[移动开发]糅合flutter-boost与MethodChannel的使用方法

????????在《flutter-boost的集成与基本使用（android与flutter的混合开发）》中提到了在大部分情况下，我们不满足于简单的跳转，想要android原生和flutter进一步的融合，需要借助MethodChannel，利用它我们可以更好的完成原生与flutter页面的数据交互。

? ? ? ? 一、MethodChannel的实现：

? ? ? ? ? ? ? ? （1）在android中，可以定义一个flutterPlugin，进行集中管理，代码如下：

package com.innovation.projector.plugin

import android.widget.Toast
import com.innovation.projector.MyApplication
import io.flutter.embedding.engine.plugins.FlutterPlugin
import io.flutter.plugin.common.MethodCall
import io.flutter.plugin.common.MethodChannel
import io.flutter.plugin.common.PluginRegistry

class FlutterNativePlugin : FlutterPlugin, MethodChannel.MethodCallHandler {
    override fun onAttachedToEngine(binding: FlutterPlugin.FlutterPluginBinding) {
        //name必须和dart端的保持一致
        val channel = MethodChannel(binding.flutterEngine.dartExecutor, "com.innovation/name")
        channel.setMethodCallHandler(FlutterNativePlugin())
    }

    companion object {
        fun registerWith(registrar: PluginRegistry.Registrar) {
            val channel = MethodChannel(registrar.messenger(), "com.innovation/name")
            channel.setMethodCallHandler(FlutterNativePlugin())
        }
    }

    override fun onDetachedFromEngine(binding: FlutterPlugin.FlutterPluginBinding) {
    }

    override fun onMethodCall(call: MethodCall, result: MethodChannel.Result) {
        when (call.method) {
            "androidMethodTest" -> result.success("android原生执行：：" + call.arguments.toString() + call.method)
            "androidMethodToast" -> {
                Toast.makeText(
                    MyApplication.getGlobalContext(),
                    call.arguments.toString(),
                    Toast.LENGTH_LONG
                ).show()
                //result.success可以将接口返回的数据回传给flutter
                result.success("python")
            }
            else -> result.notImplemented()
        }
    }
}

? ? ? ? ? ? ? ? （2）在需要调用的activity中重写以下方法：

 @Override
    public void configureFlutterEngine(@NonNull @NotNull FlutterEngine flutterEngine) {
        flutterEngine.getPlugins().add(new FlutterNativePlugin());
    }

? ? ? ? ? ? ? ? （3）上面两步完成后，android端也就实现完毕，接下来dart端：

class AddDevicesPage extends StatefulWidget {
  final String title;

  AddDevicesPage({Key key, this.title}) : super(key: key);

  @override
  _AddDevicesPageState createState() => _AddDevicesPageState(title);
}

class _AddDevicesPageState extends State<AddDevicesPage>
    with PageVisibilityObserver {
  String title;
  String result='保存';

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(
        primaryColor: Colors.white,
      ),
      home: Container(
        color: Colors.white,
        child: Column(
          mainAxisAlignment: MainAxisAlignment.start,
          children: [
            CommonTitleView(title, 1, null),
            Container(
              color: Colors.blue,
              //在这里体现
              child: GestureDetector(
                onTap: () async {
                  await androidMethodTest();
                },
                child: Text(
                  result,
                  style: TextStyle(fontSize: 12, color: Colors.white),
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }

  _AddDevicesPageState(this.title);

  Future<String> androidMethodTest() async {
    const platform = const MethodChannel('com.innovation/name');
    String result = "";
    try {
      result = await platform.invokeMethod('androidMethodToast', "test");
      //接受回调返回的参数，这里进行界面刷新提供更直观的效果
      setState(() {
        this.result = result;
      });
    } on Exception catch (e) {
      print(e.toString());
    }
    return result;
  }
}

? ? ? ? 二、糅合flutter-boost与MethodChannel的关键：

? ? ? ? ? ? ? ? 闲鱼技术团队提供的flutter-boost在跳转时会使用一个flutterboostactivity作为容器，在上一篇文章中的androidmanifest中提到，如果仅需要我们实现简单带参跳转，我们无需写出实例的activity，如果想两者一并使用，只需下面几步：

? ? ? ? ? ? ? ? （1）在androidmanifest中申明一个新activity，以ToFlutterActivity为例：

        <!-- 这里的activity是给flutter跳转native留的 -->
        <activity android:name=".ToAndroidActivity" />

        <!-- 这里的activity是给直接使用flutterboost进行跳转flutter页面留的原生activity容器 -->
        <activity
            android:name="com.idlefish.flutterboost.containers.FlutterBoostActivity"
            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density"
            android:hardwareAccelerated="true"
            android:theme="@style/Theme.FlutterTheme"
            android:windowSoftInputMode="adjustResize">
            <!--低端机上flutter-boost仍会出现跳转黑屏现象，这种方法可以解决,原理就是类似于原生闪屏页-->
            <meta-data
                android:name="io.flutter.app.android.SplashScreenUntilFirstFrame"
                android:value="true" />
        </activity>

        <meta-data
            android:name="flutterEmbedding"
            android:value="2" />

        <!-- 这里的activity是给使用flutterboost进行跳转并且想调用原生方法的flutter页面留的原生activity容器 -->
        <activity
            android:name=".ToFlutterActivity"
            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density"
            android:hardwareAccelerated="true"
            android:theme="@style/Theme.FlutterTheme"
            android:windowSoftInputMode="adjustResize">
            <meta-data
                android:name="io.flutter.app.android.SplashScreenUntilFirstFrame"
                android:value="true" />
        </activity>
        <activity android:name="io.flutter.embedding.android.FlutterActivity" />

? ? ? ? ????????（2）在自己的application中完成flutter-boost跳转的配置：

 @Override
    public void onCreate() {
        super.onCreate();
        context = getApplicationContext();

        //alibaba flutter_booster android端配置集成
        FlutterBoost.instance().setup(this, new FlutterBoostDelegate() {
            @Override
            public void pushNativeRoute(FlutterBoostRouteOptions options) {
                //这里的ToAndroidActivity是自己定义的，作为flutter跳原生的页面
                Intent intent = new Intent(FlutterBoost.instance().currentActivity(), ToAndroidActivity.class);
                FlutterBoost.instance().currentActivity().startActivityForResult(intent, options.requestCode());
            }

            @Override
            public void pushFlutterRoute(FlutterBoostRouteOptions options) {
                //这里的ToFlutterActivity是自己定义的，作为原生跳flutter页面的容器
                Intent intent = new FlutterBoostActivity.CachedEngineIntentBuilder(ToFlutterActivity.class)
                        .backgroundMode(FlutterActivityLaunchConfigs.BackgroundMode.transparent)
                        .destroyEngineWithActivity(false)
                        .uniqueId(options.uniqueId())
                        .url(options.pageName())
                        .urlParams(options.arguments())
                        .build(FlutterBoost.instance().currentActivity());
                FlutterBoost.instance().currentActivity().startActivity(intent);
            }
        }, engine -> {
        });

????????????????（3）将ToFlutterActivity继承FlutterBoostActivity，重写onCreate()方法：

public class ToFlutterActivity extends FlutterBoostActivity {
    final private String TAG = "ToFlutterActivity";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.d(TAG, "onCreate");
    }

    @Override
    public void configureFlutterEngine(@NonNull @NotNull FlutterEngine flutterEngine) {
        flutterEngine.getPlugins().add(new FlutterNativePlugin());
    }
}

·? ? ? ? 以上就是糅合flutter-boost与MethodChannel的使用方法，如有不足，还望讨论。