如何将Selenium的PageFactory批注与动态加载的元素一起使用？

public void fillinForm() {
    // Fill-in some fields ...

    // Select dynamic loaded option
    String optionXpath = "//*[@id='field']/option[text()='Software engineering']";
    waitForElement(driver, By.xpath(optionXpath), SHORT_TIMEOUT_S);
    driver.findElement(By.xpath(optionXpath)).click();

    // Fill-in more fields, etc ...
}

// Selenium wait
public static void waitForElement(WebDriver driver, By by, int timeout) {
    // implementation
}

public void setUp() {
    page = PageFactory.initElements(driver, Page.class);
}

public void fillinForm() {
    page.setField("Software engineering");
}

public class Page {
    private webElement field;

    public Page setField(String byText) {
        field.click();
        String optionXpath = String.format("./option[text()='%s']", byText);
        field.findElement(By.xpath(optionXpath)).click();
        return this;
    }
}

public void fillinForm() {
    page.setField("Software engineering");
}

public class Page {
    private webElement field;

    public Page setField(String byText) {
        field.click();
        // Note that I'm now explicitly writing "field", exactly what I wanted
        // to save using annotations and the PageFactory
        String optionXpath = String.format("//select[@id='%s']/option[text()='%s']",
            "field", byText);
        field.findElement(By.xpath(optionXpath)).click();
        return this;
    }
}

/** Page Object. */
public class Page {
    private WebElement mySelect;

    public Page setMySelect(String optionText) {
        String optXpath = String.format("./option[text()='%s']", optionText);
        mySelect.click();
        waitForOption(driver,mySelect, By.xpath(optXpath), 10)
            .click();
    }
}

public class Util {

    /**
     * Waits until the option targeted by <tt>byOption</tt> is available.
     *
     * @param select parent element of the option to wait for
     * @param byOption selector (relative to the <tt>select</tt>). It will be
     *             searched calling <tt>select.findElement(byOption)</tt>
     * @return option element
     */
    public static WebElement waitForOption(
            WebDriver driver, WebElement select, By byOption, int seconds) {
        Wait<WebDriver> wait = new WebDriverWait(driver, seconds);
        return wait.until(new OptionAvailable(select, byOption));

    }

    public static class OptionAvailable
            implements ExpectedCondition<WebElement> {
        private WebElement select;
        private By byOption;

        public OptionAvailable(WebElement select, By byOption) {
            this.select = select;
            this.byOption = byOption;
        }

        @Override
        public WebElement apply(WebDriver input) {
            return select.findElement(byOption);
        }
    }
}