Trouble with php (call to a member function on a non-object) - php

Question

I am getting this php error and I can't seem to fix it.
Fatal error: Call to a member function prepare() on a non-object in C:\xampp\htdocs\mlrst\database.php on line 26
here is the line that is calling function prepare.
$this->statement->prepare($strQuery);
and here is it being declared.
protected $statement;
any ideas?
Edit: Here is my full code (don't mind the testing dummies)
<?php
$d = new database(); // test
class database {
protected $db_connect;
protected $statement;
function database() {
$db_connect = new MySQLi("localhost", "root" ,"", "test") or die("Could not connect to the server.");
$statement = $db_connect->stmt_init();
$this->preparedQuery("INSERT INTO feedback (name, feedback) VALUES ('?', '?')");
$this->close();
echo "Done!";
}
protected function cleanString($strLine) {
$strCleansedLine = preg_replace("/[^a-zA-Z0-9\s]/", "", $strLine);
return $strCleansedLine;
}
public function preparedQuery($strQuery, $parameters = NULL) {
try {
$this->statement->prepare($strQuery);
$statement->bind_param("ss", $name, $feedback);
for ($i = 0; $i < count($parameters); $i++) {
}
$name = $this->cleanString("this is my name");
$feedback = $this->cleanString("this is some feedback");
$query = $statement->execute();
} catch(Exception $e) {
echo $e->getMessage();
}
}
protected function close() {
try {
if ($this->statement != NULL)
$this->statement->close();
if ($this->db_connect != NULL)
$this->db_connect->close();
} catch (Exception $e) {
$e->getMessage();
}
}
}
?>

Answer 1

You assigned the local variable $statement. You need to set the instance's property using $this->statement.
In other words, change this:
$statement = $db_connect->stmt_init();
To this:
$this->statement = $db_connect->stmt_init();
And this:
$statement->bind_param("ss", $name, $feedback);
To this:
$this->statement->bind_param("ss", $name, $feedback);
...and this:
$query = $statement->execute();
To this:
$query = $this->statement->execute();