PHP：使用彼此函数的类？

Question

I've been into this problem for a while already, and have asked some questions about it here Stackoverflow. I've got some advice, but I just can't understand it. Could someone provide me an example of classes working smoothly together.

I have 3 (maybe more) classes:

• mysql
• user
• alerts

As I said, could someone provide an example, so these classes could use functions from each other class, e.g. user could use mysql's functions. I'm asking for an simple example, for learning-purposes.

And please, no google-suggestions or links to other questions. I've tried to search this for a while already. No success, though.

Martti Laine

Answer 1

I really recommend you read about classes first - http://php.net/manual/en/language.oop5.php because these are basic concepts if you don't understand a single code example won't help you much.

class Mysql {
    // Public function accessible from everywhere, with class instance
    public function hello() {
        echo '<br>Mysql says Hello';
    }
    // Static function accesible from everywhere, without class instance
    static function bye() {
        echo '<br>Mysql says Bye';
    }
}

class User {
    // Public function accessible from everywhere, with class instance
    public function hello() {
        $mysql = new Mysql();
        $mysql->hello();
        Mysql::bye();
    }
}

class Alert {
    // Static function accesible from everywhere, without class instance
    static function hello() {
        $user = new User();
        $user->hello();
    }
}

$user = new User();
$user->hello();

Mysql::bye();

Alert::hello();