DerivedFlag class
A flag computed from other state: value is compute's answer at the moment it is read, and listeners hear when that answer changes.
It re-computes when one of sources notifies, or when update is
called (for a source that is not a Listenable, such as the
dispatcher's change stream), and notifies only when the answer differs
from the last one it announced: a tool that notifies on every hover
does not rebuild the toolbar.
- Inheritance
-
- Object
- ChangeNotifier
- DerivedFlag
- Implemented types
Constructors
-
DerivedFlag(List<
Listenable> sources, bool _compute())
Properties
- hashCode → int
-
The hash code for this object.
no setterinherited
- hasListeners → bool
-
Whether any listeners are currently registered.
no setterinherited
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
- value → bool
-
The current value of the object.
no setteroverride
Methods
-
addListener(
VoidCallback listener) → void -
Register a closure to be called when the object changes.
inherited
-
dispose(
) → void -
Discards any resources used by the object.
override
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
notifyListeners(
) → void -
Call all the registered listeners.
inherited
-
removeListener(
VoidCallback listener) → void -
Remove a previously registered closure from the list of closures that are
notified when the object changes.
inherited
-
toString(
) → String -
A string representation of this object.
inherited
-
update(
) → void - Re-computes, and notifies when the answer changed.
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited