Django how to show previous and next button only for related blog post?

Using Django Forms & APIs
1

In my blog details page I want to add next and previous button for only related blog post. Assume I write three blog on python and two on java. If user on java tutorial-1 details page then I want to show next button for move on java tutoral-2 page and also want previous button to go back java-tutorial-1 page.

#most important note I don’t want to show next button if he is on java-tutorial-2 page as I have only two blog post on java. So I want to show previous and next button only for related blog post not for my all blog post. see the layout below for better understand.

layout:

-------Blog Title----------parent object---------------button---------------------------
-    python tutorial-1------->No --------------------->want only next button            |
-    python tutorial-2------->python tutorial-1------->want next and previous button    |  
-    python tutorial-3------->python tutorial-2-------->want only previous button       |    
-    java tutorial-1--------->No ---------------------->want only next button           |
-    java tutorial-2---------->java tutorial-1--------->want only previous button       |
----------------------------------------------------------------------------------------

here is my code:

models.py

 class Blog(models.Model):
   blog_title = models.CharField(max_length=255)
   blog_parent = models.ForeignKey(
    'self', on_delete=models.CASCADE, blank=True, null=True)

views.py

def blogDetails(request, slug=None):
    blog = Blog.objects.filter(blog_slug=slug)
    context = {"blog": blog}
    return render(request, 'blog/blogDetails.html', context)
2

Is the first one of a set identified by the blog_parent field being null?

Is the last one of a set identified by not having any other Blog related to the current Blog

If so, you can use that information to determine whether or not you want to render a previous or next button, and what the links would be.

1 Like
3

KenWhitesell Now I added next button but can’t figure how to add previous button. I added parent from my first object to before last one. see the layout for better understood

      blog title             parent object                next button
(python tutorial - 1 )---->(python tutorial-2)----- >successfully added next button
(python tutorial-2 )------>(python tutorial-3)----- >successfully added next button
(python tutorial-3)-------> Null-------> No button as no parent

my html:

{{i.blog_title}}

{{i.blog_parent.title}}

{%if  i.blog_parent %}
<a href="{% url 'blog:blogDetails' i.blog_parent.blog_slug  %}"  id="next_button">next_button</a>
{%endif%}

{%endfor%}

Now I want to add previous button from my second blog post to last blog post. How to do that? any idea?

4

You can check the existance of an object related to another object through the related manager.

For example, if you have an instance of Blog named a_blog, then you can check to see if there’s a Blog with blog_parent = a_blog as:
a_blog.blog_set.exists()

Keep in mind that it’s possible to have many such relationships. To continue this example:
a_blog.blog_set.all()
returns the list of all Blog with blog_parent referring to a_blog.

1 Like