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调用方法时的private关键字(private keyword when calling methods)

这是我现在正在测试的一段代码,我注意到当我在Person中的getInfo()方法上将public更改为private时,都是Student()。printPerson()和Person()。printPerson ()打印出“人物”。 但是,当它公开时,会显示“学生”。 有人可以解释一下吗? 为什么private修饰符不允许从Student访问getInfo方法?

        new Student().printPerson();
        new Person().printPerson();
      }
    }

    class Student extends Person {
        public Student(){
        System.out.println("student invoked")   ;
        }

      public String getInfo() {
        return "Student";
      }
    }

    class Person {
     public Person(){

    System.out.println("person invoked");

     }
        private String getInfo() {
        return "Person";
      }

      public void printPerson() {
        System.out.println(getInfo());
      }

This is a piece of code that I have that I'm testing right now, and I noticed that when I change public to private on the getInfo() method in Person, both Student().printPerson() & Person().printPerson() print out "Person". However, when it's public, "Student" is displayed. Can someone explain this? Why is it that the private modifier disallows access to the getInfo method from Student?

        new Student().printPerson();
        new Person().printPerson();
      }
    }

    class Student extends Person {
        public Student(){
        System.out.println("student invoked")   ;
        }

      public String getInfo() {
        return "Student";
      }
    }

    class Person {
     public Person(){

    System.out.println("person invoked");

     }
        private String getInfo() {
        return "Person";
      }

      public void printPerson() {
        System.out.println(getInfo());
      }

原文:https://stackoverflow.com/questions/18753450
更新时间:2024-03-30 21:03

最满意答案

应与您的其他问题相同。 在addButton函数中,如果不是nil ,则只设置委托,如果不是,则不设置委托。 因此, if delegateDetails == nil { return }来自DetailViewControler - addButton的if delegateDetails == nil { return } ,则删除它应该有效。


Should be the same as in your other question. In the addButton function you are only setting the delegate if not niland not if you should. So delete if delegateDetails == nil { return } from the DetailViewControler - addButton and it should work.

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