ArrayList Sorting in android.

Hello Friends, Today i am going to post use of Collection class in android for manipulate data Like Sorting.

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collections;

import java.util.Comparator;

import android.app.Activity;

import android.os.Bundle;

public class TestActivity extends Activity {

      /** Called when the activity is first created. */

      @Override

      public void onCreate(Bundle savedInstanceState) {

            super.onCreate(savedInstanceState);

            setContentView(R.layout.main);

            ArrayList<String> ar_hb = new ArrayList<String>();

            //Add elements to Arraylist

            ar_hb.add("Hasmukh");

            ar_hb.add("Bhadani");

            ar_hb.add("Samir");

            ar_hb.add("BJgroup");

            //sorting function

            Collections.sort(ar_hb);

            //display elements of ArrayList

            System.out.println("ArrayList elements after sorting in ascending order : ");

            System.out.println(Arrays.toString(ar_hb.toArray()));

            System.out.println("ArrayList elements Comparing - ignorecase");

            IgnoreCaseComparator icc = new IgnoreCaseComparator();

            java.util.Collections.sort(ar_hb,icc);

            Collections.sort(ar_hb);

            System.out.println(Arrays.toString(ar_hb.toArray()));

            System.out.println("Reversing the ArrayList");

            Collections.sort(ar_hb, Collections.reverseOrder());

            System.out.println(Arrays.toString(ar_hb.toArray()));

      }

      class IgnoreCaseComparator implements Comparator<String>

      {

            public int compare(String strA, String strB) {

                  return strA.compareToIgnoreCase(strB);

            }

      }

}

here is the another example:

suppose we have array list of User

User class have following params

param : 

 uid

 name

 address 

suppose ArrayList<User> users  has many values and we want it to sory by name then use following code.

Collections.sort(users, new Comparator<User>() {

        @Override

        public int compare(User u1, User u2) {

            return u1.name.compareToIgnoreCase(u2.name);           

        }

    });

above code will sort users array by name.

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