Question

I am pretty rusty on php, and am just learning how to use classes, and now something wierd is happening, which may just be how php works – I am not sure.

I have an array which is static to a class (Project), and what I want to do is fill the array as soon as the page is loaded (in index.php), and then use projects from it from it when populating data. But I also want to use the SAME project array in other php files (such as my ajax_show_timesheet.php).

When I try to access the array from another php file:

Project::$projectArray[key];

The array is empty. If I call

Project::createProjects();

again from within the other php file, it repopulates.

So why can’t I access the same static array from within various .php files?

Here is what I am doing:

CLASS PROJECT:

class Project
{

  public static $projectArray;

  public $projectID;

  public function __construct($projID=0){
    $this->projectID = $projID;

  }

  public static function createProjects(){

    $projectResult = mysql_query("SELECT * FROM $tblProjects");

    $numRows = mysql_numrows($projectResult); 
    $i = 0;

    while($i < $numRows){
      //for each project in the DB, add one to the array
      Project::$projectArray[mysql_result($projectResult, $i, "projectID")] 
             = new Project(mysql_result($projectResult, $i, "projectID"));

      $i++;
    }
  }
}

In index.php I fill initialize Project:

Project::createProjects();

In ajax_show_timesheet.php I do something like:

echo Project::$projectArray[key]->projectID

and I just get back nothing.

Any help on how to use static variables across multiple files would be great!

Answer 1

What happens when you do this?

public static function createProjects(){

    $projectResult = mysql_query("SELECT * FROM $tblProjects");

    $numRows = mysql_numrows($projectResult); 
    $i = 0;

    while($i < $numRows){
        //for each project in the DB, add one to the array
        Project::$projectArray[mysql_result($projectResult, $i, "projectID")] 
              = new Project(mysql_result($projectResult, $i, "projectID"));

        $i++;
    }
    var_dump(Project::$projectArray);
}

Because this suggests that you can’t initialize your static variable in the way that you are. It seems like you’re trying to use Project like a singleton, but that is not how a php singleton works.