[RESOLVED] miss the boat on classes

[asucrews]

okay i trying to this to working in classes i have but i getting

Fatal error: Call to a member function show_naviBar() on a non-object in /home/content/j/m/c/jmcrews/html/animesite/index.php on line 6

Site
Click Here

Database Class:

 
<?
include("constants.php");

class MySQLDB
{
   var $connection;         //The MySQL database connection
   var $num_active_users;   //Number of active users viewing site
   var $num_active_guests;  //Number of active guests viewing site
   var $num_members;        //Number of signed-up users
   /* Note: call getNumMembers() to access $num_members! */

   /* Class constructor */
   function MySQLDB(){
      /* Make connection to database */
      $this->connection = mysql_connect(DB_SERVER, DB_USER, DB_PASS) or die(mysql_error());
      mysql_select_db(DB_NAME, $this->connection) or die(mysql_error());

  /**
   * Only query database to find out number of members
   * when getNumMembers() is called for the first time,
   * until then, default value set.
   */
  $this->num_members = -1;

  if(TRACK_VISITORS){
     /* Calculate number of users at site */
     $this->calcNumActiveUsers();

     /* Calculate number of guests at site */
     $this->calcNumActiveGuests();
  }
   }

   function buildTNB() {
	$q = "SELECT Title, Address FROM top_navibar";
	$result = mysql_query($q, $this->connection);
	$topnavibar = array();
	while ($row = mysql_fetch_assoc($result)) {
		$topnavibar[] = $row;
	}
   	return $topnavibar;
   } 

//removed all working functions

};
/* Create database connection */
$database = new MySQLDB;

?>

New class:

<?
class display {

  function display()
  {
    $this->display = new display();
  }

function show_naviBar() {
	echo "<div id='slatenav'>
                <ul>";
        foreach ($database->buildTNB() as $topnavibar) {
                    echo "<li><a href='" . htmlspecialchars($topnavibar['Address']) . "'> ". htmlspecialchars($topnavibar['Title']) . "</a></li>";
                    }
         echo "</ul> </div>";
}

}
?>

Code on index.php:

<?php 
  require_once "header.php"; 
?>
<div id="wrapper">
    <div id="header">This is the Header</div>
    <div id="navigation"><? $display->show_naviBar();?></div>
    <div id="leftcolumn"></div>
    <div id="rightcolumn"></div>
<?php
  require_once "footer.php";
?>

[laserlight]

It looks like you did not actually instantiate a display object named $display. Your display constructor looks wrong as it appears to be trying to use itself to do what it is supposed to do but with no base case (possibly resulting in infinite recursion, but I have not tested it).

[asucrews]

I change my class constructor, and now getting a new error! Could the error be in the function buildTNB()?

Fatal error: Call to a member function buildTNB() on a non-object in /home/content/j/m/c/jmcrews/html/animesite/include/display.php on line 7

changed code:

<?
class display {

function show_naviBar() {
	echo "<div id='slatenav'><br />
                 <ul>";
                 foreach ($database->buildTNB() as $topnavibar) {
                               echo "<li><a href='" . htmlspecialchars($topnavibar['Address']) . "'> ". htmlspecialchars($topnavibar['Title']) . "</a></li>";
                  }
         echo "</ul><br /></div>";
}

}

$display = new Display;
?>

[NogDog]

You need to pass a database object to your display class or otherwise give it access. One way:

display class:

<?php
class Display
{
   var $database;

   function Display($db)
   {
      $this->database = $db;
   }

   function show_naviBar()
   {
      echo "<div id='slatenav'><br />
                 <ul>";
      foreach ($database->buildTNB() as $topnavibar)
      {
         echo "<li><a href='".htmlspecialchars($topnavibar['Address'])."'> ".htmlspecialchars($topnavibar['Title'])."</a></li>";
      }
      echo "</ul><br /></div>";
   }

}

Usage:

$database = new MySQLDB();
$display = new Display($database);
$display->show_naviBar();

[asucrews]

that works really well!

Question i have if i put a function in display doesn't call the database class. well i not brake the display class?

is there a way i just use $display->show_naviBar() without the other parts

[laserlight]

asucrews wrote:

Question i have if i put a function in display doesn't call the database class. well i not brake the display class?

No, you won't. Incidentally, NogDog took his cue from your code example to use PHP4 object oriented programming syntax; you might want to consider using PHP5 object oriented programming syntax, especially the access levels (private, protected and public).

asucrews wrote:

is there a way i just use $display->show_naviBar() without the other parts

You definitely need the Display constructor to create a Display object, but other than that the choice of what member functions to call is up to you and your class design choices. Generally, functions should do one thing and do it well, and classes should model one thing and model it well.