Question

我正在尝试学习PHP面向对象编程，但在视频教程中，我收到错误，而教程演示者没有同样的问题！

PHP代码：

<?php


class Player {

public $score = 10;
public $name = "";

public function __construct($score,$name) {

    $this->score = $score;
    $this->name = $name;
}

public function __destruct() {

    echo "Object With Name ".$this->name." has been destroyed";
}

public function __toString() {
    echo "The Object with name ".$this->name." has been echoed</br>";
}

}


$newPlayer = new Player(50,"Ahmad");


echo $newPlayer;


?>

我收到以下错误：

The Object with name Ahmad has been echoed
Catchable fatal error: Method Player::__toString() must return a string value in D:\xampp\htdocs\php_oop\index.php on line 30

当我将echo更改为return时，我得到以下输出，这不应该发生，因为我没有取消设置对象。当__destruct()中的echo更改为return时，为什么会调用toString()函数？

错误变为：

The Object with name Ahmad has been echoed
Object With Name Ahmad has been destroyed

Answer 1

您需要添加return语句。

return "The Object with name ".$this->name." has been echoed</br>";

您的脚本在此文件的末尾结束，这就是调用析构函数的原因！

Answer 2

正确答案如上：

return "The Object with name ".$this->name." has been echoed</br>";

完成对象后调用Destruct方法。在你的情况下：

echo $newPlayer;

PHP __toString（）不能正常工作？

2 个答案: