java - 如何初始化 StringoriginalHandle = driver.getWindowHandle();一次？

Question

我正在将 TestNG 与 Selenium 一起使用。我正在尝试使用 driver.getWindowHandle();在弹出窗口、iframe 等之间切换。

问题是，如果我在 TNGDriver 类中这样声明它

public String originalHandle = driver.getWindowHandle();

我得到一个java.lang.NullPointerException(显然，因为这是在驱动程序之前初始化的)。我如何声明一次并开始在其他类中使用它？请记住，我的类在它们之间进行了扩展，我需要在其他类的方法内使用此originalHandle变量，例如:

public void clickOnFacebookIcon() {
    Assert.assertTrue(true, driver.findElement(By.id(FACEBOOK_ICON)).getText());
    driver.findElement(By.id(FACEBOOK_ICON)).click();   
    for(String handle : driver.getWindowHandles()) {
        if (!handle.equals(originalHandle)) {
            driver.switchTo().window(handle);
            driver.close();
        }
    }   
    driver.switchTo().window(originalHandle);
}

这是我的其他类(class):

TNGDriver 类

public class TNGDriver {

public static WebDriver driver; 
public static final String CHROME_DRIVER_PATH = "C:\\Program Files (x86)\\Google\\Chrome\\Application\\chromedriver.exe";   
private WebDriverWait wait; 

@SuppressWarnings("deprecation")
public void init() {        
    DesiredCapabilities capabilities = DesiredCapabilities.chrome();
    ChromeOptions options = new ChromeOptions();
    options.addArguments("--incognito");
    capabilities.setCapability(ChromeOptions.CAPABILITY, options);
    System.setProperty("webdriver.chrome.driver", CHROME_DRIVER_PATH);      
    driver = new ChromeDriver(capabilities);    
    driver.manage().window().maximize();            
}   

public WebDriverWait getWait() {
     wait = new WebDriverWait(driver, 60);
     return wait;
}

Testcase1 类

public class Testcase1 extends Registration {

    TNGDriver tngDriver = new TNGDriver();

    @BeforeTest
    public void setup() {
        tngDriver.init();
    }

    @Test(priority = 1)
    public void step1_clickOnSignIn() {
        clickOnSignIn();
    }
    @Test(priority = 2)
    public void step2_clickOnFacebookIcon() {
        clickOnFacebookIcon();
    }

Answer 1

您可以使用设计模式来做到这一点

https://en.wikipedia.org/wiki/Singleton_pattern

使用这种模式，您将只有一个对象实例。

class Singleton 
{ 
    // static variable single_instance of type Singleton 
    private static Singleton single_instance = null; 

    // variable of type String 
    public String originalHandle = driver.getWindowHandle(); 

    // private constructor restricted to this class itself 
    private Singleton() 
    { 
       //Do something on constructor
    } 

    // static method to create instance of Singleton class 
    public static Singleton getInstance() 
    { 
        if (single_instance == null) 
            single_instance = new Singleton(); 

        return single_instance; 
    } 
} 

要访问它，您可以执行以下操作

 Singleton x = Singleton.getInstance(); 
 //To access the String variable 
 x.s