flutter use valuechanged function in function
class 1{
//in the class where you need to use the callback declare as field
Function(String value) onChanged,
//then use the function as inChanged callback eventually adding code
TextField(
onChanged: (value){
onChanged(value);
state.didChange(value);
},
)
}
//in the other class pass the function like this
class 2{
new 1({
...
onChanged: (value) {
restaurant.name = value;
},
...
});
}