CODEWITHSUNDEEP
django
JSRB
JSRB

Reputation: 2623

How to hide html button if queryset doesn't have next blog post in Django?

I would like to hide the Next button in my blog if there is no next blog post available.

Is there some kind of built-in method to check has_next has_previous or do I need to create some logic in my view and extend the template with let's say {% if Foo %} show button {% endif %} ?

views.py

def render_post(request, id):
    category_count = get_category_count()
    most_recent = Post.objects.order_by('-timestamp')[:3]
    post = get_object_or_404(Post, id=id)
    next_post_id = int(id) + 1
    previous_post_id = int(id) - 1

    PostView.objects.get(post=post)

    context = {
        'post': post,
        'id': id,
        'next_post_id': next_post_id,
        'previous_post_id': previous_post_id,
        'most_recent': most_recent,
        'category_count': category_count,
    }
    return render(request, 'post.html', context)

html

<div id="button-wrapper">
    <button class="buttons" type="submit"><a href="/post/{{previous_post_id}}">Previous</a></button>
    <button class="buttons" type="submit"><a href="/post/{{next_post_id}}">Next</a></button>
</div>

Upvotes: 0

Views: 81

Answers (1)

MattRowbum
MattRowbum

Reputation: 2192

You could do it by checking that the previous/next posts exist and returning the results in the context:

views.py

def render_post(request, id):
    category_count = get_category_count()
    most_recent = Post.objects.order_by('-timestamp')[:3]
    post = get_object_or_404(Post, id=id)
    next_post_id = int(id) + 1
    previous_post_id = int(id) - 1

    try:
        previous_post_exists = Post.objects.filter(id=previous_post_id).exists()
    except Post.DoesNotExist:
        previous_post_exists = False

    try:
        next_post_exists = Post.objects.filter(id=next_post_id).exists()
    except Post.DoesNotExist:
        next_post_exists = False

    context = {
        'post': post,
        'id': id,
        'next_post_id': next_post_id,
        'previous_post_id': previous_post_id,
        'previous_post_exists': previous_post_exists,
        'next_post_exists': next_post_exists,
        'most_recent': most_recent,
        'category_count': category_count,
    }
    return render(request, 'post.html', context)

You would then need to check those values in your template:

html

<div id="button-wrapper">
    {% if previous_post_exists %}
    <button class="buttons" type="submit"><a href="/post/{{previous_post_id}}">Previous</a></button>
    {% endif %}
    {% if next_post_exists %}
    <button class="buttons" type="submit"><a href="/post/{{next_post_id}}">Next</a></button>
    {% endif %}
</div>

Upvotes: 2

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