How to access methods through a variable

Question

Actually, it is not possible to access class methods through a variable with another method. Here there is such a class for example

class Handler { public function getHandler() { return 'some handler'; } public function getFile() { return 'some file'; } }

I create an instance of the class $class = new Handler(); The getHandler method is available $handler = $class->getHandler();

And I want to access the getFile() method like this $file = $handler->getFile(); With this treatment, I get the error:

Fatal error: Uncaught Error: Call to a member function getFile () on string

Of course, such a call $file = $class->getFile(); it works, but I want it to work like this $file = $handler->getFile();

If you are given an exhaustive answer, mark it as correct (a daw opposite the selected answer).

vp_arth 18.6k 2 28 58 · Accepted Answer · 2017-02-19T16:15:50

To do this, in the getHandler method getHandler return a reference to the current object:

 public function getHandler() { // { // возможно блок каких-либо действий // } return $this; }

Perhaps you are doing something call chains. An example with $this might look like this:

 class TestClass { public static $currentValue; private static $_instance = null; private function __construct() { } public static function getInstance() { if (self::$_instance === null) { self::$_instance = new self; } return self::$_instance; } public function toValue($value) { self::$currentValue = $value; return $this; } public function add($value) { self::$currentValue = self::$currentValue + $value; return $this; } public function subtract($value) { self::$currentValue = self::$currentValue - $value; return $this; } public function result() { return self::$currentValue; } }

using:

 $result = TestClass::getInstance() ->toValue(5) ->add(3) ->subtract(2) ->add(8) ->result(); echo $result; // выведет 14

This is an example. I assume that something like that you want to be used in getHandler()

Answer 2 · 2017-02-20T20:03:42

For this, there are variable variables . In your case it will look like this:

 $file = $$handler->getFile();

And getHandler should return the name of a variable that has a getFile method.

As an example, in PHP you can call functions by name:

 $function_name = 'getHandler'; $result = $file->{$function_name}();

Answer 3 · 2017-02-19T17:18:51

In your example, $ handler carries the result of the getHandler () execution - string. You are trying to operate it as an instance of a class, but it is just a string (in this case) variable and does not know anything about the class, nor the class about it.

In essence, your question is the only way:

 $handler = $class->getHandler(); $file = $class->getFile();

The question is written. Конечно такое обращение $file = $class->getFile(); работает, но я хочу, чтобы работала вот так $file = $handler->getFile();
Конечно такое обращение $file = $class->getFile(); работает, но я хочу, чтобы работала вот так $file = $handler->getFile();

How to access methods through a variable

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