I am trying to access static member of a class.
my class is:
class A { public static $strName = 'A is my name' public function xyz() { .. } .. } //Since I have bunch of classes stored in an array $x = array('A'); echo $x::$strName;
I am getting error while printing. How can I print 'A is my name'
We can access the static member function using the class name or class' objects. If the static member function accesses any non-static data member or non-static member function, it throws an error. Here, the class_name is the name of the class. function_name: The function name is the name of the static member function.
As discussed above, Any static member can be accessed before any objects of its class are created, and without reference to any object. Methods declared as static have several restrictions: They can only directly call other static methods. They can only directly access static data.
The static member is always accessed by the class name, not the instance name. Only one copy of a static member exists, regardless of how many instances of the class are created.
The static keyword is used before the class keyword in a class definition to declare a static class. A static class members are accessed by the class name followed by the member name.
If A
is a class, you can access it directly via A::$strName
.
class A { public static $strName = 'A is my name'; } echo A::$strName; // outputs "A is my name"
Depending on what you have inside your array, whether its what I like to define as class objects or class literals could be a factor. I distinguish these two terms by,
$objClasses = array(new A(), new B()); // class objects $myClasses = array('A','B'); // class literals
If you go the class literals approach, then using a foreach
loop with PHP5.2.8 I am given a syntax error when using the scope resolution operator.
foreach ($myClasses as $class) { echo $class::$strName; //syntax error, unexpected '::', expecting ',' or ';' }
So then I thought about using the class objects approach, but the only way I could actually output the static variable was with an instance of an object and using the self
keyword like so,
class A { public static $strName = 'A is my name'; function getStatic() { return self::$strName; } } class B { public static $strName = 'B is my name'; function getStatic() { return self::$strName; } }
And then invoke that method when iterating,
foreach($objClasses as $obj) { echo $obj->getStatic(); }
Which at that point why declare the variable static
at all? It defeats the whole idea of accessing a variable without the need to instantiate an object.
In short, once we have more information as to what you would like to do, we can then go on and provide better answers.
If you want a working version for PHP5.2, you can use reflection to access the static property of a class.
class A { static $strName= '123'; } $lstClass = array('A'); foreach ($lstClass as $value) { $c = new ReflectionClass($value); echo $c->getStaticPropertyValue('strName'); }
Demo : http://ideone.com/HFJCW
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