How to call a swift view controller using the navigation controller in flutter through the Flutter Method Channel

Question

I am trying to call a UINavigationController I have defined in a separate file called "MainNavigationController.swift" through a private function I have defined in my AppDelegate.swift file called "callNavigator()" I am calling that method from the Flutter side through a成功發回消息的方法通道正在發生一些通信“Flutter/Dart 端沒有問題”。 我希望 function 使用“MainNavigationController.swift”中定義的導航器在 flutter 屏幕上推送視圖。我的 MainNavigationController.Z818056DBD7E201241206B9C7CD884 中的代碼如下：

import Foundation
    import UIKit

    class MainNavigationController: UINavigationController{
        override func viewDidLoad() {
            super.viewDidLoad()
        }
        private func navigateToMainInterface() {
            let mainStoryboard = UIStoryboard(name: "Main", bundle: Bundle.main)
           guard let mainNavigationVc = mainStoryboard.instantiateViewController(withIdentifier:"MainNavigationController") as? MainNavigationController else {
                return

            }
            present(mainNavigationVc, animated: true, completion: nil)

        }
    }
Then I am trying to call this class in my "AppDelegate.swift file" through my "callNavigator()" private function as a constructor. The code is as follows in the Appdelegate.swift file :


    @UIApplicationMain
    @objc class AppDelegate: FlutterAppDelegate {
      override func application(
        _ application: UIApplication,
        didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?

      ) -> Bool {
        let controller: FlutterViewController = window?.rootViewController as! FlutterViewController
        GeneratedPluginRegistrant.register(with: self)      

        let navigatorChannel = FlutterMethodChannel(name: "com.fluttertonative/navigateToCameraSDK", binaryMessenger:  controller.binaryMessenger)
       navigatorChannel.setMethodCallHandler ({
          [weak self] (call: FlutterMethodCall, result: FlutterResult) -> Void in
          // Note: this method is invoked on the UI thread.
          guard call.method == "getSwiftNavigator" else {
            result(FlutterMethodNotImplemented)
            return
          }
          self?.callNavigator()

       })
        GeneratedPluginRegistrant.register(with: self)
        return super.application(application, didFinishLaunchingWithOptions: launchOptions)
      }
        private func receiveGreeting(result: FlutterResult){
            result("Hello from Swift Code...")
        }
        private func callNavigator(){
            MainNavigationController()

        }
    }

但是，我在 Xcode 中收到警告，試圖調用“MainNavigationController”的“callNavigator”function 沒有使用其結果，它說“'UINavigationController' 初始化程序的結果未使用”。 我是 swift 的新手，我不知道該怎么做。

我在我的 Main.storyBoard 中將 Initial navigator 設置為 FlutterViewController，我在其中放置了一些虛擬文本文件。 當我從 Flutter 端調用方法通道時，我希望運行“callNavigator” function ，然后調用“MainNavigationController.swift”文件中的“MainNavigationController”，它應該在視圖頂部推送一個新視圖Flutter屏。

我需要一些幫助來實現這一點，因為我是 Swift 語言的新手

那么我的dart代碼如下：

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  static const navigateToCameraSDK = const MethodChannel('com.fluttertonative/navigateToCameraSDK');

  String _greeting = 'awaiting swift call..';


  Future _getnavigator() async{
    try {
      final result = navigateToCameraSDK.invokeMapMethod('getSwiftNavigator');
      print(result);
    } on PlatformException catch (e){
      print('error:$e');
      _greeting = 'error occured:$e';
    }
    setState(() {
      _greeting ='call successful you have got the swift Navigator';
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text(widget.title),
        ),
        body: Container(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            crossAxisAlignment: CrossAxisAlignment.center,
            children: <Widget>[
              Text(_greeting),
              CupertinoButton(
                child: Text('call swift to get the navigator'),
                onPressed: _getnavigator,
                borderRadius:BorderRadius.all(Radius.circular(13.0)),
                color: Colors.blue[300],
              ),
            ],
          ),
        ));
  }
}

而我的storyboard如下——Flutter視圖Controller是初始視圖Z9BBF373797BF7CF7BA62C800236。 在此處輸入圖像描述：

Answer 1

默認情況下，Flutter iOS 應用程序沒有UINavigationViewController 。 這是將視圖控制器推送到導航堆棧所必需的。

不過，通過AppDelegate class 添加它非常容易。

import UIKit
import Flutter

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
    
    var navigationController: UINavigationController!
    
    override func application(_ application: UIApplication,
                            didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
      
      
        let controller = window?.rootViewController as! FlutterViewController
        GeneratedPluginRegistrant.register(with: self)
        
        // create and then add a new UINavigationController
        self.navigationController = UINavigationController(rootViewController: controller)
        self.window.rootViewController = self.navigationController
        self.navigationController.setNavigationBarHidden(true, animated: false)
        self.window.makeKeyAndVisible()
        
        return super.application(application, didFinishLaunchingWithOptions: launchOptions)
    }

}

稍后，當您將FlutterMethodChannel添加到您的應用程序委托時，您可以以標准 iOS 方式簡單地推送/顯示新的UIViewController 。

    // called from within the FlutterMethodChannel handler
    private func pushViewController() {
        //get view controller from StoryBoard, XIB or in code
        let vc = ...       
        self.navigationController.setNavigationBarHidden(false, animated: true)
        self.navigationController.pushViewController(vc, animated: true)
    }