PHP和一些全局变量

发布于 2024-08-03 06:45:40 字数 761 浏览 10 评论 0原文

require_once'modules/logger.php';                                                         
$Logger = new Logger();

require_once 'templates/list.php';
$Templates = new templatesList();

require_once 'widgets/list.php';
$Widgets = new widgetsList();

我在 templates/list.php 和 widgets/list.php 中使用 $Logger。 $Templates 我在 /widgets/list.php 中使用。

上面的代码抛出这个错误：

注意：未定义的变量：Logger in .../templates/list.php 第 99 行致命错误：调用成员函数中非对象的 toLog() .../templates/list.php 第 99 行

UPD 这是第 99 行：

$Logger->toLog( $contentData );

原文

require_once'modules/logger.php';                                                         
$Logger = new Logger();

require_once 'templates/list.php';
$Templates = new templatesList();

require_once 'widgets/list.php';
$Widgets = new widgetsList();

I use $Logger in templates/list.php and in widgets/list.php.
$Templates I use in /widgets/list.php.

The code above throws this error:

Notice: Undefined variable: Logger in
.../templates/list.php on line 99
Fatal error: Call to a member function
toLog() on a non-object in
.../templates/list.php on line 99

UPD
Here is line 99:

$Logger->toLog( $contentData );

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痴骨ら 2024-08-10 06:45:40

如果您想在对象方法中使用 $Logger，则需要在该方法中将其标记为全局。如果不这样做，您最终将创建一个新的本地 $Logger 变量。我怀疑这就是问题所在。例如：

class templatesList {
    public function __construct() {
        global $Logger;
        //now we can use $logger.
    }
}

但是，最好将 $Logger 传递到需要使用它的每个对象的构造函数中。全局变量通常不被认为是好的做法。

class templatesList {
    protected $Logger;
    public function __construct(Logger $Logger) {
        //now we can use $logger.

        //store reference we can use later
        $this->Logger = $Logger;
    }

    public function doSomething() {
        $this->Logger->log('something');
    }
}

new templatesList($Logger);

If you want to use the $Logger from within an object method, you will need to mark it as global within that method. If you don't you will end up creating a new local $Logger variable. I suspect that is what the problem is. For example:

class templatesList {
    public function __construct() {
        global $Logger;
        //now we can use $logger.
    }
}

However, it would probably be better to pass $Logger into the constructor of every object which needs to use it. Global variables are not generally considered good practise.

class templatesList {
    protected $Logger;
    public function __construct(Logger $Logger) {
        //now we can use $logger.

        //store reference we can use later
        $this->Logger = $Logger;
    }

    public function doSomething() {
        $this->Logger->log('something');
    }
}

new templatesList($Logger);

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