[Flutter] FlutterMethodChannel Data Passing Issue

Hi all this is how I used to render the flutter content in my iOS Application. unfortunately data is not getting send through the FlutterMethodChannel.

class HeatmapVC: UIViewController {

lazy var flutterEngine = FlutterEngine(name: "heatmap_engine")
var methodChannel: FlutterMethodChannel?
var flutterViewController: FlutterViewController?

@IBOutlet var heatmapView: UIView!

override func viewDidLoad() {
super.viewDidLoad()

// Run the engine and register plugins
flutterEngine.run()
GeneratedPluginRegistrant.register(with: flutterEngine) // Register plugins here

flutterViewController = FlutterViewController(engine: flutterEngine, nibName: nil, bundle: nil)

// Add FlutterViewController as a child view controller
if let flutterVC = flutterViewController {
addChild(flutterVC)
flutterVC.view.frame = heatmapView.bounds
flutterVC.view.autoresizingMask = [.flexibleWidth, .flexibleHeight]
heatmapView.addSubview(flutterVC.view)
flutterVC.didMove(toParent: self)

// Set up the method channel after the view controller is added
methodChannel = FlutterMethodChannel(name: "com.b.heatmap/data", binaryMessenger: flutterVC.binaryMessenger)

// Send data to Flutter
self.sendDataToFlutter()
}
}

func sendDataToFlutter() {
let dataToSend: [[String: Any]] = [
["country": "India", "socialMedia": "Facebook", "usersInMillions": 25.4],
["country": "USA", "socialMedia": "Instagram", "usersInMillions": 19.11],
["country": "Japan", "socialMedia": "Facebook", "usersInMillions": 13.3],
["country": "Germany", "socialMedia": "Instagram", "usersInMillions": 10.65],
["country": "France", "socialMedia": "Twitter", "usersInMillions": 7.54],
["country": "UK", "socialMedia": "Instagram", "usersInMillions": 4.93]
]

methodChannel?.invokeMethod("sendData", arguments: dataToSend) { (result: Any?) in
if let response = result as? String {

print("Flutter Response: \(response)")
}
}
}



Below is the error I'm facing.

[ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: MissingPluginException(No implementation found for method sendData on channel com.b.heatmap/data) #0 MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:332:7) #1 _SocialMediaUsersTreemapState._fetchDataFromNative (package:heatmap_b/main.dart:45:36)
​

Looking for a solution.

Below is the flutter code I have used.

import 'package:flutter/material.dart';
import 'package:flutter/services.dart'; // For MethodChannel
import 'package:syncfusion_flutter_treemap/treemap.dart';

void main() => runApp(const MyApp());

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

@override
Widget build(BuildContext context) {
return const MaterialApp(
home: SocialMediaUsersTreemap(),
);
}
}

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

@override
// ignore: library_private_types_in_public_api
_SocialMediaUsersTreemapState createState() => _SocialMediaUsersTreemapState();
}

class _SocialMediaUsersTreemapState extends State<SocialMediaUsersTreemap> {
static const platform = MethodChannel('com.b.heatmap/data');
late List<SocialMediaUsers> _source;
bool _isLoading = true; // To manage loading state

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

// Initialize with an empty list until data is received
_source = <SocialMediaUsers>[];

// Fetch data from native side
_fetchDataFromNative();
}

Future<void> _fetchDataFromNative() async {
try {
// Call the method and await the response
final List<dynamic> result = await platform.invokeMethod('sendData');

// Debugging to see if data is received
print("Data received from native: $result");

// Process the received data and map it to the SocialMediaUsers list
setState(() {
_source = result.map((item) {
return SocialMediaUsers(
item['country'],
item['socialMedia'],
item['usersInMillions'].toDouble(),
);
}).toList();
_isLoading = false; // Data is loaded
});
} on PlatformException catch (e) {
print("Failed to receive data: '${e.message}'.");
setState(() {
_isLoading = false; // End loading even on error
});
}
}

@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text('Social Media Users Treemap')),
body: _isLoading
? const Center(child: CircularProgressIndicator()) // Show loading spinner
: _source.isNotEmpty
? SfTreemap(
dataCount: _source.length,
weightValueMapper: (int index) {
return _source[index].usersInMillions;
},
levels: [
TreemapLevel(
groupMapper: (int index) {
return _source[index].country;
},
color: Colors.blueAccent,
padding: const EdgeInsets.all(2),
labelBuilder: (BuildContext context, TreemapTile tile) {
return Padding(
padding: const EdgeInsets.all(2.0),
child: Text(
'${tile.group}\n(${tile.weight.toStringAsFixed(2)}M)',
style: const TextStyle(color: Colors.white),
textAlign: TextAlign.center,
),
);
},
),
],
)
: const Center(
child: Text('No data available'), // Show if no data is received
),
);
}
}

class SocialMediaUsers {
const SocialMediaUsers(this.country, this.socialMedia, this.usersInMillions);

final String country;
final String socialMedia;
final double usersInMillions;
}

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