添加首頁和尾頁:
views.py:
from django.shortcuts import render from app01 import models def book_list(request): # 從 URL 中取參數(shù) page_num = request.GET.get("page") print(page_num, type(page_num)) page_num = int(page_num) # 定義兩個變量保存數(shù)據(jù)從哪兒取到哪兒 data_start = (page_num - 1) * 10 data_end = page_num * 10 # 書籍總數(shù) total_count = models.Book.objects.all().count() # 每一頁顯示多少條數(shù)據(jù) per_page = 10 # 總共需要多少頁碼來顯示 total_page, m = divmod(total_count, per_page) # 頁面上最多展示的頁碼 max_page = 11 half_max_page = max_page // 2 # 頁面上展示的頁碼的開始頁 page_start = page_num - half_max_page # 頁面上展示的頁碼的結(jié)束頁 page_end = page_num + half_max_page # 如果當(dāng)前頁減一半比 1 小 if page_start <= 1: page_start = 1 page_end = max_page # 如果當(dāng)前頁加一半比總頁碼還大 if page_end > total_page: page_end = total_page page_start = total_page - max_page + 1 # 如果還有數(shù)據(jù) if m: total_page += 1 all_book = models.Book.objects.all()[data_start:data_end] # 拼接 html 的分頁代碼 html_list = [] # 添加首頁按鈕 html_list.append('
book_list.html:
書籍列表
{% for book in books %} 序號 id 書名 {% endfor %} {{ forloop.counter }} {{ book.id }} {{ book.title }}
運(yùn)行結(jié)果:
添加上一頁、下一頁:
views.py:
from django.shortcuts import render from app01 import models def book_list(request): # 從 URL 中取參數(shù) page_num = request.GET.get("page") print(page_num, type(page_num)) page_num = int(page_num) # 定義兩個變量保存數(shù)據(jù)從哪兒取到哪兒 data_start = (page_num - 1) * 10 data_end = page_num * 10 # 書籍總數(shù) total_count = models.Book.objects.all().count() # 每一頁顯示多少條數(shù)據(jù) per_page = 10 # 總共需要多少頁碼來顯示 total_page, m = divmod(total_count, per_page) # 頁面上最多展示的頁碼 max_page = 11 half_max_page = max_page // 2 # 頁面上展示的頁碼的開始頁 page_start = page_num - half_max_page # 頁面上展示的頁碼的結(jié)束頁 page_end = page_num + half_max_page # 如果當(dāng)前頁減一半比 1 小 if page_start <= 1: page_start = 1 page_end = max_page # 如果當(dāng)前頁加一半比總頁碼還大 if page_end > total_page: page_end = total_page page_start = total_page - max_page + 1 # 如果還有數(shù)據(jù) if m: total_page += 1 all_book = models.Book.objects.all()[data_start:data_end] # 拼接 html 的分頁代碼 html_list = [] # 添加首頁按鈕 html_list.append('
book_list.html:
書籍列表
{% for book in books %} 序號 id 書名 {% endfor %} {{ forloop.counter }} {{ book.id }} {{ book.title }}
運(yùn)行結(jié)果:
后續(xù)改進(jìn):
處理用戶傳給 url 的 page 參數(shù)異常的值的情況
例如:
訪問,http://127.0.0.1:8888/book_list/?page=a
訪問,http://127.0.0.1:8888/book_list/?page=-1
都會出錯
改進(jìn):
from django.shortcuts import render from app01 import models def book_list(request): # 從 URL 中取參數(shù) page_num = request.GET.get("page") print(page_num, type(page_num)) # page_num 為 str 類型 # 書籍總數(shù) total_count = models.Book.objects.all().count() # 每一頁顯示多少條數(shù)據(jù) per_page = 10 # 總共需要多少頁碼來顯示 total_page, m = divmod(total_count, per_page) # 如果還有數(shù)據(jù) if m: total_page += 1 try: page_num = int(page_num) # 如果輸入的頁碼數(shù)超過了最大的頁碼數(shù),默認(rèn)返回最后一頁 if page_num > total_page: page_num = total_page # 如果輸入的頁碼數(shù)小于 1,則返回第一頁 if page_num < 1: page_num = 1 except Exception as e: # 當(dāng)輸入的頁碼不是正經(jīng)數(shù)字的時候 默認(rèn)返回第一頁的數(shù)據(jù) page_num = 1 # 定義兩個變量保存數(shù)據(jù)從哪兒取到哪兒 data_start = (page_num - 1) * 10 data_end = page_num * 10 # 頁面上最多展示的頁碼 max_page = 11 half_max_page = max_page // 2 # 頁面上展示的頁碼的開始頁 page_start = page_num - half_max_page # 頁面上展示的頁碼的結(jié)束頁 page_end = page_num + half_max_page # 如果當(dāng)前頁減一半比 1 小 if page_start <= 1: page_start = 1 page_end = max_page # 如果當(dāng)前頁加一半比總頁碼還大 if page_end > total_page: page_end = total_page page_start = total_page - max_page + 1 all_book = models.Book.objects.all()[data_start:data_end] # 拼接 html 的分頁代碼 html_list = [] # 添加首頁按鈕 html_list.append('
如果數(shù)據(jù)庫中的數(shù)據(jù)數(shù)少于 max_page,則會顯示負(fù)數(shù)的頁數(shù)
例如數(shù)據(jù)庫中只有 21 條數(shù)據(jù):
改進(jìn):
from django.shortcuts import render from app01 import models def book_list(request): # 從 URL 中取參數(shù) page_num = request.GET.get("page") print(page_num, type(page_num)) # page_num 為 str 類型 # 書籍總數(shù) total_count = models.Book.objects.all().count() # 每一頁顯示多少條數(shù)據(jù) per_page = 10 # 總共需要多少頁碼來顯示 total_page, m = divmod(total_count, per_page) # 如果還有數(shù)據(jù) if m: total_page += 1 try: page_num = int(page_num) # 如果輸入的頁碼數(shù)超過了最大的頁碼數(shù),默認(rèn)返回最后一頁 if page_num > total_page: page_num = total_page # 如果輸入的頁碼數(shù)小于 1,則返回第一頁 if page_num < 1: page_num = 1 except Exception as e: # 當(dāng)輸入的頁碼不是正經(jīng)數(shù)字的時候 默認(rèn)返回第一頁的數(shù)據(jù) page_num = 1 # 定義兩個變量保存數(shù)據(jù)從哪兒取到哪兒 data_start = (page_num - 1) * 10 data_end = page_num * 10 # 頁面上最多展示的頁碼 max_page = 11 # 如果總頁碼數(shù)小于頁面上最多展示的頁碼 if total_page < max_page: max_page = total_page half_max_page = max_page // 2 # 頁面上展示的頁碼的開始頁 page_start = page_num - half_max_page # 頁面上展示的頁碼的結(jié)束頁 page_end = page_num + half_max_page # 如果當(dāng)前頁減一半比 1 小 if page_start <= 1: page_start = 1 page_end = max_page # 如果當(dāng)前頁加一半比總頁碼還大 if page_end > total_page: page_end = total_page page_start = total_page - max_page + 1 all_book = models.Book.objects.all()[data_start:data_end] # 拼接 html 的分頁代碼 html_list = [] # 添加首頁按鈕 html_list.append('
運(yùn)行結(jié)果:
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