pancake_swap_sdk 1.0.0

A package is a project forked from two prominent web libraries, pancake swap sdk and uniswap swap sdk.

example/lib/main.dart

import 'dart:math';

import 'package:flutter/material.dart';
import 'package:http/http.dart';
import 'package:pancake_swap_sdk/core/entities/index.dart';
import 'package:pancake_swap_sdk/core/entities/token/token_amount.dart';
import 'package:pancake_swap_sdk/v2/constants.dart';
import 'package:pancake_swap_sdk/v2/pair.dart';
import 'package:pancake_swap_sdk/v2/trade.dart';
import 'package:web3dart/credentials.dart';
import 'package:web3dart/web3dart.dart';

import 'json/LP_Contract.g.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
      ),
      home: const MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key});

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  double priceBNB = 0;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: <Widget>[
            const Text(
              'Price(BNB/USDT):',
            ),
            Text(
              '${priceBNB.toStringAsFixed(5)} BUSD',
              style: Theme.of(context).textTheme.headlineMedium,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _getPriceBNB,
        tooltip: 'Get Price BNB',
        child: const Icon(Icons.swap_calls),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }

  Future<void> _getPriceBNB() async {
    final web3Client = Web3Client(
      'https://bsc-dataseed.binance.org/',
      Client(),
    );
    Token tokenFrom = Token.WETH[ChainId.MAINNET.value]!;
    Token tokenTo = Token(
        56,
        EthereumAddress.fromHex('0xe9e7CEA3DedcA5984780Bafc599bD69ADd087D56'),
        18);
    var pairAddress = Pair.getAddress(tokenFrom, tokenTo);
    final balanceFunc =
        FarmContract(address: pairAddress!, client: web3Client, chainId: 56);
    final data = await balanceFunc.getReserves();
    final pair = Pair(
      TokenAmount(
        tokenFrom,
        data.reserve0,
      ),
      TokenAmount(
        tokenTo,
        data.reserve1,
      ),
    );
    final amountOne = BigInt.from(1 * pow(10, 18));
    var bestTrade = Trade.bestTradeExactIn(
      [pair],
      TokenAmount(tokenFrom, amountOne),
      tokenTo,
    );
    setState(() {
      priceBNB = getEstimateTokenSwapOut(bestTrade[0].outputAmount.raw);
    });
  }
}

double getEstimateTokenSwapOut(BigInt outPut) {
  return (outPut / BigInt.from(pow(10, 18))).toDouble();
}