Question

我正在尝试将flask_bootstrap4用于我的flask项目，并复制了flask_bootstrap文档中的代码段，但出现了错误。

<!DOCTYPE html>
<html lang="en">
    <head>
        {% block head %}
            <!-- Required meta tags -->
            <meta charset="utf-8">
            <meta name="viewport" content="width=device-width, initial-scale=1.0, shrink-to-fit=no">
            {% block styles %}
                <!-- Bootstrap CSS and Custom css -->
                {{ bootstrap.load_css() }}
                <link rel="stylesheet" type="text/css" href="{{ url_for('static', filename=style.css) }}">
            {% endblock styles %}

            {% if title %}
                <title>Community Helper - {{ title }}</title>
            {% else %}
                <title>Comminity Helper</title>
            {% endif %}

        {% endblock head %}
    </head>
    <body>
        {% from 'bootstrap/nav.html' import render_nav_item %}
        <nav class="navbar navbar-expand-md navbar-light bg-light border">
            <div class="navbar-nav mr-auto">
                {{ render_nav_item('index', 'Home') }}
                {{ render_nav_item('about', 'About') }}
            </div>
        </nav>

        {% block script %}
            <!-- Javascript -->
            {{ bootstrap.load_js() }}
        {% endblock script %}
    </body>
</html>

[2019-07-18 15:06:13,553] ERROR in app: Exception on / [GET]
Traceback (most recent call last):
  File "/home/energy/.local/lib/python3.6/site-packages/flask/app.py", line 2446, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/energy/.local/lib/python3.6/site-packages/flask/app.py", line 1951, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/energy/.local/lib/python3.6/site-packages/flask/app.py", line 1820, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/home/energy/.local/lib/python3.6/site-packages/flask/_compat.py", line 39, in reraise
    raise value
  File "/home/energy/.local/lib/python3.6/site-packages/flask/app.py", line 1949, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/energy/.local/lib/python3.6/site-packages/flask/app.py", line 1935, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/home/energy/Documents/flask-app/comhelper/application.py", line 10, in index
    return render_template("index.html")
  File "/home/energy/.local/lib/python3.6/site-packages/flask/templating.py", line 140, in render_template
    ctx.app,
  File "/home/energy/.local/lib/python3.6/site-packages/flask/templating.py", line 120, in _render
    rv = template.render(context)
  File "/home/energy/.local/lib/python3.6/site-packages/jinja2/asyncsupport.py", line 76, in render
    return original_render(self, *args, **kwargs)
  File "/home/energy/.local/lib/python3.6/site-packages/jinja2/environment.py", line 1008, in render
    return self.environment.handle_exception(exc_info, True)
  File "/home/energy/.local/lib/python3.6/site-packages/jinja2/environment.py", line 780, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/home/energy/.local/lib/python3.6/site-packages/jinja2/_compat.py", line 37, in reraise
    raise value.with_traceback(tb)
  File "/home/energy/Documents/flask-app/comhelper/templates/index.html", line 1, in top-level template code
    {% extends 'layout.html' %}
  File "/home/energy/Documents/flask-app/comhelper/templates/layout.html", line 4, in top-level template code
    {% block head %}
  File "/home/energy/Documents/flask-app/comhelper/templates/index.html", line 4, in block "head"
    {{ super() }}
  File "/home/energy/Documents/flask-app/comhelper/templates/layout.html", line 8, in block "head"
    {% block styles %}
  File "/home/energy/Documents/flask-app/comhelper/templates/layout.html", line 10, in block "styles"
    {{ bootstrap.load_css() }}
  File "/home/energy/.local/lib/python3.6/site-packages/jinja2/environment.py", line 430, in getattr
    return getattr(obj, attribute)
jinja2.exceptions.UndefinedError: 'bootstrap' is undefined
127.0.0.1 - - [18/Jul/2019 15:06:13] "GET / HTTP/1.1" 500 -

Answer 1

我认为您需要包括引导程序。

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">

Answer 2

确定要使用以下命令导入并初始化flask-bootstrap：

from flask_bootstrap import Bootstrap

然后：

Bootstrap(app)
# or bootstrap = Bootstrap(app)

在您的__init__.py中（或在其他初始化库的地方）？

我在flask_bootstrap4中遇到困难

2 个答案: