Selenium List <WebElement> 总是返回 null

Question

当getoption 用于从下拉菜单中检索值时，Selenium List<WebElement> 返回零。

代码sn-p：

public class FaceBookdropDownMenu {
    public static void main(String[] args) throws InterruptedException {
        System.getProperty("webdriver.gecko.driver", "//usr//local//bin//geckodriver 6");
        WebDriver driver = new FirefoxDriver();
        driver.manage().window().maximize();
        driver.get("https://www.facebook.com/");

        WebElement month_dropdown = driver.findElement(By.id("month"));
        //return a list of month names
        System.out.println(month_dropdown.getText());
        List<WebElement> month_lists = driver.findElements(By.id("month"));   
        int total_month= month_lists.size();
        // returns 1 instead of 12 
        System.out.println("Total month count is"+ total_month);

        for(WebElement ele:month_lists) {
            String month_name = ele.getText();
            System.out.println("Months are:"+ month_name); 
        }
    }
}

================================================ ======================== 我使用getOptions()，但它也不起作用

WebElement month_dropdown =driver.findElement(By.id("month"));
System.out.println(month_dropdown.getText());
Select month_dd = new Select(month_dropdown);
List <WebElement> month_lists = month_dd.getOptions();       
int total_month= month_lists.size();
//Zero is returned instead of 12
System.out.println("Total month count is"+ total_month);

for(WebElement ele:month_lists) {
    String month_name = ele.getText();
    System.out.println("Months are:"+ month_name);
}

Answer 1

以下代码对我有用：

import java.util.List;
import java.util.Random;
import java.util.concurrent.TimeUnit;

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.support.ui.ExpectedConditions;
import org.openqa.selenium.support.ui.Select;
import org.openqa.selenium.support.ui.WebDriverWait;

public class FacebookDateSelect {

    public static void main(String[] args) {


        WebDriver driver = new ChromeDriver();
        driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);
        driver.get("https://www.facebook.com/");
        driver.manage().window().maximize();

        WebDriverWait wait = new WebDriverWait(driver, 20);
        WebElement month_dropdown = wait.until(ExpectedConditions.visibilityOfElementLocated(By.id("month")));
        Select month_dd = new Select(month_dropdown);
        List <WebElement> month_lists = month_dd.getOptions();       
        int total_month= month_lists.size();
        System.out.println("Total month count is"+ total_month);

        for(WebElement ele:month_lists) {
            String month_name = ele.getText();
            System.out.println("Months are:"+ month_name);
        }

        //updated code - to select random option using Random class
        month_dd.selectByIndex(new Random().nextInt(user_country.getOptions().size()));
        driver.quit();

    }

}

在您的代码中，

List<WebElement> month_lists = driver.findElements(By.id("month"));

总是返回一个元素，因为只有一个 id 为 month 的元素。这确实会返回其中的选项（使用 getOptions 方法）

我做的另一个改变是使用WebDriverWait，有明确的等待条件（直到网页上显示月份下拉菜单），检查给定的持续时间（20秒）。如果元素本身在第一秒内找到，该元素将被返回，它不会等到 20 秒。同样，如果20秒后没有找到该元素，则会抛出Timeout异常。

我得到的输出：

Starting ChromeDriver 2.25.426923 (0390b88869384d6eb0d5d09729679f934aab9eed) on port 6720
Only local connections are allowed.
Total month count is13
Months are:Month
Months are:Jan
Months are:Feb
Months are:Mar
Months are:Apr
Months are:May
Months are:Jun
Months are:Jul
Months are:Aug
Months are:Sept
Months are:Oct
Months are:Nov
Months are:Dec