Android (Java) - 通过电子邮件查找联系人并预览(如果存在)

Question

现在我们有一个应用程序，我们（在权限后）查找联系人，如果存在，则显示他们的联系人卡片。 然而，查找似乎效率很低，它遍历所有人，似乎不对。 有没有更好的查询联系人数据库来仅查找具有我们需要的电子邮件地址的联系人？

当前代码如下（效率不高）：

public static void showCardIfPossible(String email, Context context) {
        Long contactId = lookupByEmail(email, context);
        if (contactId != null) {
            viewCardFor(context, contactId);
        }
    }
    public static Long lookupByEmail(String email, Context context) {
        Long contactId = null;
        ContentResolver cr = context.getContentResolver();
        Cursor cursor = cr.query(ContactsContract.Contacts.CONTENT_URI,
                null, null, null, null);
        if (cursor == null || cursor.getCount() == 0) {
            return null;
        }
        while (cursor.moveToNext())
        {
            String id = cursor.getString(cursor.getColumnIndex(ContactsContract.Contacts._ID));
            Cursor cur1 = cr.query(
                    ContactsContract.CommonDataKinds.Email.CONTENT_URI, null,
                    ContactsContract.CommonDataKinds.Email.CONTACT_ID + " = ?",
                    new String[]{id}, null);
            if (cur1 != null && cur1.getCount() > 0) {
                while (cur1.moveToNext()) {
                    //to get the contact names
                    String contactName=cur1.getString(cur1.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
                    String contactEmail = cur1.getString(cur1.getColumnIndex(ContactsContract.CommonDataKinds.Email.DATA));
                    if(email.equals(contactEmail) || email.equals(contactName)){
                        contactId = Long.valueOf(id);
                    }
                }
                cur1.close();
            }
        }
        cursor.close();
        return contactId;
    }
    public static void viewCardFor(Context context, long contactId) {
        Intent intent = new Intent(Intent.ACTION_VIEW);
        Uri uri = Uri.withAppendedPath(ContactsContract.Contacts.CONTENT_URI, String.valueOf(contactId));
        intent.setData(uri);
        context.startActivity(intent);
    }

Answer 1

是的，您可以直接在Email.CONTENT_URI上查询并使用选择来查找正确的联系人：

public static Long lookupByEmail(String email, Context context) {
    ContentResolver cr = context.getContentResolver();
    Long contactId = null;
    String[] projection = new String[] { Email.CONTACT_ID };
    String selection = Email.ADDRESS + "='" + email + "'";
    Cursor cur = cr.query(Email.CONTENT_URI, projection, selection, null, null);
    if (cur != null) {
       if (cur.moveToFirst()) {
          contactId = cur.getLong(0);      
       }
       cur.close();
    }
    return contactId;
}