如何在不创建新对象的情况下从另一个类访问变量 [英] How to Access Variable from Another Class without Creating New Object
问题描述
我的标题太长了,说明了一切...我希望能够在不创建新对象的情况下从另一个类访问变量。
My overly long title says it all... I want to be able to access a variable from another class without creating a new object.
当前,我知道如何访问另一个类的变量的唯一方法是:
Currently the only way I know how to access another class's variable is:
Control control = new Control;
int dirtCount = control.dirtCount;
但是,如果要在我的dirty对象中访问此变量,则必须创建一个新的每个控件对象。这会创建一个无休止的循环...
However, if I want to access this variable in my dirt object, I would have to create a new Control object for each one. This creates an endless cycle...
如何在不创建新对象的情况下访问变量?
how can I access the variable without creating a new object?
(如果您想查看其余的代码,可以将其发布。我认为这部分是最相关的:))
(If you want to see the rest of my code, I can post it. I think that this part is the most relevant though :))
推荐答案
一种方法是将该变量声明为 static
,这意味着它是一个类变量(不同于实例变量)。来自 Java教程(重点是我的):
One way would be declaring that variable as static
, which means that it's a class variable (it's different than an instance variable). From Java Tutorial (emphasis mine):
它们与类关联,而不与任何对象关联。该类的每个实例共享一个类变量,该变量位于内存中的一个固定位置。任何对象都可以更改类变量的值,但也可以在不创建类实例的情况下操作类变量。
在 Control
类中:
public class Control {
public static int dirCount;
// ...
}
,您无需创建即可使用它实例:
and you can use it without creating an instance:
int dirCount = Control.dirCount;
注意:
如果希望该变量为 private
,则可以定义 static
getter方法:
If you want that variable to be private
you can define a static
getter method:
public static int getDirCount() {
return dirCount;
}
,您可以使用
int dirCount = Control.getDirCount();
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