在Django 1.6中使用Python 2.7实现chartit：TypeError：'NoneType'没有属性__getitem__-需要更多信息

Question

I am referencing the stackoverflow question Implement chartit in Django 1.6 with Python 2.7 - TypeError: 'NoneType' has no attribute __getitem__

I do not have enough karma to comment on the persons post or have the ability to contact them, but they have stated that:

"I have fixed the problem. The Problem was indeed at the line hco['chart']['renderTo'] = render_to. I had to fix some data consistency problems, and now it worked."

What are these data consistency issues? It must be related to the newer version of django.

Following the tutorial http://chartit.shutupandship.com/docs/

I am having the same error: 'NoneType' object has no attribute ' getitem '

models.py

class MonthlyWeatherByCity(models.Model):
    month = models.IntegerField()
    boston_temp = models.DecimalField(max_digits=5, decimal_places=1)
    houston_temp = models.DecimalField(max_digits=5, decimal_places=1)

    def __unicode__(self):
        return unicode(self.month)

views.py

def weather_chart_view(request):
    #Step 1: Create a DataPool with the data we want to retrieve.
    context = RequestContext(request)
    weatherdata = \
        DataPool(
           series=
            [{'options': {
               'source': MonthlyWeatherByCity.objects.all()},
              'terms': [
                'month',
                'houston_temp',
                'boston_temp']}
             ])

    #Step 2: Create the Chart object
    chart_list = Chart(
            datasource = weatherdata,
            series_options =
              [{'options':{
                  'type': 'line',
                  'stacking': False},
                'terms':{
                  'month': [
                    'boston_temp',
                    'houston_temp']
                  }}],
            chart_options =
              {'title': {
                   'text': 'Weather Data of Boston and Houston'},
               'xAxis': {
                    'title': {
                       'text': 'Month number'}}})

index.html

<div id='container'> {{ weatherchart|load_charts:"container" }} </div>

<script type="text/javascript" src="/static/js/jquery-1.11.0.js"></script>
<script type="text/javascript" src="/static/js/highcharts.js"></script>

Debugging page

/home/nimbus/.virtualenvs/nimbus_portal/lib/python2.7/site-packages/chartit/templatetags/chartit.py in load_charts
                hco['chart']['renderTo'] = render_to ...
▼ Local vars
Variable    Value
**chart_list    
[]**

I have attached the chartit.py code for your viewing purposes. I am not sure what data consistences need to be fixed / changed.

chartit.py

from itertools import izip_longest
from django import template
from django.utils import simplejson
from django.utils.safestring import mark_safe
from django.conf import settings
import posixpath

from ..charts import Chart, PivotChart

try:
    CHARTIT_JS_REL_PATH = settings.CHARTIT_JS_REL_PATH
    if CHARTIT_JS_REL_PATH[0] == '/':
        CHARTIT_JS_REL_PATH = CHARTIT_JS_REL_PATH[1:]
    CHART_LOADER_URL = posixpath.join(settings.STATIC_URL, 
                                      CHARTIT_JS_REL_PATH,
                                      'chartloader.js')
except AttributeError:
    CHARTIT_JS_REL_PATH = 'chartit/js/'
    CHART_LOADER_URL = posixpath.join(settings.STATIC_URL, 
                                      CHARTIT_JS_REL_PATH,
                                      'chartloader.js')

register = template.Library()

@register.filter
def load_charts(chart_list=None, render_to=''):
    """Loads the ``Chart``/``PivotChart`` objects in the ``chart_list`` to the 
    HTML elements with id's specified in ``render_to``. 

    :Arguments:

    - **chart_list** - a list of Chart/PivotChart objects. If there is just a 
      single element, the Chart/PivotChart object can be passed directly 
      instead of a list with a single element.

    - **render_to** - a comma separated string of HTML element id's where the 
      charts needs to be rendered to. If the element id of a specific chart 
      is already defined during the chart creation, the ``render_to`` for that 
      specific chart can be an empty string or a space.

      For example, ``render_to = 'container1, , container3'`` renders three 
      charts to three locations in the HTML page. The first one will be 
      rendered in the HTML element with id ``container1``, the second 
      one to it's default location that was specified in ``chart_options`` 
      when the Chart/PivotChart object was created, and the third one in the
      element with id ``container3``.

    :returns:

    - a JSON array of the HighCharts Chart options. Also returns a link
      to the ``chartloader.js`` javascript file to be embedded in the webpage. 
      The ``chartloader.js`` has a jQuery script that renders a HighChart for 
      each of the options in the JSON array"""

    embed_script = (
      '<script type="text/javascript">\n'
      'var _chartit_hco_array = %s;\n</script>\n'
      '<script src="%s" type="text/javascript">\n</script>')

    if chart_list is not None:
        if isinstance(chart_list, (Chart, PivotChart)):
            chart_list = [chart_list]
        chart_list = [c.hcoptions for c in chart_list]
        render_to_list = [s.strip() for s in render_to.split(',')]
        for hco, render_to in izip_longest(chart_list, render_to_list):
            if render_to:
                hco['chart']['renderTo'] = render_to
        embed_script = (embed_script % (simplejson.dumps(chart_list, 
                                                         use_decimal=True),
                                        CHART_LOADER_URL))
    else:
        embed_script = embed_script %((), CHART_LOADER_URL)
    return mark_safe(embed_script)

Answer 1

The name 'weatherchart' isn't associated with a chart object.

At the end of the view function you should have:

return render_to_response(<template>, {'<chart_name>': <chart_object>})

And in the template (index.html in this case):

{{ <chart_name>|load_charts:"container" }}