Django之内置组件

Django组件介绍

　　      分页器的使用

　　      Form

　　      modelForm

　　      orm

　　      cookie和session

　　      中间件

　　      信号

 

1.分页器的使用

分页器在页面中非常常见,当数据库条数数据过多时,页面一次性显示不好看,我们就可以使用页面器,将数据分几次显示

一个简单的分页功能,可以导入用

  page_num = request.GET.get('page','1')
    try:
        page_num = int(page_num)
        if page_num <=0:
            page_num = 1
    except Exception as e:
        page_num =1
    #总数量
    all_count = len(userlist)
    #每页显示为10 页
    per_num = 10
    #总页码数
    total_page_num, more =divmod(all_count,per_num)
    if more:
        total_page_num += 1
    #最多显示的页面数
    max_show = 11
    half_show = max_show//2
    if total_page_num < max_show:
        page_start = 1
        page_end = total_page_num
    elif page_num <= half_show:
        page_start =1
        page_end =max_show
    elif page_num + half_show > total_page_num:
        page_start = total_page_num-max_show +1
        page_end = total_page_num
    else:
        #起始页面
        page_start = page_num - half_show
        #终止页面
        page_end = page_num + half_show
    start =(page_num-1) * per_num
    end =page_num*per_num

    page_list = []

    if page_num == 1:
        page_list.append('<li class="disabled"><a>上一页</a></li>')
    else:
        page_list.append('<li ><a href="?page={}">上一页</a></li>'.format(page_num - 1))

    for i in range(page_start, page_end + 1):
        if i == page_num:
            page_list.append('<li class="active" ><a href="?page={}">{}</a></li>'.format(i, i))
        else:
            page_list.append('<li><a href="?page={}">{}</a></li>'.format(i, i))
        if page_num == total_page_num:
            page_list.append('<li class="disabled"><a>下一页</a></li>')
        else:
            page_list.append('<li><a href="?page={}">下一页</a></li>'.format(page_num + 1))

        page_html = ''.join(page_list)

        return render(request, 'user_list.html',
                      {'users': userlist[start:end], 'page_html': page_html})

分页