
Team,6:9,-3,3
Team,8:13,-5,3
Team,8:9,-1,5
Team,8:11,-3,5
Team,8:7,1,5

Why does the Comparator sort wrong?

Upvotes: 0

Views: 156

Answers (1)

Code-Apprentice
Code-Apprentice

Reputation: 83557

Since you store the points as Strings, "10" comes before "2", "3", and "5". If you want to compare these in order by the numerical value, you need to convert them into ints first.

Similarly, Gdif and Goals are compared as Strings which is probably not what you want.

Upvotes: 2

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