Answer by Shrunottara Koppar for How to import contacts from phonebook to our application

            Intent intent = new Intent(Intent.ACTION_GET_CONTENT);            intent.setType(ContactsContract.CommonDataKinds.Phone.CONTENT_ITEM_TYPE);            startActivityForResult(intent, 1);

Use this piece of code under the button.setOnClick function you'll get the display of all the contacts in the phone book