How to call a method from a nested class, Java?

问题

How to call methodTwo(); from methodOne(); ?

class Name {
    void methodOne() {
        class InnerClass {
           void methodTwo() {
           }
         }
     }
 }

Thank You!

回答1:

You need to create an instance of the InnerClass, in the same way as any other instance method needs an instance on which to call it:

class Name {
   void methodOne() {
     class InnerClass {
       void methodTwo() {
       }
     }

     InnerClass x = new InnerClass();
     x.methodTwo();
   }
}

It's worth being careful before doing this - I don't think I've ever seen a named class declared within a method in the production code I've been associated with. Normally I'd either use an anonymous inner class for something really short, or a private static named class for anything longer, to avoid making the method too long.

回答2:

class Name {
    void methodOne() {
        class InnerClass {
           void methodTwo() {
               new InnerClass().methodTwo();
           }
        }
    }
}

回答3:

Non-static nested classes are tied with containing class, but it can be many instances of nested class with one containing instance. So you need to specify instance name against which you want to run a method.

来源：https://stackoverflow.com/questions/11361616/how-to-call-a-method-from-a-nested-class-java