Element is not Visible error even if my xpath is unique - xpath

Question

Element is not Visible error even if my xpath is unique
//System.setProperty("webdriver.chrome.driver", "C://chromedriver.exe");
//WebDriver driver= new FirefoxDriver();
//WebDriver driver= new ChromeDriver();
driver.manage().window().maximize();
driver.get("https://www.goindigo.in/");
driver.findElement(By.linkText("One Way")).click();
driver.findElement(By.xpath("//button[#class='btn buttonGlbl btn-close button-trigger']")).click();
driver.manage().timeouts().implicitlyWait(5, TimeUnit.SECONDS);
driver.findElement(By.xpath("//div[#class='innertab-content one-way-tab-ctnt']//li[#class='city-dropdown destination-dropdown ps-destination-dropdown without_label']//div[#class='city-dropdown-list city-name-to']//ul//li[3]")).click();
}
}//

Answer 1

/System.setProperty("webdriver.chrome.driver", "C://chromedriver.exe");
//WebDriver driver= new FirefoxDriver();
//WebDriver driver= new ChromeDriver();
driver.manage().window().maximize();
driver.get("https://www.goindigo.in/");
WebElement onewayLink=driver.findElement(By.linkText("One Way"));
onewayLink.click();
WebElement btnElement=driver.findElement(By.xpath("//button[#class='btn buttonGlbl btn-close button-trigger']"));
WebDriverWait wait= new WebDriverWait(driver,20 );
wait.until(ExpectedConditions.visibilityOf(btnElement));
btnElement.click();
driver.findElement(By.xpath("//div[#class='innertab-content one-way-tab-ctnt']//li[#class='city-dropdown destination-dropdown ps-destination-dropdown without_label']//div[#class='city-dropdown-list city-name-to']//ul//li[3]")).click();
}
}//

Answer 2

Above answer, no one hit the root cause, it has nothing to do with need to wait some element.
The root cause is you need to click on the input box of From/To city to make the city list pop-up, then click on the city you wanted.
This is a selenium design principle: an element must be visible, before selenium to click it.
The selenium desinger hope it can simulator operations from user perspective, as we know user need to see the city list before he can choose one. So we also need to make selenium 'see' the city list at first.
But one exception, when you want to select an option from a Select, you can
directly click on the option your wanted, no need to make the options pop-up firstly.
you can find such question from below link, and I give out the detail answer for it.
Using firefox webdriver trying to load the option Name from dropdown but not working?
Code snippet to fix your issue:
driver.get("https://www.goindigo.in/");
// click 'One Way' tab
driver.findElement(By.css(".one-way-tab")).click();
// Click 'OK' on Information pop-up
driver.findElement(By.css(".buttonGlbl.btn-close")).click();
// Click 'From' city input box for 'One Way'
driver.findElement(By.css("#oneWay .origins-value.city-name-value")).click();
// Choose city 'Delhi'
driver.findElement(By.css("#oneWay .origin-city-name"))
.findElement(By.partialLinkText("Delhi"))
.click();
// Click 'To' city input box for 'One Way'
driver.findElement(By.css("#oneWay .destinations-value.city-name-value")).click();
// Choose city 'Indore'
driver.findElement(By.css("#oneWay .dest-city-name"))
.findElement(By.partialLinkText("Indore"))
.click();