onBackStackChangeStarted

Called whenever the contents of the back stack are starting to be changed, before any fragment actually changes its lifecycle state. If this is caused by a forward transaction and the given fragment is incoming, it will return false from isRemoving. If this is caused by a pop operation and the given fragment is being popped, it will return true from isRemoving.

This is the first callback that will be delivered to the listener. If the transaction is caused by a predictive back gesture, it will be followed by an onBackStackChangeProgressed callback otherwise, the next callback will be onBackStackChangeCommitted.

Parameters