How to Efficiently Load 1000 Data in Lists

I have 1000 clients to load in a custom listview from the server. But I need more time to fill the list. I am using the search option to find customers, so I need to download and display all customers in one shot. I cannot display it from the local database because I can edit the details of an item by clicking in the list and store it on the server. Can anyone help me upload to a custom list efficiently?

  public class CustomersAdapter extends ArrayAdapter<Item> {

private ArrayList<Item> items;
private LayoutInflater vi;
private Item objItem;

ViewHolderSectionName holderSection;
ViewHolderName holderName;

public CustomersAdapter(Context context, ArrayList<Item> items) {
    super(context, 0, items);

    this.items = items;
    vi = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

@Override
public View getView(final int position, View convertView, ViewGroup parent) {

    objItem = items.get(position);

    if (objItem.isSectionItem()) {
        SectionHeadersModel si = (SectionHeadersModel) objItem;

        if (convertView == null
                || !convertView.getTag().equals(holderSection)) {
            convertView = vi.inflate(R.layout.alphabet_separator, null);

            holderSection = new ViewHolderSectionName();
            convertView.setTag(holderSection);
        } else {
            holderSection = (ViewHolderSectionName) convertView.getTag();
        }

        holderSection.section = (TextView) convertView
                .findViewById(R.id.alphabet_letter);
        holderSection.section.setText(si.getSectionString().toString());

    } else {
        CustomerListViewModel ei = (CustomerListViewModel) objItem;

        if (convertView == null || !convertView.getTag().equals(holderName)) {
            convertView = vi.inflate(R.layout.customer_list_item, null);

            holderName = new ViewHolderName();
            convertView.setTag(holderName);
        } else {
            holderName = (ViewHolderName) convertView.getTag();
        }

        holderName.name = (TextView) convertView
                .findViewById(R.id.CustomerName);
        holderName.email = (TextView) convertView
                .findViewById(R.id.CustomerEmail);
        holderName.phone = (TextView) convertView
                .findViewById(R.id.CustomerPhone);

        if (holderName.name != null)
            holderName.name.setText(ei.getCustomerName());
        holderName.email.setText(ei.getCustomerEmail());
        holderName.phone.setText(ei.getCustomerPhone());
    }
    return convertView;
}

public static class ViewHolderName {
    public TextView name;
    public TextView email;
    public TextView phone;
}

public static class ViewHolderSectionName {
    public TextView section;
}

      

        
        
        
      

    

}