rrousselGit/provider
Provider
Provider is a state management and dependency injection framework for Flutter. It simplifies the sharing of data across a widget tree by using a system that manages the injection of objects and services with automated lifecycle and resource disposal.
The framework distinguishes itself through reactive state containers that bridge asynchronous data from streams and futures directly into the component tree. It supports state derivation, allowing new objects to be constructed and synchronized based on values observed from multiple upstream providers. To maintain performance, it provides selective rebuild filtering and partial state subscriptions to limit updates to specific slices of the user interface.
The library covers broad capability areas including interface mapping to decouple concrete implementations from abstract interfaces and provider composition to flatten multiple dependency definitions and reduce nesting. It also includes utilities for optional dependency resolution and the preservation of application state during development hot reload cycles.
Features
- Dependency Injection Providers - Implements a provider-based system to inject services and configurations into component hierarchies for a Flutter application.
- Contextual State Lookups - Provides mechanisms for retrieving shared objects from the component tree using context-based lookups.
- Component-Tree Lifecycle Management - Handles lazy allocation and automatic disposal of objects based on their position in the component tree lifecycle.
- Dependency Lifecycle Management - Manages the complete lifecycle of dependency objects, ensuring proper instantiation and resource cleanup when removed from the tree.
- Lifecycle-Managed Initialization - Provides lazy instantiation of dependencies combined with automated resource disposal tied to the widget tree lifecycle.
- Stream-Based Data Providers - Converts asynchronous data from futures or streams into reactive providers that automatically drive Flutter UI updates.
- Flutter State Management - Provides libraries and patterns for managing and synchronizing shared application state across a Flutter widget tree.
- Future-Based State Providers - Provides specialized handling for futures, exposing the final resulting value to descendant widgets automatically.
- Dependency Injection Frameworks - Implements an inversion of control framework to manage component dependencies and their lifecycles.
- Derived Provider Composers - Constructs new state by combining multiple upstream providers and automatically recomputing values when dependencies change.
- Asynchronous Providers - Bridging asynchronous data streams into the component tree to trigger automatic UI updates when new values are emitted.
- Tree-Based Providers - Provides a system for injecting objects into the widget tree with automatic disposal based on the tree lifecycle.
- UI-Reactive Data Types - Triggers component rebuilds automatically when values update from streams, futures, or change notifiers.
- Scoped Stateful Object Sharing - Enables creating singleton instances of stateful objects shared across a component and all its descendants to avoid prop drilling.
- Reactive Async-Stream Integration - Exposes the most recent values from asynchronous streams and futures to the widget tree for reactive UI updates.
- Reactive State Managers - Synchronizes application data across components via automatic change tracking to keep the UI in sync.
- InheritedWidget Scoping - Implements state propagation using Flutter's native InheritedWidget for efficient, constant-time data lookups across the widget tree.
- State Retrieval Mechanisms - Provides mechanisms to retrieve provided objects from the component tree via either one-time reads or reactive subscriptions.
- Property-Specific Rebuild Filters - Allows watching only a subset of an object's properties so consumers rebuild only when those specific properties change.
- Rebuild Optimization Tools - Offers utilities to isolate widget sub-trees and prevent unnecessary interface redraws during state updates.
- Interface-Based Decoupling - Decouples components from concrete implementations by injecting dependencies through abstract interfaces, promoting testability.
- Provider Grouping - Allows grouping multiple dependency providers into a single structure to reduce nesting and improve readability.
- External Instance Integration - Allows publishing existing object instances to the component tree without the framework assuming ownership of their lifecycle.
- Interface-to-Implementation Bindings - Maps abstract interfaces to concrete class implementations, allowing components to depend on interfaces for better modularity.
- Partial State Selectors - Provides partial state selectors that restrict UI rebuilds to only occur when specific properties of a state object change.
- Hot-Reload State Preservation - Executes custom logic during development reload cycles to preserve application state and context.
- Flat Provider Compositions - Merges multiple providers into a flat structure to eliminate deeply nested wrapper components in the widget tree.
- Selective Rebuilds - Optimizes performance by limiting widget rebuilds to only those components that depend on specific slices of shared state.
- Selective Widget Rebuilding - Implements techniques to isolate UI updates by monitoring specific state slices to minimize rendering overhead.
- Reactive Provider Containers - Ships reactive provider containers that synchronize dependent state and expose asynchronous data to the component tree.
- Development Frameworks - Dependency injection and state management library.
- State Management - Simple and efficient state management for widget trees.
