从空值创建默认对象（在Laravel中为新用户添加项目到数据库）

Question

I have a function I am using to add

I have an array $data that contains the user data I am trying to put into the db. Everything works except for the "makeUrlTag" function portion:

public function makeUrlTag() {

        $url_tag = '';
        if(isset($this->data['user']['first_name'])) {
        $url_tag = $url_tag . $this->data['user']['first_name'];
        }
        if(isset($this->data['user']['last_name'])) {
        $url_tag = $url_tag.$this->data['user']['last_name'];
        }

        $fan->url_tag = $url_tag;

    }

public function createFan() {
        $fan                        = new Fan;
        $fan->fbid                  = isset($this->data['user']['id']) ? $this->data['user']['id'] : '';
        $fan->email                 = isset($this->data['user']['email']) ? $this->data['user']['email'] : '';
        $fan->first_name            = isset($this->data['user']['first_name']) ? $this->data['user']['first_name'] : '';
        $fan->last_name             = isset($this->data['user']['last_name']) ? $this->data['user']['last_name'] : '';


        $this->makeUrlTag();

        $fan->save();
    }

I call createFan with:

$this->createFan();

When I run this, I get the error:

Creating default object from empty value

in reference to the makeUrlTag(); portion. Particularly the line:

$fan->url_tag = $url_tag;

Any idea what's going on here? Again, taking out the makeUrlTag portion works fine. Thank you.

Answer 1

It's because your makeUrlTag() method doesn't know about the Fan which is in the $fan variable you created in the createFan() method and trying to use a non-existing object in the scope of makeUrlTag() method using this:

$fan->url_tag = $url_tag;

So, you need to make your $fan object available to makeUrlTag() and to do this you may add a protected property in your class:

class YourClass {

    protected $fan = null;

    public function makeUrlTag(){

        $url_tag = '';

        // ...

        $this->fan->url_tag = $url_tag;

    }

    public function makeUrlTag(){

        $this->fan = new Fan;

        // rest of your code
        // but use $this->fan instead of $fan

        $this->fan->save();

    }

}

So, now you can access the $fan object from any method of your class ussing $this->fan, that's it.