本文针对初学者, 讲述用flutter自带方法做简单逻辑跳转处理.
非初学者或想更方便实现功能的，可了解插件flutter_boost及其它.

• Flutter跳转到原生iOS页面

1. flutter页面中：

class _MyHomePageState extends State<MyHomePage> {

  //平台通道––––跳转到iOS页面
  static const platform = const MethodChannel('samples.flutter.jumpto.iOS');

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[

            TextButton(onPressed: _jumpToIosMethod, child: Text('跳转到iOS页面')),
        ),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }



  //跳转到iOS页面
  Future<Null> _jumpToIosMethod() async {
    final String result = await platform.invokeMethod('jumpToIosPage');
    print('result===$result');

  }

}

2. iOS的 AppDelegate.swift ：

import UIKit
import Flutter


@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate, UINavigationControllerDelegate{
    
    var navigationController: UINavigationController?
    
  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {

      
      let controller : FlutterViewController = window?.rootViewController as! FlutterViewController
      
      self.navigationController = UINavigationController.init(rootViewController: controller)
      window = UIWindow(frame: UIScreen.main.bounds)
      window?.rootViewController = self.navigationController
      self.navigationController?.delegate=self //设置代理 ，配置导航栏的显示与否
      window?.makeKeyAndVisible()
    
     
      let jumpIosChannel = FlutterMethodChannel(name: "samples.flutter.jumpto.iOS",binaryMessenger: controller.binaryMessenger)
    
   
      //处理-----跳转到iOS页面
      jumpIosChannel.setMethodCallHandler({
        [weak self] (call: FlutterMethodCall, result: FlutterResult) -> Void in
        // Note: this method is invoked on the UI thread.
        guard call.method == "jumpToIosPage" else {
          result(FlutterMethodNotImplemented)
          return
        }
        self?.jumpToIosPageMethod(result: result) //跳转页面
      })
      
      
    GeneratedPluginRegistrant.register(with: self)
    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }
    
    
    //跳转到iOS页面
    private func jumpToIosPageMethod(result: FlutterResult) {
             
                let vc: UIViewController = JumpTestViewController()
                vc.navigationItem.title = "原生页面"
               self.navigationController?.pushViewController(vc, animated: true)
      
          result("跳转")
    }
    
    
    //实现UINavigationControllerDelegate代理
    func navigationController(_ navigationController: UINavigationController, willShow viewController: UIViewController, animated: Bool) {
        //如果是Flutter页面，导航栏就隐藏
        navigationController.navigationBar.isHidden = viewController.isKind(of: FlutterViewController.self)
    }

}

：之所以让AppDelegate继承于UINavigationControllerDelegate，并实现navigationController：willShow方法，，所以实现代理方法对导航栏的显示做了判断。

JumpTestViewController.swift 为：

import Foundation

class JumpTestViewController: UIViewController {
    
    lazy var testLabel: UILabel = {
        let label = UILabel()
        label.frame.size = CGSize(width: 300, height: 50)
        label.backgroundColor = UIColor.blue
        label.textColor = UIColor.white
        label.text = "原生界面"
        label.textAlignment = .center
        
        label.center.x = self.view.bounds.width/2
        label.center.y = self.view.bounds.height/2
        
        return label
    }()

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
        self.view.backgroundColor = #colorLiteral(red: 1, green: 1, blue: 1, alpha: 1)
        self.view.addSubview(testLabel)
    }
    
}

3. 效果展示

iOS.gif

• Flutter跳转到原生Android页面

1. flutter页面中：

class _MyHomePageState extends State<MyHomePage> {

  //平台通道––––跳转到Android页面
  static const platform = const MethodChannel('samples.flutter.jumpto.android');


  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[

            TextButton(onPressed: _jumpToAndroidMethod, child: Text('跳转到Android页面')),
          ],
        ),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }


  //跳转到Android页面
  Future<Null> _jumpToAndroidMethod() async {
    final String result = await platform.invokeMethod('jumpToAndroidPage');
    print('result===$result');

  }
}

2. Android的 MainActivity.kt ：

package com.example.flutter_jumpto_native

import android.content.Context
import android.content.ContextWrapper
import android.content.Intent
import android.content.IntentFilter
import android.os.BatteryManager
import android.os.Build
import android.util.Log
import androidx.annotation.NonNull
import io.flutter.embedding.android.FlutterActivity
import io.flutter.embedding.engine.FlutterEngine
import io.flutter.plugin.common.MethodChannel

class MainActivity: FlutterActivity() {

    override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) {
        super.configureFlutterEngine(flutterEngine)

        //跳转到原生Android页面
        JumpChannel(flutterEngine.dartExecutor.binaryMessenger,this)

    }
}

JumpChannel.kt :

package com.example.flutter_jumpto_native

import android.app.Activity
import android.content.Context
import android.content.ContextWrapper
import android.content.Intent
import android.content.IntentFilter
import android.os.BatteryManager
import android.os.Build
import android.util.Log
import io.flutter.embedding.android.FlutterActivity
import io.flutter.plugin.common.BinaryMessenger
import io.flutter.plugin.common.MethodCall
import io.flutter.plugin.common.MethodChannel


class JumpChannel(flutterEngine: BinaryMessenger, activity: FlutterActivity): MethodChannel.MethodCallHandler {
    private val batteryChannelName = "samples.flutter.jumpto.android"
    private var channel: MethodChannel
    private var mActivity: FlutterActivity

    init {
        channel = MethodChannel(flutterEngine, batteryChannelName)
        channel.setMethodCallHandler(this)
        mActivity = activity;
    }

    override fun onMethodCall(call: MethodCall, result: MethodChannel.Result) {

        if (call.method == "jumpToAndroidPage") {

            var  intent = Intent(mActivity,SecondActivity::class.java)
            mActivity.startActivity(intent)

            result.success('跳转');
        }else if(call.method == "别的method"){
            //处理samples.flutter.jumpto.android下别的method方法
        } else {
            result.notImplemented()
        }
    }

}

SecondActivity.kt :

package com.example.flutter_jumpto_native

import android.os.Bundle
import android.util.Log
import androidx.fragment.app.FragmentActivity

class SecondActivity: FragmentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        Log.e("YM", "第二个页面的渲染");
        setContentView(R.layout.activity_second);
    }
}

在AndroidManifest.xml的application中注册SecondActivity：

 <activity android:name=".SecondActivity"/>

在res文件夹下创建一个layout文件夹，并添加activity_second.xml文件：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"
        android:textSize="18sp"
        android:text="安卓原生界面" />
</RelativeLayout>

3. 效果展示

android.gif

Demo：flutter_jumpto_native