How to access inner classes variables & methods from outer classes

[lonelyplanet999]

Hi,

I have below code defining 1 outer class enclosing 2 inner classes.

If I want to access or display members of MyInner class from MyOuter
class methods (the same applied to accessing NewInner members from
MyInner class methods or MyOuter class methods), is creating instances
of MyInner (or NewInner) class within MyOuter class the only way to
achieve the goal ?


class P461 {
public static void main (String [] args) {
MyOuter mo = new MyOuter();

MyOuter.MyInner inner = mo.new MyInner();
System.out.println("inner\n=====");
inner.seeOuter();
inner.see2Outer();

MyOuter.MyInner.NewInner xinner = mo. new MyInner(). new
NewInner();
MyOuter.MyInner.NewInner ninner = inner.new NewInner();
System.out.println("xinner\n======");
xinner.seeOuter();
System.out.println("ninner\n======");
ninner.seeOuter();
}
}

class MyOuter {
private int x=7;
private int y=-1;
public void makeInner() {
MyInner in = new MyInner();
in.seeOuter();
}
public int gety() { return y; }

class MyInner {
private int y=-2;
public void seeOuter() {
System.out.println("Outer x is "+x);
}
public void see2Outer() {
System.out.println(this+".see2Outer");
System.out.println("Default y is "+y);
System.out.println("Outer y is "+MyOuter.this.y);
System.out.println("Outer gety() is "+MyOuter.this.gety());
}

class NewInner {
private int x=777;
private int y=-3;
public void seeOuter() {
System.out.println("NewInner x is "+x);
}
}
}
}

 

[VisionSet]

Hi,

I have below code defining 1 outer class enclosing 2 inner classes.

If I want to access or display members of MyInner class from MyOuter
class methods (the same applied to accessing NewInner members from
MyInner class methods or MyOuter class methods), is creating instances
of MyInner (or NewInner) class within MyOuter class the only way to
achieve the goal ?

....

Yes, as with any instance attribute of any class, you must have an instance
to go with it, it only exists when you create an instance.