为什么硒有时能定位物体，有时却不能

Question

早上好，我正在尝试使简单的在线程序自动化：转到这个网站http://nvidia-research-mingyuliu.com/gaugan/选中小框，更新图片，渲染并点击下载按钮下载。我已经编写了我的代码，它非常直观，非常简短，但由于某些原因，有时它有效，有时它不起作用。果不其然，有时python会返回以下错误：没有这样的元素：无法定位元素：{"方法"："css选择器"，"选择器"："[id="myCheck"]"}

我的代码是：

import selenium
import time
from selenium import webdriver
# Using Chrome to access web
driver = webdriver.Chrome(executable_path='/Users/Marco/Downloads/chromedriver')
# Open the website
driver.get('http://nvidia-research-mingyuliu.com/gaugan/')
# Select the checkbox
time.sleep(5)
check_box = driver.find_element_by_id('myCheck')
check_box.click()
# Upload File button
element = driver.find_element_by_id("myCheck")
driver.execute_script("arguments[0].click();", element)
choose_file = driver.find_element_by_id('segmapfile')
# Send the file location to the button
choose_file.send_keys('/Users/Marco/Desktop/Foto upload/Schermata 2020-10-31 alle 00.07.03.png')
#Locate submit button and click
submit_assignment = driver.find_element_by_id('btnSegmapLoad')
submit_assignment.click()
#render
render_button = driver.find_element_by_id('render')
render_button.click()
#download
save_box = driver.find_element_by_id('save_render')
time.sleep(5)
save_box.click()

为什么会发生这种情况？我该如何解决？谢谢

Answer 1

使用等待发生的显式等待，而不是只等待5秒的"time.sleep(5("：

import selenium
from selenium import webdriver
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
# Using Chrome to access web
driver = webdriver.Chrome(executable_path='/Users/Marco/Downloads/chromedriver')
# Open the website
driver.get('http://nvidia-research-mingyuliu.com/gaugan/')
# Wait for checkbox to be located
check_box_wait = EC.presence_of_element_located((By.ID, 'myCheck'))
WebDriverWait(driver, 10).until(check_box_wait)
# Select the checkbox
check_box = driver.find_element_by_id('myCheck')
check_box.click()