从Controller加载后，我的模型不起作用，但是从另一个模型加载时，我的模型运行良好

Question

I am a beginner PHP and codeigniter learner.

There is a model that doesn't work after being loaded from Controller, but works well when was loaded from another model.

I'm building an app for users to get feedback. A user may have several questions he can make to his audience.

From coding point of view, I have a base controller " MY_Controller " that extends CI_Controller. I then have 2 controllers, that extend my controller - home (the main page users will see) and questions (to view the details of a question).

I have 2 main models: user_model and question_model

When I load the question_model from within the user_model, everything goes well and the program works fine.

But when I load the question_model from within the Question controller, it runs the constructor (I've made an echo to check that) and it finishes the constructor (again I echoed to check), but when I invoke a method of the question_model I get the error:

Fatal error: Call to a member function initialize() on a non-object in /Users/jaimequintas/Dropbox/3 CODIGO/feedbacking/application/controllers/question.php on line 17

Can someone help me with this? I've been struggling with this for more than a day, and I can't solve it anyway.

My base controller:

class MY_controller extends CI_Controller{


public function index()
{
    $this->session->set_userdata('user_id', 8); //this is here just to initialize a user while in DEV
    $this->prepare_user(); //populates user with DB info

}

My Question controller (the one that can't use the $this->question_model methods)

class Question extends MY_Controller {

public function index(){

    parent::index();

    $active_question = $this->uri->segment(2,0);

    $this->load->model('Question_model'); //this line runs well, as an echo statement after this gets printed
    $this->Question_model->initialize($active_question); //this is the line that triggers the "can't use method error"
    $this->Question_model->get_answers_list();

This is the Question_model whose methods can't be called from controller.

class Question_model extends CI_Model {

public $question_id;
public $question_text;
public $vote_count; 
public $activation_date;
public $status; //Draft, Active, Archived
public $question_notes; //user notes

public $question_url; //the segment that will be added to codeigniter url feedbacking.me/"semgent"
public $answers_list; //array with answer objects
public $last_vote; //date of the last vote

public $vote_count_interval; //this is not computed with initialize, must call method when needed


public function __construct()
{
    parent::__construct();
}

public function initialize($question_id)
{
    //populate question from DB with: question_id, question_text, vote_count, activation_date, status
    // if $question_id ==0 creates an empty question (should be followed by create_question)


        $this->question_id = $question_id;
        $this->get_question_by_id();
        $this->get_question_votes();
}

And finally the User_model. I only put this here because when this model loads the Question_model, everything works fine.

class User_model extends CI_Model {

public $user_id;
public $user_email;
public $user_name;
public $plan_id;
public $questions_list; //array with question objects




public function __construct()
{
    parent::__construct();
    $this->load->database();
}

public function initialize($user_id)
{
    //populates user_info and question_list
    $this->user_id = $user_id;
    $this->get_user_by_id();
    $this->get_user_questions(); //this line calls the Question_model and works fine
}

Answer 1

When loading a model within a model, you need to get an instance of code igniter (instead of $this):

$CI =& get_instance();
$CI->load->model('Question_model');
$CI->Question_model->initialize($active_question);
$CI->Question_model->get_answers_list();