Flutter以太坊交互插件flutter_ethers的使用

Flutter_Ethers 是一个 Dart 库，用于与以太坊区块链进行交互。它受到了 ethers.js 和 ethers 的启发。

安装

在 pubspec.yaml 文件中添加 Flutter_Ethers：

dependencies:
  flutter_ethers:

在需要使用的文件中导入 Flutter_Ethers：

import 'package:flutter_ethers/flutter_ethers.dart';

使用

Provider

Provider 用于连接到以太坊节点并获取数据。

const provider = ethers.providers.JsonRpcProvider();

// 查看当前区块编号
final blockNumber = await provider.getBlockNumber();
print(blockNumber); // 输出: 14135476

// 获取账户余额（通过地址或ENS名称，如果网络支持）
final balance = await provider.getBalance("0x0000000000000000000000000000000000000000");
print(balance); // 输出: { BigInt: "10478645750785322678769" }

// 将输出格式化为更友好的形式，例如以太币（而不是wei）
print(ethers.utils.formatEther(balance)); // 输出: '10478.645750785321'

// 如果用户输入了一个字符串，可能需要将其从以太币（作为字符串）转换为wei（作为BigNumber）
print(ethers.utils.parseEther("1.0")); // 输出: { BigInt: "1000000000000000000" }

Wallet

Wallet 用于管理以太坊钱包，包括从助记词或私钥创建钱包实例。

// 从助记词创建钱包实例
final mnemonic = "announce room limb pattern dry unit scale effort smooth jazz weasel alcohol";
final walletMnemonic = Wallet.fromMnemonic(mnemonic);

// 从私钥创建钱包实例
final walletPrivateKey = Wallet(walletMnemonic.privateKey);

// 检查两个钱包实例是否具有相同的地址
print(walletMnemonic.address == walletPrivateKey.address); // 输出: true

// 通过Signer API获取地址
print(walletMnemonic.getAddress()); // 输出: '0x71CB05EE1b1F506fF321Da3dac38f25c0c9ce6E1'

// 直接获取地址
print(walletMnemonic.address); // 输出: '0x71CB05EE1b1F506fF321Da3dac38f25c0c9ce6E1'

// 获取内部加密组件
print(walletMnemonic.privateKey); // 输出: '0x1da6847600b0ee25e9ad9a52abbd786dd2502fa4005dd5af9310b7cc7a3b25db'
print(walletMnemonic.publicKey); // 输出: '0x04b9e72dfd423bcf95b3801ac93f4392be5ff22143f9980eb78b3a860c4843bfd04829ae61cdba4b3b1978ac5fc64f5cc2f4350e35a108a9c9a92a81200a60cd64'

// 获取助记词信息
print(walletMnemonic.mnemonic);
// 输出: {
//   locale: 'en',
//   path: "m/44'/60'/0'/0/0",
//   phrase: 'announce room limb pattern dry unit scale effort smooth jazz weasel alcohol'
// }

// 注意：使用私钥创建的钱包没有助记词
print(walletPrivateKey.mnemonic); // 输出: null

完整示例Demo

以下是一个完整的示例代码，展示了如何使用 Flutter_Ethers 插件来创建钱包并显示相关信息。

import 'package:flutter/material.dart';
import 'package:flutter_ethers/flutter_ethers.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Ethers Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Flutter Ethers Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key, required this.title}) : super(key: key);

  final String title;

  [@override](/user/override)
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  final mnemonic =
      "announce room limb pattern dry unit scale effort smooth jazz weasel alcohol";
  late Wallet walletMnemonic;

  [@override](/user/override)
  void initState() {
    walletMnemonic = Wallet.fromMnemonic(mnemonic);
    super.initState();
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'Mnemonic: $mnemonic',
              textAlign: TextAlign.center,
            ),
            Text(
              'PrivateKey: ${walletMnemonic.privateKey}',
              textAlign: TextAlign.center,
            ),
            Text(
              'PublicKey: ${walletMnemonic.publicKey}',
              textAlign: TextAlign.center,
            ),
            Text(
              'Address: ${walletMnemonic.address}',
              textAlign: TextAlign.center,
            ),
          ],
        ),
      ),
    );
  }
}