Espresso: return boolean if view exists

Question

I am trying to check to see if a view is displayed with Espresso. Here is some pseudo code to show what I am trying:

if (!Espresso.onView(withId(R.id.someID)         


        

Answer 1

It's been some time since this issue was stated, but as it is one of the top hit on Google when searching for ways to make sure a view is present, before doing any actions on it in Espresso, I would like to share my very basic way of handling this.

1: Start out by writing an extension to ViewInteraction:

fun ViewInteraction.exists(): Boolean {
val viewExists = AtomicReference()

this.perform(object : ViewAction {
    override fun perform(uiController: UiController?, view: View?) {
        viewExists.set(view != null)
    }

    override fun getConstraints(): Matcher? {
        return Matchers.allOf(ViewMatchers.withEffectiveVisibility(
                ViewMatchers.Visibility.VISIBLE),
                ViewMatchers.isAssignableFrom(View::class.java))
    }

    override fun getDescription(): String {
        return "check if view exists"
    }
})
return viewExists.get()
}

2: Create a simple help method in your base class (to be used in all test classes):

fun viewExists(id: Int): Boolean {
    return try {
        onView(withId(id)).exists()
    } catch (e: RuntimeException) {
        false
    }
}

With this you either get true or false from onView(withId(id)).exists(), or safely catch the RuntimeException and return false.

Normally a simple check to .exists() would be sufficient, but in some cases, like when you are deleting ListView items until non is left -> when the last item is deleted, the ListView might no longer be present, then an Exception is thrown when trying to check if it exists.

3: With the above implementation, it is safe to check if any view exists, since the RuntimeException is handled nicely behind the scene:

if(viewExists(R.id.something)) {
    //do something
}
//do something else