等到加载器消失 python selenium

Question

<div id="loader-mid" style="position: absolute; top: 118.5px; left: 554px; display: none;">
    <div class="a">Loading</div>
    <div class="b">please wait...</div>
</div>

并想等到它消失。我有以下代码，但有时它等待的时间太长，并且在某些代码点它突然冻结所有进程，我不知道为什么。

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

self.wait = WebDriverWait(driver, 10)

self.wait.until(EC.invisibility_of_element_located((By.XPATH, "//*[@id='loader_mid'][contains(@style, 'display: block')]")))

我也试过这个：

self.wait.until_not(EC.presence_of_element_located((By.XPATH, "//*[@id='loader_mid'][contains(@style, 'display: block')]")))

我不知道如何检查，但也许我的元素总是出现在页面上并且 selenium 认为它在那里，唯一改变的是参数显示从无变为块。我想我可以得到像字符串这样的属性，并检查是否有“块”这个词，但它太不对劲了……请帮帮我。

Answer 1

重申您的答案（带有一些错误处理），以便人们更容易找到解决方案:)

导入所需的类：

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

配置变量：

SHORT_TIMEOUT  = 5   # give enough time for the loading element to appear
LONG_TIMEOUT = 30  # give enough time for loading to finish
LOADING_ELEMENT_XPATH = '//*[@id="xPath"]/xPath/To/The/Loading/Element'

代码解决方案：

try:
    # wait for loading element to appear
    # - required to prevent prematurely checking if element
    #   has disappeared, before it has had a chance to appear
    WebDriverWait(driver, SHORT_TIMEOUT
        ).until(EC.presence_of_element_located((By.XPATH, LOADING_ELEMENT_XPATH)))

    # then wait for the element to disappear
    WebDriverWait(driver, LONG_TIMEOUT
        ).until_not(EC.presence_of_element_located((By.XPATH, LOADING_ELEMENT_XPATH)))

except TimeoutException:
    # if timeout exception was raised - it may be safe to 
    # assume loading has finished, however this may not 
    # always be the case, use with caution, otherwise handle
    # appropriately.
    pass 

Answer 2

使用预期条件：invisibility_of_element_located

这对我来说很好。

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


WebDriverWait(driver, timeout).until(EC.invisibility_of_element_located((By.ID, "loader-mid")))

Answer 3

以下代码创建一个无限循环，直到元素消失：

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

while True:
        try:
            WebDriverWait(driver, 1).until(EC.presence_of_element_located((By.XPATH, 'your_xpath')))
        except TimeoutException:
            break