展示首页商品频道分类

1. 分析首页商品频道分类数据结构

{
    "1":{
        "channels":[
            {"id":1, "name":"手机", "url":"http://shouji.jd.com/"},
            {"id":2, "name":"相机", "url":"http://www.itcast.cn/"}
        ],
        "sub_cats":[
            {
                "id":38, 
                "name":"手机通讯", 
                "sub_cats":[
                    {"id":115, "name":"手机"},
                    {"id":116, "name":"游戏手机"}
                ]
            },
            {
                "id":39, 
                "name":"手机配件", 
                "sub_cats":[
                    {"id":119, "name":"手机壳"},
                    {"id":120, "name":"贴膜"}
                ]
            }
        ]
    },
    "2":{
        "channels":[],
        "sub_cats":[]
    }
}

2. 查询首页商品频道分类（分析思路，代码复制过来，查看效果没问题就可以）

from django.views import View
from collections import OrderedDict
from apps.goods.models import GoodsChannel

class IndexView(View):
    """首页广告"""

    def get(self, request):
        """提供首页广告界面"""
        # 查询商品频道和分类
        categories = OrderedDict()
        channels = GoodsChannel.objects.order_by('group_id', 'sequence')
        for channel in channels:
            group_id = channel.group_id  # 当前组

            if group_id not in categories:
                categories[group_id] = {'channels': [], 'sub_cats': []}

            cat1 = channel.category  # 当前频道的类别

            # 追加当前频道
            categories[group_id]['channels'].append({
                'id': cat1.id,
                'name': cat1.name,
                'url': channel.url
            })
            # 构建当前类别的子类别
            for cat2 in cat1.subs.all():
                cat2.sub_cats = []
                for cat3 in cat2.subs.all():
                    cat2.sub_cats.append(cat3)
                categories[group_id]['sub_cats'].append(cat2)

4. 封装首页商品频道分类

1.封装首页商品频道分类到utils.goods.py文件

def get_categories():
    """
    提供商品频道和分类
    :return 菜单字典
    """
    # 查询商品频道和分类
    categories = OrderedDict()
    channels = GoodsChannel.objects.order_by('group_id', 'sequence')
    for channel in channels:
        group_id = channel.group_id  # 当前组

        if group_id not in categories:
            categories[group_id] = {'channels': [], 'sub_cats': []}

        cat1 = channel.category  # 当前频道的类别

        # 追加当前频道
        categories[group_id]['channels'].append({
            'id': cat1.id,
            'name': cat1.name,
            'url': channel.url
        })
        # 构建当前类别的子类别
        for cat2 in cat1.subs.all():
            cat2.sub_cats = []
            for cat3 in cat2.subs.all():
                cat2.sub_cats.append(cat3)
            categories[group_id]['sub_cats'].append(cat2)
    return categories

2.contents.view.py中使用utils.goods.py文件

class IndexView(View):
    """首页广告"""

    def get(self, request):
        """提供首页广告界面"""
        # 查询商品频道和分类
        categories = get_categories()

        # 渲染模板的上下文
        context = {
            'categories': categories,

        }