Django框架学习笔记（19.自定义分页）

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在讲自定义分页之前，先讲一个简单的。

在模板语言中还有一些特殊的存在，比如这个：

def tpl4(request):    name = "asdf123456"    return render(request, 'tpl4.html', {'name': name})

tpl4.html:

<body>{{ name }}{{ name|upper }}</body>

运行后：

这些我们只需了解，但应该要学会自定义这种操作：

自定义simple_tag:

1.在某个app目录下创建一个名为templatetags文件夹（必须为这个名字）

2.在文件夹内创建py文件写入函数（任意取名）‘

3.写函数之前还有一个固定的格式，不能变，然后记得要在settings里面注册app

例：创建了一个st.py

from django import templatefrom django.utils.safestring import mark_saferegister = template.Library()@register.simple_tagdef func(a1, a2):    return a1 + a2

4.在html文件中固定格式：

{% load st %}<!DOCTYPE html><html lang="en"><head>    <meta charset="UTF-8">    <title>Title</title></head><body>{% func 6 7 %}</body></html>

这里就实现了一个加法功能。

自定义filter:

和上面这个差不过，不过它只能传2个参数：

from django import templatefrom django.utils.safestring import mark_saferegister = template.Library()@register.filterdef func(a1, a2):    return a1 + a2

html中：

<body>{{ "fun"|func:"ction" }}</body>

看似这种远不如上面那种好用，不过，它也有它的优点：

{% if "fun"|func:"ction" %}{% endif %}

它可以用于if判断中，不过simple_tag不支持

自定义分页：

这里做一个简单的分页示例：

views.py加入：

LIST = []for i in range(109):    LIST.append(i)    def user_list(request):    current_page = request.GET.get('p', 1)    current_page = int(current_page)    start = (current_page - 1) * 10    end = current_page * 10    data = LIST[start: end]    all_count = len(LIST)    count, y = divmod(all_count, 10)    if y:        count += 1    page_list = []    for i in range(1, count + 1):        if i == current_page:            temp = '<a class="page active" href="/user_list/?p=%s">%s</a>' % (i, i)        else:            temp = '<a class="page" href="/user_list/?p=%s">%s</a>' % (i, i)        page_list.append(temp)    from django.utils.safestring import mark_safe    page_str = "".join(page_list)    page_str = mark_safe(page_str)    # 为了防止XSS攻击    return render(request, 'user_list.html', {'li': data, 'page_str': page_str})

user_list.html:

<!DOCTYPE html><html lang="en"><head>    <meta charset="UTF-8">    <title>Title</title>    <style>        .pagination .page{            display: inline-block;            padding: 5px;            background-color: aqua;            margin: 5px;        }        .pagination .active{            background-color: brown;            color: white;        }    </style></head><body><ul>    {% for item in li %}        {% include 'li.html' %}    {% endfor %}</ul><div class="pagination">    {{ page_str }}</div></body></html>

顺便用下上一篇的知识：

li.html:

<li>{{ item }}</li>

效果这样：

选中的那个会变成红色的。

这里做到了，但是如果数据过多，就显得不好了。

完善：

LIST = []for i in range(1009):    LIST.append(i)def user_list(request):    current_page = request.GET.get('p', 1)    current_page = int(current_page)    per_page_count = 10    start = (current_page - 1) * per_page_count    end = current_page * per_page_count    data = LIST[start: end]    all_count = len(LIST)    total_count, y = divmod(all_count, per_page_count)    if y:        total_count += 1    page_list = []    page_num = 11    if total_count <= page_num:        start_index = 1        end_index = total_count+1    else:        if current_page <= (page_num+1)/2:            start_index = 1            end_index = page_num+1        else:            start_index = current_page-(page_num-1)/2            end_index = current_page+(page_num+1)/2            if (current_page+(page_num-1)/2) > total_count:                end_index = total_count+1                start_index = total_count-(page_num-1)    if int(current_page) == 1:        prev = '<a class="page" href="javascript:void(0);">上一页</a>'    else:        prev = '<a class="page" href="/user_list/?p=%s">上一页</a>' % (current_page-1)    page_list.append(prev)    for i in range(int(start_index), int(end_index)):        if i == current_page:            temp = '<a class="page active" href="/user_list/?p=%s">%s</a>' % (i, i)        else:            temp = '<a class="page" href="/user_list/?p=%s">%s</a>' % (i, i)        page_list.append(temp)    if current_page == total_count:        nex = '<a class="page" href="javascript:void(0);">下一页</a>'    else:        nex = '<a class="page" href="/user_list/?p=%s">下一页</a>' % (current_page+1)    page_list.append(nex)    jump = '''    <input type="text"/><a onclick='jumpTo(this, "/user_list/?p=");'>GO</a>    <script>        function jumpTo(ths,base){             var val = ths.previousSibling.value;             location.href = base + val;        }    </script>    '''    page_list.append(jump)    from django.utils.safestring import mark_safe    page_str = "".join(page_list)    page_str = mark_safe(page_str)    # 为了防止XSS攻击    return render(request, 'user_list.html', {'li': data, 'page_str': page_str})

完善后的效果：

发现代码量很大，可以对它进行封装：

创一个utils文件夹，新建一个pagination.py

class Page:    def __init__(self, current_page, data_count, per_page_count=10, page_num=7):        self.current_page = current_page        self.data_count = data_count        self.per_page_count = per_page_count        self.page_num = page_num    def start(self):        return (self.current_page - 1) * self.per_page_count    def end(self):        return self.current_page * self.per_page_count    def all_count(self):        v, y = divmod(self.data_count, self.per_page_count)        if y:            v += 1        return v    def page_str(self, base_url):        page_list = []        if self.all_count() <= self.page_num:            start_index = 1            end_index = self.all_count() + 1        else:            if self.current_page <= (self.page_num + 1) / 2:                start_index = 1                end_index = self.page_num + 1            else:                start_index = self.current_page - (self.page_num - 1) / 2                end_index = self.current_page + (self.page_num + 1) / 2                if (self.current_page + (self.page_num - 1) / 2) > self.all_count():                    end_index = self.all_count() + 1                    start_index = self.all_count() - (self.page_num - 1)        if int(self.current_page) == 1:            prev = '<a class="page" href="javascript:void(0);">上一页</a>'        else:            prev = '<a class="page" href="%s?p=%s">上一页</a>' % (base_url, self.current_page - 1)        page_list.append(prev)        for i in range(int(start_index), int(end_index)):            if i == self.current_page:                temp = '<a class="page active" href="%s?p=%s">%s</a>' % (base_url, i, i)            else:                temp = '<a class="page" href="%s?p=%s">%s</a>' % (base_url, i, i)            page_list.append(temp)        if self.current_page == self.all_count():            nex = '<a class="page" href="javascript:void(0);">下一页</a>'        else:            nex = '<a class="page" href="%s?p=%s">下一页</a>' % (base_url, self.current_page + 1)        page_list.append(nex)        jump = '''        <input type="text"/><a onclick='jumpTo(this, "%s?p=");'>GO</a>        <script>            function jumpTo(ths,base){                 var val = ths.previousSibling.value;                 location.href = base + val;            }        </script>        ''' % (base_url,)        page_list.append(jump)        from django.utils.safestring import mark_safe        page_str = "".join(page_list)        page_str = mark_safe(page_str)        # 为了防止XSS攻击        return page_str

在views.py里面这样写即可：

from utils import paginationLIST = []for i in range(1009):    LIST.append(i)def user_list(request):    current_page = request.GET.get('p', 1)    current_page = int(current_page)    page_obj = pagination.Page(current_page, len(LIST))    data = LIST[page_obj.start():page_obj.end()]    page_str = page_obj.page_str("/user_list/")    return render(request, 'user_list.html', {'li': data, 'page_str': page_str})

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