Flutter未知功能插件bdk_flutter的使用

bdk_flutter 是一个用于在Flutter应用中集成比特币开发工具包（Bitcoin Development Kit）的插件。本文将介绍如何在Flutter项目中使用这个插件，并提供完整的示例代码。

依赖与要求

要求

• Flutter: 3.0或更高版本
• Android minSdkVersion: API 23或更高
• iOS部署目标: iOS 12.0或更高

添加依赖

在你的 pubspec.yaml 文件中添加以下依赖：

dependencies:
  bdk_flutter: ^0.31.2

示例Demo

创建钱包并同步余额

以下是一个创建钱包并同步其余额的完整示例：

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: WalletScreen(),
    );
  }
}

class WalletScreen extends StatefulWidget {
  @override
  _WalletScreenState createState() => _WalletScreenState();
}

class _WalletScreenState extends State<WalletScreen> {
  String walletStatus = "Creating Wallet...";

  @override
  void initState() {
    super.initState();
    createAndSyncWallet();
  }

  Future<void> createAndSyncWallet() async {
    try {
      final mnemonic = await Mnemonic.create(WordCount.words12);
      final descriptorSecretKey = await DescriptorSecretKey.create(
        network: Network.testnet,
        mnemonic: mnemonic,
      );

      final externalDescriptor = await Descriptor.newBip44(
        secretKey: descriptorSecretKey,
        network: Network.testnet,
        keychain: KeychainKind.externalChain,
      );

      final internalDescriptor = await Descriptor.newBip44(
        secretKey: descriptorSecretKey,
        network: Network.testnet,
        keychain: KeychainKind.internalChain,
      );

      final blockchain = await Blockchain.create(
        config: BlockchainConfig.electrum(
          config: ElectrumConfig(
            stopGap: 10,
            timeout: 5,
            retry: 5,
            url: "ssl://electrum.blockstream.info:60002",
          ),
        ),
      );

      final wallet = await Wallet.create(
        descriptor: externalDescriptor,
        changeDescriptor: internalDescriptor,
        network: Network.testnet,
        databaseConfig: const DatabaseConfig.memory(),
      );

      await wallet.sync(blockchain);

      setState(() {
        walletStatus = "Wallet Created and Synced!";
      });
    } catch (e) {
      setState(() {
        walletStatus = "Error: $e";
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('BDK Flutter Wallet'),
      ),
      body: Center(
        child: Text(walletStatus),
      ),
    );
  }
}

创建公共钱包描述符

以下是如何创建一个公共钱包描述符的示例：

import 'package:bdk_flutter/bdk_flutter.dart';

Future<void> createPublicDescriptor() async {
  final mnemonic = await Mnemonic.create(WordCount.words12);
  final descriptorSecretKey = await DescriptorSecretKey.create(
    network: Network.testnet,
    mnemonic: mnemonic,
  );

  final externalDescriptor = await Descriptor.newBip44(
    secretKey: descriptorSecretKey,
    network: Network.testnet,
    keychain: KeychainKind.externalChain,
  );

  final externalPublicDescriptor = await Descriptor.create(
    descriptor: externalDescriptor.toString(),
    network: Network.testnet,
  );

  print("Public Descriptor: ${externalPublicDescriptor}");
}

获取交易详情

以下是获取交易详情的示例：

import 'package:bdk_flutter/bdk_flutter.dart';
import 'dart:convert';

Future<void> getTransactionDetails(Wallet bdkWallet, Blockchain blockchain) async {
  final txBuilder = TxBuilder();
  final address = await Address.fromString(
    s: "mv4rnyY3Su5gjcDNzbMLKBQkBicCtHUtFB",
    network: Network.testnet,
  );

  final script = await address.scriptPubkey();
  final feeRate = await blockchain.estimateFee(target: 25);

  final (psbt, transactionDetails) = await txBuilder
      .feeRate(feeRate.satPerVb)
      .addRecipient(script, 2000)
      .finish(bdkWallet);

  final serializedPsbt = await psbt.jsonSerialize();
  final jsonObject = json.decode(serializedPsbt);
  final outputs = jsonObject['unsigned_tx']['output'] as List;
  final inputs = jsonObject['inputs'][0]['non_witness_utxo']['output'] as List;

  print("=========Inputs=====");
  for (var e in inputs) {
    print("amount: ${e['value']}");
    print("script_pubkey: ${e['script_pubkey']}");
  }

  print("=========Outputs=====");
  for (var e in outputs) {
    print("amount: ${e['value']}");
    print("script_pubkey: ${e['script_pubkey']}");
  }
}

创建内部和外部钱包描述符

以下是通过派生路径创建内部和外部钱包描述符的示例：

import 'package:bdk_flutter/bdk_flutter.dart';

Future<void> createDescriptorsFromDerivationPath() async {
  final mnemonic = await Mnemonic.create(WordCount.words12);
  final descriptorSecretKey = await DescriptorSecretKey.create(
    network: Network.testnet,
    mnemonic: mnemonic,
  );

  // 创建外部描述符
  final derivationPath = await DerivationPath.create(path: "m/44h/1h/0h/0");
  final descriptorPrivateKey =
      await descriptorSecretKey.derive(derivationPath);
  final Descriptor descriptorPrivate = await Descriptor.create(
    descriptor: "pkh(${descriptorPrivateKey.toString()})",
    network: Network.testnet,
  );

  // 创建内部描述符
  final derivationPathInt = await DerivationPath.create(path: "m/44h/1h/0h/1");
  final descriptorPrivateKeyInt =
      await descriptorSecretKey.derive(derivationPathInt);
  final Descriptor descriptorPrivateInt = await Descriptor.create(
    descriptor: "pkh(${descriptorPrivateKeyInt.toString()})",
    network: Network.testnet,
  );

  final bdkWallet = await Wallet.create(
    descriptor: descriptorPrivate,
    changeDescriptor: descriptorPrivateInt,
    network: Network.testnet,
    databaseConfig: const DatabaseConfig.memory(),
  );

  final address = await bdkWallet.getAddress(addressIndex: const AddressIndex.increase());
  final internalAddress = await bdkWallet.getInternalAddress(addressIndex: const AddressIndex.increase());

  print("External Address: ${address.address}");
  print("Internal Address: ${internalAddress.address}");
}

参考资料

• BDK Flutter GitHub
• API 文档
• 设置本地 Esplora 实例进行测试

希望这些示例能帮助你更好地理解和使用 bdk_flutter 插件！如果有任何问题，欢迎在评论区留言。