StatefulSheetDelegateFunction<T, S> class

A delegate that holds a function which uses the MultiStateSheetController to compute a dynamic value.

This delegate allows you to provide a callback function that receives the current MultiStateSheetController with its generic state type S, enabling you to return a value of type T based on the controller's current state or animation.

Useful for creating dynamic, responsive properties that update as the sheet moves or changes state.

⚠️ Important: You should create this delegate outside the widget's build method — ideally as a final field in a State class, or within a view model or other persistent scope. Avoid constructing it inline within build() to ensure consistency and performance.

Example:

final delegate = StatefulSheetDelegateFunction<int, MySheetState>(
  function: (controller) {
    if (controller.currentState == MySheetState.expanded) {
      return 100;
    }
    return 50;
  },
);
Inheritance

Constructors

StatefulSheetDelegateFunction({required T? function(MultiStateSheetController<S> controller)})
Creates a delegate with a function function that calculates the value dynamically based on the given MultiStateSheetController.
const

Properties

function → T? Function(MultiStateSheetController<S> controller)
A function that receives the current MultiStateSheetController and returns a value of type T or null.
final
hashCode → int
The hash code for this object.
no setterinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

getStaticValue() → T?
We need this method to get the value of the delegate if it is a static value. We want to avoid calling the function every time we need the value and we can use this method in init() to get the value of the delegate and store it in a variable.
inherited
getValue<StateType>(MultiStateSheetController<StateType> controller) → T?
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited