Django学习（五）优雅地分页展示网页

雨点打透心脏的1/2处 2022-06-02 04:13 160阅读 0赞

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：

![20180103094402568][]

其模板的代码如下：

<ul>
    {% for contact in contacts %}
    <li>{
       {contact}}<br><br></li>
    {% endfor %}
    </ul>
    
    <div>
    <center>
    {% if contacts.has_previous %}  
    <a href="?page={
       { contacts.previous_page_number }}"> 上一页</a>  
    {% endif %}  
    <span>  
        {% for p in contacts.paginator.page_range %}  
        {% ifequal p contacts.number %}  
        <span class="current">{
       {p}}</span>  
    	{% else %}  
    	<a href="?page={
       {p}}" title="第{
       {p}}页"><button>{
       {p}}</button></a>  
    	{% endifequal %}
        {% endfor %}  
    </span>  
    {% if contacts.has_next %}  
    <a href="?page={
       { contacts.next_page_number }}">下一页 > </a>  
    {% endif %}  
    <a>[page:{
       { contacts.number }}/{
       { contacts.paginator.num_pages }}]</a>
    </center> 
    </div> 
    
    <br>
    <form action="/fenye/" method="get">
    	<center>
    	<select name='items'>
    		<option value='10' checked="checked">10 items each page</option>
    		<option value='15'>15  items each page</option>
    		<option value='20'>20  items each page</option>
    	</select>
    	<input type="submit" value="select">
    	</center>     
    </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：

![20180103094811119][]

选择好条目数，在点击select按钮，可链接到如下页面：

![20180103095039523][]

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：

<ul>
    {% for contact in contacts %}
    <li>{
       {contact}}<br><br></li>
    {% endfor %}
    </ul>
    
    <div>
    <center>
    {% if contacts.has_previous %}  
    <a href="?page={
       { contacts.previous_page_number }}"> 上一页</a>  
    {% endif %}  
    <span>  
        {% for p in contacts.paginator.page_range %}  
        {% ifequal p contacts.number %}  
        <span class="current">{
       {p}}</span>  
    	{% else %}  
    	<a href="?page={
       {p}}" title="第{
       {p}}页"><button>{
       {p}}</button></a>  
    	{% endifequal %}
        {% endfor %}  
    </span>  
    {% if contacts.has_next %}  
    <a href="?page={
       { contacts.next_page_number }}">下一页 > </a>  
    {% endif %}  
    <a>[page:{
       { contacts.number }}/{
       { contacts.paginator.num_pages }}]</a>
    </center> 
    </div> 
    <center>
    	<br>
        <button οnclick="window.location.href='http://localhost:8000/page'">Return To Original Page</button>
    </center>

最后，我们的后端views.py代码如下：

from django.http import HttpResponse
    from django.shortcuts import render_to_response
    from django.utils.datastructures import MultiValueDictKeyError
    from django.core.paginator import Paginator,PageNotAnInteger,EmptyPage
    
    #show items in default 
    def output(request):
        # get items show on the page from poems.txt
        with open('/home/vagrant/poems.txt', 'r') as f:
            text = f.readlines()
    		
        items_each_page = 15  # how many items in each page
        paginator = Paginator(text, items_each_page)
        page = request.GET.get('page')  # get 'page'
        try:
            contacts = paginator.page(page)
        except PageNotAnInteger:
            # If page is not an integer, deliver first page.
            contacts = paginator.page(1)
        except EmptyPage:
            # If page is out of range (e.g. 9999), deliver last page of results.
            contacts = paginator.page(paginator.num_pages)
        return render_to_response('page.html',{'contacts': contacts})
    
    #show items by your choice
    def output2(request):
        with open('/home/vagrant/poems.txt', 'r') as f:
            text = f.readlines()
    		
        try:
            #try to get 'items', if None or failed, do nothing.
            a = request.GET.get('items')
            if str(a) != 'None':
                with open('/home/vagrant/num.txt', 'w') as f:
                    f.write(a)
        except:
            pass
    
        with open('/home/vagrant/num.txt','r') as f:
            items_each_page = int(f.read())
    
        paginator = Paginator(text, items_each_page)
        page = request.GET.get('page')
        try:
            contacts = paginator.page(page)
        except PageNotAnInteger:
            # If page is not an integer, deliver first page.
            contacts = paginator.page(1)
        except EmptyPage:
            # If page is out of range (e.g. 9999), deliver last page of results.
            contacts = paginator.page(paginator.num_pages)	
        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~~

[20180103094402568]: /images/20220602/66d8488820cb41ff96313975e40c8161.png
[20180103094811119]: /images/20220602/bd7f7d559f66405aa80a10685bbf2a0c.png
[20180103095039523]: /images/20220602/4423b91866e54effbf66efa812778369.png