如果OnItemClickListener是Android的一个接口，我们如何能够创建基于它的对象？ [英] If OnItemClickListener is an interface in Android, how can we create an object based on it?

问题描述

我使用的这个网站下面的code ：

// Create a message handling object as an anonymous class.
private OnItemClickListener mMessageClickedHandler = new OnItemClickListener() {
    public void onItemClick(AdapterView parent, View v, int position, long id) {
        // Do something in response to the click
    }
};

listView.setOnItemClickListener(mMessageClickedHandler); 

现在它说：

您可以通过响应实施 AdapterView.OnItemClickListener 界面点击事件中的每一项的适配器视图。

You can respond to click events on each item in an AdapterView by implementing the AdapterView.OnItemClickListener interface.

如果 OnItemClickListener（）是一个接口那么我们如何创造它的对象如上code？什么是背后的概念？

If OnItemClickListener() is an interface then how can we create its object as in above code? What is the concept behind that?

推荐答案

我不太确定我明白你的问题，但在你上面的例子 mMessageClickedHandler 是对象和对象实现了 OnItemClickListener.onItemClick 方法。如果你是从C ++世界的未来，有你需要实现一个 OnClickListener 子等作为一个单独的实体，但在Java中，你可以像上面所看到的，创建一个匿名子类（我希望这是正确的名称！）在直列code。

I'm not quite sure I get your question, but in your example above mMessageClickedHandler is the object, and the object implements the OnItemClickListener.onItemClick method. If you are coming from a C++ world, there you would need to implement an OnClickListener subclass or the like as a separate entity, but in Java you can, as seen above, create an anonymous subclass (I hope that's the correct designation!) in inline code.

这不是我个人很喜欢这么多的技术，但它是这样一个常见的​​Java成语，我只是顺其自然！

It's not a technique I personally like that much, but it's such a common Java idiom that I just go with the flow!

这篇关于如果OnItemClickListener是Android的一个接口，我们如何能够创建基于它的对象？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！