从子类PHP调用子类

Question

i am a new PHP, i have some files like this:

In root.php i have

<?php
class Root
{
// Some functions here
}

In child_1.php i have:

class Child_1 extends Root
{
  function abc()
  {
  //Some code here
  }
}

In child_2.php i have:

class Child_2 extends Root
{
  function cde()
  {
  // How can i call function abc() from class Child_1 here
  }
}

Yes, how can i call a function of Child_1 class from a function of Child_2 class.

Answer 1

As classes that extend one parent ( Root ) know nothing about each other (and you cannot change this), you can do:

class Chirld_2 extends Root
{
  function cde()
  {
    $obj = new Chirld_1();
    $obj->abc();
  }
}

But obviously it's a lack of good design. I suppose, you have to define abc() in a Root class to make it available in both children:

class Root
{
  function abc()
  {
  //Some code here
  }
}

class Chirld_1 extends Root
{

}

class Chirld_2 extends Root
{

}

$c1 = new Chirld_1();
$c1->abc();
$c2 = new Chirld_2();
$c2->abc();

Answer 2

您可以调用父类的class_1或Class_2中的任何函数，但不能在任何子类中调用另一个函数。因为它们没有关联，因此解决方案是您在class_1的构造函数中调用class_2

Answer 3

If you want to use functions of Chirld_1 from Chirld_2 or vice versa without creating an object of the child class, then one option is to declare Chirld_1 and Chirld_2 as traits of the parent class Root. This will allow you to call functions of Chirld_1 from Chirld_2 and vice verse using the $this keyword. The classes should be declared as follows:

<?php

trait Chirld_1
{
    public function test1()
    {
       $this->test2();
    }        
}

trait Chirld_2
{
    public function test2()
    {
       $this->test1();
    }   
}

class Root
{
    use Chirld_1;
    use Chirld_2;
// Some functions here
}

See this links for more information about traits: http://php.net/manual/en/language.oop5.traits.php

Answer 4

Try using parent:: or static:: or self:: notation to designate the class you want to use. http://php.net/manual/pl/keyword.parent.php