java - 访问嵌套接口(interface)数据变量

Question

我无法访问此代码的变量 i:

interface three{
    void how();
    interface two{
        int i=2;
        void what();
    }
}

class one implements three,two{

    public void how(){
        System.out.println("\nHow! i = " + i);
        what();
    }

    public void what(){
        System.out.println("\nWhat! i = " + i);
    }

    public static void main(String args[]){
        one a = new one();
        a.how();
        a.what();

    }
}

生成的错误是:

one.java:17: error: cannot find symbol
System.out.println("\nWhat! i = " + i);                                          
symbol:   variable i
location: class one

Answer 1

您应该在外部创建接口(interface)，以便其他类可以访问它。

interface three {
    void how();
}

interface two {
    int i = 2;

    void what();
}

public class one implements three, two {

    public void how() {
        System.out.println("\nHow! i = " + i);
        what();
    }

    public void what() {
        System.out.println("\nWhat! i = " + i);
    }

    public static void main(String args[]) {
        one a = new one();
        a.how();
        a.what();

    }
}