PHP:如何使用类函数作为回调 [英] PHP: How to use a class function as a callback

问题描述

我有一个带有要用作回调的方法的类.如何将它们作为参数传递?

I have a class with methods which I want to use as callbacks. How to pass them as arguments?

Class MyClass {

    public function myMethod() {
        $this->processSomething(this->myCallback); // How it must be called ?
        $this->processSomething(self::myStaticCallback); // How it must be called ?
    }

    private function processSomething(callable $callback) {
        // process something...
        $callback();
    }

    private function myCallback() {
        // do something...
    }

    private static function myStaticCallback() {
        // do something...
    }   

}

UPD :如何通过static方法(当$this不可用时)执行相同操作

UPD: How to do the same but from static method (when $this is not available)

推荐答案

检查 callable手册，了解将函数作为回调传递的所有不同方式.我在此处复制了该手册，并根据您的情况添加了每种方法的一些示例.

Check the callable manual to see all the different ways to pass a function as a callback. I copied that manual here and added some examples of each approach based on your scenario.

可通话

---

• PHP函数以其名称的形式作为字符串传递.可以使用任何内置或用户定义的函数，但语言构造除外，例如: array()， echo ， empty()， eval()， exit()， isset()， list()， print 或 unset().

• A PHP function is passed by its name as a string. Any built-in or user-defined function can be used, except language constructs such as: array(), echo, empty(), eval(), exit(), isset(), list(), print or unset().

  // Not applicable in your scenario
  $this->processSomething('some_global_php_function');

---

• 实例化对象的方法作为数组传递，该数组包含索引为 0 的对象和方法名称为 1 的方法. /li>

• A method of an instantiated object is passed as an array containing an object at index 0 and the method name at index 1.

  // Only from inside the same class
  $this->processSomething([$this, 'myCallback']);
  $this->processSomething([$this, 'myStaticCallback']);
  // From either inside or outside the same class
  $myObject->processSomething([new MyClass(), 'myCallback']);
  $myObject->processSomething([new MyClass(), 'myStaticCallback']);

---

• 静态类方法也可以通过传递类名称而不是索引为 0 的对象来传递而无需实例化该类的对象.

• Static class methods can also be passed without instantiating an object of that class by passing the class name instead of an object at index 0.

  // Only from inside the same class
  $this->processSomething([__CLASS__, 'myStaticCallback']);
  // From either inside or outside the same class
  $myObject->processSomething(['\Namespace\MyClass', 'myStaticCallback']);
  $myObject->processSomething(['\Namespace\MyClass::myStaticCallback']); // PHP 5.2.3+
  $myObject->processSomething([MyClass::class, 'myStaticCallback']); // PHP 5.5.0+

---

• 除了常见的用户定义函数外，匿名函数也可以传递给回调参数.

• Apart from common user-defined function, anonymous functions can also be passed to a callback parameter.

  // Not applicable in your scenario unless you modify the structure
  $this->processSomething(function() {
      // process something directly here...
  });

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