安卓原生添加Flutter Module混合开发

1. 使用FlutterEngine和FlutterView可以简单的将flutter 页面嵌入原生，但是会有问题
   1. 一次只能加载一个dart入口
   2. 原生加载flutter引擎需要消耗性能， 需要实现秒开

所以使用一个FlutterCacheManager来管理所有的flutter engine

package org.devio.`as`.proj.common.flutter
import android.content.Context
import android.os.Looper
import io.flutter.embedding.engine.FlutterEngine
import io.flutter.embedding.engine.FlutterEngineCache
import io.flutter.embedding.engine.dart.DartExecutor
import io.flutter.view.FlutterMain
/**
 * Flutter 优化提升加载速度 实现秒开flutter模块
 * 1.预加载不损失首页性能
 * 2.实例化多个flutter引擎，并分别加载不同的dart入口文件
 */
class FlutterCacheManager private constructor() {
    //preload
    fun preload(context: Context) {
        // 在空闲线程里预加载flutter引擎  不会影响原生页面加载
        Looper.myQueue().addIdleHandler {
            initFlutterEngine(context, MODULE_NAME_FAVORITE)
            initFlutterEngine(context, MODULE_NAME_RECOMMEND)
            false // 执行完之后出队列
        }
    }
    // 获取flutter engine
    fun getCachedFlutterEngine(moduleName: String, context: Context?): FlutterEngine {
        var engine = FlutterEngineCache.getInstance()[moduleName]
        if (engine == null && context != null) {
            engine = initFlutterEngine(context, moduleName)
        }
        return engine!!
    }
    // init
    private fun initFlutterEngine(context: Context, moduleName: String): FlutterEngine {
        val flutterEngine = FlutterEngine(context)
        flutterEngine.dartExecutor.executeDartEntrypoint(
            DartExecutor.DartEntrypoint(
                FlutterMain.findAppBundlePath(),
                moduleName
            )
        )
        FlutterEngineCache.getInstance().put(moduleName, flutterEngine)
        return flutterEngine
    }
    companion object {
        // 对应dart端的endpoint
        const val MODULE_NAME_FAVORITE = "main"
        const val MODULE_NAME_RECOMMEND = "recommend"
        @JvmStatic
        @get: Synchronized
        var instance: HiFlutterCacheManager? = null
            get() {
                if (field == null) {
                    field = HiFlutterCacheManager()
                }
                return field
            }
            private set
    }
}

package org.devio.`as`.proj.common.flutter
import android.content.Context
import android.os.Bundle
import android.view.View
import android.view.ViewGroup
import android.widget.FrameLayout
import io.flutter.embedding.android.FlutterTextureView
import io.flutter.embedding.android.FlutterView
import io.flutter.embedding.engine.FlutterEngine
import org.devio.`as`.proj.common.R
import org.devio.`as`.proj.common.ui.component.HiBaseFragment
import org.devio.`as`.proj.util.AppGlobals
abstract class HiFlutterFragment : HiBaseFragment() {
    private val flutterEngine: FlutterEngine?
    private var flutterView: FlutterView? = null
    abstract val moduleName: String?
    init {
        // 在此处获取flutterEngin
        flutterEngine =
            HiFlutterCacheManager.instance!!.getCachedFlutterEngine(moduleName!!, AppGlobals.get())
    }
    override fun getLayoutId(): Int {
        return R.layout.fragment_flutter
    }
    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        val lp: FrameLayout.LayoutParams = FrameLayout.LayoutParams(
            ViewGroup.LayoutParams.MATCH_PARENT,
            ViewGroup.LayoutParams.MATCH_PARENT
        )
        (layoutView as ViewGroup).addView(createFlutterView(activity!!), lp)
    }
    // 核心代码  将flutterView add 到页面中
    private fun createFlutterView(context: Context): FlutterView {
        val flutterTextureView = FlutterTextureView(activity!!)
        flutterView = FlutterView(context, flutterTextureView)
        return flutterView!!
    }
    override fun onStart() {
        flutterView!!.attachToFlutterEngine(flutterEngine!!)
        super.onStart()
    }
    override fun onResume() {
        super.onResume()
        flutterEngine!!.lifecycleChannel.appIsResumed()
    }
    override fun onPause() {
        super.onPause()
        flutterEngine!!.lifecycleChannel.appIsInactive()
    }
    override fun onDetach() {
        super.onDetach()
        flutterEngine!!.lifecycleChannel.appIsDetached()
    }
    override fun onStop() {
        super.onStop()
        flutterEngine!!.lifecycleChannel.appIsPaused()
    }
//    override fun onDestroy() {
//        try {
//            super.onDestroy()
//        } catch (e: Exception) {
//
//        }
//    }
}