在web开发中,分页是必不可少的功能,Flask实现展示内容的分页也非常简单,这里通过实例来学习一下Flask如何为网站分页。
首先,自定义一个分页工具类page_utils:
from urllib import urlencode class Pagination(object): def __init__(self, current_page, total_count, base_url, params, per_page_count=10, max_pager_count=11): try: current_page = int(current_page) except Exception as e: current_page = 1 if current_page <=0: current_page = 1 self.current_page = current_page self.total_count = total_count self.per_page_count = per_page_count max_page_num, div = divmod(total_count, per_page_count) if div: max_page_num += 1 self.max_page_num = max_page_num self.max_pager_count = max_pager_count self.half_max_pager_count = int((max_pager_count - 1) / 2) self.base_url = base_url import copy params = copy.deepcopy(params) get_dict = params.to_dict() self.params = get_dict @property def start(self): return (self.current_page - 1) * self.per_page_count @property def end(self): return self.current_page * self.per_page_count def page_html(self): if self.max_page_num <= self.max_pager_count: pager_start = 1 pager_end = self.max_page_num # 如果总页数 > 11 else: if self.current_page <= self.half_max_pager_count: pager_start = 1 pager_end = self.max_pager_count else: if (self.current_page + self.half_max_pager_count) > self.max_page_num: pager_end = self.max_page_num pager_start = self.max_page_num - self.max_pager_count + 1 #倒这数11个 else: pager_start = self.current_page - self.half_max_pager_count pager_end = self.current_page + self.half_max_pager_count page_html_list = [] self.params['page'] = 1 first_page = '<li><a href="%s?%s">首页</a></li>'.decode("utf-8") % (self.base_url,urlencode(self.params),) page_html_list.append(first_page) self.params["page"] = self.current_page - 1 if self.params["page"] < 1: pervious_page = '<li class="disabled"><a href="%s?%s" aria-label="Previous">上一页</span></a></li>'. decode("utf-8") % (self.base_url, urlencode(self.params)) else: pervious_page = '<li><a href = "%s?%s" aria-label = "Previous" >上一页</span></a></li>'.decode("utf-8") % ( self.base_url, urlencode(self.params)) page_html_list.append(pervious_page) # 中间页码 for i in range(pager_start, pager_end + 1): self.params['page'] = i if i == self.current_page: temp = '<li class="active"><a href="%s?%s">%s</a></li>' % (self.base_url,urlencode(self.params), i,) else: temp = '<li><a href="%s?%s">%s</a></li>' % (self.base_url,urlencode(self.params), i,) page_html_list.append(temp) self.params["page"] = self.current_page + 1 if self.params["page"] > self.max_page_num: self.params["page"] = self.current_page next_page = '<li class="disabled"><a href = "%s?%s" aria-label = "Next">下一页</span></a></li >'.decode ("utf-8") % (self.base_url, urlencode(self.params)) else: next_page = '<li><a href = "%s?%s" aria-label = "Next">下一页</span></a></li>'.decode("utf-8") % (self.base_url, urlencode(self.params)) page_html_list.append(next_page) self.params['page'] = self.max_page_num last_page = '<li><a href="%s?%s">尾页</a></li>'.decode("utf-8") % (self.base_url, urlencode(self.params),) page_html_list.append(last_page) return ''.join(page_html_list)
自定义方法中的参数:
current_page——表示当前页。
total_count——表示数据总条数。
base_url——表示分页URL前缀,请求的前缀获取可以通过Flask的request.path方法,无需自己指定。
例如:我们的路由方法为@app.route('/test'),request.path方法即可获取/test。
params——表示请求传入的数据,params可以通过request.args动态获取。
例如:我们链接点击为:http://localhost:5000/test?page=10,此时request.args获取数据为ImmutableMultiDict([('page', u'10')])
per_page_count——指定每页显示数。
max_pager_count——指定页面最大显示页码
接着,我们使用一个测试方法来使用这个工具类,达到分页效果,test.py:
from flask import Flask, render_template, request from page_utils import Pagination app = Flask(__name__) @app.route('/test') def test(): li = [] for i in range(1, 100): li.append(i) pager_obj = Pagination(request.args.get("page", 1), len(li), request.path, request.args, per_page_count=10) print(request.path) print(request.args) index_list = li[pager_obj.start:pager_obj.end] html = pager_obj.page_html() return render_template("obj/test.html", index_list=index_list, html=html) if __name__ == '__main__': app.run(debug=True)
在上面的程序中,li为我们要分页的对象,数组list,我们获取到这个list之后,把他用工具类中的起止方法包起来。
传递数据用包装后的list,这样就达到了需要哪一段数据我们传递哪一段的效果,包装的方法:index_list = li[pager_obj.start:pager_obj.end]
我们用一个HTML页面去显示它,分页样式不是重点,我们这里直接引入bootstrap封装好的分页效果,代码如下:
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>Title</title> <link rel="stylesheet" href="{{ url_for('static', filename='css/bootstrap.min.css') }}"> <style> .container{ margin-top: 20px; } </style> </head> <body> <div> <div class="row " style="margin-top: 10px"> <ul> {% for foo in index_list %} <li>{{ foo }}:这是列表内容~~</li> {% endfor %} </ul> <nav aria-label="Page navigation"> <ul> {{ html|safe }} </ul> </nav> </div> </div> </body> </html>
这样一个分页的效果就做好了,我们查看效果,如下图:
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