How to handle print dialog in Selenium?

Unfortunately, WebDriver can't handle these (or any other browser or OS dialog). Moreover, they tend to look differently across browsers / systems / language settings, so there's probably no definite answer. You'll need to detect and handle every possible case in order to make it work everywhere. Your options include:

• The Robot class, it allows you to "press" programatically anything on the keyboard (or clicking blindly) and therefore getting rid of the dialog by, say, pressing Enter or Esc. However, as told above, any advanced interaction is dependant on OS / language / printer.

  // press Escape programatically - the print dialog must have focus, obviously
  Robot r = new Robot();
  r.keyPress(KeyEvent.VK_ESCAPE);
  r.keyRelease(KeyEvent.VK_ESCAPE);
  

• AutoIt. It's a Windows program useful for handling any system-level automation. Same dependancy as above.

That's more or less it. If you can avoid the print dialog, try to take screenshot of the page and print it using standard Java tools.

One CAN handle Print dialog with Selenium in Chrome. Not sure about other browsers.

Access to Print dialog was added in ChromeDriver-2.17. Details can be found here: https://bugs.chromium.org/p/chromedriver/issues/detail?id=1087

Right-click on Print dialog -> Inspect Element. As a result, the DOM of Print dialog will open in a separate window. Now you can produce locators for any element on the dialog and use them in your tests.

To close the Print dialog one can do the following:

//Switch to Print dialog
Set<String> windowHandles = driver.getWindowHandles();
if (!windowHandles.isEmpty()) {
    driver.switchTo().window((String) windowHandles.toArray()[windowHandles.size() - 1]);
}
//Now work with the dialog as with an ordinary page:  
driver.findElement(By.className("cancel")).click();

I was able to resolve this issue by adding --kiosk-printing which bypasses the print dialog completely. I have my default print set to pdf, so I end up with a pdf in my Downloads folder, but at least selenium doesn't hang. Here's what the code looks like:

        ChromeOptions cOptions = new ChromeOptions();
        cOptions.addArguments("kiosk-printing");
        RemoteWebDriver driver = new RemoteWebDriver(hostUrl, cOptions);

Slanec's answer is correct - WebDriver doesn't have native capability for this. The way I solved this in Windows is with the System.Windows.Forms.SendKeys object:

    SendKeys.SendWait("^p");
    System.Threading.Thread.Sleep(500);
    SendKeys.SendWait("~");

    // give it a minute to spool onto the printer
    System.Threading.Thread.Sleep(5000);

I've actually got this in a loop printing off a bunch of statements. Works like a charm.