Android Test Automation Getting to grips with UI Automator

Over the last week I have spent about a day of effort getting to grips with the recently launched UIAutomator test automation framework for Android. It was launched with version 16 of Android (Android 4.1) however on 4.1 devices the framework doesn’t even have all the documented methods available. With version 17 of Android (Android 4.2), support has improved to the point that the examples can work acceptably. Here is the official example

However in the minor update between Android 4.2.1 and Android 4.2.2 someone seems to have broken the support for automatic scrolling through pages of results.  I have reported the problem on the adt-dev forum,!topic/adt-dev/TjeewtpNWf8 which seems to be where the Android development team monitor comments. I have implemented a workaround, using a helper method, below:

     * Launches an app by it's name. 
     * @param nameOfAppToLaunch the localized name, an exact match is required to launch it.
    protected static void launchAppCalled(String nameOfAppToLaunch) throws UiObjectNotFoundException {
        UiScrollable appViews = new UiScrollable(new UiSelector().scrollable(true));
          // Set the swiping mode to horizontal (the default is vertical)
          appViews.scrollToBeginning(10);  // Otherwise the Apps may be on a later page of apps.
          int maxSearchSwipes = appViews.getMaxSearchSwipes();

          UiSelector selector;
          selector = new UiSelector().className(android.widget.TextView.class.getName());
          UiObject appToLaunch;
          // The following loop is to workaround a bug in Android 4.2.2 which
          // fails to scroll more than once into view.
          for (int i = 0; i < maxSearchSwipes; i++) {

              try {
                  appToLaunch = appViews.getChildByText(selector, nameOfAppToLaunch);
                  if (appToLaunch != null) {
                      // Create a UiSelector to find the Settings app and simulate      
                      // a user click to launch the app.
              } catch (UiObjectNotFoundException e) {
                  System.out.println("Did not find match for " + e.getLocalizedMessage());

              for (int j = 0; j < i; j++) {
                  System.out.println("scrolling forward 1 page of apps.");

I ended up writing several skeletal demo Android apps to help me explore the capabilities of UI Automator. In each case I was working through publicly reported problems on where I’ve posted answers and feedback to several reported problems.

Here are the links to my comments:

Strengths of UI Automator

The key strengths include:

  • We can test most applications, including Google’s installed apps such as Settings. Thankfully the example from the Android site does just that, albeit at a perfunctory level. However the example to change the Wi-Fi setting on stackoverflow provides a better example of what we can now do. Because the tests interact with the objects, they have a direct connection to the app being tested, rather than crude interactions by clicking at locations, OCR, etc.
  • Using UI Automator relies on the underlying support for Accessibility in the platform and therefore may help to encourage improved support for Accessible Android apps as developers refine their apps to make them testable by Ui Automator.
  • We can test apps on several devices from one computer, through related changes to the Android build tools.
  • There are debug and exploration tools available on both the device (using adb shell uiautomator) and from my computer, using uiautomationviewer.


  • Text based matching makes testing localized apps much harder than using the older Android Instrumentation which could easily share resource files with the app being tested.
  • There is virtually no documentation or examples, and the documentation that does exist doesn’t provide enough clues to address key challenges e.g. obtaining the text from WebViews.
  • UI Automation cannot be used when the Accessibility features e.g. Explore-By-Touch is enabled on the device.
  • There are bugs in the current version of Android and there’s no easy way to revert devices to 4.2.1
  • Automation is very slow e.g. paging through the set of apps takes several seconds to go to the next page.

Other characteristics

  • All the tests are bundled into a single jar file, deployed to the device. This risks one set of tests overwriting the bundle of tests.

Further reading