問題描述

我一直在拼命想讓 WebDriver 可靠地單擊按鈕或鏈接，但它就是不想合作.我嘗試了不同的方法，從設(shè)置隱式超時到下面的代碼，假設(shè)單擊并等待元素出現(xiàn).

I have been desperately trying to get WebDriver to click a button or link reliably, but it just does not want to cooperate. I have tried different methods from setting an implicit timeout, to the below code which is suppose to click and wait for the element to appear.

下面的代碼片段是在互聯(lián)網(wǎng)上的某個地方找到的，它是我最接近可靠地獲得一個按鈕或鏈接來點(diǎn)擊的地方.除了它在調(diào)試模式下的工作方式與我在夜間回歸測試期間執(zhí)行時的工作方式不同.

The below snippet of code was found somewhere on the internet, and it the closest I have come to reliably getting a button or link to click. Except it does not work the same in debug mode as it does when executed during my nightly regression testing.

有誰知道在瀏覽器中單擊按鈕或鏈接的另一種方法?或者我應(yīng)該使用 Selenium 1 而不是 WebDriver，因為它太新而無法可靠使用.

Does anyone know of another method to click a button or link in a browser? Or should I be using Selenium 1 and not WebDriver as it is too new to be used reliably.

public void waitAndClick(WebDriver driver, By by) {
    WebDriverWait wait = new WebDriverWait(driver, 10000, 2000);
    Function<WebDriver, Boolean> waitForElement = new waitForElement(by);
    wait.until(waitForElement);

    Actions builder = new Actions(driver);
    builder.click(driver.findElement(by))
            .perform();
}

private class waitForElement implements Function<WebDriver, Boolean> {
    private final By by;

    private String text = null;

    public waitForElement(By by) {
        this.by = by;
    }

    public waitForElement(By by, String text) {
        this.by = by;
        this.text = text;
    }

    @Override
    public Boolean apply(WebDriver from) {
        if (this.text != null) {
            for (WebElement e : from.findElements(this.by)) {
                if (e.getText().equals(this.text)) {
                    return Boolean.TRUE;
                }
            }

            return Boolean.FALSE;
        } else {
            try {
                driver.switchTo().defaultContent().switchTo().frame("top");
                from.findElement(this.by);
            } catch (Exception e) {
                logger.error("Unable to find "" + this.by.toString() + "". Retrying....");
                return Boolean.FALSE;
            }
            logger.info("Found "" + this.by.toString() + "".");
            return Boolean.TRUE;
        }
    }
}

在 Eclipse 調(diào)試模式下控制臺輸出:

Console out in Eclipse Debug mode:

16:07:08,109 INFO  WebDriverUtility: apply Found "By.linkText: Classes".
16:07:10,514 INFO  WebDriverUtility: apply Found "By.linkText: Reports".
16:07:17,028 ERROR WebDriverUtility: apply Unable to find "By.linkText: Users". Retrying....
16:07:26,369 INFO  WebDriverUtility: apply Found "By.linkText: Users".
16:07:38,272 ERROR WebDriverUtility: apply Unable to find "By.linkText: System". Retrying....
16:07:41,334 INFO  WebDriverUtility: apply Found "By.linkText: System".
16:07:47,722 ERROR WebDriverUtility: apply Unable to find "By.linkText: Schools". Retrying....
16:07:50,565 INFO  WebDriverUtility: apply Found "By.linkText: Schools".

從 Eclipse 運(yùn)行時控制臺退出:

Console out when running from Eclipse:

16:14:04,179 INFO  WebDriverUtility: apply Found "By.linkText: Classes".
16:14:04,726 INFO  WebDriverUtility: apply Found "By.linkText: Reports".
16:14:09,771 INFO  PageAPITesting: login org.openqa.selenium.NoSuchElementException: Unable to find element with link text == Reports (WARNING: The server did not provide any stacktrace information)
For documentation on this error, please visit: http://seleniumhq.org/exceptions/no_such_element.html
Build info: version: '2.0rc3', revision: '12536', time: '2011-06-20 18:19:52'
System info: os.name: 'Windows XP', os.arch: 'x86', os.version: '5.1', java.version: '1.6.0_24'
Driver info: driver.version: RemoteWebDriver
16:14:09,865 INFO  PageAPITesting: login current tabs is Classes
16:14:09,958 INFO  WebDriverUtility: apply Found "By.linkText: Schools".
16:14:10,240 INFO  PageAPITesting: login java.lang.IllegalStateException: Unable to navigate to the ca.schoolspecialty.qa.api.pages.schools.MenuSchoolPage page

推薦答案

我沒有看到任何奇怪的行為，

I don't see any strange behavior,

wait.until 方法，它的作用是在函數(shù)上調(diào)用apply 方法，直到它返回一些東西或者有一個Time Out.

The wait.until method, what it does is to call the apply method on the function until it returns something or there is a Time Out.

如果元素尚未創(chuàng)建，則有時會收到 NotFoundExceptions，實際上，如果您查看代碼，您會看到:

It's expected to receive NotFoundExceptions sometimes if the element hasn't been created yet, actually if you look in the code you'll see this:

 while (clock.isNowBefore(end)) {
  try {
    T value = isTrue.apply(driver);

    if (value != null && Boolean.class.equals(value.getClass())) {
      if (Boolean.TRUE.equals(value)) {
        return value;
      }
    } else if (value != null) {
      return value;
    }
  } catch (NotFoundException e) {
    // Common case in many conditions, so swallow here, but be ready to
    // rethrow if it the element never appears.
    lastException = e;
  }
  sleep();

它捕獲異常并且什么都不做，問題是您覆蓋了應(yīng)用程序以捕獲并記錄該異常，所以您看到的是預(yù)期的行為，沒有其他方法可以檢查元素是否已創(chuàng)建不斷地要求它.

It catches the exception and does nothing with it, the problem is that you overwrote the apply to catch and logs that exception, so what you are seeing is the expected behavior, there's no other way to check if the element has been created that continuously asking for it.

我自己正在將這段代碼用于函數(shù)生成器:

I myself I'm using this code for the Function generator:

public static Function<WebDriver, WebElement> presenceOfElementLocated(
        final By locator) {
    return new Function<WebDriver, WebElement>() {
        @Override
        public WebElement apply(WebDriver driver) {
            return driver.findElement(locator);
        }
    };
}

更簡單，您可以用于任何定位器

Is a lot simpler and you can use for any Locator

這篇關(guān)于WebDriver 不能可靠地單擊鏈接或按鈕的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網(wǎng)！