Flutter - Flutter模块集成到一个现有的Andro

话不多说，拿起键盘就是干！Ctrl+C & Ctrl+V

使用As导入FlutterModule项目，选择菜单栏的 File -> New Module -> Import Flutter Module , 导入成功后，项目中的两个gradle文件会被修改。一个是 settings.gradle 和 app/build.gradle , 修改的内容分别如下：
settings.gradle, 最后会添加这样一段话 :

setBinding(new Binding([gradle: this]))
evaluate(new File(
  settingsDir.parentFile,
  '../flutter/each_family/.android/include_flutter.groovy'
))

app/build.gradle中的依赖会在第一排添加：

dependencies {
    implementation project(':flutter')  //这是导入的Flutter的东西
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation 'com.android.support:appcompat-v7:27.+'
    .... //此处省略N多
}

由于 libflutter.so 的问题，或者说是安卓编译架构的问题，在编译运行后打开flutter显示的那个页面可能会出现 couldn't find libflutter.so 的问题，解决办法是只使用 armeabi-v7a, 具体配置是修改 app/build.gradle 文档，如下：

android{
    defaultConfig{
        ndk {
            abiFilters "armeabi-v7a", "x86"
       }
    }
    buildTypes {
          debug {
              ndk {
                abiFilters "armeabi-v7a", "x86"
              }
          }
          release {
              ndk {
                 abiFilters "armeabi-v7a"
              }   
         }
    }
}

按照以上配置，就不会出现so库找不到的问题了！

demo示例

原生代码 - kotlin

class FlutterPresenterActivity : AppCompatActivity() {

    companion object {

        /** 通讯频道名称 **/
        private const val ChannelName = "com.demo.flutter/activity"

    }

    private var methodChannel: MethodChannel? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        with(initActivityUI()) {  //初始化ActivityUI
            initMethodChannel(this) //初始化MethodChannel
            ToastPlugin.register(this@FlutterPresenterActivity, this) //注册Toast插件
        }
    }

    /** 初始化ActivityUI **/
    private fun initActivityUI(): FlutterView {
        window.requestFeature(Window.FEATURE_NO_TITLE)
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            window.clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS
                    or WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION)
            window.decorView.systemUiVisibility = View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN or View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION or View.SYSTEM_UI_FLAG_LAYOUT_STABLE
            window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS)
            window.statusBarColor = Color.TRANSPARENT
            window.navigationBarColor = Color.TRANSPARENT
        }
        with(Flutter.createView(this@FlutterPresenterActivity, lifecycle, "about")) {
            setContentView(this, FrameLayout.LayoutParams(FrameLayout.LayoutParams.MATCH_PARENT,
                    FrameLayout.LayoutParams.MATCH_PARENT))
            return this
        }
    }

    /**
     * 初始化MethodChannel
     * @param flutterView FlutterView对象
     */
    private fun initMethodChannel(flutterView: FlutterView) {
        methodChannel = MethodChannel(flutterView, ChannelName)
        methodChannel?.setMethodCallHandler { methodCall, result ->
            when (methodCall.method) {
                "activityFinish" -> goBack() //关闭当前页面
            }
        }
    }

    override fun onKeyDown(keyCode: Int, event: KeyEvent?): Boolean {
        if (event?.action == KeyEvent.ACTION_DOWN && keyCode == KeyEvent.KEYCODE_BACK) {
            goBack() //返回上一个页面
            return true
        }
        return super.onKeyDown(keyCode, event)
    }

    private fun goBack() {
        this.finish()
        overridePendingTransition(R.anim.slide_in_left, R.anim.slide_out_right)
    }

}

Flutter端代码：
main.dart

import 'dart:ui';
import 'package:each_family/data/color_theme.dart';
import 'package:each_family/ui/about_page.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() {
  runApp(new MyApp());
  SystemChrome.setSystemUIOverlayStyle(new SystemUiOverlayStyle(
    statusBarColor: new Color(0x00000000),
  ));
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Flutter Demo',
      theme: new ThemeData(
        primarySwatch: ColorTheme.lightBlue,
        primaryColorBrightness: Brightness.dark,
        brightness: Brightness.light,
        accentColorBrightness: Brightness.dark,
      ),
      home: _showPageByRouteName(window.defaultRouteName), //window.defaultRouteName 是路由入口
    );
  }

  Widget _showPageByRouteName(String routeName) {
    switch (routeName) {
      case "about":
        return new AboutPage();
      default:
        return new AboutPage();
//        return new HomePage(title: "主页");
    }
  }
}

about_page.dart

import 'package:each_family/core/channel/activity_channel.dart';
import 'package:flutter/material.dart';

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

  final String title;

  @override
  _AboutPageState createState() => new _AboutPageState();
}

class _AboutPageState extends State<AboutPage> {
  void _goBack() => ActivityChannel.goBackToHistory();

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        centerTitle: true,
        elevation: 0.0,
        leading: new InkWell(
          onTap: _goBack,
          child: new Padding(
            padding: const EdgeInsets.all(18.0),
            child: new Image.asset(
              "assets/images/ic_nav_back.png",
              fit: BoxFit.scaleDown,
            ),
          ),
        ),
        title: new Text('关于我们'),
      ),
      body: new Center(
        child: new Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            new Text(
              '关于我们',
            ),
          ],
        ),
      ),
    );
  }
}

toast.dart

import 'package:flutter/services.dart';

class Toast {
  static const _platform = const MethodChannel("com.demo.flutter/toast");

  static void showShortToast(String message) =>
      _platform.invokeMethod("showShortToast", {"message": message});

  static void showLongToast(String message) =>
      _platform.invokeMethod("showLongToast", {"message": message});

  static void showToast(String message, int duration) =>
      _platform.invokeMethod("showToast", {"message": message, "duration": duration});
}

activity_channel.dart

import 'package:flutter/services.dart';

class ActivityChannel {
  static const _platform = const MethodChannel("com.whitehorse.everyhouse/activity");

  static void goBackToHistory() => _platform.invokeMethod("activityFinish");
}

color_theme.dart

import 'package:flutter/material.dart';

class ColorTheme extends MaterialColor {
  ColorTheme(int primary, Map<int, Color> swatch) : super(primary, swatch);

  static const int _bluePrimaryValue = 0xFF25C4FF;

  static const MaterialColor lightBlue = MaterialColor(
    _bluePrimaryValue,
    <int, Color>{
      50: Color(0xFFE3F2FD),
      100: Color(0xFFBBDEFB),
      200: Color(0xFFa0CAF9),
      300: Color(0xFF94B5F6),
      400: Color(0xFF89A5F5),
      500: Color(_bluePrimaryValue),
      600: Color(0xFF5688E5),
      700: Color(0xFF4576D2),
      800: Color(0xFF3565C0),
      900: Color(0xFF23a9ff),
    },
  );
}

这大致就是一个完成的demo示例了，有兴趣的小伙伴可以拿来跑跑看！