AmbigousViewMatcherException means that your code does not know which UI element needs to invoke a certain action. The reason is that there are multiple elements in the current screen that has the same ViewMatcher inside your
Consider the following UI mockup above that has similar resource id to it's start button (the only difference is that the other buttons are disabled). If you use the below snippet it will return an
AmbigousViewMatcherException because it doesn't know which start button to click. Quick fix to this is to update each of the button with similar resource ids unique. But what if it's not possible because the cost benefit of updating the code is not worth it?
So how do I click the Blue Button?
In my previous article I explained the basics on how to use
ViewMatchers and promised to do a follow up on how to effectively use it on complex scenarios. One of the things that I mentioned is that you can
chain is not the right term, but you can use multiple
onView() with the help of
Hamcrest Matchers, specifically the
For simple unique views you can use the
onView() function like this. The code simply looks for an android view with a resource id of
But if there are two UI elements sharing the same resource id and you use the code above it will then return the
AmbigousViewMatcherException. What you need to do is to use the
allOf Hamcrest Matcher inside the
onView() and then pass the
ViewMatchers that you need inside the
allOf() function, so it will look something like this.
import org.hamcrest.Matchers.allOf val multipleSelectors = allOf(withId(R.id.startButton), isEnabled()) Espresso.onView(multipleSelectors).perform(ViewActions.click())
or like this...
import org.hamcrest.Matchers.allOf Espresso.onView( allOf( withId(R.id.startButton), isEnabled() ) ).perform(ViewActions.click())
Note that you need to import the hamcrest matcher as it's not part of the Espresso Library. Simply put the
allOf() function serves as an
AND operand for ViewMatchers. It's like saying
Find an element with all of these attributes on the screen and then perform this action
When I was learning Espresso for the first time, I was kinda new to Hamcrest Matchers and reading the
onView in conjuction of
allOf threw me off. I was reading it to something like this. "Find all of the elements with these attributes and perform this action" which is technically not the case!
Fixing AmbigousViewMatcherException doesn't end here
Nope! it doesn't end here because there are cases where Android UI elements are completely identical! So how do we tell our code to perform a click to the element that we truly want? Find out on the Part 2 of of How to fix AmbigousViewMatcherException on my upcoming article.