Fetching a large number of contacts

Question

I'm trying to fetch all the Phone numbers and Emails in Android.by using this code.

enter code here 

            String KEY_NAME = "Name";
            String KEY_NO   = "No";

    String selection = ContactsContract.CommonDataKinds.Phone.IN_VISIBLE_GROUP + " = 1";
    String sortOrder = ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME + " COLLATE LOCALIZED ASC";


    String data="";
    String name="";
    ContactEntry contactObj;
    String id;

    List<String> temp = new ArrayList<String>();

    final String[] projection = new String[]{ContactsContract.Contacts._ID , ContactsContract.Contacts.DISPLAY_NAME , ContactsContract.Contacts.HAS_PHONE_NUMBER};

    final String[] email_projection = new String[] {ContactsContract.CommonDataKinds.Email.DATA , ContactsContract.CommonDataKinds.Email.TYPE};

    final String[] phone_projection = new String[] {ContactsContract.CommonDataKinds.Phone.NUMBER, ContactsContract.CommonDataKinds.Phone.TYPE};

    ContentResolver cr = context.getContentResolver();
    Cursor cur = cr.query(ContactsContract.Contacts.CONTENT_URI , projection , selection , null , sortOrder);

    if(cur.getCount()>0){

        while(cur.moveToNext()){

             id = cur.getString(cur.getColumnIndex(ContactsContract.Contacts._ID));
             name = cur.getString(cur.getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME));

            if (Integer.parseInt(cur.getString(cur.getColumnIndex(ContactsContract.Contacts.HAS_PHONE_NUMBER))) > 0) {

                // get the phone number
                Cursor pCur = cr.query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI , phone_projection , 
                                        ContactsContract.CommonDataKinds.Phone.CONTACT_ID +" = ?",new String[]{id}, null);

                while (pCur.moveToNext()){

                         data =  pCur.getString(pCur.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));

                        if(!temp.contains(data) && !data.equals(null)){

                        }
                } 
                    pCur.close();
            }

           Cursor emailCur = cr.query(ContactsContract.CommonDataKinds.Email.CONTENT_URI, email_projection,
                                        ContactsContract.CommonDataKinds.Email.CONTACT_ID + " = ?",  new String[]{id}, null); 

           while (emailCur.moveToNext()){ 


                data = emailCur.getString(emailCur.getColumnIndex(ContactsContract.CommonDataKinds.Email.DATA));

                if(!temp.contains(data) && !data.equals(null)){             

                }
            } 
            emailCur.close();

        }

    }

This code is working fine. but for the large number number of contacts let's say 5000 contacts then it blocks the UI thread.how to create a ListAdapter for displaying all these contacts.If i fetch all the contacts in background user will see the empty list for a long time.please suggest some solution

Answer 1

I had very similar problem some time ago even with significantly lower number of contacts.

I needed to populate all contacts in list view and allow the user to select from them. Initially I was loading all the contact information in the list view. However this required really a lot of queries, which is what actually is slow.

So I changed my design: I selected only the Contact name and the Contact id and recorded it in an object. Afterwards when the user of my app selected any contact I loaded only his data. This turned to be drastically faster (as expected). And in my case it worked perfectly, because I was querying a lot of information which I actually never needed (that is phone numbers and emails of all not-selected contacts).

Hopefully you will be able to redesign your app in similar way. However if you need to display the contents of the data variable in the listview right away, you really might turn to need lazy-loading list view with adapter (lets just hope it will perform smoothly even on fast scroll).