关于interface的问题
[code=Java][/code]public class A {
interface B {
void f();
}
public class BImp implements B {
public void f() {}
}
private class BImp2 implements B {
public void f() {}
}
public interface C {
void f();
}
class CImp implements C {
public void f() {}
}
private class CImp2 implements C {
public void f() {}
}
private interface D {
void f();
}
private class DImp implements D {
public void f() {}
}
public class DImp2 implements D {
public void f() {}
}
public D getD() { return new DImp2(); }
private D dRef;
public void receiveD(D d) {
dRef = d;
dRef.f();
}
}
public static void main(String[] args) {
A a = new A();
// Can't access A.D:
//! A.D ad = a.getD();
// Doesn't return anything but A.D:
//! A.DImp2 di2 = a.getD();
// Cannot access a member of the interface:
//! a.getD().f();
// Only another A can do anything with getD():
A a2 = new A();
a2.receiveD(a.getD());//为什么a2.receiveD（）可以？
}
} ///:~
[解决办法]
为什么不可以？
a2是类A的一个对象，而类A中有公共方法receiveD，a2调用它a2.receiveD（）
这很正常啊
[解决办法]
A.DImp2 di2 = a.getD(); 这个不可以，其它都可以吧，D不能转型成DImp2吧
[解决办法]
