How to get the frame and switch to in Selenium Java?-CodePudding

I've been spending more than an hour to find similar cases but nothing helpful. I am new to Java and Selenium and only one member who develops the Selenium Automation script at the moment.

Okay, the target system's HTML code structure is as below.

What I did to click on the element on the topframe is, for example, (simplified snippet);

Page page = new Page();

page.setTopFrame();
page.a_button.click();

class Page{
    @FindBy(id="a_button")
    public WebElement a_button;

    public void setTopFrame() {
        driver.switchTo().frame("topframe");
    }
}

But when I run this codes it returns "org.openqa.selenium.NoSuchElementException" Exception. I don't know what I am missing now. Any advice will be thankful.

--Edited-- Since I post this one, other Exception found which is "NullPointerException: Cannot invoke "org.openqa.selenium.SearchContext.findElement(org.openqa.selenium.By)" because "this.searchContext" is null.

The constructor in Page class should initialised with driver from main Test class. Be like.

Page page = new Page(driver);

And Page class has

Page class{
    WebDriver driver;

    public Page (WebDriver driver){
        this.driver = driver;
        PageFactory.initElements(driver, this);
    }
...
}

CodePudding user response：

Maybe you are currently in another frame. So try:

public void setTopFrame() {
    driver.switchTo().defaultContent();
    driver.switchTo().frame("topframe");
}

CodePudding user response：

Page class{ WebDriver driver;

public Page (WebDriver driver){
    this.driver = driver;
    PageFactory.initElements(driver, this);
}

... }

Thank you all read my question. I hope this answer help someone in trouble with same issue.