添加应用到项目： 在 project_name/settings.py 文件中，找到 INSTALLED_APPS 列表，将新创建的应用名添加进去，如 INSTALLED_APPS = ['myapp'].添加完了怎么保存呢？

在Django项目中，当你为项目添加新的自定义应用时，需要在`project_name/settings.py`文件的`INSTALLED_APPS`设置中包含该应用。`INSTALLED_APPS`是一个包含了所有启用的Django应用程序名称的列表。例如，如果你想把之前创建的名为`myapp`的应用添加进去，应该像下面这样操作：

INSTALLED_APPS = [
    # 其他已安装的默认Django应用
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    # ...,
    'myapp',  # 新添加的应用
]

确保`myapp`的名称与你在`manage.py`中创建应用时使用的名称一致。添加完应用后，你需要保存这个更改。通常，在文本编辑器中，只需按键盘上的`Ctrl + S`快捷键，或者选择“文件”>“保存”，即可保存修改后的`settings.py`文件。然后，你需要重启Django开发服务器（如果已经启动），让项目加载新的配置。这是因为更改`INSTALLED_APPS`后，系统需要重新读取并载入这些应用。如果你在IDE中工作，可能会有专门的菜单选项用于重启服务器或刷新配置。

相关问题

Traceback (most recent call last): File "D:\PyCharm Community Edition 2022.3.3\plugins\python-ce\helpers\pydev\pydevconsole.py", line 364, in runcode coro = func() File "<input>", line 1, in <module> File "D:\PyCharm Community Edition 2022.3.3\plugins\python-ce\helpers\pydev\_pydev_bundle\pydev_import_hook.py", line 21, in do_import module = self._system_import(name, *args, **kwargs) File "D:\PythonProject\Django_dianshang\utils\loaddata.py", line 2, in <module> from goods.models import * File "D:\PyCharm Community Edition 2022.3.3\plugins\python-ce\helpers\pydev\_pydev_bundle\pydev_import_hook.py", line 21, in do_import module = self._system_import(name, *args, **kwargs) File "D:\PythonProject\Django_dianshang\goods\models.py", line 7, in <module> class Category(models.Model): File "D:\anaconda3\envs\djangopro\lib\site-packages\django\db\models\base.py", line 129, in __new__ app_config = apps.get_containing_app_config(module) File "D:\anaconda3\envs\djangopro\lib\site-packages\django\apps\registry.py", line 260, in get_containing_app_config self.check_apps_ready() File "D:\anaconda3\envs\djangopro\lib\site-packages\django\apps\registry.py", line 137, in check_apps_ready settings.INSTALLED_APPS File "D:\anaconda3\envs\djangopro\lib\site-packages\django\conf\__init__.py", line 102, in __getattr__ self._setup(name) File "D:\anaconda3\envs\djangopro\lib\site-packages\django\conf\__init__.py", line 82, in _setup raise ImproperlyConfigured( django.core.exceptions.ImproperlyConfigured: Requested setting INSTALLED_APPS, but settings are not configured. You must either define the environment variable DJANGO_SETTINGS_MODULE or call settings.configure() before accessing settings.

这个错误提示是因为在你的代码中调用了 Django 的模型但是没有正确配置 Django 的设置。你需要确保在使用 Django 模型前，正确配置了 Django 的设置，可以通过以下两种方式之一来实现：

1.设置环境变量 DJANGO_SETTINGS_MODULE，例如：

export DJANGO_SETTINGS_MODULE=myproject.settings

2.在代码中手动配置 Django 的设置，例如：

import os
import django

os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'myproject.settings')
django.setup()

其中，myproject.settings 是你的 Django 项目的设置文件。

Traceback (most recent call last): File "D:\PyCharm Community Edition 2022.3.3\plugins\python-ce\helpers\pydev\pydevconsole.py", line 364, in runcode coro = func() File "<input>", line 1, in <module> File "D:\PyCharm Community Edition 2022.3.3\plugins\python-ce\helpers\pydev\_pydev_bundle\pydev_import_hook.py", line 21, in do_import module = self._system_import(name, *args, **kwargs) File "D:\PythonProject\Django_dianshang\dianshang\utils\loaddata.py", line 2, in <module> from dianshang.goods.models import * File "D:\PyCharm Community Edition 2022.3.3\plugins\python-ce\helpers\pydev\_pydev_bundle\pydev_import_hook.py", line 21, in do_import module = self._system_import(name, *args, **kwargs) File "D:\PythonProject\Django_dianshang\dianshang\goods\models.py", line 7, in <module> class Category(models.Model): File "D:\anaconda3\envs\djangopro\lib\site-packages\django\db\models\base.py", line 129, in __new__ app_config = apps.get_containing_app_config(module) File "D:\anaconda3\envs\djangopro\lib\site-packages\django\apps\registry.py", line 260, in get_containing_app_config self.check_apps_ready() File "D:\anaconda3\envs\djangopro\lib\site-packages\django\apps\registry.py", line 137, in check_apps_ready settings.INSTALLED_APPS File "D:\anaconda3\envs\djangopro\lib\site-packages\django\conf\__init__.py", line 102, in __getattr__ self._setup(name) File "D:\anaconda3\envs\djangopro\lib\site-packages\django\conf\__init__.py", line 82, in _setup raise ImproperlyConfigured( django.core.exceptions.ImproperlyConfigured: Requested setting INSTALLED_APPS, but settings are not configured. You must either define the environment variable DJANGO_SETTINGS_MODULE or call settings.configure() before accessing settings.

这个错误提示是因为你的 Django 项目没有正确配置。它告诉你需要设置环境变量 DJANGO_SETTINGS_MODULE 或者调用 settings.configure() 方法来配置 Django 的设置。你可以尝试在代码中添加以下内容来手动配置 Django 的设置：

import os
from django.conf import settings

os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'your_project.settings')
settings.configure()

请注意，你需要将 `your_project` 替换为你的 Django 项目的名称，并且在 `settings.configure()` 方法之前必须导入你的 Django 设置模块。