替换so文件来动态替换Flutter代码实现详解

protected void onCreate(@Nullable Bundle savedInstanceState) {
  switchLaunchThemeForNormalTheme();
  super.onCreate(savedInstanceState);
  delegate = new FlutterActivityAndFragmentDelegate(this);
  delegate.onAttach(this);
  delegate.onRestoreInstanceState(savedInstanceState);
  lifecycle.handleLifecycleEvent(Lifecycle.Event.ON_CREATE);
  configureWindowForTransparency();
  setContentView(createFlutterView());
  configureStatusBarForFullscreenFlutterExperience();
}

FlutterActivity->
    FlutterActivityAndFragmentDelegate->
        onAttach()->
            setupFlutterEngine->
                1.尝试去Cache中获取Engine
                2.尝试从Host中获取Engine
                3.都没有的话创建一个新的Engine->
                    Engine #Constructor->
                    1. 会对Assets、DartExecutor、各种Channel、FlutterJNI做处理
                    2. 还会对FlutterLoader做处理->
                        startInitialization方法做初始化
                            -> 1. 必须在主线程初始化Flutter
                            -> 2. 先检查settings变量；
                            -> 3. 获取全局的ApplicationContext防止内存泄漏
                            -> 4. VsyncWaiter对象的初始化
                            -> 5. 最后会生成一个initTask交给线程池去执行

initResultFuture = Executors.newSingleThreadExecutor().submit(initTask);

 // Use a background thread for initialization tasks that require disk access.
Callable<InitResult> initTask =
    new Callable<InitResult>() {
      @Override
      public InitResult call() {
         ResourceExtractor resourceExtractor = initResources(appContext); 
         flutterJNI.loadLibrary(); 
           // Prefetch the default font manager as soon as possible on a background thread.  
          // It helps to reduce time cost of engine setup that blocks the platform thread.  
         Executors.newSingleThreadExecutor() 
             .execute(
                 new Runnable () { 
                     @Override
                     public void run () { 
                         flutterJNI.prefetchDefaultFontManager(); 
                     } 
                 }
         ); 
         if (resourceExtractor != null) { 
             resourceExtractor.waitForCompletion(); 
         } 
         return new InitResult( 
             PathUtils.getFilesDir(appContext), 
             PathUtils.getCacheDirectory(appContext), 
             PathUtils.getDataDirectory(appContext)
         ); 
      }
    };

 /** Extract assets out of the APK that need to be cached as uncompressed files on disk. */
private ResourceExtractor initResources(@NonNull Context applicationContext) {
  ResourceExtractor resourceExtractor = null;
  if (BuildConfig.DEBUG || BuildConfig.JIT_RELEASE) {
    final String dataDirPath = PathUtils.getDataDirectory(applicationContext);
    final String packageName = applicationContext.getPackageName();
    final PackageManager packageManager = applicationContext.getPackageManager();
    final AssetManager assetManager = applicationContext.getResources().getAssets();
    resourceExtractor =
        new ResourceExtractor(dataDirPath, packageName, packageManager, assetManager);
    // In debug/JIT mode these assets will be written to disk and then
    // mapped into memory so they can be provided to the Dart VM.
     resourceExtractor
        .addResource(fullAssetPathFrom(flutterApplicationInfo.vmSnapshotData))
        .addResource(fullAssetPathFrom(flutterApplicationInfo.isolateSnapshotData))
        .addResource(fullAssetPathFrom(DEFAULT_KERNEL_BLOB));
    resourceExtractor.start();
  }
  return resourceExtractor;
}

ResourceExtractor resourceExtractor = initResources(appContext);
flutterJNI.loadLibrary();
// Prefetch the default font manager as soon as possible on a background thread.
// It helps to reduce time cost of engine setup that blocks the platform thread.
Executors.newSingleThreadExecutor()
    .execute(
        new Runnable() {
          @Override
          public void run() {
            flutterJNI.prefetchDefaultFontManager();
          }
        });
if (resourceExtractor != null) {
  resourceExtractor.waitForCompletion();
}

public void loadLibrary() {
  if (FlutterJNI.loadLibraryCalled) {
    Log.w(TAG, "FlutterJNI.loadLibrary called more than once" );
  }
  System.loadLibrary( "flutter" );
  FlutterJNI.loadLibraryCalled = true;
}

flutterLoader.startInitialization(context.getApplicationContext());
flutterLoader.ensureInitializationComplete(context, dartVmArgs);

public void ensureInitializationComplete(
    @NonNull Context applicationContext, @Nullable String[] args) {
  if (initialized) {
    return;
  }
  if (Looper.myLooper() != Looper.getMainLooper()) {
    throw new IllegalStateException(
        "ensureInitializationComplete must be called on the main thread" );
  }
  if (settings == null) {
    throw new IllegalStateException(
        "ensureInitializationComplete must be called after startInitialization" );
  }
  try {
    InitResult result = initResultFuture.get();
    List<String> shellArgs = new ArrayList<>();
    shellArgs.add( "--icu-symbol-prefix=_binary_icudtl_dat" );
    shellArgs.add(
        "--icu-native-lib-path="
+ flutterApplicationInfo.nativeLibraryDir
            + File.separator
            + DEFAULT_LIBRARY);
    if (args != null) {
      Collections.addAll(shellArgs, args);
    }
    String kernelPath = null;
    if (BuildConfig.DEBUG || BuildConfig.JIT_RELEASE) {
      String snapshotAssetPath =
          result.dataDirPath + File.separator + flutterApplicationInfo.flutterAssetsDir;
      kernelPath = snapshotAssetPath + File.separator + DEFAULT_KERNEL_BLOB;
      shellArgs.add( "--" + SNAPSHOT_ASSET_PATH_KEY + "=" + snapshotAssetPath);
      shellArgs.add( "--" + VM_SNAPSHOT_DATA_KEY + "=" + flutterApplicationInfo.vmSnapshotData);
      shellArgs.add(
          "--" + ISOLATE_SNAPSHOT_DATA_KEY + "=" + flutterApplicationInfo.isolateSnapshotData);
    } else {
      shellArgs.add(
          "--" + AOT_SHARED_LIBRARY_NAME + "=" + flutterApplicationInfo.aotSharedLibraryName);
      // Most devices can load the AOT shared library based on the library name
// with no directory path.  Provide a fully qualified path to the library
// as a workaround for devices where that fails.
shellArgs.add(
          "--"
+ AOT_SHARED_LIBRARY_NAME
              + "="
+ flutterApplicationInfo.nativeLibraryDir
              + File.separator
              + flutterApplicationInfo.aotSharedLibraryName);
    }
    shellArgs.add( "--cache-dir-path=" + result.engineCachesPath);
    if (!flutterApplicationInfo.clearTextPermitted) {
      shellArgs.add( "--disallow-insecure-connections" );
    }
    if (flutterApplicationInfo.domainNetworkPolicy != null) {
      shellArgs.add( "--domain-network-policy=" + flutterApplicationInfo.domainNetworkPolicy);
    }
    if (settings.getLogTag() != null) {
      shellArgs.add( "--log-tag=" + settings.getLogTag());
    }
    ApplicationInfo applicationInfo =
        applicationContext
            .getPackageManager()
            .getApplicationInfo(
                applicationContext.getPackageName(), PackageManager.GET_META_DATA);
    Bundle metaData = applicationInfo.metaData;
    int oldGenHeapSizeMegaBytes =
        metaData != null ? metaData.getInt(OLD_GEN_HEAP_SIZE_META_DATA_KEY) : 0;
    if (oldGenHeapSizeMegaBytes == 0) {
      // default to half of total memory.
ActivityManager activityManager =
          (ActivityManager) applicationContext.getSystemService(Context.ACTIVITY_SERVICE);
      ActivityManager.MemoryInfo memInfo = new ActivityManager.MemoryInfo();
      activityManager.getMemoryInfo(memInfo);
      oldGenHeapSizeMegaBytes = (int) (memInfo.totalMem / 1e6 / 2);
    }
    shellArgs.add( "--old-gen-heap-size=" + oldGenHeapSizeMegaBytes);
    if (metaData != null && metaData.getBoolean(ENABLE_SKPARAGRAPH_META_DATA_KEY)) {
      shellArgs.add( "--enable-skparagraph" );
    }
    long initTimeMillis = SystemClock.uptimeMillis() - initStartTimestampMillis;
    flutterJNI.init(
        applicationContext,
        shellArgs.toArray(new String[0]),
        kernelPath,
        result.appStoragePath,
        result.engineCachesPath,
        initTimeMillis);
    initialized = true;
  } catch (Exception e) {
    Log.e(TAG, "Flutter initialization failed." , e);
    throw new RuntimeException(e);
  }
}

shellArgs.add(
    "--" + AOT_SHARED_LIBRARY_NAME + "=" + flutterApplicationInfo.aotSharedLibraryName);
shellArgs.add(
    "--"
+ AOT_SHARED_LIBRARY_NAME
+ "="
+ flutterApplicationInfo.nativeLibraryDir
+ File.separator
+ flutterApplicationInfo.aotSharedLibraryName);

--aot-shared-library-name=libapp.so
--aot-shared-library-name=/data/app/~~RjRJYnLhVBHYW8pHHPeX2g==/com.example.untitled1-wcMTYW1VkfGA2LxW62gUFA==/lib/arm64/libapp.so

FlutterActivity->
    FlutterActivityAndFragmentDelegate->
        onAttach()->
            setupFlutterEngine->
                ……
                startInitialization
                ensureInitializationComplete // alpha

--aot-shared-library-name=libapp.so
--aot-shared-library-name= /data/app/~~RjRJYnLhVBHYW8pHHPeX2g==/com.example.untitled1-wcMTYW1VkfGA2LxW62gUFA==/lib/arm64/libapp.so

--aot-shared-library-name=libfixedapp.so
--aot-shared-library-name= /temp/lib/arm64/libfixedapp.so

public void startInitialization(@NonNull Context applicationContext, @NonNull Settings settings) {
  // ……
  try {
 final Context appContext = applicationContext.getApplicationContext();
    // ……
    flutterApplicationInfo = ApplicationInfoLoader.load(appContext);
    ……

flutterEngine =
    new FlutterEngine(
        host.getContext(),
        host.getFlutterShellArgs().toArray(),
        /*automaticallyRegisterPlugins=*/ false,
        /*willProvideRestorationData=*/ host.shouldRestoreAndSaveState());

class MainActivity: FlutterActivity() {
    override fun getFlutterShellArgs(): FlutterShellArgs {
        return super.getFlutterShellArgs().apply {
this.add( "--aot-shared-library-name=libfixedapp.so" )
            this.add( "--aot-shared-library-name=/data/data/com.example.untitled1/libfixedapp.so" )
        }
}
}

flutter build apk --release
adb install build/app/outputs/flutter-apk/app-release.apk

flutter build apk --release
open build/app/outputs/flutter-apk/