How to take screenshot at the point where test fail in Espresso?

Question

I am looking for a way to take a screenshot of device after test failed and before get closed.

Answer 1

I made some improvements on this answer. No need to add an extra dependency for UiAutomator and it also works below api level 18.

public class ScreenshotTestWatcher extends TestWatcher
{
   private static Activity currentActivity;

   @Override
   protected void failed(Throwable e, Description description)
   {
      Bitmap bitmap;

      if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2)
      {
         bitmap = getInstrumentation().getUiAutomation().takeScreenshot();
      }
      else
      {
         // only in-app view-elements are visible.
         bitmap = Screenshot.capture(getCurrentActivity()).getBitmap();
      }

      // Save to external storage '/storage/emulated/0/Android/data/[package name app]/cache/screenshots/'.
      File folder = new File(getTargetContext().getExternalCacheDir().getAbsolutePath() + "/screenshots/");
      if (!folder.exists())
      {
         folder.mkdirs();
      }

      storeBitmap(bitmap, folder.getPath() + "/" + getFileName(description));
   }

   private String getFileName(Description description)
   {
      String className = description.getClassName();
      String methodName = description.getMethodName();
      String dateTime = Calendar.getInstance().getTime().toString();

      return className + "-" + methodName + "-" + dateTime + ".png";
   }

   private void storeBitmap(Bitmap bitmap, String path)
   {
      BufferedOutputStream out = null;
      try
      {
         out = new BufferedOutputStream(new FileOutputStream(path));
         bitmap.compress(Bitmap.CompressFormat.PNG, 100, out);
      }
      catch (IOException e)
      {
         e.printStackTrace();
      }
      finally
      {
         if (out != null)
         {
            try
            {
               out.close();
            }
            catch (IOException e)
            {
               e.printStackTrace();
            }
         }
      }
   }

   private static Activity getCurrentActivity()
   {
      getInstrumentation().runOnMainSync(new Runnable()
         {
            public void run()
            {
               Collection resumedActivities = ActivityLifecycleMonitorRegistry.getInstance().getActivitiesInStage(
                     RESUMED);
               if (resumedActivities.iterator().hasNext())
               {
                  currentActivity = (Activity) resumedActivities.iterator().next();
               }
            }
         });

      return currentActivity;
   }
}

Then include the following line in your test class:

@Rule
public TestRule watcher = new ScreenshotTestWatcher();