PHP面向对象：解决父类构造函数传递值在子类方法中丢失的问题

// Form 类继承 Controller
class Form extends Controller
{
    public function __construct()
    {
        // 调用父类构造函数，传递视图路径
        parent::__construct(__DIR__ . "/../../../themes/" . THEME . "/pages/");
    }
}

// Controller 类负责管理视图
class Controller
{
    /** @var View */
    protected $view;

    public function __construct(string $pathToViews = null)
    {
        // 在 Controller 构造函数中实例化 View
        $this->view = new View($pathToViews);
        // 在这里 var_dump($pathToViews) 会显示正确的值
        var_dump("Controller::__construct - pathToViews: " . $pathToViews);
    }
}

// View 类负责处理视图请求
class View
{
    protected $pathToViews;

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

    // 加载视图并发送内容
    public function show($viewName, $data = [])
    {
        // 当此方法被调用时，var_dump($this->pathToViews) 却显示 null
        var_dump("View::show - pathToViews: " . $this->pathToViews);
    }
}

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

    public function __construct(string $pathToViews = null)
    {
        $this->view = new View($pathToViews);
        var_dump("Controller::__construct - pathToViews: " . $pathToViews);
    }

    /**
     * 获取 Controller 内部的 View 实例
     * @return View
     */
    public function getView(): View
    {
        return $this->view;
    }
}

class View
{
    protected $pathToViews;

    public function __construct(string $pathToViews = null)
    {
        $this->pathToViews = $pathToViews;
        // 可以在构造函数中打印，验证值是否传入
        echo "View::__construct - pathToViews: " . $this->pathToViews . PHP_EOL;
    }

    public function show($viewName, $data = [])
    {
        var_dump("View::show - pathToViews: " . $this->pathToViews);
    }
}

// 示例用法：
$controller = new Controller('testString'); // 假设 Form 实例化时会传入这个
$view = $controller->getView(); // 获取 Controller 管理的 View 实例
$view->show('test'); // 在正确的 View 实例上调用 show 方法

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

    /**
     * Controller 构造函数通过依赖注入接收 View 实例
     * @param View $view
     * @param string|null $pathToViews
     */
    public function __construct(View $view, string $pathToViews = null)
    {
        $this->view = $view;
        // 通过 View 实例的 Setter 方法设置路径
        $this->view->setPathtoViews($pathToViews);

        var_dump("Controller::__construct - pathToViews: " . $pathToViews);
    }

    /**
     * 获取 Controller 内部的 View 实例（如果需要，但通常不推荐直接暴露）
     * @return View
     */
    public function getView(): View
    {
        return $this->view;
    }
}

class View
{
    protected $pathToViews;

    // 构造函数可以为空，或接收其他通用参数
    public function __construct()
    {
        // 构造函数不强制接收 pathToViews，允许后续设置
    }

    /**
     * 设置视图路径
     * @param string $pathToViews
     */
    public function setPathtoViews(string $pathToViews): void
    {
        $this->pathToViews = $pathToViews;
        echo "View::setPathtoViews - pathToViews: " . $this->pathToViews . PHP_EOL;
    }

    public function show($viewName, $data = [])
    {
        var_dump("View::show - pathToViews: " . $this->pathToViews);
    }
}

// 示例用法：
$view = new View(); // 首先创建 View 实例
// 然后将 View 实例和路径注入到 Controller
$controller = new Controller($view, 'testString');

$view->show('test'); // 在原始的 View 实例上调用 show 方法