如何更改父属性值

I have a parent class Base

abstract class Base
 {
    protected $prop1 = null;

    protected $prop2 = null;
 }

And in the child class I want to change the both of property

class Child extends Base
 {


    public function method1($val1, $val2)
    {
        $this->prop1 = $val1;
        $this->prop2 = $val2;
    }

    public function method2()
    {
        echo prop1;
        echo prop2;
    }

 }

Is there any way to get changed values after calling first method of child class and after when I calling the second method of the child class? I tried to do that but I'm getting not changed values in this exsample thay are null's.

Use $this->prop1 to read the prop1 property:

class Child extends Base{

    public function method1 ($val1, $val2) {
        $this->prop1 = $val1;
        $this->prop2 = $val2;
    }

    public function method2 () {
        echo $this->prop1;
        echo $this->prop2;
    }

}

Read about OOP in PHP in the docs.

You have to handle prop1 and prop2 as class properties. Therefore - object scope/context - you have to write in code (whenever you read/write their values) as you have done it in method1():

public function method2() {
    echo $this->prop1;
}

In child class method2 you are not referring to actual properties. use $ otherwise php will understand it as a constant

<?php

     abstract class Base
     {
        protected $prop1 = null;

        protected $prop2 = null;
     }

     class Child extends Base
     {

        public function method1($val1, $val2)
        {
            $this->prop1 = $val1;
            $this->prop2 = $val2;
        }

        public function method2()
        {
            echo $this->prop1; 
            echo $this->prop2;
        }

     }

     $child = new Child();
     $child->method1(30, "ABC");
     $child->method2(); //will show 30ABC

    ?>