How can i connect Swift file and dart file? - flutter

Question

I`m connecting Flutter and Swift so that i can use it in Flutter by connecting the public certificate api that works only in Swift. but, I have an issue and i want to ask a question.
What i want to do is import a Swift function through a channel to main.dart so that Swift code can work when a button is pressed in main.dart
How can i get func in Tilko.swift to main.dart
Here is that Structures
enter image description here
main.dart is in ios/lib folder and Tilko.swift is in ios/Runner

Answer 1

There should be a FlutterMethodChannel.swift
and it look like
class MethodChannelFlutter {
var controller: FlutterViewController
var printerChannel: FlutterMethodChannel
init(controller: FlutterViewController) {
self.controller = controller
printerChannel = FlutterMethodChannel(name: "hem_cert_copy_plugin", binaryMessenger: controller.binaryMessenger)
printerChannel.setMethodCallHandler {
(call: FlutterMethodCall, _: #escaping FlutterResult) -> Void in
//Your handler
//...
and your AppDelegate.swift should be like
import UIKit
import Flutter
#UIApplicationMain
#objc class AppDelegate: FlutterAppDelegate {
override func application(
_ application: UIApplication,
didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
) -> Bool {
let controller : FlutterViewController = window?.rootViewController as! FlutterViewController
MethodChannelFlutter(controller: controller)
GeneratedPluginRegistrant.register(with: self)
return super.application(application, didFinishLaunchingWithOptions: launchOptions)
}
}

Answer 2

I have create a working sample here
https://github.com/theamorn/flutter-template
In this file, I have 3 ways of connecting to Native SDK
calling Native and return value immediately
calling Native and pass to function and return from that function
calling Native and wait for the delegate to callback so we can callback to Flutter
First you add Flutter Channel in iOS
https://github.com/theamorn/flutter-template/blob/main/ios/Runner/AppDelegate.swift
private func initFlutterChannel() {
// com.theamorn.flutter can change to whatever you want, just have to be the same between Flutter and iOS and unique ‘domain prefix. just com.theamorn is not enough
if let controller = window?.rootViewController as? FlutterViewController {
let channel = FlutterMethodChannel(
name: methodChannel,
binaryMessenger: controller.binaryMessenger)
channel.setMethodCallHandler({ [weak self] (
call: FlutterMethodCall,
result: #escaping FlutterResult) -> Void in
switch call.method {
case "methodNameOne":
if let data = call.arguments as? String {
self?.callNativeSDK(data)
} else {
result(FlutterMethodNotImplemented)
}
case "deviceHasPasscode":
result(self?.isDeviceHasPasscode)
case "returnValue":
if let data = call.arguments as? String {
self?.returnValueSDK(result: result, id: data)
} else {
result(FlutterMethodNotImplemented)
}
default:
result(FlutterMethodNotImplemented)
}
})
}
}
methodNameOne use for calling Native function with a delegate which name should be consistent within Flutter
private func callNativeSDK(_ id: String) {
// You can put any Native SDK in here, if the result return from Delegate
let sdk = ThirdPartySDK(delegate: self, id: id)
sdk.start()
}
private func returnValueSDK(result: FlutterResult, id: String) {
// You can call any SDK in here if the result return immediately
let sdk = ThirdPartySDK(delegate: self, id: id)
return result(sdk.process())
}
To call from Flutter using this
https://github.com/theamorn/flutter-template/blob/main/lib/main.dart
final channel = MethodChannel('com.theamorn.flutter');
try {
await channel.invokeMethod('methodNameOne', "12345");
} on PlatformException catch (e) {
debugPrint("==== Failed to get data '${e.message}' ====");
}
Calling back from Native to Flutter, I call this function in Delegate of mocking SDK
extension AppDelegate: ThirdPartySDKDelegate {
func onFinish(value: String) {
// You can send anything into arguments, String, Boolean, or even Dictionary
// Send data back to Flutter
if let controller = self.window?.rootViewController as? FlutterViewController {
let channel = FlutterMethodChannel(
name: methodChannel,
binaryMessenger: controller.binaryMessenger)
channel.invokeMethod("methodNameTwoFromSDK", arguments: value)
}
}
}
Waiting Value from Native
_waitingDataFromNative() async {
channel.setMethodCallHandler((call) async {
// Receive data from Native
switch (call.method) {
case "methodNameTwoFromSDK":
_nativeValue = call.arguments;
setState(() {});
break;
default:
break;
}
});
}
You see that method name in iOS, and Flutter needs to be exactly the same otherwise they can't see each others.