Sort an ArrayList based on Integer

Question

When i am fetching data into ListView, getting data in a same sequence, but what if i want to sort data based on MemberID, But i want to show recent on top

public class AppointmentsActivity extends Activity {

    ...
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        ....
        adapter = new MembersAdapter (MembersActivity.this, R.layout.adapter_members, membersArrayList);

        listView.setAdapter(adapter);

    }

    ........
}

follow this link i think you can do this with member id : http://stackoverflow.com/questions/15149994/android-how-to-sort-data-for-listview — Paul, Jul 17 '15 at 07:29
I think you can find the answer here http://stackoverflow.com/questions/18441846/how-to-sort-an-arraylist-in-java — BNK, Jul 17 '15 at 07:35
possible duplicate of [Java Comparator class to sort arrays](http://stackoverflow.com/questions/5393254/java-comparator-class-to-sort-arrays) — user902383, Jul 17 '15 at 08:05

score 2 · Answer 1 · answered Jul 17 '15 at 07:41

Use Collections.sort() for sort ArrayList, there is sample:

Collections.sort(membersArrayList, new Comparator<Member>(){
    public int compare(Member m1, Member m2) {
        if (m1.getMemberID() == m2.getMemberID()) {
            return 0;
        } else if (m1.getMemberID() > m2.getMemberID()) {
            return 1;
        } else {
            return -1;
        }
    }
});

everyman · Answer 2 · 2015-07-17T07:48:40.010

1

This should work:

Collections.sort(membersArrayList, new Comparator<Member>(){
    public int compare(Member m1, Member m2) {
        return m1.getMemberID() - m2.getMemberID(); // sort order
    }
});

Note: You should name the class Members in singular, since it is a representation of one Member.

EDIT: Sort order depends on how you set http://developer.android.com/reference/android/widget/AbsListView.html#setStackFromBottom(boolean)

When stack from bottom is set to true, the list fills its content starting from the bottom of the view.

edited Jul 17 '15 at 07:48

answered Jul 17 '15 at 07:32

everyman

3,377
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the sorting is required in descending order, so you can put m2.. - m1 – anish Jul 17 '15 at 07:36
@anish yes, it depends on how http://developer.android.com/reference/android/widget/AbsListView.html#setStackFromBottom(boolean) is set – everyman Jul 17 '15 at 07:39

score 1 · Accepted Answer · answered Jul 17 '15 at 07:43

1

You might use lambda expression if you are developing in Java 8:

Collections.sort(membersArrayList, 
     (m1, m2) -> (int) (m2.getMemberID() - m1.getMemberID()));

answered Jul 17 '15 at 07:43

PythaLye

314
1
8

Sort an ArrayList based on Integer

3 Answers3