Java Learning Notes (46)-Inner class details

member Inner class

/ * Inner class * Defines classes in another class, called Inner classes inner class * contains classes of inner classes, called external classes outer class * * Applications: Event handling in a form program * Classification: * member Inner class * Local inner class * static Inner class * Anonymous inner class * * member Inner class * 1. Accessing the inner class in an external class allows access to all members of the inner class, including the private decorated * 2. Accessing inner classes outside the outer class, cannot access the members of the private adornment in the inner class * 3. Accessing external classes in internal classes, direct access, If the variable names of the inner and outer classes are the same, use the outer class. this. Variable * / Public classTest12 { Public Static void Main(string[] args) {Outer out=NewOuter ();//Create an object of an external class        /*out.print ();//method of calling External class */          //2. Accessing an inner class outside of a class        //Create an inner class object outside the outer class, syntax: External class. Inner class object name = External class object. New inner Class ();        //outer.inner in=out.new Inner ();//must first create an object of the outer classInnerinch= out.NewInner ();//system.out.println (in.age);//cannot access private members of inner classes        inch. Show (); }}/ * External class Outer, internal class Inner * compiled, generates three bytecode files: Test12.class, Outer.class, Outer$inner.class * Member internal class name: External class name $ internal class name. class */ Class outer{//External class    PrivateString name="Tom";member variables for the//external class    StaticString address="Nanjing"; Class inner{//Inner class        Private intAge= -;//member variable in inner class        PrivateString name="Zhang San"; String address="Beijing"; Public void Show() {String address="Tianjin"; System. out. println ("Show method in inner class");//3. Accessing an external class in an internal classSystem. out. println ("Name in the Inner class:"+ This. name); System. out. println ("Name in the external class:"+outer. This. name); System. out. println ("Age in inner class:"+age); System. out. println ("Address in the Inner class:"+ This. address); System. out. println ("Address in an external class:"+outer.address); System. out. println ("local variable address in inner class:"+address); }    }//1. Accessing inner classes in an external class     Public void Print() {System. out. println ("Print methods in external classes"); Innerinch=NewInner ();//Create an object of the inner class directlySystem. out. println (inch. age);//Access the properties of the inner class to access the private member        inch. Show (); }}

Local inner class

/* Local inner class * is also referred to as the method inner class, that is, the class defined in the method of the outer class * 1. Access scope: Can only be used in methods of external classes, cannot be decorated with modifiers * 2. Non-final-decorated members of methods that cannot access external classes in a local inner class */ Public classTest01 { Public Static void Main(string[] args) {Mouter out=NewMouter (); out. Show (); }}class mouter{String name="Tom"; Public void Show() {FinalintAge= -; System. out. println ("Show method in external class"); Class minner{//local inner classString sex="Male";PrivateString address="Nanjing"; Public void Print() {System. out. println ("Print method in local inner class"); System. out. println ("Member variable in external class name:"+name); System. out. println ("Local variables in external classes age:"+age); }        }//can only be used in methods of external classesMinnerinch=NewMinner (); System. out. println (inch. Sex); System. out. println (inch. address);inch. print (); }}

Static Inner class

/* static inner class * member inner class using static decoration * Cannot access non-static members of Outer class * / Public classTest02 { Public Static void Main(string[] args) {//Create static inner classes without creating objects of external classesSinnerinch=NewSinner ();inch. Show (); }}class souter{StaticString name="Tom";StaticClass sinner{//static inner classString sex="Male"; Public void Show() {System. out. println ("Show method in Static inner class"); System. out. println ("Name in the external class:"+name); }    }}

Anonymous inner class

/ * Anonymous Inner class * is an inner class without a name, because this class only needs to be used once, so there is no need to name * 1. When creating an anonymous inner class, you must declare it as part of the new statement, using: * interface | Abstract class object name = New Interface | Abstract class {* Anonymous inner class *} * 2. When an anonymous inner class is created, an object of an anonymous inner class is automatically created and assigned to the variable */ Public classTest03 { Public Static void Main(string[] args) {Service s=NewService () {//anonymous inner class            //Implement an abstract method in an interface             Public void Show() {System. out. println ("Anonymous inner class for implementing the Service Interface");        }        };        S.show (); Animal pig=NewAnimal () {@Override Public void Play() {System. out. println ("Piggy run .... "); } @Override Public void Show() {System. out. println ("The Pig eats fast ... ");        }        };        Pig.show ();        Pig.play (); Student stu=NewStudent () { Public void Show() {System. out. println ("I am a pupil, Hee hee hehe");        }        };    Stu.show (); }}/ * * Define interface * /Interfaceservice{//Abstract method    voidShow ();}/ * Abstract class * /AbstractClass animal{String name; Public void Show() {System. out. println ("animals are eating .... "); } Public Abstract void Play();} Class student{ Public void Show() {System. out. println ("Hey, hey , hey."); }}

Java Learning Notes (46)-Inner class details