Unable to find element with tree-node-id

Question

I am trying to automate the process of downloading a file through an online tool. I am using Selenium 3.0.1, and new to it. What am i trying to do?

1. Login
2. Move to specific element
3. From there, Find the element which I need to double click

I am struggling to finding the element. I've done quite a bit of googling but still unable to find the element.

Here is the front end(I don't know how to copy past the html directly):

I am trying to get to the div ext:tree-node-id="xnode-520" (second last line in the picture) I want to get there but I'm unable to, I'm not sure if the unselectable="on" attribute is effecting that.

Here is my code:

public class Main {

public static void main(String[] args) {

    String exePath = "C://Users//user1//Documents//chromedriver.exe";
    System.setProperty("webdriver.chrome.driver", exePath);
    WebDriver driver = new ChromeDriver();
    Actions action = new Actions(driver);

    driver.get("website url");
    driver.manage().window().maximize();
    driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);
    driver.findElement(By.id("username")).sendKeys("u9");
    driver.findElement(By.name("password")).sendKeys("u9");
    driver.findElement(By.id("ext-gen24")).click();
    driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);

    WebElement findElement = driver.findElement(By.id("ext-gen277"));

    WebElement findElement2 = driver.findElement(By.id("ext-gen278"));

    action.moveToElement(findElement);
    action.moveToElement(findElement2);

    String genXPath= "//div[@tree-node-id='xnode-520']";
    driver.findElement(By.xpath(genXPath)).click();
}
}

I left the website url generic for privacy purpose. I haven't really used the Actions class that much at all. I'm relatively new to this and I'm unaware of this dynamic front end.

EDIT: The exception that is being thrown is that the element is not clickable at point..Other element would receive the click

EDIT #2: Well this seems even more complicated the id numbers are changing everytime the page loads.

Answer 1

If the structure of the HTML does not change, a simple CSS selector can be useful.

By.cssSelector("div.xpanel ul.x-tree-root-ct li.tree-node div.x-tree-node-el")

This will select the first element of the tree. If you need to select other element - let's say - the third one:

 By.cssSelector("div.xpanel ul.x-tree-root-ct li.tree-node:nth-of-type(3) div.x-tree-node-el")

With the nth-of-type option and a bit of string concatenation, you can easily select dynamically any element of the tree.