Java4android (basic interface syntax)

What is an interface? An interface is defined to define the standard of the called object.

Basic interface Syntax:

1. Use interface definition;

2. All methods in the interface are abstract methods;

3. All methods in the interface have the public permission.

Basic interface syntax (2 ):

1. Implement the interface using the implements keyword

2. One class can implement multiple interfaces

3. One interface can inherit multiple interfaces

Example:

Interface USB {// defines the interface public void read (); public void write ();}

Interface Wifi {// defines the Wifi interface public void open (); public void close ();}

Class Phone implements USB, Wifi {// implements implement USB Phone implement all abstract methods in USB interface // implement interface public void read () {System. out. print ("read");} public void write () {System. out. print ("write");} public void open () {System. out. print ("Wifi Open");} public void close () {System. out. print ("Wifi close ");}}

Class Test {public static void main (String args []) {Phone phone = new Phone (); USB usb = phone; // converts the usb to the upper-right corner. read (); usb. write (); Wifi wifi = phone; // converts to wifi. open (); wifi. close ();}}

One interface can inherit multiple interfaces:

interface A{    Public void funA();}

interface B{    Public void funB();}

Interface C extends A, B {// C does not implement interfaces A and B, but inherits interfaces A and B. Therefore, C contains all the methods of interfaces A, B, and C. // when there is A class to implement the C interface, all methods A, B, and C must be rewritten as Public void funC ();}