How to sort ArrayList<Object> in Ascending order android

Question

I have a requirement to sort ArrayList<Object>(Custom objects) in Ascending order based upon name. For that purpose I am using comparator method as like

My ArrayList :

ArrayList<Model> modelList = new ArrayList<Model>();

Code I am using:

   Comparator<Model> comparator = new Comparator<Model>() {
            @Override
            public int compare(CarsModel lhs, CarsModel rhs) {

                String  left = lhs.getName();
                String right = rhs.getName();

                return left.compareTo(right);

            }
        };

   ArrayList<Model> sortedModel = Collections.sort(modelList,comparator);

//While I try to fetch the sorted ArrayList, I am getting error message

I am completely stuck up and really dont know how to proceed further in order to get sorted list of ArrayList<Object>. Please help me with this. Any help and solutions would be helpful for me. I am posting my exact scenario for your reference. Thanks in advance.

Example:

ArrayList<Model> modelList = new ArrayList<Model>();
modelList.add(new Model("chandru"));
modelList.add(new Model("mani"));
modelList.add(new Model("vivek"));
modelList.add(new Model("david"));

Normal List:

for(Model mod : modelList){
  Log.i("names", mod.getName());
}

Output :

chandru
mani
vivek
david

My requirement after sorting to be like:

for(Model mod : modelList){
  Log.i("names", mod.getName());
}

Output :

chandru
david
mani
vivek

The output seems the same as the output in the requirement. So what exactly is the problem? — Mureinik
– Mureinik, Commented Aug 22, 2015 at 21:02

Sahar Avr · Accepted Answer · 2015-08-22 21:31:45Z

57

Your approach was right. Make your Comparator inner like in the following example (or you can create a new class instead):

ArrayList<Model> modelList = new ArrayList<>();
modelList.add(new Model("chandru"));
modelList.add(new Model("mani"));
modelList.add(new Model("vivek"));
modelList.add(new Model("david"));

Collections.sort(modelList, new Comparator<Model>() {
    @Override
    public int compare(Model lhs, Model rhs) {
        return lhs.getName().compareTo(rhs.getName());
    }
});

output:

chandru
david
mani
vivek

edited Aug 22, 2015 at 21:31

answered Aug 22, 2015 at 21:21

Sahar Avr

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3 Comments

Prasad Over a year ago

can you tell for descending order

Sahar Avr Over a year ago

@Prasad Change lhs and rhs positions.

hetsgandhi Over a year ago

Thank you so much for the solution, it works well and saved much of my time!

Akshay Katariya · Accepted Answer · 2018-04-02 14:51:25Z

7

 Collections.sort(actorsList, new Comparator<Actors>() {
      @Override
      public int compare(Actors lhs, Actors rhs) {
       return lhs.getName().compareTo(rhs.getName());
     }
    });

edited Apr 2, 2018 at 14:51

Akshay Katariya

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answered Nov 18, 2017 at 10:45

poonam sharma

711 silver badge1 bronze badge

1 Comment

poonam sharma Over a year ago

this code is work properly i will use this code....this code work in string & also integer value

Ahamadullah Saikat · Accepted Answer · 2019-12-14 17:53:44Z

1

Collections.sort(modelList, (lhs, rhs) -> lhs.getName().compareTo(rhs.getName()));

answered Dec 14, 2019 at 17:53

Ahamadullah Saikat

4,66445 silver badges41 bronze badges

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