Java 如何等到 Selenium 中不再存在元素
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How to wait until an element no longer exists in Selenium
提问by Thunderforge
I am testing a UI in which the user clicks a delete button and a table entry disappears. As such, I want to be able to check that the table entry no longer exists.
我正在测试用户单击删除按钮并且表条目消失的 UI。因此，我希望能够检查表条目是否不再存在。
I have tried using ExpectedConditions.not()to invert ExpectedConditions.presenceOfElementLocated(), hoping that it would mean "expect that there is not a presence of the specified element". My code is like so:
我曾尝试使用ExpectedConditions.not()to invert ExpectedConditions.presenceOfElementLocated()，希望这意味着“期望不存在指定的元素”。我的代码是这样的：
browser.navigate().to("http://stackoverflow.com");
new WebDriverWait(browser, 1).until(
ExpectedConditions.not(
ExpectedConditions.presenceOfElementLocated(By.id("foo"))));
However, I found that even doing this, I get a TimeoutExpcetioncaused by a NoSuchElementExceptionsaying that the element "foo" does not exist. Of course, having no such element is what I want, but I don't want an exception to be thrown.
但是，我发现即使这样做，我也会因为元素“foo”不存在TimeoutExpcetion的NoSuchElementException说法而受到影响。当然，没有这样的元素是我想要的，但我不希望抛出异常。
So how can I wait until an element no longer exists? I would prefer an example that does not rely on catching an exception if at all possible (as I understand it, exceptions should be thrown for exceptional behavior).
那么我怎么能等到一个元素不再存在呢？如果可能的话，我更喜欢一个不依赖于捕获异常的示例（据我所知，异常行为应该抛出异常）。
采纳答案by Vivek Singh
You can also use -
您还可以使用 -
new WebDriverWait(driver, 10).until(ExpectedConditions.invisibilityOfElementLocated(locator));
If you go through the sourceof it you can see that both NoSuchElementExceptionand staleElementReferenceExceptionare handled.
如果你去通过源的它，你可以看到，无论NoSuchElementException和staleElementReferenceException进行处理。
/**
* An expectation for checking that an element is either invisible or not
* present on the DOM.
*
* @param locator used to find the element
*/
public static ExpectedCondition<Boolean> invisibilityOfElementLocated(
final By locator) {
return new ExpectedCondition<Boolean>() {
@Override
public Boolean apply(WebDriver driver) {
try {
return !(findElement(locator, driver).isDisplayed());
} catch (NoSuchElementException e) {
// Returns true because the element is not present in DOM. The
// try block checks if the element is present but is invisible.
return true;
} catch (StaleElementReferenceException e) {
// Returns true because stale element reference implies that element
// is no longer visible.
return true;
}
}
回答by alecxe
The solution would still rely on exception-handling. And this is pretty much ok, even standard Expected Conditionsrely on exceptions being thrown by findElement().
该解决方案仍将依赖于异常处理。这几乎没问题，即使是标准的预期条件也依赖于findElement().
The idea is to create a custom Expected Condition:
这个想法是创建一个自定义的预期条件：
public static ExpectedCondition<Boolean> absenceOfElementLocated(
final By locator) {
return new ExpectedCondition<Boolean>() {
@Override
public Boolean apply(WebDriver driver) {
try {
driver.findElement(locator);
return false;
} catch (NoSuchElementException e) {
return true;
} catch (StaleElementReferenceException e) {
return true;
}
}
@Override
public String toString() {
return "element to not being present: " + locator;
}
};
}
回答by Saifur
Why don't you simply find the size of elements. We know the the collection of elements' sizewould be 0if elementdoes not exist.
你为什么不简单地找到elements. 我们知道如果元素不存在，元素集合的大小将为0。
if(driver.findElements(By.id("foo").size() > 0 ){
//It should fail
}else{
//pass
}
回答by Nagaraju
// pseudo code
public Fun<driver,webelement> ElemtDisappear(locator)
{
webelement element=null;
iList<webelement> elemt =null;
return driver=>
{
try
{
elemt = driver.findelements(By.locator);
if(elemt.count!=0)
{
element=driver.findelement(By.locator);
}
}
catch(Exception e)
{
}
return(elemnt==0)?element:null;
};
// call function
public void waitforelemDiappear(driver,locator)
{
webdriverwaiter wait = new webdriverwaiter(driver,time);
try
{
wait.until(ElemtDisappear(locator));
}
catch(Exception e)
{
}
}
As findelement throws exception on element unaviability.so i implemented using findelements. please feel free to correct and use it as per your need.
由于 findelement 在元素 unaviability.so 上引发异常，所以我使用 findelement 实现。请随时根据您的需要更正和使用它。
回答by Abhinav Saxena
I found a workaround to fix this for me in efficient way, used following C# code to handle this, you may convert it to Java
我找到了一种解决方法以有效的方式为我解决此问题，使用以下 C# 代码来处理此问题，您可以将其转换为 Java
public bool WaitForElementDisapper(By element)
{
try
{
while (true)
{
try
{
if (driver.FindElement(element).Displayed)
Thread.Sleep(2000);
}
catch (NoSuchElementException)
{
break;
}
}
return true;
}
catch (Exception e)
{
logger.Error(e.Message);
return false;
}
}
回答by Huy Hóm H?nh
I don't know why but ExpectedConditions.invisibilityOf(element)is the only work for me while ExpectedConditions.invisibilityOfElementLocated(By), !ExpectedConditions.presenceOfElementLocated(By)... not. Try it!
我不知道为什么，但是ExpectedConditions.invisibilityOf(element)是唯一为我工作，同时ExpectedConditions.invisibilityOfElementLocated(By)，!ExpectedConditions.presenceOfElementLocated(By)...不是。尝试一下！
Hope this help!
希望这有帮助！
