给定束路径，如何从react-native-ui组件返回ReactRootView？

Question

我正在尝试创建Ken Wheeler应用浏览器的android实现，以进行本机响应。 https://github.com/kenwheeler/app-browser 我相信我需要从UI组件返回一个新的React根目录，但是会收到错误消息

package com.inceptionhost.rctframe;

import android.app.Activity;
import android.app.Application;
import android.content.Context;
import com.facebook.react.bridge.ReactApplicationContext;
import 
com.facebook.react.modules.core.DefaultHardwareBackBtnHandler;
import com.facebook.react.uimanager.SimpleViewManager;
import com.facebook.react.uimanager.ThemedReactContext;
import com.facebook.react.uimanager.annotations.ReactProp;
import com.facebook.react.common.LifecycleState;
import com.facebook.react.ReactApplication;
import com.facebook.react.bridge.ReactContext;
import com.facebook.react.bridge.ReactApplicationContext;
import com.facebook.react.*;
import com.facebook.react.ReactInstanceManager;
import com.facebook.react.ReactRootView;
import com.facebook.react.ReactNativeHost;
import com.facebook.react.ReactPackage;
import com.facebook.react.shell.MainReactPackage;

public class RCTFrameManager extends SimpleViewManager<ReactRootView> {
    public static final String REACT_CLASS = "RCTFrame";
    public String _bundlePath;
    RCTFrameManager(){
        String _bundlePath = "";
    }


    @Override
    public String getName() {
        return REACT_CLASS;
    }

    @Override
    public ReactRootView createViewInstance(
ThemedReactContext context){
        ReactInstanceManager mReactInstanceManager;
        Application app = new Application();
        Context appctx = app.getBaseContext();
        ReactApplicationContext RCT_CTX = new ReactApplicationContext(appctx);
        mReactInstanceManager = ReactInstanceManager
                .builder()
                .setApplication(app)
                .setCurrentActivity(new Activity())
                .setDefaultHardwareBackBtnHandler(new 
DefaultHardwareBackBtnHandler() {
                    @Override
                    public void invokeDefaultOnBackPressed() {

                    }
                })
                .setJSBundleFile(_bundlePath)// or
                ////.setJSMainModulePath("")
                .build();




mReactInstanceManager
.getDevSupportManager()
.setDevSupportEnabled(false);
        mReactInstanceManager.createReactContextInBackground();
        ReactRootView _rootView = new ReactRootView(context);
        _rootView.startReactApplication(
mReactInstanceManager,
"ExampleApp");
        return _rootView;

        //maybe something like this?
        //ReactRootView mReactRootView = new ReactRootView(app.getApplicationContext());
        //mReactInstanceManager = ReactInstanceManager.builder()
        //        .setApplication(app)//getApplication()
        //        .setJSBundleFile(_bundlePath)
        //        .addPackage(new MainReactPackage())
        //        .setUseDeveloperSupport(BuildConfig.DEBUG)
        //        .setInitialLifecycleState(LifecycleState.RESUMED)
        //        .build();
        // The string here (e.g. "MyReactNativeApp") has to match
        // the string in AppRegistry.registerComponent() in index.js
        //mReactRootView.startReactApplication(
        //        mReactInstanceManager,
        //        "ExampleApp",
        //        null
        //);
        //return mReactRootView;
    }

    @ReactProp(name = "bundle")
    public void setBundle(ReactRootView view, String prop) {
        _bundlePath = prop;
    }
}

预期：给定的包将被加载到反应根视图中，该根视图将显示在当前反应视图树中。

实际：在logcat中出现带有此错误的红色框：

"Attempt to invoke virtual method 'android.content.Context android.content.Context.getApplicationContext()' on a null object reference
        at com.facebook.react.bridge.ReactApplicationContext.<init>(ReactApplicationContext.java:21)
        at com.inceptionhost.rctframe.RCTFrameManager.createViewInstance(RCTFrameManager.java:61)
        at com.inceptionhost.rctframe.RCTFrameManager.createViewInstance(RCTFrameManager.java:29)
        at com.facebook.react.uimanager.ViewManager.createView(ViewManager.java:42)
        at com.facebook.react.uimanager.NativeViewHierarchyManager.createView(NativeViewHierarchyManager.java:260)
        at com.facebook.react.uimanager.UIViewOperationQueue$CreateViewOperation.execute(UIViewOperationQueue.java:200)
        at com.facebook.react.uimanager.UIViewOperationQueue$1.run(UIViewOperationQueue.java:888)
        at com.facebook.react.uimanager.UIViewOperationQueue.flushPendingBatches(UIViewOperationQueue.java:1001)
        at com.facebook.react.uimanager.UIViewOperationQueue.access$2400(UIViewOperationQueue.java:46)
        at com.facebook.react.uimanager.UIViewOperationQueue$DispatchUIFrameCallback.doFrameGuarded(UIViewOperationQueue.java:1061)
        at com.facebook.react.uimanager.GuardedFrameCallback.doFrame(GuardedFrameCallback.java:29)
        at com.facebook.react.modules.core.ReactChoreographer$ReactChoreographerDispatcher.doFrame(ReactChoreographer.java:134)
        at com.facebook.react.modules.core.ChoreographerCompat$FrameCallback$1.doFrame(ChoreographerCompat.java:105)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:909)
        at android.view.Choreographer.doCallbacks(Choreographer.java:723)
        at android.view.Choreographer.doFrame(Choreographer.java:655)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:897)
        at android.os.Handler.handleCallback(Handler.java:790)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:164)
        at android.app.ActivityThread.main(ActivityThread.java:6494)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)"