HelpStateManagement class

Help with State Management in Flutter

Terminology

Ephemeral State

  • Definition
    • UI or local state
    • Contained in single widget
    • e.g., animation progress, current page in pageview
  • Use cases
    • Does not change in complex ways
    • Other parts of widget tree seldom require access
  • Methods
    • Stateful widget

App State

  • Definition
    • Shared across many widgets
    • e.g., user prefs, login info, notifications, shopping cart, read/unread articles
  • Use cases
    • Required by many widgets
    • Preserve some state between session, e.g., current page in page view
  • Methods
    • see 1.1.3
    • App State should be placed above widgets which use it
    • Allows sub widgets to access parent state from anywhere in the tree without passing state down through multiple widgets

Approaches

Provider

  • Recommended by Flutter; Easy to use and understandable
  • Use Cases
    • No strong reason to choose another approach

InheritedWidget

  • Low-level approach in widget tree
  • Used by high-level approaches under the hood, e.g., InheritedWidget

InheritedWidget

  • Provides children in subtree access to its state
  • Components:
    • State variables,
      • e.g., final int itemsInCart;
    • of method
      • Provides exact instance of InheritedWidget to child
    • updateShouldNotify method
      • Controls when consumers are rebuilt
      • Has oldWidget as argument, which allows comparing of current and previous state

Usage

  • InheritedWidget.of(context).stateVariableName

Redux

Rx

Hooks

Constructors

HelpStateManagement()

Properties

hashCode → int
The hash code for this object.
no setterinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

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