内部类Java中的Modify变量

我无法解决Java内部类的问题。假设你有

class Outer
{
     int outer = 0;
     class Inner
     {
          int inner = Outer.this.outer; //(or just outer as it is not shadowed)
          inner = 3; //or whatever, even outer = 3
     }
}

嗯，当我写最后一个作业时，我得到了编译错误

Syntax error on token ";", , expected

根据先例

为什么我不能修改内部

---

谢谢大家!

您对

内部的赋值必须在方法或构造函数中，而不是类中的“松散”赋值。
您必须将代码放置在方法或构造函数中：

class Outer
{
     int outer = 0;
     class Inner
     {
          int inner = Outer.this.outer; 
          public Inner() {
               inner = 3; 
          }

          public increment() {
               inner++;
          }
      }
}

class Outer
{
     int outer = 0;
     class Inner
     {
          int inner = Outer.this.outer; //(or just outer as it is not shadowed)
          Inner() {
              inner = 3; //or whatever, even outer = 3
          }
     }
}

不能在方法之外有语句。一种技术是使用实例初始值设定项块：

或者，定义一个构造函数：

class Outer
{
     int outer = 0;
     class Inner
     {
          int inner = Outer.this.outer; 
          public Inner() {
               inner = 3; 
          }

          public increment() {
               inner++;
          }
      }
}

class Outer
{
     int outer = 0;
     class Inner
     {
          int inner = Outer.this.outer; //(or just outer as it is not shadowed)
          Inner() {
              inner = 3; //or whatever, even outer = 3
          }
     }
}

您需要包括以下行：

 inner=3;

在内部类的方法中
 Yuo不能直接初始化
internal=3外部方法。确保
内部=3在任何方法或构造函数中

 public Inner() 
 {
       inner = 3; 
 }