https://github.com/alibaba/flutter_boost

• Flutter Engine
• Dart VM
  一个进程里面最多只会初始化一个Dart VM。然而一个进程可以有多个Flutter Engine，多个Engine实力共享共同一个Dart VM
• BinaryMessenger flutter和native通信是依赖BinaryMessenger去传递消息的。而目前BinaryMessenger是有FlutterViewController（Activity）去实现的。

Flutter Engine复用

iOS实现

通过以下代码就可以将flutterEngine渲染的页面转移到新的viewController显示。

flutterEngine?.viewController

新建FlutterViewController使用传递flutterEngine的方法初始化

- (instancetype)initWithEngine:(FlutterEngine*)engine
                       nibName:(nullable NSString*)nibName
                        bundle:(nullable NSBundle*)nibBundle NS_DESIGNATED_INITIALIZER;

android实现

• FlutterView：Android 中用于展示 Flutter 页面的控件，一个 FlutterView 中可以展示多个 Flutter Widget，官方的注释是："An Android View containing a Flutter app"。内部包含了 FlutterNativeView。
• FlutterNativeView：每个 FlutterView 中包含一个FlutterNativeView，该类的主要作用是 Android 与 Flutter 之间的通信，保持生命周期与 Activity 及 FlutterView 同步。内部包含了 DartExecutor。
• DartExecutor：根据名称我们可以了解，这个类就是 Dart VM 相关处理 Java 与 C/C++ 的调用。官方的注释是："Configures, bootstraps, and starts executing Dart code"。

主要代码如下
Application

// Instantiate a FlutterEngine.
        FlutterEngine flutterEngine = new FlutterEngine(this);

        // Start executing Dart code to pre-warm the FlutterEngine.
        flutterEngine.getDartExecutor().executeDartEntrypoint(
                DartExecutor.DartEntrypoint.createDefault()
        );

        // Cache the FlutterEngine to be used by FlutterActivity.
        FlutterEngineCache
                .getInstance()
                .put(TuyaConstant.flutterEngineId, flutterEngine);

MainActivity

override fun getCachedEngineId(): String? {
        return TuyaConstant.flutterEngineId;
    }

跳转到新的FlutterActivity

Intent intent = FlutterActivity
                                            .withCachedEngine(TuyaConstant.flutterEngineId)
                                            .build(getCurrentActivity());
getCurrentActivity().startActivity(intent);