Handle the NoSuchElementException in Fluent Wait

问题

I know that in terms of waiting for web element that isn't in the DOM yet, the most efficient is a fluent wait. So my question is:

Is there a way to handle and catch the NoSuchElementException or any exception that fluent wait might throw because the element is not existing?

I need to have a boolean method wherein it will give me result whether the element is found or not.

This method is quite popular on the web.

public void waitForElement(WebDriver driver, final By locator){
    Wait<WebDriver> wait = new FluentWait<WebDriver>(driver)
            .withTimeout(60, TimeUnit.SECONDS)
            .pollingEvery(2, TimeUnit.SECONDS)
            .ignoring(NoSuchElementException.class);

   wait.until(new Function<WebDriver, WebElement>() {
        public WebElement apply(WebDriver driver) {
            return driver.findElement(locator);
        }
    });
}

What I need is, **.ignoring(NoSuchElementException.class);** will not be ignored. And once the exception is caught, it will return FALSE. On the other hand, when an element is found, it will return TRUE.

回答1:

As an alternative as you have wanted to see the implementation of WebDriverWait with polling, here are the constructor details :

WebDriverWait(WebDriver driver, long timeOutInSeconds) : Wait will ignore instances of NotFoundException that are encountered (thrown) by default in the 'until' condition, and immediately propagate all others.
```
WebDriverWait wait1 = new WebDriverWait(driver, 10);
```
WebDriverWait(WebDriver driver, long timeOutInSeconds, long sleepInMillis) : Wait will ignore instances of NotFoundException that are encountered (thrown) by default in the 'until' condition, and immediately propagate all others.
```
WebDriverWait wait2 = new WebDriverWait(driver, 10, 500);
```

Update :

To answer to your comment, we have just defined the WebDriverWait instance here. Next we have to implement the WebDriverWait instance i.e. wait1/wait2 within our code through proper ExpectedCondition clauses. The JavaDocs for ExpectedCondition is here.

回答2:

You can use WebDriverWait with polling and ignoring

Example:

public boolean isElementPresentWithWait(WebDriver driver, WebElement element) {
    try {
        WebDriverWait wait = new WebDriverWait(driver, 10);
        wait.pollingEvery(3, TimeUnit.SECONDS).ignoring(NoSuchElementException.class).until(ExpectedConditions.visibilityOf(element);
        return true;
    } catch (TimeoutException e) {
        return false;
    }
}

Methods ignoring and pollingEvery return instance of FluentWait<WebDriver>

回答3:

Here it is:

public boolean waitForElementBoolean(WebDriver driver, By object){
    try {
        WebDriverWait wait = new WebDriverWait(driver,60);
        wait.pollingEvery(2, TimeUnit.SECONDS);
        wait.until(ExpectedConditions.visibilityOfAllElementsLocatedBy(object));
        return true;
    } catch (Exception e) {
        System.out.println(e.getMessage()); 
        return false;
    }
}

I integrated the fluent wait with the explicit wait. :D Thank you guys! :)

回答4:

you can try with this below code snippet

    /*
 * wait until expected element is visible
 */
public boolean waitForElement(WebDriver driver, By expectedElement) {
    boolean isFound = true;
    try {
        WebDriverWait wait = new WebDriverWait(driver, timeoutInSeconds , 300);
        wait.until(ExpectedConditions.visibilityOfElementLocated(expectedElement));
        makeWait(1);
    } catch (Exception e) {
        //System.out.println(e.getMessage());
        isFound = false;
    }
    return isFound;
}

来源：https://stackoverflow.com/questions/47575339/handle-the-nosuchelementexception-in-fluent-wait

标签

java

selenium-webdriver

selenium-chromedriver

nosuchelementexception

fluentwait