跳转问题，代码检查多次，但是运行时上下文还是显示和跳转到第一篇文章
def get_details_page(request, article_id):
all_article = Article.objects.all()
curr_article = None
previous_index = 0
next_index = 0
previous_article = None
next_article = None
for index, article in enumerate(all_article):
if index == 0:
previous_index == 0
next_index == index + 1
elif index == len(all_article) - 1:
previous_index == index - 1
next_index == index
else:
previous_index == index - 1
next_index == index + 1
if article.article_id == article_id:
curr_article = article
previous_article = all_article[previous_index]
next_article = all_article[next_index]
break
section_list = curr_article.content.split('\n')
return render(request, 'blog/details.html',
{
'curr_article': curr_article,
'section_list': section_list,
'previous_article': previous_article,
'next_article': next_article,
}
)<li><a href="/blog/detail/{{ previous_article.article_id }}">上一篇:{{ previous_article.article_title }}</a></li>
<li><a href="/blog/detail/{{ next_article.article_id }}">下一篇:{{ next_article.article_title }}</a></li>如上代码检查多次，但显示依然如图所示 ： 
在django shell测试了enumerate（），结果也正常，从0到9
所以问题出现在哪里，望老师和其他同学指教一下，谢谢
