“|="是什么意思?意思?(管道等于运算符) [英] What does "|=" mean? (pipe equal operator)

问题描述

我尝试使用 Google 搜索和 StackOverflow 进行搜索，但没有显示任何结果.我在开源库代码中看到过这个:

I tried searching using Google Search and Stack Overflow, but it didn't show up any results. I have seen this in opensource library code:

Notification notification = new Notification(icon, tickerText, when);
notification.defaults |= Notification.DEFAULT_SOUND;
notification.defaults |= Notification.DEFAULT_VIBRATE;

|="(管道等于运算符)是什么意思?

What does "|=" ( pipe equal operator ) mean?

推荐答案

|= 读取方式与 += 相同.

|= reads the same way as +=.

notification.defaults |= Notification.DEFAULT_SOUND;

与

notification.defaults = notification.defaults | Notification.DEFAULT_SOUND;

其中 | 是按位 OR 运算符.

where | is the bit-wise OR operator.

在此处引用了所有运算符.

使用按位运算符是因为，这些常量经常使 int 能够携带标志.

A bit-wise operator is used because, as is frequent, those constants enable an int to carry flags.

如果您看看这些常量，你会发现它们是 2 的幂:

If you look at those constants, you'll see that they're in powers of two :

public static final int DEFAULT_SOUND = 1;
public static final int DEFAULT_VIBRATE = 2; // is the same than 1<<1 or 10 in binary
public static final int DEFAULT_LIGHTS = 4; // is the same than 1<<2 or 100 in binary

所以你可以使用按位或来添加标志

So you can use bit-wise OR to add flags

int myFlags = DEFAULT_SOUND | DEFAULT_VIBRATE; // same as 001 | 010, producing 011

所以

myFlags |= DEFAULT_LIGHTS;

只是意味着我们添加了一个标志.

simply means we add a flag.

并且对称地，我们测试使用 & 设置的标志:

And symmetrically, we test a flag is set using & :

boolean hasVibrate = (DEFAULT_VIBRATE & myFlags) != 0;

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