錯誤：未定義的變量json

Question

按國家獲取州

我創建了三個選項框來選擇區域，州和國家。 問題是國家運作良好但是當我想獲得城市和區域給我錯誤未定義的變量在我使用的其他腳本工作。

未定義的變量：country_id

調節器

public function get_city()
{   
    $this->load->model('cities_model');
    header('Content-Type: application/json');

    $country_id = $country_id?$country_id:$this->input->post('country_id');
    if($country_id) 
    echo json_encode($this->cities_model->get_city());
}

模型

public function get_city($country_id = 0){
    return 
    $this->db->select('name as text, city_id as value')
            ->where('country_id', $country_id)
            ->get('cities')
            ->result();
 }

視圖

<li>
                            <label class="form-label required">Country</label>
                            <div class="form-item">
                                <select class="selectpicker" name="country_id" data-url="/admin/events/get_countries" data-select="city-1" data-select-group="1" required></select>
                            </div>
                        </li>   
                        <li class="hide" data-select-group="1" data-select-sub="city-1">
                            <label class="form-label required">City</label>
                            <div class="form-item">
                                <select class="selectpicker" name="city_id" data-url="/admin/events/get_city" data-select="area-1" required></select>
                            </div>
                        </li>                                    
                        <li class="hide" data-select-group="1" data-select-sub="area-1">
                            <label class="form-label required">Area</label>
                            <div class="form-item area_id">
                                <select class="selectpicker" name="area_id" data-url="/admin/events/get_area" required></select>
                            </div>
                        </li>

Answer 1

在我看來這應該足夠了：

public function get_city()
{   
    $this->load->model('cities_model');
    header('Content-Type: application/json');

    $country_id = $this->input->post('country_id');
    if(isset($country_id) && $country_id) {
        echo json_encode($this->cities_model->get_city());
    }
}

Answer 2

在你的控制器試試這個

$ country_id = $ this-> load-> model（'cities_model'，$ country_id）;

Answer 3

嘗試這個

$ id = $ this-> input-> post（'country_id'）

$ country_id = $ this-> load-> model（'cities_model'，$ id）;