Flutter & Ethereum : Unhandled Exception: RangeError: Value not in range: 32 - flutter

Question

I am trying to make a simple Decentralization Application with flutter and Ethereum. But I keep on getting this error. It was working fine. Please have a look at my code and my error
I use :
Flutter
Remix Ethereum
MetaMask => Rinkeby
Infua.io
Question : Why do I get this RangerError?
Solidity
pragma solidity 0.6.6;
contract PKCoin{
int balance;
constructor() public {
balance = 0;
}
function getBalance() view public returns(int) {
return balance;
}
function depositBalance(int amount) public {
balance = balance + amount;
}
function withdrawBalance(int amount) public {
balance = balance - amount;
}
}
Flutter
#override
void initState() {
super.initState();
httpClient = Client();
// print(httpClient);
ethClient = Web3Client(
"https://rinkeby.infura.io/v3/b2a9d5831e3b4675a51144cfed03bafa",
httpClient);
getBalance(myAddress);
}
Future<DeployedContract> loadContract() async {
String abi = await rootBundle.loadString("assets/abi.json");
String contractAddress = "0xd9145CCE52D386f254917e481eB44e9943F39138";
final contract = DeployedContract(ContractAbi.fromJson(abi, "PKCoin"),
EthereumAddress.fromHex(contractAddress));
return contract;
}
// ==== This is to get the information only ==== //
// ==== Get method ==== //
Future<List<dynamic>> query(String functionName, List<dynamic> args) async {
//
final contract = await loadContract();
final ethFunction = contract.function(functionName);
// This line below doesn't work.
final result = await ethClient.call(
contract: contract, function: ethFunction, params: args);
// print(result.toString());
return result;
}
Future<void> getBalance(String targetAddress) async {
// EthereumAddress address = EthereumAddress.fromHex(targetAddress);
List<dynamic> result = await query("getBalance", []);
print('In getGreeting');
print(result[0]);
setState(() {
myData = result[0];
data = true;
});
}
Error
Performing hot restart...
Restarted application in 950ms.
E/flutter (28032): [ERROR:flutter/lib/ui/ui_dart_state.cc(177)] Unhandled Exception: RangeError: Value not in range: 32
E/flutter (28032): #0 _rangeCheck (dart:typed_data-patch/typed_data_patch.dart:4807:5)
E/flutter (28032): #1 _ByteBuffer.asUint8List (dart:typed_data-patch/typed_data_patch.dart:1940:5)
E/flutter (28032): #2 _IntTypeBase.decode (package:web3dart/src/contracts/abi/integers.dart:23:31)
E/flutter (28032): #3 TupleType.decode (package:web3dart/src/contracts/abi/tuple.dart:102:29)
E/flutter (28032): #4 ContractFunction.decodeReturnValues (package:web3dart/src/contracts/abi/abi.dart:255:30)
E/flutter (28032): #5 Web3Client.call (package:web3dart/src/core/client.dart:310:21)
E/flutter (28032): <asynchronous suspension>
E/flutter (28032): #6 _MyHomePageState.query (package:greeting_blockchain/main.dart:70:36)
E/flutter (28032): <asynchronous suspension>
E/flutter (28032): #7 _MyHomePageState.getBalance (package:greeting_blockchain/main.dart:79:34)
E/flutter (28032): #8 _MyHomePageState.initState (package:greeting_blockchain/main.dart:48:5)
E/flutter (28032): #9 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4765:58)
E/flutter (28032): #10 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4601:5)
E/flutter (28032): #11 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14)
E/flutter (28032): #12 Element.updateChild (package:flutter/src/widgets/framework.dart:3327:18)
E/flutter (28032): #13 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:6118:14)
E/flutter (28032): #14 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14)
E/flutter (28032): #15 Element.updateChild (package:flutter/src/widgets/framework.dart:3327:18)
E/flutter (28032): #16 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4652:16)
E/flutter (28032): #17 Element.rebuild (package:flutter/src/widgets/framework.dart:4343:5)
E/flutter (28032): #18 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4606:5)
E/flutter (28032): #19 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4601:5)
E/flutter (28032): #20 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14)
E/flutter (28032): #21 Element.updateChild (package:flutter/src/widgets/framework.dart:3327:18)
E/flutter (28032): #22 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:6118:14)
E/flutter (28032): #23 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14)
E/flutter (28032): #24 Element.updateChild (package:flutter/src/widgets/framework.dart:3327:18)
E/flutter (28032): #25 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:6118:14)
E/flutter (28032): #26 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14)
E/flutter (28032): #27 Element.updateChild (package:flutter/src/widgets/framework.dart:3327:18)
E/flutter (28032): #28 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4652:16)
E/flutter (28032): #29 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4800:11)
E/flutter (28032): #30 Element.rebuild (package:flutter/src/widgets/framework.dart:4343:5)
E/flutter (28032): #31 ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4606:5)
E/flutter (28032): #32 StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4791:11)
E/flutter (28032): #33 ComponentElement.mount (package:flutter/src/widgets/framework.dart:4601:5)
E/flutter (28032): #34 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14)
E/flutter (28032): #35 Element.updateChild (package:flutter/src/widgets/framework.dart:3327:18)
E/flutter (28032): #36 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:6118:14)
E/flutter (28032): #37 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14)
E/flutter (28032): #38 Element.updateChild (package:flutter/src/widgets/framework.dart:3327:18)
E/flutter (28032): #39 SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:6118:14)
E/flutter (28032): #40 Element.inflateWidget (package:flutter/src/widgets/framework.dart:3569:14)
E/flutter (28032): #41 Element.updateChild (package:flutter/src/widgets/framework.dart:3327:18)
E/flutter (28032): #42 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4652:16)
E/flutter (28032): #43 StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:4800:11)
E/flutter (28032): #44 Element.rebuild (package:flutter/src/widgets/framework.dart:4343:5)
E/flutter (28032): #45 ComponentElement._firstBuild (package:flutter/src/widgets/framework.d
Conclusion
Please take a look at my code and I am looking forward to see all of your answers. Thank you in advance.

Answer 1

Un-comment //EthereumAddress address = EthereumAddress.fromHex(targetAddress);
Future<void> getBalance(String targetAddress) async {
EthereumAddress address = EthereumAddress.fromHex(targetAddress);
List<dynamic> result = await query("getBalance", []);
print('In getGreeting');
print(result[0]);
setState(() {
myData = result[0];
data = true;
});
}