How to check Toast window, on android test-kit Espresso

If we read the following public document, we can check other window.
Using inRoot to target non-default windows

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onView(withText("South China Sea"))   .inRoot(withDecorView(not(is(getActivity().getWindow().getDecorView()))))   .perform(click());

But, I think this is not cool.

We can create a custom matcher.
Toast window has the WindowManager.LayoutParams.TYPE_TOAST.

The followinf code is sample.

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/**  * Matcher that is Toast window.  */ public static Matcher<Root> isToast() {     return new TypeSafeMatcher<Root>() {           @Override         public void describeTo(Description description) {             description.appendText("is toast");         }           @Override         public boolean matchesSafely(Root root) {             int type = root.getWindowLayoutParams().get().type;             if ((type == WindowManager.LayoutParams.TYPE_TOAST)) {                 IBinder windowToken = root.getDecorView().getWindowToken();                 IBinder appToken = root.getDecorView().getApplicationWindowToken();                 if (windowToken == appToken) {                     // windowToken == appToken means this window isn't contained by any other windows.                     // if it was a window for an activity, it would have TYPE_BASE_APPLICATION.                     return true;                 }             }             return false;         }     }; }