Java：如何通过使用“this”来访问外部类的实例变量？ [英] Java: how to access outer class's instance variable by using "this"?

问题描述

我有一个静态内部类，其中我想使用外部类的实例变量。目前，我必须以Outerclass.this.instanceVariable的格式使用它，这看起来很奇怪，是否有更简单的方法来访问外部类的实例字段？

I have a static inner class, in which I want to use the outer class's instance variable. Currently, I have to use it in this format "Outerclass.this.instanceVariable", this looks so odd, is there any easier way to access the instance field of the outer class?

Public class Outer
{
  private int x;
  private int y;
 private static class Inner implements Comparator<Point>
{
  int xCoordinate = Outer.this.x;   // any easier way to access outer x ?
}
}

推荐答案

A static 嵌套类不能引用外部类实例，因为它的 static ，没有相关的外部类实例。如果你想让一个静态嵌套类引用一个外部类，传递一个实例作为构造函数的参数。

A static nested class cannot reference the outer class instance because it's static, there is no related outer class instance. If you want a static nested class to reference an outer class, pass an instance as a constructor argument.

public class Outer
{
    private int x;
    private int y;
    private static class Inner implements Comparator<Point>
    {    
        int xCoordinate;

        public Inner(Outer outer) {
            xCoordinate = outer.x;       
        }
    }
}

非 - static 嵌套）类和没有变量名冲突（即两个变量都叫同名），可以直接引用外部类变量

If you meant an inner (non-static nested) class and there is no variable name collision (ie. both variables called the same name), you can directly reference the outer class variable

public class Outer
{
    private int x;
    private int y;
    private class Inner 
    {    
        int xCoordinate = x;
    }
}

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