扩展 PHP 类及其子类

Question

在我的一个项目中，我使用一个提供两个类的外部库：DrawingImage和DrawingCharset，它们都扩展了BaseDrawing。

我想扩展BaseDrawing以添加一些属性并更改现有的方法。但我也希望在"；复制"；现有儿童(DrawingImage和DrawingCharset(。

有一个简单的方法吗？扩展don似乎不是一个解决方案：我必须在每个子类之间复制代码。我不确定我是否可以通过Trait调用父方法。

Answer 1

Traits可以访问超类的属性和方法，就像导入它们的子类一样，因此您可以在具有Traits的BaseDrawing的子类之间添加新功能。

<?php
class BaseDrawing
{
public $baseProp;
public function __construct($baseProp)
{
$this->baseProp = $baseProp;
}
public function doSomething()
{
echo 'BaseDrawing: '.$this->baseProp.PHP_EOL;
}
}
class DrawingImage extends BaseDrawing
{
public $drawingProp;
public function __construct($baseProp, $drawingProp)
{
parent::__construct($baseProp);
$this->drawingProp = $drawingProp;
}
public function doSomething()
{
echo 'DrawingImage: '.$this->baseProp.' - '.$this->drawingProp.PHP_EOL;
}
}
class DrawingCharset extends BaseDrawing
{
public $charsetProp;
public function __construct($baseProp, $charsetProp)
{
parent::__construct($baseProp);
$this->charsetProp = $charsetProp;
}
public function doSomething()
{
echo 'DrawingCharset: '.$this->baseProp.' - '.$this->charsetProp.PHP_EOL;
}
}
/**
* Trait BaseDrawingEnhancements
* Adds new functionality to BaseDrawing classes
*/
trait BaseDrawingEnhancements
{
public $traitProp;
public function setTraitProp($traitProp)
{
$this->traitProp = $traitProp;
}
public function doNewThing()
{
echo 'BaseDrawingEnhancements: '.$this->baseProp.' - '.$this->traitProp.PHP_EOL;
}
}
class MyDrawingImageImpl extends DrawingImage
{
// Add the trait to our subclass
use BaseDrawingEnhancements;
}
class MyDrawingCharsetImpl extends DrawingCharset
{
// Add the trait to our subclass
use BaseDrawingEnhancements;
}
$myDrawingImageImpl = new MyDrawingImageImpl('Foo', 'Bar');
$myDrawingImageImpl->setTraitProp('Wombats');
$myDrawingCharsetImpl = new MyDrawingCharsetImpl('Bob', 'Alice');
$myDrawingCharsetImpl->setTraitProp('Koalas');
$myDrawingImageImpl->doSomething();
$myDrawingCharsetImpl->doSomething();
$myDrawingImageImpl->doNewThing();
$myDrawingCharsetImpl->doNewThing();