如何等待属性？ java + webdriver

Question

我需要等待，直到属性收到值，并得到关于“直到”的错误。我做错了什么？谢谢

List<WebElement> messages = driver.findElements(By.className("message-item")); 
//select last message 
WebElement lastMessage = messages.get(messages.size() - 1); 
//wait for last message attribute received failed 
WebDriverWait waitLastMessage = new WebDriverWait(driver, 10); 
waitLastMessage.until(lastMessage.getAttribute("data-deliverystatus").contains("failed")); 
//here i check vaules of attribute 
Assert.assertEquals(lastMessage.getAttribute("data-deliverystatus"), "failed"); 

Answer 1

until方法接收ExpectedConditions，没有任何boolean。你可以做类似的事情（未经测试）

private ExpectedCondition<Boolean> waitForAttribute(final WebElement element) { 
    return new ExpectedCondition<Boolean>() { 
     public Boolean apply(WebDriver driver) { 
      return element.getAttribute("data-deliverystatus").contains("failed"); 
     } 
    }; 
} 

WebDriverWait waitLastMessage = new WebDriverWait(driver, 10); 
waitLastMessage.until(waitForAttribute);