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Django学习(5)优雅地分页展示网页

2018-01-03 10:03 120 查看

       在我们平时浏览网页时,经常会遇到网页里条目很多的情形,这时就会用到分页展示的功能。那么,在Django中,是如何实现网页分类的功能的呢?答案是Paginator类。

       本次分享讲具体展示如何利用Django的Paginator类来实现网页的分页展示功能。

       首先我们要展示的内容是159首陶渊明的诗歌,它们储存在'/home/vagrant/poem.txt'文件中。

       默认的不分页的网页(page.html)如下:

         其模板的代码如下:

1 <ul>
2 {% for contact in contacts %}
3 <li>{{contact}}<br><br></li>
4 {% endfor %}
5 </ul>
6
7 <div>
8 <center>
9 {% if contacts.has_previous %}
10 <a href="?page={{ contacts.previous_page_number }}"> 上一页</a>
11 {% endif %}
12 <span>
13     {% for p in contacts.paginator.page_range %}
14     {% ifequal p contacts.number %}
15     <span class="current">{{p}}</span>
16     {% else %}
17     <a href="?page={{p}}" title="第{{p}}页"><button>{{p}}</button></a>
18     {% endifequal %}
19     {% endfor %}
20 </span>
21 {% if contacts.has_next %}
22 <a href="?page={{ contacts.next_page_number }}">下一页 > </a>
23 {% endif %}
24 <a>[page:{{ contacts.number }}/{{ contacts.paginator.num_pages }}]</a>
25 </center>
26 </div>
27
28 <br>
29 <form action="/fenye/" method="get">
30     <center>
31     <select name='items'>
32         <option value='10' checked="checked">10 items each page</option>
33         <option value='15'>15  items each page</option>
34         <option value='20'>20  items each page</option>
35     </select>
36     <input type="submit" value="select">
37     </center>
38 </form>

该网页中的数字按钮可连接到对应的页码,当然也可以用‘下一页’链接。也可以自由选择每页需要显示的条目数量,如下:

选择好条目数,在点击select按钮,可链接到如下页面:

           这个页面(fenye.html)显示每页10条,可以点击按钮‘Return To Original Page’回到刚才的页面(page.html)。该页面(fenye.html)的模板代码如下:

 

1 <ul>
2 {% for contact in contacts %}
3 <li>{{contact}}<br><br></li>
4 {% endfor %}
5 </ul>
6
7 <div>
8 <center>
9 {% if contacts.has_previous %}
10 <a href="?page={{ contacts.previous_page_number }}"> 上一页</a>
11 {% endif %}
12 <span>
13     {% for p in contacts.paginator.page_range %}
14     {% ifequal p contacts.number %}
15     <span class="current">{{p}}</span>
16     {% else %}
17     <a href="?page={{p}}" title="第{{p}}页"><button>{{p}}</button></a>
18     {% endifequal %}
19     {% endfor %}
20 </span>
21 {% if contacts.has_next %}
22 <a href="?page={{ contacts.next_page_number }}">下一页 > </a>
23 {% endif %}
24 <a>[page:{{ contacts.number }}/{{ contacts.paginator.num_pages }}]</a>
25 </center>
26 </div>
27 <center>
28     <br>
29     <button onclick="window.location.href='http://localhost:8000/page'">Return To Original Page</button>
30 </center>

           最后,我们的后端views.py代码如下:

 

1 from django.http import HttpResponse
2 from django.shortcuts import render_to_response
3 from django.utils.datastructures import MultiValueDictKeyError
4 from django.core.paginator import Paginator,PageNotAnInteger,EmptyPage
5
6 #show items in default
7 def output(request):
8     # get items show on the page from poems.txt
9     with open('/home/vagrant/poems.txt', 'r') as f:
10         text = f.readlines()
11
12     items_each_page = 15  # how many items in each page
13     paginator = Paginator(text, items_each_page)
14     page = request.GET.get('page')  # get 'page'
15     try:
16         contacts = paginator.page(page)
17     except PageNotAnInteger:
18         # If page is not an integer, deliver first page.
19         contacts = paginator.page(1)
20     except EmptyPage:
21         # If page is out of range (e.g. 9999), deliver last page of results.
22         contacts = paginator.page(paginator.num_pages)
23     return render_to_response('page.html',{'contacts': contacts})
24
25 #show items by your choice
26 def output2(request):
27     with open('/home/vagrant/poems.txt', 'r') as f:
28         text = f.readlines()
29
30     try:
31         #try to get 'items', if None or failed, do nothing.
32         a = request.GET.get('items')
33         if str(a) != 'None':
34             with open('/home/vagrant/num.txt', 'w') as f:
35                 f.write(a)
36     except:
37         pass
38
39     with open('/home/vagrant/num.txt','r') as f:
40         items_each_page = int(f.read())
41
42     paginator = Paginator(text, items_each_page)
43     page = request.GET.get('page')
44     try:
45         contacts = paginator.page(page)
46     except PageNotAnInteger:
47         # If page is not an integer, deliver first page.
48         contacts = paginator.page(1)
49     except EmptyPage:
50         # If page is out of range (e.g. 9999), deliver last page of results.
51         contacts = paginator.page(paginator.num_pages)
52     return render_to_response('fenye.html',{'contacts': contacts})

       这样,我们就基本实现了在Django中网页分页展示的功能,而且能够自己选择每一页需要展示的条目的数量,这显然是非常方便使用的。

       本次分享到此结束,如有问题,欢迎大家交流与批评~~

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