Flutter與Native混合開發-FlutterBoost集成應用和開發實踐(iOS)

背景：

現在Flutter火熱，各個公司都會嘗試使用Flutter開發，一般採用的都會是混合形式的開發，混合開發目前Flutter官方提供的不太完善、iOS和Android有差異性、接口也不同意、很麻煩，也有一些大廠爲了實現高效率高可用自己實現一套混合開發技術,比如閒魚的flutter_boost和哈羅的flutter_thrio。兩者之間優缺點及設計原理、架構等後續再來具體分析。接下我們先說下flutter_boost在iOS項目中的接入混合實踐。

準備工作：

1.Flutter SDK

爲了便於後續我們flutter sdk版本的快速切換，我們需要安裝管理工具，方便我們在後續開發或者調試過程中快速切換版本。

這裏推薦使用的Flutter SDK管理工具fvm,能快速切換版本，具體不做介紹，直接去查看文檔就可以，很詳細。

安裝自己所需的flutter sdk版本（我這裏安裝的是1.17.1版本，因爲需要跟下邊的flutter_boost版本對應）：

2.flutter_boost框架

瞭解混合框架flutter_boost,首先需要知道我們需要使用他們的那個版本及版本對應的flutter sdk版本，比如：flutter_boost:v1.17.1-hotfixes 對應的flutter sdk：1.17.1 。

正式接入：

一、flutter_module工程

1.創建空文件夾後，使用命令：

flutter create -t module flutter_module

如果iOS使用的是Swift開發使用命令：

flutter create -i swift -t module flutter_module

2.flutter_module創建完成後，打開flutter_module文件夾下pubspec.yaml文件。如下：

注意：這裏我用的flutter_boost的SDK最新版本：v1.17.1-hotfixes

3.cd到flutter_module文件夾下，執行命令：

flutter packages get

包下載完成後flutter_module工程基本配置已經完成。

二、iOS原生工程

1.創建iOS項目

注意：iOS工程根目錄與flutter_module根目錄平級。

2.cd到iOS工程目錄下創建Podfile文件，執行命令：

touch Podfile 生成文件，然後可以使用vim Podfile 編輯或者直接open Podfile 或者直接打開文本編輯也可以。

在文件中添加

flutter_application_path = '../flutter_module'
load File.join(flutter_application_path, '.ios', 'Flutter', 'podhelper.rb')
install_all_flutter_pods(flutter_application_path)

3.執行 pod install下載依賴庫。

4.配置項目

如果是OC工程，則不會要做什麼額外處理，如果是Swift項目需要建個橋接文件FlutterHybridiOS-Bridging-Header.h，同時Build Sttings中需要配置該文件路徑。

注意：

（1）.看其他博客出現過，查看Build Phases中是否存在Flutter Build Script的腳本，如果不存在需要添加對應腳本，但是目前我沒出現缺失的情況。

"$FLUTTER_ROOT/packages/flutter_tools/bin/xcode_backend.sh" build

"$FLUTTER_ROOT/packages/flutter_tools/bin/xcode_backend.sh" embed

三.代碼接入實踐

這塊可以直接下載flutter_boost官方例子OC，flutter_boost官方例子Swift查看具體實踐，其中OC例子是最全的，這裏只已Swift項目爲基礎介紹基礎使用。

<1>.iOS平臺

• 1.創建實現flutter_boost路由類，實現FLBPlatform中的協議，和Flutter中也會有對應的方法來處理跳轉操作。（直接參考上邊官方的代碼類就行），即push模式跳轉、present模式跳轉、關閉頁面等方法。

import Foundation
//import flutter_boost

class PlatformRouterImp: NSObject, FLBPlatform {
   func open(_ url: String, urlParams: [AnyHashable : Any], exts: [AnyHashable : Any], completion: @escaping (Bool) -> Void) {
       //跳轉打開原生Native頁面
       if (url == "native") {
          self.openNativeVC(url, urlParams: urlParams, exts: exts)
          return
       }

       var animated = false;
       if exts["animated"] != nil{
           animated = exts["animated"] as! Bool;
       }
       let vc = FLBFlutterViewContainer.init();
       vc.setName(url, params: urlParams);
       self.navigationController().pushViewController(vc, animated: animated);
       completion(true);
   }
   
   func present(_ url: String, urlParams: [AnyHashable : Any], exts: [AnyHashable : Any], completion: @escaping (Bool) -> Void) {
       var animated = false;
       if exts["animated"] != nil{
           animated = exts["animated"] as! Bool;
       }
       let vc = FLBFlutterViewContainer.init();
       vc.setName(url, params: urlParams);
       navigationController().present(vc, animated: animated) {
           completion(true);
       };
   }
   
   func close(_ uid: String, result: [AnyHashable : Any], exts: [AnyHashable : Any], completion: @escaping (Bool) -> Void) {
       var animated = false;
       if exts["animated"] != nil{
           animated = exts["animated"] as! Bool;
       }
       let presentedVC = self.navigationController().presentedViewController;
       let vc = presentedVC as? FLBFlutterViewContainer;
       if vc?.uniqueIDString() == uid {
           vc?.dismiss(animated: animated, completion: {
               completion(true);
           });
       }else{
           self.navigationController().popViewController(animated: animated);
       }
   }
   
private func openNativeVC(
       _ name: String?,
       urlParams params: [AnyHashable : Any]?,
       exts: [AnyHashable : Any]?
   ) {
       let vc = UIViewController()
       let animated = (exts?["animated"] as? NSNumber)?.boolValue ?? false
       if (params?["present"] as? NSNumber)?.boolValue ?? false {
           self.navigationController().present(vc, animated: animated) {}
       } else {
     
           self.navigationController().pushViewController(vc, animated: animated)
       }
   }

   func navigationController() -> UINavigationController {
       let delegate = UIApplication.shared.delegate as! AppDelegate
       let navigationController = delegate.window?.rootViewController as! UINavigationController
       return navigationController;
   }
}

• 2.flutter_boost初始化，即在啓動的時候初始化框架代碼。

import UIKit

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {

   override func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
          //路由創建
          let router = PlatformRouterImp.init();
          //FlutterBoost初始化
           FlutterBoostPlugin.sharedInstance().startFlutter(with: router, onStart: { (engine) in
            
           });
           
           self.window = UIWindow.init(frame: UIScreen.main.bounds)
           let viewController = ViewController.init()
           let navi = UINavigationController.init(rootViewController: viewController)
           self.window.rootViewController = navi
           self.window.makeKeyAndVisible()
           
        return true
    }

• 3.具體使用（創建自己的ViewController，添加兩個按鈕進行測試跳轉Native）

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.backgroundColor = UIColor.white
        // Do any additional setup after loading the view.
        let btn = UIButton(type: .custom);
        btn.backgroundColor = UIColor.red
        btn.frame = CGRect(x: 10, y: 60, width: 60, height: 40)
        btn.setTitle("Push Flutter Page", for: .normal)
        self.view.addSubview(btn);
        btn.addTarget(self, action: #selector(onClickPushFlutterPage), for: .touchUpInside);
        
        let btn2 = UIButton(type: .custom);
        btn2.backgroundColor = UIColor.blue
        btn2.frame = CGRect(x: 10, y: 120, width: 60, height: 40)
        self.view.addSubview(btn2);
        btn2.setTitle("Present Flutter Page", for: .normal)
        btn2.addTarget(self, action: #selector(onClickPresentFlutterPage), for: .touchUpInside);

    }


    @objc func onClickPushFlutterPage(_ sender: UIButton, forEvent event: UIEvent){
//        self.navigationController?.navigationBar.isHidden = true
        //其中這裏的first，在Flutter也會對應初始化的時候註冊該標識對應的Widget。
         FlutterBoostPlugin.open("first", urlParams:[kPageCallBackId:"MycallbackId#1"], exts: ["animated":true], onPageFinished: { (_ result:Any?) in
             print(String(format:"call me when page finished, and your result is:%@", result as! CVarArg));
         }) { (f:Bool) in
             print(String(format:"page is opened\(f)"));
         }
     }
    @objc func onClickPresentFlutterPage(_ sender: UIButton, forEvent event: UIEvent){
         FlutterBoostPlugin.present("second", urlParams:[kPageCallBackId:"MycallbackId#2"], exts: ["animated":true], onPageFinished: { (_ result:Any?) in
             print(String(format:"call me when page finished, and your result is:%@", result as! CVarArg));
         }) { (f:Bool) in
             print(String(format:"page is presented"));
         }
     }
}

*注意點：

（1）.調用FlutterBoostPlugin.open和present方法時候，傳遞的urlname（first、second）會在Flutter中註冊對應的Widget。

<2>.Flutter平臺

• 1.main.dart （可以理解爲入口類，類似iOS中的Appdelete類），實現Flutter_boost初始化和註冊Native對應的widget。
  （1）初始化flutter_boost插件及註冊對應的widgets。
  （2）初始化路由router。

import 'package:flutter/material.dart';
import 'package:flutter_boost/flutter_boost.dart';
import 'simple_page_widgets.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  @override
  void initState() {
    super.initState();

//（1）初始化註冊
    FlutterBoost.singleton.registerPageBuilders(<String, PageBuilder>{
      'first': (String pageName, Map<String, dynamic> params, String _) => FirstRouteWidget(),
      'firstFirst': (String pageName, Map<String, dynamic> params, String _) =>
          FirstFirstRouteWidget(),
      'second': (String pageName, Map<String, dynamic> params, String _) => SecondRouteWidget(),
      'secondStateful': (String pageName, Map<String, dynamic> params, String _) =>
          SecondStatefulRouteWidget(),
    });
    
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        title: 'Flutter Boost example',
        //（2）初始化路由
        builder: FlutterBoost.init(postPush: _onRoutePushed),
        home: Container(color: Colors.white));
  }

//（2）
  void _onRoutePushed(
    String pageName,
    String uniqueId,
    Map<String, dynamic> params,
    Route<dynamic> route,
    Future<dynamic> _,
  ) {}
}

注意點：

(1)import 'simple_page_widgets.dart'這個dart類中是實現了很多widget，比如first對應的FirstRouteWidget，second對應的SecondRouteWidget等。但是在實際開發中不要把widget放到一個Dart類種實現，降低代碼冗餘、代碼複雜度、降低維護成本等。

• 2.實現widget（具體可以查看官方類中的simple_page_widgets.dart）
  下邊只展示我們之前對應的first和second。

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_boost/flutter_boost.dart';
import 'package:flutter_module/platform_view.dart'; //封裝的view


/// *********************** FirstRouteWidget*/
class FirstRouteWidget extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => _FirstRouteWidgetState();
}

class _FirstRouteWidgetState extends State<FirstRouteWidget> {
  _FirstRouteWidgetState();

  // flutter 側MethodChannel配置，channel name需要和native側一致
// static const MethodChannel _methodChannel = MethodChannel('flutter_native_channel');
  // String _systemVersion = '';

  // Future<dynamic> _getPlatformVersion() async {

  //   try {
  //     final String result = await _methodChannel.invokeMethod('getPlatformVersion');
  //     print('getPlatformVersion:' + result);
  //     setState(() {
  //       _systemVersion = result;
  //     });
  //   } on PlatformException catch (e) {
  //     print(e.message);
  //   }

  // }

  @override
  void initState() {
    print('initState');
    super.initState();
  }

  @override
  void didChangeDependencies() {
    print('didChangeDependencies');
    super.didChangeDependencies();
  }

  @override
  void didUpdateWidget(FirstRouteWidget oldWidget) {
    print('didUpdateWidget');
    super.didUpdateWidget(oldWidget);
  }

  @override
  void deactivate() {
    print('deactivate');
    super.deactivate();
  }

  @override
  void dispose() {
    print('[XDEBUG] - FirstRouteWidget is disposing~');
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('First Route')),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            RaisedButton(
              child: const Text('Open native page'),
              onPressed: () {
                print('open natve page!');
                FlutterBoost.singleton
                    .open('native')
                    .then((Map<dynamic, dynamic> value) {
                  print(
                      'call me when page is finished. did recieve native route result $value');
                });
              },
            ),
            RaisedButton(
              child: const Text('Open FF route'),
              onPressed: () {
                print('open FF page!');
                FlutterBoost.singleton
                    .open('firstFirst')
                    .then((Map<dynamic, dynamic> value) {
                  print(
                      'call me when page is finished. did recieve FF route result $value');
                });
              },
            ),
            RaisedButton(
              child: const Text('Open second route1'),
              onPressed: () {
                print('open second page!');
                FlutterBoost.singleton
                    .open('second')
                    .then((Map<dynamic, dynamic> value) {
                  print(
                      'call me when page is finished. did recieve second route result $value');
                });
              },
            ),
            RaisedButton(
              child: const Text('Present second stateful route'),
              onPressed: () {
                print('Present second stateful page!');
                FlutterBoost.singleton.open('secondStateful',
                    urlParams: <String, dynamic>{
                      'present': true
                    }).then((Map<dynamic, dynamic> value) {
                  print(
                      'call me when page is finished. did recieve second stateful route result $value');
                });
              },
            ),
            RaisedButton(
              child: const Text('Present second route'),
              onPressed: () {
                print('Present second page!');
                FlutterBoost.singleton.open('second',
                    urlParams: <String, dynamic>{
                      'present': true
                    }).then((Map<dynamic, dynamic> value) {
                  print(
                      'call me when page is finished. did recieve second route result $value');
                });
              },
            ),
            RaisedButton(
              child: Text('Get system version by method channel:' + _systemVersion),
              onPressed: () => _getPlatformVersion(),
            ),
          ],
        ),
      ),
    );
  }
}

/// *********************** SecondRouteWidget*/
class SecondRouteWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Second Route')),
      body: Center(
        child: RaisedButton(
          onPressed: () {
            // Navigate back to first route when tapped.
            final BoostContainerSettings settings =
                BoostContainer.of(context).settings;
            FlutterBoost.singleton.close(
              settings.uniqueId,
              result: <String, dynamic>{'result': 'data from second'},
            );
          },
          child: const Text('Go back with result!'),
        ),
      ),
    );
  }
}

注意點：

（1）.狀態管理的處理，如果細心地同學會發現，上邊FirstRouteWidget和SecondRouteWidget的繼承類不同，一個是StatelessWidget（非動態的）、StatefulWidget（動態的）兩種狀態管理。具體理解可以自己去查資料學習，後續也會專門講下這個。

場景：

1.原生-->>原生

這個不多說直接還是原生跳轉就行

2.原生-->>Flutter

調用PlatformRouterImp中的方法

3.Flutter-->>原生

需要Flutter代碼執行

 FlutterBoost.singleton
                    .open('native')
                    .then((Map<dynamic, dynamic> value) {
                  print(
                      'call me when page is finished. did recieve native route result $value');
                });

4.Flutter-->>Flutter (走Native原生Controller容器跳轉)

 FlutterBoost.singleton
                    .open('firstFirst')
                    .then((Map<dynamic, dynamic> value) {
                  print(
                      'call me when page is finished. did recieve FF route result $value');
                });

5.Flutter-->>Flutter(走Flutter自己的Flutter Navigator 跳轉)

 Navigator.push<dynamic>(
                    context,
                    MaterialPageRoute<dynamic>(builder: (_) => PushWidget()),
                  );

這個自己去做處理，建議既然使用flutter_boost就都採用flutter_boost統一的路有跳轉。

如果想實現只打開一個Flutter的原生控制器，其他走flutter內部跳轉router邏輯，則需要自己處理，或者也可以看下flutter_thrio框架。

到這裏基本上全部工作都可以了，Flutter和iOS都會關聯上。直接運行Xcode就可以了。

關於分離開發：

需要注意的地方如果之後考慮分開開發，Flutter同學只開發Flutter的話，需要在flutter_module/.ios/下工程配置之前iOS端的東西即可，就可以使用flutter run直接跑起來，且也能使用flutter_boost路由。做到Flutter開發Flutter，原生開發原生。做到分離。

下一篇會寫下Flutter_Boost在Android中的集成應用和代碼實踐，Flutter與Native混合開發-FlutterBoost集成應用和開發實踐(Android)。