Question

In selected contact i am having duplicate values so that iam first taking copy of selected contact copy

    for(int q=0;q<selectedcontact.size();q++)
    {
        selectedcontactcopy.add(selectedcontact.get(q));
    }

and then Comparing two array list

    for(int r=0;r<selectedcontactcopy.size();r++)
        {
            for(int j=0;j<selectedcontact.size();j++)
            {
                if(r!=j && r<j)
                {

                    if(selectedcontactcopy.get(r).getLandLineNumber().toString().trim().equals(selectedcontact.get(j).getLandLineNumber().toString().trim()))
                    {
                    Log.i("hai",selectedcontact.get(j).getLandLineNumber().toString());
                    selectedcontact.remove(j);
                    j--;
                    }

                }
            }
        }

But the situation is that first duplication is avoided then the arraylist won’t compare the next consecutive values

Answer 1

This is a bad way of doing a uniqueness check. A better method is to make use of the functionality of java.util.Set – make sure your contacts implement Comparable and compare landline numbers, and then add them to the set and iterate over the set contents.

Set guarantees you uniqueness, and provides a far cleaner interface than nested for loops.