[移动开发]Android项目支持flutter module按需加载，解决崩溃：VM snapshot invalid and could not be inferred from settings.

最近有需求：在旧android项目中需要加入flutter编写的小游戏作为按需加载模块。

于是按常规方法

1.新建flutter module：flutter_games，引用以前写好的flutter app

2.将flutter_games打包aar： flutter build aar

3.在旧项目的root目录里创建Dynamic Feature module：?games

4.在games的build.gradle里面增加?

dependencies{

...

implementation project(":app")

implementation project(":flutter")

}

5.在旧项目的root目录的settings.gradle加入?

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

6.在app module的build.gradle里面增加

android{

...

dynamicFeatures = [':games']
}

7.打包：build bundles

8.下载bundletool

9.将生成的.aab文件使用bundletool生成apks

java -jar bundletool-all-1.7.0.jar build-apks --local-testing --bundle=app-release.aab --output=app.apks 

10.安装apks

java -jar bundletool-all-1.7.0.jar install-apks --apks app.apks

最后运行app，结果在下载完module后，运行崩溃

E/flutter: [ERROR:flutter/runtime/dart_vm_data.cc(19)] VM snapshot invalid and could not be inferred from settings.
    [ERROR:flutter/runtime/dart_vm.cc(245)] Could not setup VM data to bootstrap the VM from.
    [ERROR:flutter/runtime/dart_vm_lifecycle.cc(89)] Could not create Dart VM instance.
A/flutter: [FATAL:flutter/shell/common/shell.cc(209)] Check failed: vm. Must be able to initialize the VM.

通过查看源码分析java和native层，大概了解了引擎启动流程。

最后找到了原因：找不到libapp.so。因为flutter引擎默认在

applicationInfo.nativeLibraryDir目录去找so，但按需加载模块的so是不打进base包的，所以并不在该目录下。

解决方案：

在FlutterActivity的子类里面重写

getFlutterShellArgs方法，指定libapp.so的路径

override fun getFlutterShellArgs(): FlutterShellArgs {
        val shellArgs = super.getFlutterShellArgs()
        if (!BuildConfig.DEBUG && !BuildConfig.JIT_RELEASE) {
            val aotSharedLibraryNameKey = "aot-shared-library-name"
            val pathLoader = applicationContext.classLoader as PathClassLoader
            val path = pathLoader.findLibrary("app")
            shellArgs.add("--$aotSharedLibraryNameKey=$path")
        }
        return shellArgs
    }

最后再打包测试，一切正常了！