先放在自己网站 现在在这里PO出来希望对大家有些帮助 以前写的 今儿才记得 以后再续吧

from __future__ import unicode_literals


from django.core.exceptions import ImproperlyConfigured, ObjectDoesNotExist
from django.db import models
from django.http import Http404
from django.utils.translation import ugettext as _
from django.views.generic.base import TemplateResponseMixin, ContextMixin, View




class SingleObjectMixin(ContextMixin):
    """
    Provides the ability to retrieve a single object for further manipulation.
    """
    model = None
    queryset = None #直接指明即可 为get_object服务
    slug_field = ‘slug‘#配合get_object使用 queryset = queryset.filter(**{slug_field: slug})
    context_object_name = None
    slug_url_kwarg = ‘slug‘ # 获得urlconf ?slug=的传输值 用于 pk = self.kwargs.get(self.pk_url_kwarg, None) 配合get_object
    pk_url_kwarg = ‘pk‘ #获得urlconf ?pk=的传输值 slug = self.kwargs.get(self.slug_url_kwarg, None) 配合get_object


    def get_object(self, queryset=None): #取得符合条件的obj 条件就是 pk=? 或者 {slug_field: slug}
        """
首先判断queryset是否存在 若不在则调用get_queryset赋值给queryset
urlconf中的pk或者slug通过pk = self.kwargs.get(self.pk_url_kwarg, None)
和slug = self.kwargs.get(self.slug_url_kwarg, None)获得
之后通过filter()以及get()获得obj
        Returns the object the view is displaying.


        By default this requires `self.queryset` and a `pk` or `slug` argument
        in the URLconf, but subclasses can override this to return any object.
        """
        # Use a custom queryset if provided; this is required for subclasses
        # like DateDetailView
        if queryset is None:
            queryset = self.get_queryset()


        # Next, try looking up by primary key.
        pk = self.kwargs.get(self.pk_url_kwarg, None)
        slug = self.kwargs.get(self.slug_url_kwarg, None)
        if pk is not None:
            queryset = queryset.filter(pk=pk)


        # Next, try looking up by slug.
        elif slug is not None:
            slug_field = self.get_slug_field()
            queryset = queryset.filter(**{slug_field: slug})


        # If none of those are defined, it‘s an error.
        else:
            raise AttributeError("Generic detail view %s must be called with "
                                 "either an object pk or a slug."
                                 % self.__class__.__name__)


        try:
            # Get the single item from the filtered queryset
            obj = queryset.get()
        except ObjectDoesNotExist:
            raise Http404(_("No %(verbose_name)s found matching the query") %
                          {‘verbose_name‘: queryset.model._meta.verbose_name})
        return obj


    def get_queryset(self): # 若queryset为null 则返回self.model._default_manager.all()
        """
        Get the queryset to look an object up against. May not be called if
        `get_object` is overridden.
        """
        if self.queryset is None:
            if self.model:
                return self.model._default_manager.all()
            else:
                raise ImproperlyConfigured("%(cls)s is missing a queryset. Define "
                                           "%(cls)s.model, %(cls)s.queryset, or override "
                                           "%(cls)s.get_queryset()." % {
                                                ‘cls‘: self.__class__.__name__
                                        })
        return self.queryset._clone()


    def get_slug_field(self):
        """
        Get the name of a slug field to be used to look up by slug.
        """
        return self.slug_field


    def get_context_object_name(self, obj):
        """
返回的是self.context_object_name 或者 obj._meta.model_name
        Get the name to use for the object.
        """
        if self.context_object_name:
            return self.context_object_name
        elif isinstance(obj, models.Model):
            return obj._meta.model_name
        else:
            return None


    def get_context_data(self, **kwargs):
        """
result--->Insert the single object into the context dict.
在self.object=self.get_object()后调用  处理context[‘object‘] = self.object context_object_name = self.get_context_object_name(self.object)-->context[context_object_name] = self.object
        Insert the single object into the context dict.
        """
        context = {}
        if self.object:
            context[‘object‘] = self.object
            context_object_name = self.get_context_object_name(self.object)
            if context_object_name:
                context[context_object_name] = self.object
        context.update(kwargs)
        return super(SingleObjectMixin, self).get_context_data(**context)




class BaseDetailView(SingleObjectMixin, View):
    """
    A base view for displaying a single object
    """
    def get(self, request, *args, **kwargs):
        self.object = self.get_object()
        context = self.get_context_data(object=self.object)
        return self.render_to_response(context)




class SingleObjectTemplateResponseMixin(TemplateResponseMixin):
    template_name_field = None
    template_name_suffix = ‘_detail‘


    def get_template_names(self):
        """
        Return a list of template names to be used for the request. May not be
        called if render_to_response is overridden. Returns the following list:


        * the value of ``template_name`` on the view (if provided)
        * the contents of the ``template_name_field`` field on the
          object instance that the view is operating upon (if available)
        * ``<app_label>/<model_name><template_name_suffix>.html``
        """
        try:
            names = super(SingleObjectTemplateResponseMixin, self).get_template_names()
        except ImproperlyConfigured:
            # If template_name isn‘t specified, it‘s not a problem --
            # we just start with an empty list.
            names = []


            # If self.template_name_field is set, grab the value of the field
            # of that name from the object; this is the most specific template
            # name, if given.
            if self.object and self.template_name_field:
                name = getattr(self.object, self.template_name_field, None)
                if name:
                    names.insert(0, name)


            # The least-specific option is the default <app>/<model>_detail.html;
            # only use this if the object in question is a model.
            if isinstance(self.object, models.Model):
                names.append("%s/%s%s.html" % (
                    self.object._meta.app_label,
                    self.object._meta.model_name,
                    self.template_name_suffix
                ))
            elif hasattr(self, ‘model‘) and self.model is not None and issubclass(self.model, models.Model):
                names.append("%s/%s%s.html" % (
                    self.model._meta.app_label,
                    self.model._meta.model_name,
                    self.template_name_suffix
                ))


            # If we still haven‘t managed to find any template names, we should
            # re-raise the ImproperlyConfigured to alert the user.
            if not names:
                raise


        return names




class DetailView(SingleObjectTemplateResponseMixin, BaseDetailView):
    """
    Render a "detail" view of an object.


    By default this is a model instance looked up from `self.queryset`, but the
    view will support display of *any* object by overriding `self.get_object()`.
    """