AsyncTask 的 doInBackground(Params... params) [英] AsyncTask's doInBackground(Params... params)

问题描述

我不熟悉doInBackground(Params... params)

这种东西叫什么，我该如何使用?

What is this type of thing called, and how do I utilize it?

推荐答案

正如 devA 和 VVV 所说，这称为varargs".实际上，以下两行代码是等效的:

As devA and VVV have said, that is called "varargs". Effectively, the following two lines of code are equivalent:

public void makeLemonade(String[] args) {

和

public void makeLemonade(String... args) {

方法内部的代码是一样的，但是当它被调用时，它们的调用方式会不同.第一个需要像这样调用:

the code inside the method would be the same, but when it was called, they would be called differently. The first would need to be called like this:

makeLemonade(new String[]{"lemon1", "lemon2", "lemon3"});

虽然第二个的方法签名可以有 0 到(假定的)无限数量的参数，但它们都需要是字符串参数.以下所有调用都有效:

while the second one's method signature could have 0 to (an assumed)infinite number of arguments, but they would all need to be String arguments. All of the following calls would work:

makeLemonade("lemon1");
makeLemonade("lemon4", "lemon7", "lemon11", "lemon12"); 
makeLemonade();
// ... etc ...

两者之间的细微差别是，如果您使用可变参数，则可以在此处合法地调用 makeLemonade().

A subtle difference between the two is that you can call makeLemonade() legally here if you're using varargs.

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