[Selenium]怎样等待元素出现之后再消失，譬如Loading icon

界面上有些元素是要先等它出现，再等它消失，譬如loading icon

这个是等多个loading icon出现后消失

/**
     * Wait for loading icon disappear in dialog and Widgets
     * @author jz
     */
    public void waitForLoadingIconDisappearInDialog(WebDriver driver) {
        System.out.println("Wait for loading icons display in dialog or widgets.");
        Function<WebDriver, Boolean> waitFn = new Function<WebDriver, Boolean>() {
            @Override
            public Boolean apply(WebDriver driver) {
                try {
                    for (WebElement el : driver.findElements(By.cssSelector("div.win-bd-mask[style*='display: block'] div.win-bd-mask-waiting"))) {
                        if (el.isDisplayed()) {
                            System.out.println("Loading icon display in dialog or widgets.");
                            return false;
                        }
                    }
                } 
                catch (Exception ex) {
                    return true;
                }
                return true;
            }
        };
 
        WebDriverWait wait = new WebDriverWait(driver, 120, 1000);
        wait.withMessage("Loading icons should disppear in dialog or widgets in 120s");
        wait.until(waitFn);
        System.out.println("Loading icons disspear in dialog or widgets.");
    }

这个是等一个loading icon 出现后消失

public void waitForLoadingIconDisappearInNewWebPage(WebDriver driver) {
        System.out.println("Wait for loading icon display in new web page.");
        final By cssSelector=By.cssSelector("div.x-mask-msg");
        Function<WebDriver, Boolean> waitFn = new Function<WebDriver, Boolean>() {
            public Boolean apply(WebDriver driver) {
                try{
                    if(driver.findElement(cssSelector).isDisplayed()){
                        System.out.println("Loading icon display in new web page.");
                        return false;
                    }
                }
                catch(Exception e){
                    return true;
                }
                return true;
            }
        };
        WebDriverWait wait = new WebDriverWait(driver, 120, 2000);
        wait.withMessage("Loading icon should disappear in new web page in 120s");
        wait.until(waitFn);
        System.out.println("Loading icon disappear in new web page.");
    }

如果等显现的元素变成隐藏，相对要简单一些，先等它可见，再等它不可见

public void waitForLoadingIconDisappearInHomePage(WebDriver driver) {
        this.waitForElementVisible(driver, By.cssSelector("div#window-waiting-box"), 20 ,"Waiting box should display in 20s");
        this.waitForElementNotVisible(driver, By.cssSelector("div#window-waiting-box"), 120 ,"Waiting box should disppear in 120s");
    }