PHP Tutorials - Herong's Tutorial Examples - v5.17, by Herong Yang
What Is an Interface
This section describes what is an interface - An interface is a like a 'half' abstract class that only declares some abstract methods and has no properties. Classes that implement an interface must implement all abstract methods declared in the interface.
What Is an Interface? An interface is a like a "half" abstract class that only declares some "abstract" methods and has no properties. Classes that implement an interface must implement all abstract methods declared in the interface.
In PHP, an interface is declared with the "interface" statement block. For example, the following tutorial example provides an interface PowerSwitch with one method declared turnSwitch().
<?php /* MyTelevision.php #- Copyright 2015 (c) HerongYang.com. All Rights Reserved. */ Interface PowerSwitch { public function turnSwitch(); } class MyTelevision implements PowerSwitch { public $status; public $size; public function __construct($size) { $this->size = $size; $this->status = "Off"; } public function turnSwitch() { if ($this->status=="On") { $this->status = "Off"; } else { $this->status = "On"; } } public function showInfo() { echo " Size in inches: " . $this->size ."\n"; echo " Power status: " . $this->status ."\n"; } } $object = new MyTelevision(50.0); $object->turnSwitch(); $object->turnSwitch(); $object->turnSwitch(); echo "MyTelevision object: \n"; $object->showInfo(); ?>
Notice that "implements" is used as a keyword to indicate that a class wants to implement an interface in the "class" declaration.
If you run the above tutorial example, you will get something like this:
herong> \php\php MyTelevision.php MyTelevision object: Size in inches: 50 Power status: On
Table of Contents
Introduction and Installation of PHP
PHP Data Types and Data Literals
Variables, References, and Constants
Expressions, Operations and Type Conversions
Conditional Statements - "if" and "switch"
Loop Statements - "while", "for", and "do ... while"
Function Declaration, Arguments, and Return Values
Interface with Operating System
►Introduction of Class and Object
What Is a Superclass and a Subclass
What Is an Overloaded Property
What Is Object Property Iteration
Updating Variables Who Share an Object
Passing Objects as Function Arguments
Integrating PHP with Apache Web Server
Retrieving Information from HTTP Requests
Creating and Managing Sessions in PHP Scripts
Sending and Receiving Cookies in PHP Scripts
Controlling HTTP Response Header Lines in PHP Scripts
MySQL Server Connection and Access Functions
Functions to Manage Directories, Files and Images
SOAP Extension Function and Calling Web Services
SOAP Server Functions and Examples
Localization Overview of Web Applications
Using Non-ASCII Characters in HTML Documents
Using Non-ASCII Characters as PHP Script String Literals
Receiving Non-ASCII Characters from Input Forms
"mbstring" Extension and Non-ASCII Encoding Management
Managing Non-ASCII Character Strings with MySQL Servers
Parsing and Managing HTML Documents
Configuring and Sending Out Emails
Managing PHP Engine and Modules on macOS