React Native Android版核心层js-bridge实现浅析

public class MoviesActivity extends Activity implements DefaultHardwareBackBtnHandler {
  private ReactInstanceManager mReactInstanceManager;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mReactInstanceManager = ReactInstanceManager.builder()
        .setApplication(getApplication())
        .setBundleAssetName("MoviesApp.android.bundle")
        .setJSMainModuleName("Examples/Movies/MoviesApp.android")
        .addPackage(new MainReactPackage())
        .setUseDeveloperSupport(true)
        .setInitialLifecycleState(LifecycleState.RESUMED)
        .build();
    ((ReactRootView) findViewById(R.id.react_root_view))
        .startReactApplication(mReactInstanceManager, "MoviesApp", null);
  }

private void attachMeasuredRootViewToInstance(
    ReactRootView rootView,
    CatalystInstance catalystInstance) {
  UiThreadUtil.assertOnUiThread();
  // Reset view content as it's going to be populated by the application content from JS
  rootView.removeAllViews();
  rootView.setId(View.NO_ID);
  UIManagerModule uiManagerModule = catalystInstance.getNativeModule(UIManagerModule.class);
  int rootTag = uiManagerModule.addMeasuredRootView(rootView);
  @Nullable Bundle launchOptions = rootView.getLaunchOptions();
  WritableMap initialProps = launchOptions != null
      ? Arguments.fromBundle(launchOptions)
      : Arguments.createMap();
  String jsAppModuleName = rootView.getJSModuleName();
  WritableNativeMap appParams = new WritableNativeMap();
  appParams.putDouble("rootTag", rootTag);
  appParams.putMap("initialProps", initialProps);
  catalystInstance.getJSModule(AppRegistry.class).runApplication(jsAppModuleName, appParams);
}

/* package */ class CoreModulesPackage implements ReactPackage {
  private final ReactInstanceManager mReactInstanceManager;
  private final DefaultHardwareBackBtnHandler mHardwareBackBtnHandler;
  CoreModulesPackage(
      ReactInstanceManager reactInstanceManager,
      DefaultHardwareBackBtnHandler hardwareBackBtnHandler) {
    mReactInstanceManager = reactInstanceManager;
    mHardwareBackBtnHandler = hardwareBackBtnHandler;
  }
  @Override
  public List<NativeModule> createNativeModules(
      ReactApplicationContext catalystApplicationContext) {
    return Arrays.<NativeModule>asList(
        new AnimationsDebugModule(
            catalystApplicationContext,
            mReactInstanceManager.getDevSupportManager().getDevSettings()),
        new AndroidInfoModule(),
        new DeviceEventManagerModule(catalystApplicationContext, mHardwareBackBtnHandler),
        new ExceptionsManagerModule(mReactInstanceManager.getDevSupportManager()),
        new Timing(catalystApplicationContext),
	...
  }
  @Override
  public List<Class<? extends JavaScriptModule>> createJSModules() {
    return Arrays.asList(
        DeviceEventManagerModule.RCTDeviceEventEmitter.class,
        JSTimersExecution.class,
        RCTEventEmitter.class,
        AppRegistry.class,
        ReactNative.class,
        DebugComponentOwnershipModule.RCTDebugComponentOwnership.class);
  }
  ...

public class NativeModuleRegistry {
  private final ArrayList<ModuleDefinition> mModuleTable;
  private final Map<Class<NativeModule>, NativeModule> mModuleInstances;
  private final String mModuleDescriptions;
  private final ArrayList<OnBatchCompleteListener> mBatchCompleteListenerModules;
  ...

/*package*/ class JavaScriptModuleRegistry {
  private final HashMap<Class<? extends JavaScriptModule>, JavaScriptModule> mModuleInstances;
  ...
}

public class ToastModule extends ReactContextBaseJavaModule {
  public ToastModule(ReactApplicationContext reactContext) {
    super(reactContext);
  }
  ...
  @ReactMethod
  public void show(String message, int duration) {
    Toast.makeText(getReactApplicationContext(), message, duration).show();
  }
}

/**
 * JS module interface - main entry point for launching react application for a given key.
 */
public interface AppRegistry extends JavaScriptModule {
  void runApplication(String appKey, WritableMap appParameters);
}

private static class JavaScriptModuleInvocationHandler implements InvocationHandler {
    private final CatalystInstance mCatalystInstance;
    private final JavaScriptModuleRegistration mModuleRegistration;
    public JavaScriptModuleInvocationHandler(
        CatalystInstance catalystInstance,
        JavaScriptModuleRegistration moduleRegistration) {
      mCatalystInstance = catalystInstance;
      mModuleRegistration = moduleRegistration;
    }
    @Override
    public @Nullable Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
      String tracingName = mModuleRegistration.getTracingName(method);
      mCatalystInstance.callFunction(
          mModuleRegistration.getModuleId(),
          mModuleRegistration.getMethodId(method),
          Arguments.fromJavaArgs(args),
          tracingName);
      return null;
    }
  }

private void initializeBridge(
      JavaScriptExecutor jsExecutor,
      NativeModuleRegistry registry,
      JavaScriptModulesConfig jsModulesConfig,
      JSBundleLoader jsBundleLoader) {
    mCatalystQueueConfiguration.getJSQueueThread().assertIsOnThread();
    Assertions.assertCondition(mBridge == null, "initializeBridge should be called once");
    mBridge = new ReactBridge(
        jsExecutor,
        new NativeModulesReactCallback(),
        mCatalystQueueConfiguration.getNativeModulesQueueThread());
    mBridge.setGlobalVariable(
        "__fbBatchedBridgeConfig",
        buildModulesConfigJSONProperty(registry, jsModulesConfig));
    jsBundleLoader.loadScript(mBridge);
  }

public native void loadScriptFromAssets(AssetManager assetManager, String assetName);
public native void loadScriptFromNetworkCached(String sourceURL, @Nullable String tempFileName);
public native void callFunction(int moduleId, int methodId, NativeArray arguments);
public native void invokeCallback(int callbackID, NativeArray arguments);
public native void setGlobalVariable(String propertyName, String jsonEncodedArgument);
...

private class NativeModulesReactCallback implements ReactCallback {
    @Override
    public void call(int moduleId, int methodId, ReadableNativeArray parameters) {
      mCatalystQueueConfiguration.getNativeModulesQueueThread().assertIsOnThread();
      // Suppress any callbacks if destroyed - will only lead to sadness.
      if (mDestroyed) {
        return;
      }
      mJavaRegistry.call(CatalystInstance.this, moduleId, methodId, parameters);
    }