消息框架
向用户显示成功和错误提示
消息框架 是 CoddyKit 上的免费 Django Academy 课时。 这是第 3 节课，共 4 节。 你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。 这是 Django Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Django Academy 课程共包含 4 节课。
本课时的部分内容尚未翻译，以英文显示。
What Flash Messages Are
After an action you often want a one-time notice like Saved! The messages framework shows it on the next page, then forgets it. ✨
Already Set Up
New projects include the messages app plus its middleware and context processor, so you can start flashing notices right away.
Adding a Message
In a view, call messages.add_message with the request, a level, and your text to queue a notice for the visitor.
from django.contrib import messages
messages.add_message(request, messages.SUCCESS, 'Saved!')Handy Shortcuts
Skip the level argument with helpers like messages.success. They read clearly and cover the levels you use most often.
messages.success(request, 'Profile updated.')The Message Levels
Five built-in levels exist: DEBUG, INFO, SUCCESS, WARNING, and ERROR. Each maps to a CSS tag you can style differently.
Warnings and Errors
Use messages.error when something fails so the visitor sees a clear, red-styled notice instead of a silent failure.
messages.error(request, 'Could not delete that item.')They Survive Redirects
Messages are stored until displayed, so they survive a redirect. That fits the post-then-redirect pattern after a form submit perfectly.
Showing Them in Templates
The context processor exposes a messages variable. Loop over it in your base template so every page can show notices.
{% for m in messages %}
<li>{{ m }}</li>
{% endfor %}Styling by Level
Each message carries message.tags, like success or error. Drop that into a class to color notices with your CSS.
<li class="{{ m.tags }}">{{ m }}</li>Read Once, Then Gone
Iterating the messages variable marks them read. They will not reappear on the next request, which is exactly the flash behavior you want.
Where They Are Stored
By default messages use the FallbackStorage, which tries the cookie first and spills into the session for longer notices.
Quick Check
What happens to a message once a template loops over it?
Recap
You learned the messages framework: add notices with levels, survive redirects, render them in your base template, and they vanish after one view. Cookies versus sessions is next. 🍪
常见问题解答
「消息框架」课时是免费的吗？
是的 — 「消息框架」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Django Academy 课程的其余内容，请升级到 CoddyKit PRO。 Django Academy 课程共包含 4 节课。
「消息框架」这节课中我会学到什么？
向用户显示成功和错误提示 你通过在浏览器中直接运行的动手代码来练习 Django Academy，全天候 AI 导师会在你学习这节课的过程中回答你的问题。
学习 Django Academy 需要有经验吗？
无需任何先前经验。CoddyKit 上的 Django Academy 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。 这是第 3 节课，共 4 节。
「消息框架」课时需要多长时间？
大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。
我能在这节 Django Academy 课中编写并运行代码吗？
能。每节 Django Academy 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。