Java中的完成处理程序？ [英] Completion handlers in Java?

问题描述

我一直在为iOS编码，我对Objective-C中的块概念非常熟悉。
现在我正在利用Java for Android并尝试将一些应用程序从Android转换为iOS。

I've been coding for iOS and I'm quite familiar with the concept of blocks in Objective-C. Now I'm leaning Java for Android and trying to convert some apps from Android to iOS.

我读到Java中没有完美的等效块，所以我想知道实现完成处理程序或类似工作的最佳替代方法是什么。

I read that there no perfect equivalent of blocks in Java, so I'd like to know what is the best alternative to implement completion handlers or anything that could work similarly.

推荐答案

接口类型， 一般来说。你可以使用 Runnable （这是一个接口），如果你的处理程序没有参数和 void 返回类型。但是定义你自己的很简单：

Interface types, in general. You can use Runnable (which is an interface) as Rob suggested if your handler has no parameters and a void return type. But it's simple enough to define your own:

interface CompletionHandler {
    public void handle(String reason);
}

然后将其传递给您自己的班级：

and then to pass it to your own class:

something.setCompletionHandler(new CompletionHandler() {
    @Override
    public void handle(String reason) {
        ...
    }
});

在其他类别中：

void setCompletionHandler(CompletionHandler h) {
     savedHandler = h;
}

然后只需调用方法调用它：

and then call it just by calling the method:

savedHandler.handle("Some mysterious reason");

这种事情是为Java Swing和Android库中的听众完成的;请参阅 View.OnClickListener ，例如。

This sort of thing is done for "listeners" in Java Swing and Android libraries all over the place; see View.OnClickListener, for example.

（PS我相信Java 8 lambdas可用于所有这些接口示例。）

(P.S. I believe that Java 8 lambdas will be usable with all of these interface examples.)

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