parent::__construct() 发送的方法中的访问值

Question

我在控制器的子 class 中获取通过 parent__construct 传递的值并在名为 View 的 class 中使用该值时遇到问题。

在控制器 __Construct 中执行 var_dump 时 class 我可以检索从表单 class 发送的值，但是当我尝试检索此值时视图内方法中的相同值 class，它显示为 null。

你能帮我解决这个问题吗？

代码如下：

============================================
class Form extends Controller
{
    //General builder of the WEB pages
    public function __construct()
    {
        //Redirecting the entire site for maintenance
        //redirect("/ops/maintenance");

        parent::__construct(__DIR__ . "/../../../themes/" . THEME . "/pages/");
    }
}
============================================
class controller
{
    /** @var View */
    protected $view;

    /** @var Message */
    protected $message;

    //Builder extending classes
    /**
     * Controller constructor
     * @param string|null $pathToViews
     */
    public function __construct(string $pathToViews = null)
    {
        $this->view = new View($pathToViews);
        //the value passed in parent::__construct() appears here
        var_dump($pathToViews);
        $this->message = new Message();
    }
}
============================================

//Class responsible for handling Views requests
class view
{
    protected $pathToViews;

    public function __construct(string $pathToViews = null)
    {
        $this->pathToViews = $pathToViews;
    }

    //Function to Load the View and send content from the backend to the frontend
    public function show($viewName, $data = [])
    {
        var_dump($this->pathToViews);
    }
}

Answer 1

更新:

如果你不想在控制器 class 中调用 show 方法，但你想在你的控制器 class 中实例化 class 你应该找到一种方法来让视图 class 可以在控制器 class 之外访问。只是在控制器外部再次实例化视图 class 是另一个实例，并且确实会在 $pathToViews 变量上显示空值。

一种方法是这样的：

    class controller
{
    /** @var View */
    protected $view;


    //Builder extending classes
    /**
     * Controller constructor
     * @param string|null $pathToViews
     */
    public function __construct(string $pathToViews = null)
    {
        $this->view = new View($pathToViews);


        var_dump($pathToViews);
    }

    public function getView() : View
    {
        return $this->view;
    }
}



//Class responsible for handling Views requests
class View
{
    protected $pathToViews;

    public function __construct(string $pathToViews = null)
    {
        $this->pathToViews = $pathToViews;

        echo $this->pathToViews;
    }

    //Function to Load the View and send content from the backend to the frontend
    public function show($viewName, $data = [])
    {
        var_dump($this->pathToViews);
    }
}

$controller = new controller('testString');
$view = $controller->getView();

$view->show('test');

另一种方法是使用依赖倒置原则

    class controller
{
    /** @var View */
    protected $view;


    //Builder extending classes
    /**
     * Controller constructor
     * @param View $view
     * @param string|null $pathToViews
     */
    public function __construct(View $view, string $pathToViews = null)
    {
        $this->view = $view;
        $this->view->setPathtoViews($pathToViews);


        var_dump($pathToViews);
    }

    public function getView() : View
    {
        return $this->view;
    }
}



//Class responsible for handling Views requests
class View
{
    protected $pathToViews;


    public function setPathtoViews(string $pathToViews)
    {
        $this->pathToViews = $pathToViews;
    }

    //Function to Load the View and send content from the backend to the frontend
    public function show($viewName, $data = [])
    {
        var_dump($this->pathToViews);
    }
}

$view = new View();
$controller = new controller($view, 'testString');

$view->show('test');
?>

原回答 你的代码运行在我的机器上没问题。我有运行下面的代码块。我所做的更改使其工作实际上是调用 $this->view->show()。在您的代码示例中，情况并非如此。

作为小记。我知道 php 不区分大小写，但作为一个好习惯，请使用与您定义它们的方式相同的大小写调用您的 classes（视图与视图）。

<?php

class controller
{
    /** @var View */
    protected $view;


    //Builder extending classes
    /**
     * Controller constructor
     * @param string|null $pathToViews
     */
    public function __construct(string $pathToViews = null)
    {
        $this->view = new View($pathToViews);

        $this->view->show('test');

        var_dump($pathToViews);
    }
}



//Class responsible for handling Views requests
class View
{
    protected $pathToViews;

    public function __construct(string $pathToViews = null)
    {
        $this->pathToViews = $pathToViews;

        echo $this->pathToViews;
    }

    //Function to Load the View and send content from the backend to the frontend
    public function show($viewName, $data = [])
    {
        var_dump($this->pathToViews);
    }
}

$controller = new controller('testString');
?>

parent::__construct() 发送的方法中的访问值

Access value in method sent by parent::__construct()

php

oop

constructor