io.appium.uiautomator2 Cached elements 'By.xpath: */child::*' do not exist in DOM anymore when scrolling through a ListView

The problem

When scrolling through a ListView and gathering the child elements the “Cached elements ‘By.xpath: /child::’ do not exist in DOM anymore” exception is thrown.

Environment

• Appium version (or git revision) that exhibits the issue: 1.18
• Last Appium version that did not exhibit the issue (if applicable): 1.9.1
• Desktop OS/version used to run Appium: Windows 10 64bit
• Node.js version (unless using Appium.app|exe): 12.18.2
• Npm or Yarn package manager: npm
• Mobile platform/version under test: Android 8/10
• Real device or emulator/simulator: Both
• Appium CLI or Appium.app|exe: CLI

Details

I have an app with a list view that contain 20 elements but only 11 are visible at once. I need all of the child elements so in a loop I gather all the visible ones, then swipe a bit. After that I collect the new child elements and if no new elements appear after a swipe I finish the loop. 100% of the time, when I make the final swipe that does not change the contents of the list view I get the exceptions. (Occasionally I get it in one of the “mid” swipes)

Link to Appium logs

appium_log.txt

Code To Reproduce Issue [ Good To Have ]

            var capabilities = getAndroidOptions(AppPath);
            driver = new AndroidDriver<IWebElement>(AndroidServerUri,
                capabilities);
            driver.ResetApp();
            Size device = driver.Manage().Window.Size;
            var bar = (AppiumWebElement)driver.FindElementById("android:id/tabs");
            ReadOnlyCollection<AppiumWebElement> children = bar.FindElementsByXPath("*/child::*");
            children[9].Click();
            var button = driver.FindElementById("com.tricentis.androidtestapp:id/openListView");
            button.Click();
            Thread.Sleep(300);
            var list = (AppiumWebElement)driver.FindElementById("android:id/select_dialog_listview");
            ReadOnlyCollection<AppiumWebElement> listItems = list.FindElementsByXPath("*/child::*");
            List<string> labels = new List<string>();
            bool breaking;

            while (true) {
                breaking = true;
                Thread.Sleep(500);
                listItems = list.FindElementsByXPath("*/child::*");
                foreach (AppiumWebElement item in listItems) {
                    if (!labels.Contains(item.Text)) {
                        labels.Add(item.Text);
                        breaking = false;
                    }
                }

                if (breaking) {
                    break;
                }

                TouchAction swipe = new TouchAction(driver);
                swipe.Press(device.Width / 2, device.Height / 2).Wait(300)
                    .MoveTo(device.Width / 2, device.Height * 0.3).Release();
                swipe.Perform();               
            }

            driver.CloseApp();




private static AppiumOptions getAndroidOptions(string app)
        {
            var capabilities = new AppiumOptions();
            capabilities.AddAdditionalCapability(AndroidMobileCapabilityType.NoSign, true);
            capabilities.AddAdditionalCapability(MobileCapabilityType.PlatformName, "Android");
            capabilities.AddAdditionalCapability(MobileCapabilityType.Udid, "emulator-5554");
            capabilities.AddAdditionalCapability(MobileCapabilityType.AutomationName,
                AutomationName.AndroidUIAutomator2);
            capabilities.AddAdditionalCapability(AndroidMobileCapabilityType.UnicodeKeyboard, true);
            capabilities.AddAdditionalCapability(AndroidMobileCapabilityType.ResetKeyboard, true);
            //capabilities.AddAdditionalCapability(MobileCapabilityType.App, app);
            capabilities.AddAdditionalCapability("dontStopAppOnReset", true);
            capabilities.AddAdditionalCapability("noReset", true);
            capabilities.AddAdditionalCapability("fullReset", false);
            capabilities.AddAdditionalCapability("appActivity", "MainActivity");
            capabilities.AddAdditionalCapability("appPackage", ****);
            return capabilities;
        }

[Auto81]

looks to be behaving as expected

[mykola-mokhnach]

@sme81 I think I know what the cause might be. Please check if the fix https://github.com/appium/appium-uiautomator2-server/pull/371 works for you