我正在尝试在PHP的另一个scipt中使用public变量，但是我遇到了两个错误

Question

Config.php

 <?php 
    //Database Connection constants         
    define('DB_HOST' , 'localhost');
    define('DB_USER' , 'root');
    define('DB_PASS' , '');
    define('DB_NAME' , 'gallery_db');
?>

Database.php

<?php 
    require_once ("config.php");

     class Database {

        public $connection;

        function __construct() {

        $this->open_db_connection();
        } 
        public function open_db_connection () {

        $this->connection = mysqli_connect(DB_HOST,DB_USER,DB_PASS,DB_NAME);
        if(mysqli_connect_errno()){
            die("database connection failed badly" . mysqli_error());
        }        
        }        
    }

    // $database = new Database();
    $database = new Database();    

?>

init.php

 <?php       
     include "config.php";
     include "database.php";        
 ?>

admin_content.php

     <div id="page-wrapper">

                <div class="container-fluid">

                    <!-- Page Heading -->
                    <div class="row">
                        <div class="col-lg-12">
                            <h1 class="page-header">
                                Blank Page
                                <small>Subheading</small>
                            </h1>
                        <?php 


                            if($database->connection) // the line that the error is pointing to
                            {
                                echo "true";
                            }
                        ?>

                            <ol class="breadcrumb">
                                <li>
                                    <i class="fa fa-dashboard"></i>  <a href="index.html">Dashboard</a>
                                </li>
                                <li class="active">
                                    <i class="fa fa-file"></i> Blank Page
                                </li>
                            </ol>
                        </div>
                    </div>
                    <!-- /.row -->

                </div>
                <!-- /.container-fluid -->

            </div>

the code is working fine on the same file, but following (2) erors are there when i try to access the public variable from a different file/scipt

errors

Notice: Undefined variable: database in C:\\xampp\\htdocs\\gallery\\admin\\includes\\admin_content.php on line 15

Notice: Trying to get property of non-object in C:\\xampp\\htdocs\\gallery\\admin\\includes\\admin_content.php on line 15

Answer 1

You forgot to include init.php file in admin_content.php

Write below line in top of your admin_content.php file

<?php include 'init.php'; ?>

Note:- You do not need to include config.php file in your init.php file because that file is already loaded in database.php file.

Answer 2

init.php

<?php       
     include "config.php";
     include "database.php";        
 ?>

edit (init.php)

<?php       
 include "config.php";
 include "Database.php";        
?>

admin_content.php

//include init.php file
<?php include 'init.php' ?>
<div id="page-wrapper">

                <div class="container-fluid">

                    <!-- Page Heading -->
                    <div class="row">
                        <div class="col-lg-12">
                            <h1 class="page-header">
                                Blank Page
                                <small>Subheading</small>
                            </h1>
                        <?php 


                            if($database->connection) // the line that the error is pointing to
                            {
                                echo "true";
                            }
                        ?>

                            <ol class="breadcrumb">
                                <li>
                                    <i class="fa fa-dashboard"></i>  <a href="index.html">Dashboard</a>
                                </li>
                                <li class="active">
                                    <i class="fa fa-file"></i> Blank Page
                                </li>
                            </ol>
                        </div>
                    </div>
                    <!-- /.row -->

                </div>
                <!-- /.container-fluid -->

            </div>

result