django

 

 

模板继承 

1、继承母板:{% extends '母板html文件名称' %}

2、包含子模板:{% include  '子母板html 文件名' %}

模板内容分块 {% block <分块名> %}{% endblock %}

对某一区域分块命名,继承模板时覆盖 “母板” 中的同名块儿 {% block title %}{% endblock %} 

  3、利用request 请求对象中内容,例如session {{ request.session.current_user }}

自定义python函数应用于模板

  (方法一:simple_tag)

1、在app 目录下创建templatetags 目录(名称不可更改)

2、创建任意.py文件,如xxoo.py ,在文件内写自定义功能的函数。使用django.template.Library()创建register对象(对象名不可更改)

使用 @register.simple_tag 装饰自定义函数

示例xxoo.py

from django import template

register = template.Library()


@register.simple_tag
def plus(a1, a2):
    return a1 + a2

   对象名必须为register

  3、模板中使用 {% load '书写自定义函数的文件名' %}

  函数用法 {% 函数名 参数...%}

{% load xxoo %}

{% plus 1 3 %}

  优点:参数个数没有限制,缺点:不能使用if语句

   (方法二:filter)

1、在app 目录下创建templatetags 目录(名称不可更改)

2、创建任意.py文件,如xxoo.py ,在文件内写自定义功能的函数。使用django.template.Library()创建register对象(对象名不可更改)

使用 @register.simple_tag 装饰自定义函数

示例xxoo.py

from django import template

register = template.Library()


@register.filter
def plus(a1, a2): # 形参最多支持2个
    return a1 + a2

3、模板中使用 {% load '书写自定义函数的文件名' %} 加载,

函数用法:{{ 参数1|函数名:参数二 }}

html中语法示例:

{{ 2|plus:1 }}

  优点:可以使用if语句 缺点:定义函数时参数个数最多两个,使用时参数1|函数名:参数2 之间不能有空格

    {% if 2|plus:2  > 3 %}
        <span>大于3</span>
    {% endif %}

 

分页功能

django.utils.safestring import make_safe  后端设置字符串为安全字符串,在模板中渲染时字符串中的html标签不做转义。浏览器可以正常解析html标签

views.py 获取指定分页值,根据分页获展示指定分页数据

from django.shortcuts import render
from django.shortcuts import HttpResponse
from django.views import View

from app02 import models
from django.utils.safestring import mark_safe
# Create your views here.

LIST = range(1, 101)

class PageTest(View):
    def get(self,request):
        # 获取当前页码
        current_page = int(request.GET.get('p', 1))
        # 单页显示数量
        page_size = request.GET.get('size', 10)

        start = (current_page - 1) * page_size
        end = current_page * page_size
        # 当前页显示的数据
        data = LIST[start:end]

        # 分页个数逻辑,根据数据总数/每页显示个数计算
        all_count = len(LIST)
        count, y = divmod(all_count, page_size)
        # 如果余数不为零 则需要加一页显示
        if y:
            count += 1
        # 分页标签html字符串
        page_list = []
        for i in range(1, count + 1):
            if current_page == i:
                temp = '<a class="page active" href="/database_study/page-test/?p=%s">%s</a>' % (i, i)
            else:
                temp = '<a class="page " href="/database_study/page-test/?p=%s">%s</a>' % (i, i)
            page_list.append(temp)
        # 将列表中每个分页html字符串相连接
        page_str = ''.join(page_list)
        # 将字符串设置为安全字符串from django.utils.safestring import mark_safe
        page_str = mark_safe(page_str)
        return render(request, 'page_test.html', {'li': data, 'page_str': page_str})

  分页数量过多,分页标签只展示部分。

示例代码:

from django.shortcuts import render
from django.shortcuts import HttpResponse
from django.views import View

from app02 import models
from django.utils.safestring import mark_safe
# Create your views here.

LIST = []
for i in range(1, 1001):
    LIST.append({'key': 'value' + str(i)})

class PageTest(View):
    def get(self,request):
        # 获取当前页码
        current_page = int(request.GET.get('p', 1))
        # 单页显示数量
        page_size = int(request.GET.get('size', 10))

        # 当前页显示的数据
        start = (current_page - 1) * page_size
        end = current_page * page_size
        data = LIST[start:end]

        # 分页个数计算,根据数据总数/每页显示个数计算
        all_count = len(LIST)
        page_count, y = divmod(all_count, page_size)
        # 如果余数不为零 则需要加一页显示
        if y:
            page_count += 1
            
        # 每页显示几个分页标签
        page_num = 7

        # 分页标签html字符串
        page_list = []

        # 当前分页标签居中,计算起始和结束分页标签
        # 分页数量不足设定的最少标签(本例:7个)的时候,起始为第一页,结束为分页总数
        if page_count < page_num:
            start_index = 1
            end_index = page_count + 1
        # 分页大于一次性显示的分页标签时
        else:
            # 判断当前页位置,如果在设定显示页数的最前面1/2时,起始和结束分页标签的位置
            if current_page <= (page_num + 1)/2:
                start_index = 1
                end_index = page_num + 1
            # 当前也在中间或者总分页最后几页时,计算起始和结束标签页
            else:
                # 当前页在总页数 - 单页显示标签数1/2之间时,避免超出总分页,计算起始和结束页码
                if current_page + (page_num + 1)/2 > page_count:
                    end_index = page_count +1
                    start_index = page_count - page_num + 1
                # 当前页码在中间位置,前后都没有超出页码范围,计算起始和结束标签
                else:
                    start_index = current_page - (page_num -1)/2
                    end_index = current_page + (page_num + 1)/2
        start_index = int(start_index)
        end_index = int(end_index)

        # 上一页标签
        if current_page == 1:
            prev_page = '<a class="page " href="javascript:void(0);">上一页</a>'
        else:
            prev_page = '<a class="page " href="/database_study/page-test/?p=%s&size=%s">上一页</a>' % ((current_page - 1), page_size)
        page_list.append(prev_page)

        for i in range(start_index, end_index):
            if current_page == i:
                temp = '<a class="page active" href="/database_study/page-test/?p=%s&size=%s">%s</a>' % (i,  page_size, i)
            else:
                temp = '<a class="page " href="/database_study/page-test/?p=%s&size=%s">%s</a>' % (i, page_size, i)
            page_list.append(temp)
        # 下一页标签
        if current_page == page_count:
            next_page = '<a class="page " href="javascript:void(0);">下一页</a>'
        else:
            next_page = '<a class="page " href="/database_study/page-test/?p=%s&size=%s">下一页</a>' % ((current_page + 1), page_size)
        page_list.append(next_page)

        # 将列表中每个分页html字符串相连接
        page_str = ''.join(page_list)
        # 将字符串设置为安全字符串from django.utils.safestring import mark_safe
        page_str = mark_safe(page_str)
        return render(request, 'page_test.html', {'li': data, 'page_str': page_str})

    html 文件

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .pagination .page {
            display: inline-block;
            padding: 5px;
            margin: 5px;
            background-color: #6DDCBD;
        }
        .pagination .page.active {
            background-color: brown;
            color: white;
        }
    </style>
</head>
<body>
    <ul>
        {% for item in li %}
            <li>{{ item }} </li>
        {% endfor %}
    </ul>

    <div class="pagination">
        {{ page_str }}
    </div>
</body>
</html>

 

面向对象方式,封装分页功能

from django.shortcuts import render
from django.shortcuts import HttpResponse
from django.views import View

from app02 import models
from django.utils.safestring import mark_safe
# Create your views here.

# 模拟 数据库获取到千余条数据
LIST = []
for i in range(1, 1001):
    LIST.append({'key': 'value' + str(i)})

class CalcPageTag(object):
    def __init__(self,page_size, data_count, current_page, page_num, ):
        self.data_count = data_count
        self.page_size = page_size
        self.current_page = current_page
        self.page_num = page_num

    def start(self):
        start_data_index = (self.current_page - 1) * self.page_size
        return start_data_index

    def end(self):
        end_data_index = self.current_page * self.page_size
        return end_data_index

    def page_count(self):
        # 分页个数计算,根据数据总数/每页显示个数计算
        count_num, y = divmod(self.data_count, self.page_size)
        # 如果余数不为零 则需要加一页显示
        if y:
            count_num += 1
        return count_num
    def page_tag(self):

        page_count = self.page_count()
        # 当前分页标签居中,计算起始和结束分页标签
        # 分页数量不足设定的最少标签(本例:7个)的时候,起始为第一页,结束为分页总数
        if page_count < self.page_num:
            start_index = 1
            end_index = page_count + 1
        # 分页大于一次性显示的分页标签时
        else:
            # 判断当前页位置,如果在设定显示页数的最前面1/2时,起始和结束分页标签的位置
            if self.current_page <= (self.page_num + 1)/2:
                start_index = 1
                end_index = self.page_num + 1
            # 当前也在中间或者总分页最后几页时,计算起始和结束标签页
            else:
                # 当前页在总页数 - 单页显示标签数1/2之间时,避免超出总分页,计算起始和结束页码
                if self.current_page + (self.page_num + 1)/2 > page_count:
                    end_index = page_count + 1
                    start_index = page_count - self.page_num + 1
                # 当前页码在中间位置,前后都没有超出页码范围,计算起始和结束标签
                else:
                    start_index = self.current_page - (self.page_num - 1)/2
                    end_index = self.current_page + (self.page_num + 1)/2
        start_index = int(start_index)
        end_index = int(end_index)
        return start_index, end_index
    def page_tag_str(self,base_url):
        # 分页标签html字符串
        page_list = []
        start_index, end_index = self.page_tag()

        # 上一页标签
        if self.current_page == 1:
            prev_page = '<a class="page " href="javascript:void(0);">上一页</a>'
        else:
            prev_page = '<a class="page" href="%s?p=%s&size=%s">上一页</a>' % (base_url, (self.current_page - 1), self.page_size)
        page_list.append(prev_page)

        # 分页标签html字符串
        for i in range(start_index, end_index):
            if self.current_page == i:
                temp = '<a class="page active" href="%s?p=%s&size=%s">%s</a>' % (base_url, i, self.page_size, i)
            else:
                temp = '<a class="page " href="%s?p=%s&size=%s">%s</a>' % (base_url, i, self.page_size, i)
            page_list.append(temp)

        # 下一页标签
        if self.current_page == self.page_count():
            next_page = '<a class="page " href="javascript:void(0);">下一页</a>'
        else:
            next_page = '<a class="page " href="%s?p=%s&size=%s">下一页</a>' % (base_url, (self.current_page + 1), self.page_size)
        page_list.append(next_page)

        # 将列表中每个分页html字符串相连接
        page_str = ''.join(page_list)
        # 将字符串设置为安全字符串from django.utils.safestring import mark_safe
        page_str = mark_safe(page_str)
        return page_str

class PageTest(View):
    def get(self,request):
        # 获取当前页码
        current_page = int(request.GET.get('p', 1))

        # 单页显示数量
        page_size = int(request.GET.get('size', 10))

        # 显示几个分页标签
        page_num = 7

        # 实例化自定义数据范围&标签计算类。
        page = CalcPageTag(page_size=page_size, data_count=len(LIST), current_page=current_page,page_num=page_num)

        # 当前页显示的数据
        data = LIST[page.start():page.end()]

        tag_base_url = '/database_study/page-test/'
        page_str = page.page_tag_str(tag_base_url)

        return render(request, 'page_test.html', {'li': data, 'page_str': page_str})

 备注: <a class="page " href="javascript:void(0);">上一页</a> 标签 中 href="javascript:void(0)表示什么都不做

原文地址:https://www.cnblogs.com/zhangmingda/p/13336615.html