无法使用 Python Selenium 单击元素

Question

我正在开发一个程序，该程序将帮助我在位于窗口右上角的https://www.pcfinancial.ca/ 的下拉菜单中选择第二个选项。到目前为止，这是我的代码：

import time
from selenium import webdriver
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.support import ui

driver = webdriver.Chrome() 

driver.get('https://www.pcfinancial.ca/');
driver.find_element_by_xpath('//*[@id="lnkSignInOp"]').click() #click on dropdown menu - working
driver.find_element_by_xpath('//*[@id="PCM"]/a').click() #select "pc mastercard" - not working

奇怪的是，我可以使用第一行 driver.find_elements_by_xpath(...) 访问下拉菜单，但在选择第二个选项时出现以下错误。

Traceback (most recent call last):
  File "C:\Users\Imad\Documents\Programming\Python\test.py", line 10, in <module>
    driver.find_element_by_xpath('//*[@id="PCM"]/a').click() #open up dropdown menu works
  File "C:\Python27\lib\site-packages\selenium\webdriver\remote\webelement.py", line 80, in click
    self._execute(Command.CLICK_ELEMENT)
  File "C:\Python27\lib\site-packages\selenium\webdriver\remote\webelement.py", line 501, in _execute
    return self._parent.execute(command, params)
  File "C:\Python27\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 308, in execute
    self.error_handler.check_response(response)
  File "C:\Python27\lib\site-packages\selenium\webdriver\remote\errorhandler.py", line 194, in check_response
    raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.ElementNotVisibleException: Message: element not visible
  (Session info: chrome=63.0.3239.84)
  (Driver info: chromedriver=2.33.506120 (e3e53437346286c0bc2d2dc9aa4915ba81d9023f),platform=Windows NT 10.0.16299 x86_64)

谁能帮助我了解发生了什么以及如何解决这个问题？提前致谢！

Answer 1

根据WebSite，链接文本中的WebElement PC MasterCard在<a>标签内，所以我们将构造一个唯一的xpath，如下所示：

from selenium import webdriver

driver = webdriver.Chrome() 
driver.get('https://www.pcfinancial.ca/');
driver.find_element_by_xpath('//*[@id="lnkSignInOp"]').click() #click on dropdown menu - working
driver.find_element_by_xpath("//a[@href='#PCM' and @rel='/re_register/index.html']").click() #click on "PC MasterCard" - now working
print("Clicked on PC MasterCard")

Answer 2

这是计时问题的经典案例。打开下拉菜单后，等待菜单链接可点击，WebDriverWait 和 element_to_be_clickable 预期条件：

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC


driver = webdriver.Chrome()
wait = WebDriverWait(driver, 10)

driver.get('https://www.pcfinancial.ca/')
driver.find_element_by_xpath('//*[@id="lnkSignInOp"]').click()


wait.until(EC.element_to_be_clickable((By.CSS_SELECTOR, "#PCM a"))).click()