114.实现手动分页效果

分页

在网站的开发当中，我们常常需要将各种列表中的数据分页显示，想要实现分页的效果，就可以通过django.core.Paginator.Paginator和django.core.Paginator.Page来实现。

1. 比如，将Paginator_pageAPP中表article中的range(1,100)的数据分页显示，每页显示10条数据，可以实现手动分页的效果。

（1）首先在models.py文件中定义模型Article，示例代码如下：

from django.db import models


class Article(models.Model):
    title = models.CharField(max_length=100)
    content = models.CharField(max_length=100)
    create_time = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = 'paginator_page'

（2）在views.py文件中为数据库中的表paginator_page添加1-99条数据，示例代码如下：

from django.http import HttpResponse
from .models import Article

def index(request):
    articles = []
    for page in range(1,100):
        
        article = Article(title='标题：{}'.format(page), content='内容：{}'.format(page))
        
        articles.append(article)
    
    Article.objects.bulk_create(articles)
    return HttpResponse('success')

（3）将所有的数据分页显示。这就涉及到了我们之前提到的ListView类，就需要通过ListView来新创建一个类视图，实现我们的分页效果。views.py文件中示例代码如下：

from django.views.generic from ListView
from django.http import HttpResponse

class Paginator_page_view(ListView):
    
    model = Article
    
    template_name = 'paginator_page/static/paginator_page.html'
    
    context_object_name = 'articles'
    
    paginate_by = 10
    
    ordering = 'create_time'
    
    page_kwarg = 'p'
    
    
    
    def get_context_data(self, request, *args, **kwargs):
        context = super(Paginator_page_view, self).get_context_data(**kwargs)
        return context
        
    
    def get_queryset(self):
        return Article.objects.filter(id__lte=80)

（4）在项目的urls.py文件中进行视图函数与url之间的映射，示例代码如下：

from . import views
from django.urls import path, include


urlpatterns = [
    path('paginator/', include('Paginator_page.urls')),
]

（5）在Paginator_pageAPP中的urls.py文件中进行视图与url的映射，示例代码如下：

from . import views
from .views import Paginator_page_view
from django.urls import path

app_name = 'Paginator_page'

urlpatterns = [

    path('', Paginator_page_view.as_view(), name='page'),
]

（6）在paginator_page/static/paginator_page.html中实现分页（这种情况下会显示每一页，这种不是太方便。接下来会进行完善），示例代码如下：

    



{% for article in articles %}
    {{% article.title %}}
{% endfor %}





    {% if page_obj.has_previous%}
    
        
{{ page_obj.previous_page_number }}
    {% else %}
    
        
上一页
    {% endif %}
    
    

    {% for page in paginator.range_page %}
        {% if page == page_obj.number %}
            
{{ page_obj.number }}
        {% else %}
            
{{ page }}
        {% endif %}
    {% endfor %}
    
    


    {% if page_obj.has_next %}
        
{{ page_obj.next_page_number }}
    {% else %}
    
        
下一页
    {% endif %}

（7）完善在paginator_page/static/paginator_page02.html中实现显示部分分页，示例代码如下：

from django.views.generic import ListView
from django.http import HttpResponse
from .models import ListView


class Paginator_page_view02(ListView):
    model = Article
    template_name = 'paginator_page/static/paginator_page02.html'
    context_object_name = 'articles'
    paginate_by = 10
    ordering = 'create_time'
    page_kwarg = 'p'
    
    def get_context_data(self, request, *args, **kwargs):
        context = super(Paginator_page_view02, self).get_context_data(**kwargs)
        paginator = context.get('paginator')
        page_obj = context.get('page_obj')
        
        
        pagination_data = self.get_pagination_data(paginator, page_obj)
        
        context.update(pagination_data)
        return context
    
    
    
    
    def get_pagination_data(self, paginator,page_obj, around_count=2):
        current_page = page_obj.number
        num_pages = paginator.num_pages
        
        left_has_more = False
        right_has_more = False
        
        if current_page <= around_count + 2:
            left_pages = range(1, current_page)
        else:
            lefT_has_more = True
            left_pages = range(current_page-around_count, current_page)
            
        if current_page >= num_pages-around_count - 1:
            right_page = range(current_page, num_pages)
        else:
            right_has_more = True
            right_page = range(current_page+1, current_page+around_count+1)
            
        return context={
            'left_pages': left_pages,
            'right_pages': right_pages,
            'num_pages': num_pages,
            'left_has_more': left_has_more,
            'right_has_more': right_has_more,
            'current_page': current_page,
        }

（8）paginator_page/static/paginator_page02.html中示例代码如下：

    


{# 上一页 #}
    {% if page_obj.has_previous %}
        
上一页
    {% else %}
        
上一页
    {% endif %}

    {% if left_has_more %}
        
1
        
...
    {% endif %}

{# 中间页 #}
{#  left页  #}
    {% for left_page in left_pages %}
        
{{ left_page }}
    {% endfor %}

{#  中间页  #}
    
{{ current_page }}

{#  right页  #}
    {% for right_page in right_pages %}
        
{{ right_page }}
    {% endfor %}

    {% if right_has_more %}
        
...
        
{{ num_pages }}
    {% endif %}


{# 下一页 #}
    {% if page_obj.has_next %}
        
下一页
    {% else %}
        
下一页
    {% endif %}