Mobile App Interface Programming Technology-Learn other PHP class features

• Static statically-keyword

  Static. In a class, a variable or method that is marked by him does not belong to any one object. Use "::" When you visit. And when invoking itself in a class, use "Self::"
  For example:

    
     classCar {privatestatic$speed = 10;    publicfunctiongetSpeed() {returnself::$speed;    }    //在这里定义一个静态方法，实现速度累加10publicstaticfunctionspeedUp()    {returnself::$speed += 10;    }}$car = new Car();Car::speedUp();  //调用静态方法加速echo$car->getSpeed();  //调用共有方法输出当前的速度值

Static methods can also be dynamically called through variables.

$func'getSpeed';$className'Car';echo$className::$func();  //动态调用静态方法

• Access control

Access control is implemented by keyword public,protected and private. Class members that are defined as public can be accessed from anywhere. A class member that is defined as protected can be accessed by itself and its subclasses and parent classes. A class member that is defined as private can only be accessed by the class in which it is defined.

Class properties must be defined as public, protected, and private.

A method in a class can be defined as public, private, or protected. If these keywords are not set, the method defaults to public.

If the constructor is defined as a private method, it is not allowed to instantiate the object directly, which is typically instantiated by a static method, which is often used in design mode to control the creation of objects, such as a singleton pattern that only allows a globally unique object.

classCar {privatefunction__construct() {echo'object create';    }    privatestatic$_objectnull;    publicstaticfunctiongetInstance() {if (empty(self::$_object)) {            self::$_objectnew Car();             //内部方法可以调用私有方法，因此这里可以创建对象        }        returnself::$_object;    }}//$car = new Car(); //这里不允许直接实例化对象$car//通过静态方法来获得一个实例

• Inherited

    
     classCar {public$speed = 0; //汽车的起始速度是0publicfunctionspeedUp() {$this->speed += 10;        return$this->speed;    }}//定义继承于Car的Truck类classTruckextendsCar{publicfunctionspeedUp() {$this->speed = parent::speedUp() + 50;    }}$car = new Truck();$car->speedUp();echo$car->speed;

• Overload

Overloading in PHP refers to the dynamic creation of properties and methods, which are implemented by magic methods. The overloads of a property are implemented by __set,__get,__isset,__unset to assign, read, and determine whether a property is set or destroyed, respectively, for a nonexistent property.

 classCar {Private$ary=Array(); Public function__set($key, $val) {$this->ary[$key] =$val; } Public function__get($key) {if(isset($this->ary[$key])) {return$this->ary[$key]; }returnNULL; } Public function__isset($key) {if(isset($this->ary[$key])) {returntrue; }returnfalse; } Public function__unset($key) {unset($this->ary[$key]); }}$car=NewCar ();$car->name =' car ';//name properties are dynamically created and assigned valuesEcho$car->name;

The overloads of the method are implemented by __call, and when a non-existent method is called, the __call method is called, and the __callstatic overload is used when a static method that does not exist is called.

lass Car {    public$speed0;    publicfunction__call($name, $args) {if ($name'speedUp') {            $this10;        }    }}$carnew Car();$car//调用不存在的方法会使用重载echo$car->speed;

• Class object Comparison

Object comparison, when all the properties of two instances of the same class are equal, you can use the comparison operator "= =" to determine whether the two variable is a reference to the same object, you can use the congruent operator "= = =" to judge.

classCar {}$anew Car();$bnew Car();if ($a$becho'==';   //trueif ($a$becho'==='//false

Object replication, in some special cases, you can copy an object by using the keyword clone, at which point the __clone method is called, and the value of the property is set by this magic method.

classCar {public$name'car';    publicfunction__clone() {$objnew Car();        $obj$this->name;    }}$anew Car();$a'new car';$bclone$a;var_dump($b);

Object serialization, which can be serialized as a string by the Serialize method, used to store or pass data, and then deserialize the string into an object when needed by Unserialize.

classCar {public$name'car';}$anew Car();$str = serialize($a//对象序列化成字符串echo$str.'
';$b = unserialize($str//反序列化为对象var_dump($b);

Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced.

The above describes the mobile app interface programming technology-learning to implement the PHP class other features, including aspects of the content, I hope to be interested in PHP tutorial friends helpful.

