Flutter 工程化搭建

为了积极拥抱新技术并优化RN的性能问题，所以决定在新业务需求中引入Flutter技术栈

Flutter混合栈开发大致可以分为一下两种模式

native工程直接依赖开发

具体接入方式为，先在setting.gradle 中加入如下代码：

setBinding(new Binding([gradle: this]))
evaluate(new File(
        settingsDir,
        '../../Flutter Module工程根目录/.android/include_flutter.groovy'
))

其次在App的build.gradle 中加入如下代码：

 implementation project(':flutter')

最后在主工程的build.gradle 中加入如下代码即可：

repositories {
buildscript {
        maven {
            url 'http://download.flutter.io'
        }
    }
}
    
allprojects {
    repositories {
        maven {
            url 'http://download.flutter.io'
        }
    }
}

native工程接入aar

新建Flutter module工程

flutter create -t module xx_module

目录结构如下

xx_modlue 
          - .android // Android测试工程
          - .ios  // iOS测试工程
          - lib  // Flutter主工程
                - main.dart // Flutter入口文件
          - pubspec.yaml  // Flutter三方包配置文件

Flutter中提供了将module打包成aar的命令，生成的aar文件路径为 xx_modlue/build/host/outputs/repo

flutter build aar

将生成的aar文件引入Android开发工程即可完成aar的引用

到目前为止整个aar的引入基本是可以正常开发的，但是存在问题，那就是在每次开发都需要手动的将生成的aar包复制到主工程中进行依赖，不仅操作麻烦而且会出错，所以讲Flutter打包及引入流程变成日常开发常用的模式是最佳实践

flutter 打包上传流程分析：

为符合日常开发流程，需要将Flutter打成的aar文件上传至maven，因此首要任务就是解决将aar上传至maven问题

查看生成的aar目录下面的pom文件会发现主工程依赖的第三方aar包也会被下载至xx_modlue/build/host/outputs/repo路径下，pom文件如下：

  4.0.0
  com.xxx.flutter
  xxx 
  release-0.0.7
  aar
  
    
      io.flutter
      flutter_embedding_release
      1.0.0-af51afceb8886cc11e25047523c4e0c7e1f5d408
      compile
    
    
      io.flutter
      armeabi_v7a_release
      1.0.0-af51afceb8886cc11e25047523c4e0c7e1f5d408
      compile
    
    
      io.flutter
      arm64_v8a_release
      1.0.0-af51afceb8886cc11e25047523c4e0c7e1f5d408
      compile
    
    
      io.flutter
      x86_64_release
      1.0.0-af51afceb8886cc11e25047523c4e0c7e1f5d408
      compile
    
  

分析pom文件可知在上传主工程生成的aar的时候我们还需要将下载下来的第三方aar上传至maven库，因此我们得知具体工程化脚本流程如下：

1、获取生成的aar路径
2、上传第三方依赖的aar文件
3、更新主工程aar的artifactId
4、上传主工程aar文件

具体脚本如下：

deploy_aar(){
    mvn deploy:deploy-file \
    -DpomFile="$FILE_PATH/$NAME.pom" \
    -DgeneratePom=false \
    -Dfile="$FILE_PATH/$NAME.aar" \
    -Durl="http://xxx.xxx.xxx:xxx/repository/public/" \
    -DrepositoryId="nexus" \
    -Dpackaging=aar \
    -s="mvn-settings.xml" \
    -Dversion="$VERSION"
}

projectDir=`pwd`

# 清除Flutter生成文件
flutter clean

# 获取pub包
flutter pub get

# 删除文件夹
rm -rf `pwd`/build/host/outputs/repo/


# 修改版本号
group="com.xxx.flutter"
type="release"
#type="debug"
#type="profile"
version="${type}-0.0.7"
artifactId="xxx"


echo "替换Flutter/build.gradle 中的group 为${group}"
path=`pwd`/.android/Flutter/build.gradle
sed -i '' '29s/^.*$/group "'${group}'"/'  ${path}
echo "替换Flutter/build.gradle 中的version 为${version}"
path=`pwd`/.android/Flutter/build.gradle
sed -i '' '30s/^.*$/version "'${version}'"/'  ${path}


# 打包AAR
flutter build aar --no-debug --no-profile

# 找到AAR并上传
path=`pwd`
# shellcheck disable=SC2006
p=`find ${path}/build/host/outputs/repo -type f  -name "*${type}*.aar"`
echo "${p}"


array=(${p//'\n'/})
currentName=""
currentPath=""
currentPom=""
currentDir=""

# shellcheck disable=SC2068
for item in ${array[@]}
do
    resFile=`basename ${item}`
    echo "${item}"
    result=$(echo ${resFile} | grep "flutter_release")
    if [[ "$result" == "" ]]
    then
      lenght=${#item}
      sub=${item:0:${lenght}-3}
      pom="${sub}pom"
      resFileLenght=${#resFile}
      subDir=${item:0:${lenght}-${resFileLenght}}
      curName=`echo ${resFile} | cut -d "-" -f 2`
      curNameLenght=${#curName}
      subVersion=${curName:0:${curNameLenght}-4}
      nameLenght="${#resFile}"
      subName=${resFile:0:${nameLenght}-4}
      export FILE_PATH="${subDir}"
      export NAME="${subName}"
      export VERSION=${subVersion}
      deploy_aar
    else
      nameLenght="${#resFile}"
      subName=${resFile:0:${nameLenght}-4}
      currentName="${subName}"
      currentPath=${item}
      currentPath=${item}
      lenght=${#item}
      sub=${item:0:${lenght}-3}
      currentPom="${sub}pom"
      resFileLenght=${#resFile}
      subDir=${item:0:${lenght}-${resFileLenght}}
      currentDir=${subDir}
    fi
done

cd "${currentDir}"
echo `pwd`
mv "${currentName}.aar" "${artifactId}-${version}.aar"
mv "${currentName}.pom" "${artifactId}-${version}.pom"
cd ${projectDir}
echo `pwd`

currentName="${artifactId}-${version}"
currentPath="${currentDir}${currentName}.aar"
currentPom="${currentDir}${currentName}.pom"
echo "current name is ${currentName}"
echo "current path is ${currentPath}"
echo "currentPom is ${currentPom}"
echo "替换pom artifactId为${artifactId}"
sed -i '' '6s/^.*$/  '${artifactId}'<\/artifactId> /'  ${currentPom}
echo "currentDir is ${currentDir}"
echo "currentVersion is ${version}"


export FILE_PATH="${currentDir}"
export NAME="${currentName}"
export VERSION=${version}
deploy_aar

上传maven成功后，主工程依赖Flutter代码就和添加第三方SDK流程一致了。

选型对比

名称	优点	缺点
native工程直接依赖开发	接入快	工程结构复杂，无法将Flutter开发从native开发流程中剥离
native工程接入aar	Flutter开发与native开发流程解耦	初期接入流程复杂

最终选择为通过maven方式接入aar方便后续拓展

Flutter 混合栈选型

在完成Flutter混合开发接入流程后，会有混合栈管理问题，在混合方案中解决的主要问题是如何去处理交替出现的Flutter和Native页面。综合目前的开源框架，选型为FlutterBoost

flutterBoost Flutter端接入：

FlutterBoost.singleton.registerPageBuilders({
      testhome: (String pageName, Map params, String _) =>
          MyHomePage(title: ''),
      shoppingcar: (String pageName, Map params, String _) {
        String platformItemNo = '';
        if (params.containsKey("platformItemNo")) {
          platformItemNo = params['platformItemNo'];
          NativeChat.print(platformItemNo);
        }
        return ShoppingCar(platformItemNo: platformItemNo);
      },
      login: (String pageName, Map params, String _) =>
          LoginPage(),
      overlay: (String pageName, Map params, String _) =>
          OverlayPage(),
    });

android端接入：

application 初始化代码：

val router =
            INativeRouter { context, url, urlParams, requestCode, exts ->
                PageRouter.openPageByUrl(context, url, urlParams)
            }

        val boostLifecycleListener = object : FlutterBoost.BoostLifecycleListener {
            override fun onEngineCreated() {
            }

            override fun onPluginsRegistered() {
            }

            override fun beforeCreateEngine() {
            }

            override fun onEngineDestroy() {
            }

        }

        val platform = FlutterBoost.ConfigBuilder(application, router)
            .isDebug(BuildConfig.DEBUG)
            .whenEngineStart(FlutterBoost.ConfigBuilder.ANY_ACTIVITY_CREATED)
            .renderMode(FlutterView.RenderMode.texture)
            .lifecycleListener(boostLifecycleListener)
            .build()
        FlutterBoost.instance().init(platform)

路由配置代码

// PageRouter 路由跳转及配置页面
object PageRouter {
    /**
     * 路由映射
     */
    val pageName: HashMap =
        object : HashMap() {
            init {
                put("xxxx://shoppingCar", "shoppingCar")
                put("xxxx://login", "login")
                put("xxxx://home", "home")
                put("xxxx://overlay", "overlay")
            }
        }
    const val SHOPPING_CAR = "xxxx://shoppingCar"
    const val LOGIN_PAGE = "xxxx://login"
    const val OVERLAY = "xxxx://overlay"
    const val BUYER_PRODUCT_DETAIL = "xxxx://buyer/productdetail"
    const val TEST_SECOND = "xxxx://testSecond"

    @JvmOverloads
    fun openPageByUrl(
        context: Context,
        url: String,
        params: Map<*, *>?,
        requestCode: Int = 0
    ): Boolean {
        val path = url.split("\\?").toTypedArray()[0]
        Log.i("openPageByUrl", path)
        return try {
            when {
                pageName.containsKey(path) -> {
                    val intent =
                        BoostFlutterActivity.withNewEngine().url(pageName[path]!!)
                            .params(params!!)
                            .backgroundMode(BoostFlutterActivity.BackgroundMode.opaque)
                            .build(context)
                    if (context is Activity) {
                        context.startActivityForResult(intent, requestCode)
                    } else {
                        context.startActivity(intent)
                    }

                    return true
                }
                url.startsWith(TEST_SECOND) -> {
                    context.startActivity(
                        Intent(
                            context,
                            SecondActivity::class.java
                        )
                    )
                    return true
                }
                else -> false
            }
        } catch (t: Throwable) {
            false
        }
    }
}

native 跳转逻辑

// 初始化channel通知

 FlutterBoost.instance().channel().addMethodCallHandler { call, result ->
            when (call.method) {
                "baseUrl" -> {
                    result.success(ApiConstant.getApiUrl())
                }
            }
        }

// 跳转代码

 val params = hashMapOf()
            params["param"] = param
            PageRouter.openPageByUrl(this, PageRouter.SHOPPING_CAR, params)

Flutter 测试环境搭建

在混合开发的工程中被吐槽最多的大概就是测试了吧，和native打包在一起调试费时费力，对前端开发要求高需要了解native的基本流程