问题
So I am trying to avoid using duplicate code. At the moment I have several lists which contain Strings; one list is called "images" and the other "videos" etc. These lists contain the properties of the content and they are in a linked list because that information was read from a text file.
I am trying to go through these lists and create image/video objects to place in another object (later on).
At the moment I have a method
private void loadContent(List<String> contentType)
inside of it how do I change the object declarations etc depending on the name of the list that was passed through. For example: If I call the method with the image list:
loadContent(images)
I want the function to create image objects:
Image media = new Image(title, visibility);
And if I passed Videos list:
loadContent(videos)
I want the function to create video objects:
Video media = new Video(title, visibility);
Sorry if this is worded badly, I find it hard to articulate this question. I also understand the the concept of polymorphism; I just don't see it viable for the content object to do this job (of reading the string etc) as the object is created depending the contents of the list.
回答1:
You brought up the subject of Polymorphism. This scenario would be a good candidate to demonstrate your understanding of how it works. You could create an abstract class named Media and have one method defined named Render(). Then extend the Media class to two subclasses, ImageMedia and VideoMedia. Where each subclass extends class Media, they should override the method Render() with their own implementation of how to render the content. In the end you can just have a List of type Media like this: List<Media> and iterate over it while calling the Render() method on each. In this way you impose polymorphic behaviour and greatly simplify your code.
回答2:
private void loadContent(List<String> content, int contentType)
You could pass in an integer as an id for the type of media you are giving it.
You could then use an if/else statement do only do certain things for certain content types.
来源：https://stackoverflow.com/questions/22751176/changing-object-initializer-constructor-depending-on-method-input