Need to wait until page is completely loaded - Selenium WebDriver

Question

I'm automating the execution of test cases using Java and Selenium WebDriver. Below is the scenario:

There is a page named 'Products' and When I click on 'View Details' in the 'Product' page, a popup (modal-dialog) containing the details of the items appears.
On clicking the 'Close' button in the popup, the popup closes and the page refreshes automatically (the page is just reloading, the contents remains unchanged).

After closing the popup, I need to click on 'Add Item' button in the same page as part of the test. But, when WebDriver is trying to find the 'Add Item' button, and if the internet speed is good, then webdriver can find and click the element.

But in case the internet speed is bad or slow, then WebDriver finds the button before the page is refreshed, but right when webdriver clicks on the button, the page gets refreshed and StaleElementReferenceException occurs.

Even if different waits are used, all the wait conditions become true (since the contents in the page are the same before and after reloading) even before the page is reloaded and StaleElementReferenceException occurs.
The test case works perfectly if Thread.sleep(); is used before clicking on the 'Add Item' button. But that's not correct usage. Is there any other workaround for this problem?

Answer 1

Using Thread.Sleep(); is one approach; but its not the recommended approach.
Theoretically speaking, there are 3 types of wait statements. You can use either Implicit waits, or explicit waits, or fluent waits to wait untill the page reloads. In your case, use implicit waits: driver.manage().timeouts().implicitlyWait() is the command. 

Since you need to wait for the page to be reloaded before clicking on the "Add" button, you need to wait for the "Add Item" element to become stale before clicking on the reloaded element. Usage:

driver.manage().timeouts().implicitlywait(30 timeunit.seconds). 

For further understanding, you can refer to the Selenium Certification.

Answer 2

Either you can use Explicit wait for particular web element by following commands: 

WebDriverWait wait = new WebDriverWait(WebDriverRefrence,20);
WebElement web1;
web_1= wait.until(ExpectedConditions.visibilityOfElementLocated(By.id("web_1")));

Or you can use Implicit wait to let the page load completely:

driver.manage().timeouts().implicitlywait(30 timeunit.seconds) 

Answer 3

You can try something like - 

new WebDriverWait(firefoxDriver, pageLoadTimeout).until(
      webDriver -> ((JavascriptExecutor) webDriver).executeScript("return document.readyState").equals("complete"));

Answer 4

Thread.sleep() not a good practice.

if it is a page use implicit wait 

driver.manage().timeouts().implicitlywait(30 timeunit.seconds)

any control use explicit wait :

WebDriverWait wait = new WebDriverWait(WebDriverRefrence,20);
WebElement web1;
web_1= wait.until(ExpectedConditions.visibilityOfElementLocated(By.id("web_1")));