Question

我试图重新创建随flask-bootstrap提供的示例应用程序，但是遇到了渲染导航栏的问题。我收到错误： inja2.exceptions.UndefinedError：＆＃39; flask_nav.Nav object＆＃39;没有属性＆＃39; fronend_top＆＃39;

示例应用程序位于： https://github.com/mbr/flask-bootstrap/tree/master/sample_app

这里的flask-nav示例如下： http://pythonhosted.org/flask-nav/getting-started.html#rendering-the-navbar

据我所知，我做的似乎是正确的，但我猜导航不会被传递到网页上下文？不确定。

这是我的server.py

from flask import Blueprint, render_template, flash, redirect, url_for
from flask_bootstrap import __version__ as FLASK_BOOTSTRAP_VERSION
from flask_bootstrap import Bootstrap
from flask_nav.elements import Navbar, View, Subgroup, Link, Text, Separator
from markupsafe import escape
from flask_nav import Nav
from forms import SignupForm
from flask import Flask
#from nav import nav


frontend = Blueprint('frontend', __name__)

# We're adding a navbar as well through flask-navbar. In our example, the
# navbar has an usual amount of Link-Elements, more commonly you will have a
# lot more View instances.
nav = Nav()
nav.register_element('frontend_top', Navbar(
    View('Flask-Bootstrap', '.index'),
    View('Home', '.index'),
    View('Forms Example', '.example_form'),
    View('Debug-Info', 'debug.debug_root'), ))


# Our index-page just shows a quick explanation. Check out the template
# "templates/index.html" documentation for more details.
@frontend.route('/')
def index():
    return render_template('index.html', nav=nav)



app = Flask(__name__)

app.register_blueprint(frontend)
bootstrap = Bootstrap(app)
nav.init_app(app)

app.run(debug=True)

以下是我在base.html中抛出错误的行

{% block navbar %}
{{nav.fronend_top.render()}}
{% endblock %}

感谢您的帮助！

Answer 1

我能够使用这个： https://github.com/mbr/flask-nav/blob/master/example/init.py

并且： http://pythonhosted.org/flask-nav/getting-started.html#rendering-the-navbar

创建一个有效的简化版本。我从init示例开始使用create_app方法，该方法有效，然后删除了下面示例中的方法。也许这与蓝图有关？所以它没有导航对象？

from flask import Blueprint, render_template, flash, redirect, url_for
from flask_bootstrap import __version__ as FLASK_BOOTSTRAP_VERSION
from flask_bootstrap import Bootstrap
from flask_nav.elements import Navbar, View, Subgroup, Link, Text, Separator
from markupsafe import escape
from flask_nav import Nav
from forms import SignupForm
from flask import Flask
#from nav import nav
app = Flask(__name__)

nav = Nav()
topbar = Navbar('',
    View('Home', 'index'),
)
nav.register_element('top', topbar)


# not good style, but like to keep our examples short
@app.route('/')
def index():
    return render_template('index.html')

@app.route('/products/<product>/')
def products(product):
    return render_template('index.html', msg='Buy our {}'.format(product))

@app.route('/about-us/')
def about():
    return render_template('index.html')


# Shows a long signup form, demonstrating form rendering.
@app.route('/example-form/', methods=('GET', 'POST'))
def example_form():
    form = SignupForm()

    if form.validate_on_submit():
        flash('Hello, {}. You have successfully signed up'
              .format(escape(form.name.data)))

        # In a real application, you may wish to avoid this tedious redirect.
        return redirect(url_for('.index'))

    return render_template('signup.html', form=form)


nav.init_app(app)
bootstrap = Bootstrap(app)
app.run(debug=True)

Answer 2

您要使用flask-boostrap4尝试此操作吗？如果是这样，我发现它的Navbar Renderer损坏了，并导致了您发现的相同错误。将flask-boostrap v3与BS 3一起使用似乎可以解决此问题。

flask-nav无法使用flask-bootstrap示例应用程序

2 个答案: