Django簡單博客實戰（五）--- 文章詳情頁的上下篇

實現上一篇和下一篇

項目地址：https://github.com/ylpxzx/lifeblog

1. 視圖中定義上一篇下一篇邏輯

class PostDetailView(DetailView):
    model = Post
    template_name = 'detail_post.html'
    context_object_name = "post"
    pk_url_kwarg = 'post_id'

    def get_object(self, queryset=None):
        obj = super(PostDetailView,self).get_object()
        obj.total_views += 1
        obj.save(update_fields=['total_views'])

        return obj

    def get_context_data(self, **kwargs):
        kwargs['author_list'] = Blogger.objects.all()
        kwargs['category_list'] = Category.objects.all().order_by('post_category')
        kwargs['popular_post'] = Post.objects.all().order_by('-total_views')[:4]
        content = super(PostDetailView, self).get_context_data(**kwargs)


        num = content['post'].id
        # 下一篇，找出id大於當前文章id的文章,升序排序後取第一個，即爲下一篇
        next_post = Post.objects.filter(id__gt=num).order_by("id")[:1] 
        if len(next_post) == 0:
            content['next_post'] = 0
        else:
            for next in next_post:
                content['next_post'] = next

        # 上一篇，找出id小於當前文章id的文章，降序排序後取第一個，即爲上一篇
        prev_post = Post.objects.filter(id__lt=num).order_by("-id")[:1] 
        if len(prev_post) == 0:  
            content['prev_post'] = 0
        else:
            for prev in prev_post:
                content['prev_post'] = prev

        return content

2. 模板判斷是否有上一篇和下一篇

{% if prev_post != 0 %}
    <div class="detials">
		<p>Prev Post</p>
		<a href="{% url 'post:detail' prev_post.id %}"><h4>{{ prev_post.title }}</h4></a>
    </div>
{% endif %}

{% if next_post != 0 %}
    <div class="detials">
        <p>Next Post</p>
        <a href="{% url 'post:detail' next_post.id %}"><h4>{{ next_post.title }}</h4></a>
    </div>
{% endif %}