Observer<T> class abstract

Observer is someone who observe something.

Technical speaking, Observer is an interface that has an onData method:

abstract class Observer<T> {
  void onData(T data);
}

Example:

final observer = Observer<int>((data) {
  print('onData: $data');
});

Above example create an Observer using inline onData method (data) { ... }. Then we can notify observer using observer.onData:

observer.onData(0); 
observer.onData(1);
observer.onData(2);

Prints:

onData: 0
onData: 1
onData: 2

Implementers

• Subject

Constructors

Observer(OnData<T> onData)

Use Observer(...) to create an Observer with an inline onData method (data) { ... }.

const

factory

Properties

hashCode → int

The hash code for this object.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

onData(T data) → void

Use observer.onData to notify observer.

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited