How to call arguments from Flutter in Swift native code? - ios

Question

I am trying to use PlatformViews in Flutter to show Swift code natively in my Flutter app, however my app is crashing with my current code.
This is my AppDelegate currently where I am invoking my method channel:
import Foundation
#UIApplicationMain
#objc class AppDelegate: FlutterAppDelegate, TJPlacementDelegate {
var p = TJPlacement()
override func application(
_ application: UIApplication,
didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
) -> Bool {
let channelName = "NativeView"
let rootViewController : FlutterViewController = window?.rootViewController as! FlutterViewController
let methodChannel = FlutterMethodChannel(name: channelName, binaryMessenger: rootViewController as! FlutterBinaryMessenger)
methodChannel.setMethodCallHandler {(call: FlutterMethodCall, result: FlutterResult) -> Void in
if (call.method == "setDebugEnabled") {
let isDebug = call.arguments as! Bool
Tapjoy.setDebugEnabled(isDebug)
}
}
GeneratedPluginRegistrant.register(with: self)
return super.application(application, didFinishLaunchingWithOptions: launchOptions)
}
}
This is my Dart implementation for the native code:
import 'package:flutter/material.dart';
import 'tapjoy.dart';
class Home extends StatefulWidget {
#override
_HomeState createState() => _HomeState();
}
class _HomeState extends State<Home> {
#override
void initState() {
callTapjoy();
super.initState();
}
Widget build(context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: Text('Test'),
),
body: UiKitView(viewType: 'NativeView'),
),
);
}
void callTapjoy() {
Tapjoy.setDebugEnabled(true);
}
}
//My code in tapjoy.dart
class Tapjoy {
static const MethodChannel _channel = const MethodChannel('NativeView');
static void setDebugEnabled(bool isDebug) {
_channel.invokeMethod('setDebugEnabled', {"isDebug": isDebug});
}
}
My app crashes and shows me an error in the debug console:
Could not cast value of type '__NSDictionaryM' (0x7fff87a61d78) to 'NSNumber' (0x7fff87b1eb08).
2020-04-29 16:56:42.985269+0530 Runner[18484:224162] Could not cast value of type '__NSDictionaryM' (0x7fff87a61d78) to 'NSNumber' (0x7fff87b1eb08).

Answer 1

You are passing a Map from Dart to native: {"isDebug": isDebug}, so you need extract the parameter from the map/dictionary at the Swift end.
if let args = call.arguments as? Dictionary<String, Any>,
let isDebug = args["isDebug"] as? Bool {
// please check the "as" above - wasn't able to test
// handle the method
result(nil)
} else {
result(FlutterError.init(code: "errorSetDebug", message: "data or format error", details: nil))
}
Alternatively, just pass the boolean from the Dart end, without first putting it into a map.
_channel.invokeMethod('setDebugEnabled', isDebug);