Building Blockchain Applications with Flutter: A "Hello World" Decentralized App
In this tutorial, we'll walk you through the process of creating a simple Decentralized Application (Dapp) using Ethereum, Solidity, and Flutter. This tutorial is designed for those with a basic knowledge of Ethereum and smart contracts, who have some knowledge of the Flutter framework but are new to mobile dapps.
Setting Up the Project
First, let's set up the project structure. We'll need the following files and directories:
- in the directory for our smart contract.
- in the directory for linking the contract with Flutter.
- in the directory for deploying the contract.
- for configuring Truffle.
- in the directory for creating a UI to interact with the smart contract.
- in the directory for testing the smart contract.
Creating the Smart Contract
Our smart contract, , will include a constructor, a function to set the name, and a variable to store the name. The minimum version of Solidity required is noted at the top of the contract.
```solidity pragma solidity ^0.5.16;
contract HelloWorld { string public yourName;
} ```
Interacting with the Smart Contract
The file will declare several variables and functions for interacting with the smart contract. The function in this file will directly invoke the function of the smart contract.
```dart import 'dart:async'; import 'package:web3dart/web3dart.dart'; import 'package:ethereum_address/ethereum_address.dart';
class ContractLinking { // Contract ABI and address final EthereumAddress _contractAddress = EthereumAddress.fromHex('YOUR_CONTRACT_ADDRESS'); final List
final EthereumHttp _ethereumHttp = EthereumHttp('YOUR_INFURA_URL'); final Web3Client _web3Client = Web3Client(_ethereumHttp, Client()); final Contract _contract = Contract(_contractABI, address: _contractAddress);
// Function to set the name Future
} } ```
Updating the UI and Testing
The file is updated to use the new file for the UI. A new file, , is created to handle the UI logic. A test file, , is created in the directory for testing the smart contract.
Deploying the Contract
The content of file includes instructions for migrating the contract to the blockchain. The file is modified to include the necessary configuration for migrating the contract.
To install Truffle, one command is required after node is installed. Once Truffle is installed, you can deploy the contract using the command.
Running the Dapp
Ganache, a personal blockchain for Ethereum development, is used to run the blockchain locally. With Ganache running, you can compile, migrate, and test your contract. Once everything is set up, you can run the Flutter project to see your Dapp in action.
The Smart Contract acts as the back-end logic and storage for the Dapp, while the UI displays the name from the smart contract variable .
This tutorial was created by the team behind "readyplace," a company specializing in AI-supported tutorial management systems for creating quick and easy click tutorials and documentation.
Happy coding!
