DIGIT Core
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2.9-LTS
2.9-LTS
  • 🖥️Platform
    • Overview
    • Why DIGIT?
    • Principles
    • Architecture
      • Service Architecture
      • Technology Architecture
        • Open Source Tools
      • Infrastructure Architecture
      • Deployment Architecture
    • API Specifications
      • Access Control
      • Boundary
      • Document Uploader
      • Encryption
      • File Store
      • ID Generation
      • Indexer
      • Localisation
      • Master Data Management
      • OTP
      • Payment Gateway
      • PDF Generation
      • URL Shortner
      • WhatsApp Chatbot
      • Workflow
    • Core Services
      • Access Control Services
      • Audit Service
        • Signed Audit Performance Testing Results
      • API Gateway
        • Configuring Gateway Rate Limiting
      • Boundary Service
        • Migrate Old Boundary Data - Steps
      • Email Notification Service
      • Encryption Service
        • Encryption Client Library
        • User Data Security Architecture
        • Guidelines for supporting User Privacy in a module
      • FileStore Service
      • ID Generation Service
      • Indexer Service
        • Indexer Configuration
      • Internal Gateway
      • Location
      • Localization Service
        • Configuring Localization
          • Setup Base Product Localisation
          • Configure SMS and Email
      • MDMS V2 (Master Data Management Service)
        • Adopt New MDMS - Steps
        • MDMS (Master Data Management Service)
          • Setting up Master Data
            • MDMS Overview
            • MDMS Rewritten
            • Configuring Tenants
            • Configuring Master Data
            • Adding New Master
            • State Level Vs City Level Master
        • MDMS Migration
      • OTP Service
      • Payment Gateway Service
      • PDF Generation Service
      • Persister Service
        • Persister Configuration
      • Service Request
      • SMS Notification Service
        • Setting Up SMS Gateway
          • Using The Generic GET & POST SMS Gateway Interface
      • User
        • User Session Management
      • User OTP Service
      • URL Shortening Service
      • Workflow
        • Setting Up Workflows
        • Configuring Workflows For An Entity
        • Workflow Auto Escalation
        • Migration To Workflow 2.0
      • Libraries
        • Tracer Library
        • Encryption Client
      • Accelerators
        • Inbox Service
    • DIGIT: How-Tos
      • SMS Template Approval Process
      • Notification Enhancement Based On Different Channel
    • Releases
      • DIGIT 2.9 LTS
        • Test Automation
        • Release Checklist
        • Service Build Updates
          • Hotfix
        • Test Cases
        • Automated DIGIT Deployment
        • Upgrade Guide: Transitioning DIGIT Modules to Spring Boot Version 3.2.2
        • Postgres Upgrade: Service Code Changes
        • Updating RDS Version in AWS
        • LTS DIGIT Migration - v2.8 To v2.9
        • Changelog
        • Backup PostgreSQL Database In AWS - Steps
    • Source Code
  • 📓Guides
    • Installation Guide
      • Infrastructure Setup
        • AWS
          • 1. Pre-requisites
          • 2. Setup AWS Account
          • 3. Provision Infrastructure
          • FAQ
        • Azure
          • 1. Azure Pre-requisites
          • 2. Understanding AKS
          • 3. Infra-as-code (Terraform)
        • SDC
          • 1. SDC Pre-requisites
          • 2. Infra-as-code (Kubespray)
          • CI/CD Setup On SDC
        • CI/CD Set Up
          • CI/CD Build Job Pipeline Setup
      • DIGIT Deployment
        • Full Deployment
          • Deploy DIGIT
            • Prepare Deployment Configuration
        • Full Deployment (Beta)
          • Creating New HelmChart
          • Prepare Helm Release Chart
      • Quick Setup (AWS)
    • Data Setup Guide
      • Bootstrap DIGIT
      • Productionize DIGIT
      • User Module
      • Localisation Module
      • Location Module
      • MDMS - V2
    • Design Guide
      • Model Requirements
      • Design Services
      • Design User Interface
      • Checklists
    • Developer Guide
      • Pre-requisites Training Resources
      • Backend Developer Guide
        • Section 0: Prep
          • Development Pre-requisites
          • Design Inputs
            • High Level Design
            • Low Level Design
          • Development Environment Setup
        • Section 1: Create Project
          • Generate Project Using API Specs
          • Create Database
          • Configure Application Properties
          • Import Core Models
          • Implement Repository Layer
          • Create Validation & Enrichment Layers
          • Implement Service Layer
          • Build The Web Layer
        • Section 2: Integrate Persister & Kafka
          • Add Kafka Configuration
          • Implement Kafka Producer & Consumer
          • Add Persister Configuration
          • Enable Signed Audit
        • Section 3: Integrate Microservices
          • Integrate IDGen Service
          • Integrate User Service
          • Add MDMS Configuration
          • Integrate MDMS Service
          • Add Workflow Configuration
          • Integrate Workflow Service
          • Integrate URL Shortener Service
        • Section 4: Integrate Billing & Payment
          • Custom Calculator Service
          • Integrate Calculator Service
          • Payment Back Update
        • Section 5: Other Advanced Integrations
          • Add Indexer Configuration
          • Certificate Generation
        • Section 6: Run Final Application
        • Section 7: Build & Deploy Instructions
        • FAQs
      • UI Developer Guide
        • DIGIT-UI
          • UI Components Standardisation
            • DIGIT UI Core React Components
            • DIGIT UI Core Flutter Components
              • Input Field
              • Radio
              • Toggle
              • Button
              • Dropdown
              • Checkbox
              • Toast
              • Info Card
            • DIGIT UI Components v0.2.0
              • Foundation
                • Typography
                • Colour Pallete
                • Spacer
              • Atom
                • Accordion
                • Button
                • Checkbox
        • DIGIT UI Development Pre-requisites
        • UI Configuration (DevOps)
        • Local Development Setup
        • Run Application
        • Build & Deploy
        • Pre-defined Screens In DIGIT-UI
          • Create Screen (FormComposer)
          • Inbox/Search Screen
          • Workflow Component
        • Create a New UI Module/Package
          • Project Structure
          • Install Dependency
          • Module.js
          • Import Required Components
          • Common Hooks
        • Employee Module Setup
          • Write Employee Module Code
          • Create Form - Create Screen
        • Citizen Module Setup
          • Sample screenshots
          • Citizen Landing Screen
          • Write Citizen Module Code
        • Customisation
          • Integrate External Web Application/UI With DIGIT UI
          • Utility - Pre-Process MDMS Configuration
          • CSS Customisation
          • Kibana Dashboard Integration With DSS Module
          • Login Page
        • Setup Monitoring Tools
        • Android Web View & How To Generate APK
        • FAQs
          • Troubleshoot Using Browser Network Tab
          • Debug Android App Using Chrome Browser
      • Flutter (Mobile App) UI Developer Guide
        • Introduction to Flutter
          • Flutter - Key Features
          • Flutter Architecture & Approach
          • Flutter Pre-Requisites
        • Setup Development Environment
          • Flutter Installation & Setup Guide
          • Setup Device Emulators/Simulators
          • Run Application
        • Build User Interfaces
          • Create Form Screen
        • Build Deploy & Publish
          • Build & Deploy Flutter Web Application
          • Generate Android APKs & App Bundles
          • Publishing App Bundle To Play Store
        • State Management With Provider & Bloc
          • Provider State Management
          • BloC State Management
        • Best Practices & Tips
        • Troubleshooting
    • Operations Guide
      • DIGIT - Infra Overview
      • Kubernetes
        • RBAC Management
        • Database Dump - Playground
      • Setup Jenkins - Docker way
      • GitOps
        • Git Client installation
        • GitHub organization creation
        • Adding new SSH key to it
        • GitHub repo creation
        • GitHub Team creation
        • Enabling Branch protection:
        • CODEOWNER Reviewers
        • Adding Users to the Git
        • Setting up an OAuth with GitHub
        • Fork (Fork the mdms,config repo with a tenant-specific branch)
      • Working with Kubernetes
        • Installation of Kubectl
      • Containerizing application using Docker
        • Creation of Dockerhub account
      • Infra Provisioning Using Terraform
        • Installation of Terraform
      • Customise Existing Terraform Templates
      • Cert-Manager
        • Obtaining SSL certificates with the help of cluster-issuer
      • Moving Docker Images
      • Pre and post deployment checklist
      • Multi-tenancy Setup
      • Availability
        • Infrastructure
        • Backbone services
          • Database
          • Kafka
          • Kafka Connect
          • Elastic search
            • Elastic Search Rolling Upgrade
            • ElasticSearch Direct Upgrade
        • Core services
        • DIGIT apps
        • DSS dashboard
      • Observability
        • ES-Curator - Clear Old Logs/indices
        • Monitoring
        • Environment Changes
        • Tracing
        • Jaeger Tracing Setup
        • Logging
        • eGov Monitoring & Alerting Setup
        • eGov Logging Setup
      • Performance
        • What to monitor?
          • Infrastructure
          • Backbone services
          • Core services
        • Identifying bottlenecks
        • Solutions
      • Handling errors
      • Security
      • Reliability and disaster recovery
      • Privacy
      • Skillsets/hiring
      • Incident management processes
      • Kafka Troubleshooting Guide
        • How to clean up Kafka logs
        • How to change or reset consumer offset in Kafka?
      • SRE Rituals
      • FAQs
        • I am unable to login to the citizen or employee portal. The UI shows a spinner.
        • My DSS dashboard is not reflecting accurate numbers? What can I do?
      • Deployment using helm
        • Helm Installation
        • Helm chart creation
        • Helm chart customization
      • How to Dump Elasticsearch Indexes
      • Deploy Nginx-Ingress-Controller
      • Deployment Job Pipeline Setup
      • OAuth2-Proxy Setup
      • Jira Ticket Creation
    • Implementation Guide
    • Security & Privacy Guide
      • Security & Privacy Guidelines For Product Developers
      • Security & Privacy Guidelines For Solution Implementing Agencies
      • Security & Privacy Guidelines For Program Owners
  • 🚀Accelerators
    • UI Frameworks
      • Service Build Updates
    • Integrations
      • Payment
      • Notification
      • Transaction
      • Verification
      • View
      • Calculation
    • Concepts
      • Deployment - Key Concepts
        • Security Practices
        • Readiness & Liveness
        • Resource Requests & Limits
        • Deploying DIGIT Services
        • Deployment Architecture
        • Routing Traffic
        • Backbone Deployment
    • API Playground
    • Sandbox
    • Checklists
      • API Checklist
      • Security Checklist
        • Security Guidelines Handbook
        • Security Flow - Exemplar
      • Performance Checklist
      • Deployment Checklist
    • Contribute
    • Discussion Board
    • Academy
    • Events
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  1. Guides
  2. Developer Guide
  3. Flutter (Mobile App) UI Developer Guide
  4. State Management With Provider & Bloc

BloC State Management

BLoC State Management with Bloc Consumer, Bloc Provider, and Bloc Listener

BLoC (Business Logic Component) is a state management pattern in Flutter that helps separate the business logic from the UI.

It follows a unidirectional data flow, where the UI interacts with the BLoC to trigger events, and the BLoC emits new states that the UI can react to. In addition to the core BLoC pattern, the Flutter BLoC library provides useful widgets such as Bloc Consumer, Bloc Provider, and Bloc Listener to simplify the integration of BLoC in Flutter applications.

Key Concepts

  • BLoC: The Business Logic Component represents the core logic of your application. It manages the state and exposes streams or methods to interact with that state.

  • Event: An event is a user action or an external trigger that is passed to the BLoC. It can trigger state changes or other operations in the BLoC.

  • State: The state represents the current condition of the application. It is emitted by the BLoC in response to events and reflects the data that the UI needs to display or react to.

Using Bloc Consumer

The BlocConsumer widget is a powerful tool for consuming the state emitted by a BLoC and rebuilding specific parts of the UI when the state changes.

  1. Wrap the portion of your widget tree that depends on the BLoC state with the BlocConsumer widget.

  2. Provide the BLoC instance and a builder function to define how the UI should be rebuilt based on the emitted state.

  3. Inside the builder function, access the state and return the corresponding widget or widgets.

BlocConsumer<BlocType, StateType>(
  bloc: blocInstance,
  listener: (BuildContext context, StateType state) {
    // Perform side effects based on the emitted state
  },
  builder: (BuildContext context, StateType state) {
    // Build and return the widgets based on the emitted state
    return YourWidget();
  },
)

The listener parameter can be used to perform side effects and function calls based on the emitted state, such as showing a toast message or navigating to a different screen.

Using Bloc Provider

The BlocProvider widget is responsible for providing the BLoC instance to the widget tree and ensuring that it's accessible to all descendant widgets.

  1. Wrap the root of your widget tree with BlocProvider.

  2. Specify the BLoC type using the create parameter to create a new instance of the BLoC.

  3. Access the BLoC instance using BlocProvider.of<BlocType>(context) within descendant widgets.

BlocProvider<BlocType>(
  create: (BuildContext context) => BlocInstance(),
  child: YourApp(),
)

Using Bloc Listener

The BlocListener widget is useful for listening to state changes emitted by the BLoC and performing side effects without rebuilding the UI.

  1. Wrap the BlocListener widget around the portion of the widget tree that needs to listen to state changes.

  2. Provide the BLoC instance and a listener function to handle state changes.

BlocListener<BlocType, StateType>(
  bloc: blocInstance,
  listener: (BuildContext context, StateType state) {
    // Perform side effects based on the state

For more information on Bloc Pattern, navigate through the below reference links -

PreviousProvider State ManagementNextBest Practices & Tips

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Bloc State Management
BloC State Management - Event, State , Bloc