Transition name mislead
It's confusing that you use EXTRA_IMAGE as an intent extra (https://github.com/antoniolg/MaterialEverywhere/blob/master/app/src/main/java/com/antonioleiva/materialeverywhere/DetailActivity.java#L74),
but also as a transition name between views (https://github.com/antoniolg/MaterialEverywhere/blob/master/app/src/main/java/com/antonioleiva/materialeverywhere/DetailActivity.java#L72).
More confusing is that the ImageView in DetailActivity has a transition name defined (https://github.com/antoniolg/MaterialEverywhere/blob/master/app/src/main/res/layout/activity_detail.xml#L32),
but later overridden with EXTRA_IMAGE (https://github.com/antoniolg/MaterialEverywhere/blob/master/app/src/main/java/com/antonioleiva/materialeverywhere/DetailActivity.java#L41).
It would be clearer if the transition name defined in the layout is the same that is used in ActivityOptionsCompat.makeSceneTransitionAnimation call. Then there's no need to call ViewCompat.setTransitionName. Even better, that transition name can be a string resource.
@mbarrben I agree with you. At first when I was looking at the source, it took me awhile to understand it until I checked other sources.
error: Error: No resource found that matches the given name: attr 'android:windowAllowReturnTransitionOverlap'.