php access object values

问题

EDIT: Thanks everyone. I didn't even notice it was private lol, so I changed them from private to public, now it should be accessible... question now is how can I access the value of say 'backpackPosition'? thanks again!

回答1:

Private members are just that - private. Only the class they belong to can access them. If you want to be able to retrieve their values, you need to either make them protected (and thus available to parent and children classes) or public (available to all classes). Another option is to write some getters, functions that look like

public function get_slot() {
    return $this->slot;
}

or use the __get() magic function to make a general getter that looks like

public function __get($name) {
    return $this->$name;
}

More info can be found in the documentation at http://php.net/manual/en/language.oop5.visibility.php

回答2:

Those items are only accessible by the object itself. You will have to modify the code for that class and provide an accessor method, or change their scope.

http://www.php.net/manual/en/language.oop5.properties.php

回答3:

You will need accessor method on each object in order to access the values. Since they are private they can only be accessed within each of the classes they belong.

回答4:

The private properties just can be accessed from inside the object itself. To access try to use $this->propertyName

回答5:

This answer is for the scenario of trying to get around an imposed private data restriction, for instance if you are by chance working with a library which you don't have access to change the privilege level of the class member, then there is a work around. Presuming the object is serializable/unserializable then consider:

<?php
class SourceProtected {
    private $foo = 'one';
    protected $baz = 'two';
    public $bar = 'three';
}   

class SourceUnprotected {
    public $foo = 'blah';       
    public $baz = 'two';
    public $bar = 'three';
}


$protected = new SourceProtected();
$unprotected = new SourceUnprotected();
var_dump(serialize($protected), serialize($unprotected));

The output looks something like:

string(110) "O:15:"SourceProtected":3:{s:20:"?SourceProtected?foo";s:3:"one";s:6:"?*?baz";s:3:"two";s:3:"bar";s:5:"three";}"
string(92) "O:17:"SourceUnprotected":3:{s:3:"foo";s:4:"blah";s:3:"baz";s:3:"two";s:3:"bar";s:5:"three";}"

So one solution, is to create a duplicate class that changes the privilege level on the variables to all public. Then serialize the working object, convert*** the serialized class to your versions, then simply unserialize the string and you'll have a working object of your class type with unlimited access.

Obviously the convert method is where you'll have to do some foot work. You'll need to either build a generalized parser which can handle any case or you can code a hacky works just for your specific use case series of str_replaces.

回答6:

you should see first object oriented php http://www.google.sk/url?sa=t&rct=j&q=object%20oriented%20php&source=web&cd=6&ved=0CGQQFjAF&url=http%3A%2F%2Ftalks.somabo.de%2F200703_montreal_oop.pdf&ei=k3EUT8HnGYHHswbi09A6&usg=AFQjCNEjsA2JgbGQfxnQ26XxTtFuHmvGIA&sig2=Vw4d7aD2GhulZYAM892EKA

来源：https://stackoverflow.com/questions/8884782/php-access-object-values

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