改变布尔值？ [英] Change boolean Values?

问题描述

我有一个关于Java中的布尔值的问题。比方说，我有一个程序是这样的：

I have a question about boolean values in Java. Let's say I have a program like this:

boolean test = false;
...
foo(test)
foo2(test)

foo(Boolean test){
  test = true;
}
foo2(Boolean test){
  if(test)
   //Doesn't go in here
}

我注意到，在foo2的，布尔测试并没有改变，因此不进入if语句。我怎么会去改变它呢？我看着布尔值，但我无法找到，将设置测试，从真实的假的功能。如果有人可以帮助我走出这将是巨大的。

I noticed that in foo2, the boolean test does not change and thereby doesn't go into the if statement. How would I go about changing it then? I looked into Boolean values but I couldn't find a function that would "set" test from true to false. If anyone could help me out that would be great.

推荐答案

您是一个原始的布尔值传递给你的函数，没有参考。所以你只有你的阴影富方法中的价值。相反，你可能需要使用以下步骤之一 -

You're passing the value of a primitive boolean to your function, there is no "reference". So you're only shadowing the value within your foo method. Instead, you might want to use one of the following -

的的Holder 的

public static class BooleanHolder {
  public Boolean value;
}

private static void foo(BooleanHolder test) {
  test.value = true;
}

private static void foo2(BooleanHolder test) {
  if (test.value)
    System.out.println("In test");
  else
    System.out.println("in else");
}

public static void main(String[] args) {
  BooleanHolder test = new BooleanHolder();
  test.value = false;
  foo(test);
  foo2(test);
}

，输出测试。

或者，通过使用

的成员变量的

private boolean value = false;

public void foo() {
  this.value = true;
}

public void foo2() {
  if (this.value)
    System.out.println("In test");
  else
    System.out.println("in else");
}

public static void main(String[] args) {
  BooleanQuestion b = new BooleanQuestion();
  b.foo();
  b.foo2();
}

其中，还输出测试。

Which, also outputs "In test".

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