CMD:staffonline(playerid, params[])
    {
        new string[125];
        for(new i = 0; i < MAX_PLAYERS; i++)
        {
            if(IsPlayerAdmin(i))
            {
                format(string, sizeof(string), "%s is currently an administrator.");
            }
        }
        SendClientMessage(playerid, WHITE, string);
        return 1;
    }

#define DIALOG_STAFF 1 // top of your script

CMD:staff(playerid, params[])
{
    new count, string[128];

    for(new i = 0; i < MAX_PLAYERS; i++)
    {
        if(!(1 <= PlayerInfo[i][pAdmin] <= 4)) continue;
        format(string, sizeof(string), "%s%i) %s[%i] (Level %i)\n", string, ++count, PlayerName(i), i, PlayerInfo[i][pAdmin]);
    }
    if(!count)
    {
        ShowPlayerDialog(playerid, DIALOG_STAFF, DIALOG_STYLE_MSGBOX, "Online Admins", "There are no admins online", "OK", "");
        return 1;
    }
    else
        ShowPlayerDialog(playerid, DIALOG_STAFF, DIALOG_STYLE_MSGBOX, "Online Admins", string, "OK", "");
    return true;
}