Flutter delegate

addListener method Null safety Adds a listener callback that is called whenever a new concrete ImageInfo object is available or an error is reported . If a concrete image is already available, or if an error has been already reported, this object will notify the listener synchronously.

“add click listener in flutter” Code Answer’s

A widget that calls callbacks in response to common pointer events . It listens to events that can construct gestures, such as when the pointer is pressed, moved, then released or canceled.