如何为 react-native android WebView 设置AllowFileAccess？

Question

我想在我使用 react-native 的内置 WebView 组件创建的 Android WebView 中禁用文件访问。

Android WebView docs 说“默认情况下启用文件访问。”，这对我的组织来说是一个安全问题。

react-native 0.31 docs 提到了一个getWebViewHandle 方法，可以用来访问底层的WebView 节点；如果这行得通，那么我可以（大概）写：

import { WebView, Platform } from 'react-native';
//...
var reactWebview = <Webview [props here] />
if (Platform.OS === 'android') {
    var webview = reactWebview.getWebViewHandle();
    webview.setAllowFileAccess(false);
}

但是，react-native docs 的更高版本没有提及getWebViewHandle，当我在 Android 设备上以 react-native 0.44 运行这样的代码时，我收到错误 webview.getWebViewHandle is not a function。

我的问题是：

1. react-native 创建的 Android WebView 是否默认启用文件访问？

2. 如果是这样，我们如何禁用此文件访问？我们可以通过扩展 WebView 类来实现这一点，还是需要 fork 和修改 react-native？

感谢您的宝贵时间！

Answer 1

问题一：从ReactWebViewManager.java的源码看，RN并没有调用WebView.setAllowFileAccess，所以文件访问是通过Android WebView开启的，不是RN。

问题2：您可以创建一个自定义WebView来做您需要的事情，或者只是从Native Module获取您的WebView的引用，然后您可以访问Android WebView的所有api，例如setAllowFileAccess在那个@987654323 @。

原生模块

public class WebViewSettingModule extends ReactContextBaseJavaModule {

    public WebViewSettingModule(ReactApplicationContext reactContext) {
        super(reactContext);
    }

    @Override
    public String getName() {
        return "WebViewSetting";
    }

    @ReactMethod
    public void setWebView() {

        Activity activity = getCurrentActivity();
        //the id for the ReactRootView is always be 1
        @IdRes int id = 1;
        View view = activity.findViewById(id);
        if (view instanceof ReactRootView) {
            ReactRootView reactRootView = (ReactRootView) view;
            //make sure the WebView is directly child of ReactRootView
            reactRootView.setOnHierarchyChangeListener(new ViewGroup.OnHierarchyChangeListener() {
                @Override
                public void onChildViewAdded(View parent, final View child) {
                    if (child instanceof WebView) {
                        Log.e("onChildViewAdded: ", ((WebView) child).getUrl());
                        //get the reference to the WebView and setAllowFileAccess
                        ((WebView) child).getSettings().setAllowFileAccess(false);
                    }
                }

                @Override
                public void onChildViewRemoved(View parent, View child) {

                }
            });
        }
    }
}

index.android.js

import React, {Component} from "react";
import {AppRegistry, View, WebView} from "react-native";
//the native module
import MyWebView from "./src/MyWebView";

export default class WebViewSetting extends Component {

    componentDidMount() {
        //notify native code to modify WebView setting
        MyWebView.setWebView();
    }

    render() {
        return (
            <View style={{flex: 1}}>
                <WebView
                    source={{uri: 'https://github.com/'}}
                    style={{marginTop: 20}}/>
            </View>
        );
    }
}


AppRegistry.registerComponent('WebViewSetting', () => WebViewSetting);

整个代码可以在here找到

Answer 2

node_modules/react-native/ReactAndroid/src/main/java/com/facebook/react/views/ReactWebViewManager.java

/**
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */

package com.facebook.react.views.webview;
import javax.annotation.Nullable;
import java.io.File;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.ActivityNotFoundException;
import android.content.ComponentName;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.Picture;
import android.net.Uri;
import android.os.Build;
import android.os.Environment;
import android.provider.MediaStore;
import android.text.TextUtils;
import android.util.Log;
import android.view.ViewGroup.LayoutParams;
import android.webkit.ConsoleMessage;
import android.webkit.GeolocationPermissions;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.webkit.JavascriptInterface;
import android.webkit.ValueCallback;
import android.webkit.WebSettings;
import com.facebook.common.logging.FLog;
import com.facebook.react.bridge.ActivityEventListener;
import com.facebook.react.common.ReactConstants;
import com.facebook.react.bridge.Arguments;
import com.facebook.react.bridge.LifecycleEventListener;
import com.facebook.react.bridge.ReactContext;
import com.facebook.react.bridge.ReadableArray;
import com.facebook.react.bridge.ReadableMap;
import com.facebook.react.bridge.ReadableMapKeySetIterator;
import com.facebook.react.bridge.WritableMap;
import com.facebook.react.common.MapBuilder;
import com.facebook.react.common.build.ReactBuildConfig;
import com.facebook.react.module.annotations.ReactModule;
import com.facebook.react.uimanager.SimpleViewManager;
import com.facebook.react.uimanager.ThemedReactContext;
import com.facebook.react.uimanager.UIManagerModule;
import com.facebook.react.uimanager.annotations.ReactProp;
import com.facebook.react.uimanager.events.ContentSizeChangeEvent;
import com.facebook.react.uimanager.events.Event;
import com.facebook.react.uimanager.events.EventDispatcher;
import com.facebook.react.views.webview.events.TopLoadingErrorEvent;
import com.facebook.react.views.webview.events.TopLoadingFinishEvent;
import com.facebook.react.views.webview.events.TopLoadingStartEvent;
import com.facebook.react.views.webview.events.TopMessageEvent;
import org.json.JSONObject;
import org.json.JSONException;
@ReactModule(name = ReactWebViewManager.REACT_CLASS)
public class ReactWebViewManager extends SimpleViewManager<WebView> {

    protected static final String REACT_CLASS = "RCTWebView";

    private static final String HTML_ENCODING = "UTF-8";
    private static final String HTML_MIME_TYPE = "text/html; charset=utf-8";
    private static final String BRIDGE_NAME = "__REACT_WEB_VIEW_BRIDGE";

    private static final String HTTP_METHOD_POST = "POST";

    public static final int COMMAND_GO_BACK = 1;
    public static final int COMMAND_GO_FORWARD = 2;
    public static final int COMMAND_RELOAD = 3;
    public static final int COMMAND_STOP_LOADING = 4;
    public static final int COMMAND_POST_MESSAGE = 5;
    public static final int COMMAND_INJECT_JAVASCRIPT = 6;

    private static final String BLANK_URL = "about:blank";
    public static final int INPUT_FILE_REQUEST_GALLERY_IMAGE = 1001;
    public static final int REQUEST_SELECT_FILE_LEGACY = 1012;

    private WebViewConfig mWebViewConfig;
    private
    @Nullable
    WebView.PictureListener mPictureListener;
    private ValueCallback<Uri[]> mFilePathCallbackArr;
    private ValueCallback<Uri> mFilePathCallback; // Legacy (Android 4.1+)
    private String mCameraPhotoPath;

    protected static class ReactWebViewClient extends WebViewClient {

        private boolean mLastLoadFailed = false;

        @Override
        public void onPageFinished(WebView webView, String url) {
            super.onPageFinished(webView, url);

            if (!mLastLoadFailed) {
                ReactWebView reactWebView = (ReactWebView) webView;
                reactWebView.callInjectedJavaScript();
                reactWebView.linkBridge();
                emitFinishEvent(webView, url);
            }
        }
        @Override
        public void onPageStarted(WebView webView, String url, Bitmap favicon) {
            super.onPageStarted(webView, url, favicon);
            mLastLoadFailed = false;

            dispatchEvent(
                    webView,
                    new TopLoadingStartEvent(
                            webView.getId(),
                            createWebViewEvent(webView, url)));
        }
        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            if (url.startsWith("http://") || url.startsWith("https://") ||
                    url.startsWith("file://")) {
                return false;
            } else {
                try {
                    Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
                    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                    view.getContext().startActivity(intent);
                } catch (ActivityNotFoundException e) {
                    FLog.w(ReactConstants.TAG, "activity not found to handle uri scheme for: " + url, e);
                }
                return true;
            }
        }

        @Override
        public void onReceivedError(
                WebView webView,
                int errorCode,
                String description,
                String failingUrl) {
            super.onReceivedError(webView, errorCode, description, failingUrl);
            mLastLoadFailed = true;

            emitFinishEvent(webView, failingUrl);

            WritableMap eventData = createWebViewEvent(webView, failingUrl);
            eventData.putDouble("code", errorCode);
            eventData.putString("description", description);

            dispatchEvent(
                    webView,
                    new TopLoadingErrorEvent(webView.getId(), eventData));
        }

        @Override
        public void doUpdateVisitedHistory(WebView webView, String url, boolean isReload) {
            super.doUpdateVisitedHistory(webView, url, isReload);

            dispatchEvent(
                    webView,
                    new TopLoadingStartEvent(
                            webView.getId(),
                            createWebViewEvent(webView, url)));
        }

        private void emitFinishEvent(WebView webView, String url) {
            dispatchEvent(
                    webView,
                    new TopLoadingFinishEvent(
                            webView.getId(),
                            createWebViewEvent(webView, url)));
        }

        private WritableMap createWebViewEvent(WebView webView, String url) {
            WritableMap event = Arguments.createMap();
            event.putDouble("target", webView.getId());
            event.putString("url", url);
            event.putBoolean("loading", !mLastLoadFailed && webView.getProgress() != 100);
            event.putString("title", webView.getTitle());
            event.putBoolean("canGoBack", webView.canGoBack());
            event.putBoolean("canGoForward", webView.canGoForward());
            return event;
        }
    }

    protected static class ReactWebView extends WebView implements LifecycleEventListener {
        private
        @Nullable
        String injectedJS;
        private boolean messagingEnabled = false;

        private class ReactWebViewBridge {
            ReactWebView mContext;

            ReactWebViewBridge(ReactWebView c) {
                mContext = c;
            }

            @JavascriptInterface
            public void postMessage(String message) {
                mContext.onMessage(message);
            }
        }
        public ReactWebView(ThemedReactContext reactContext) {
            super(reactContext);
        }

        @Override
        public void onHostResume() {
            // do nothing
        }

        @Override
        public void onHostPause() {
            // do nothing
        }

        @Override
        public void onHostDestroy() {
            cleanupCallbacksAndDestroy();
        }

        public void setInjectedJavaScript(@Nullable String js) {
            injectedJS = js;
        }

        public void setMessagingEnabled(boolean enabled) {
            if (messagingEnabled == enabled) {
                return;
            }

            messagingEnabled = enabled;
            if (enabled) {
                addJavascriptInterface(new ReactWebViewBridge(this), BRIDGE_NAME);
                linkBridge();
            } else {
                removeJavascriptInterface(BRIDGE_NAME);
            }
        }

        public void callInjectedJavaScript() {
            if (getSettings().getJavaScriptEnabled() &&
                    injectedJS != null &&
                    !TextUtils.isEmpty(injectedJS)) {
                loadUrl("javascript:(function() {\n" + injectedJS + ";\n})();");
            }
        }

        public void linkBridge() {
            if (messagingEnabled) {
                if (ReactBuildConfig.DEBUG && Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
                    // See isNative in lodash
                    String testPostMessageNative = "String(window.postMessage) === String(Object.hasOwnProperty).replace('hasOwnProperty', 'postMessage')";
                    evaluateJavascript(testPostMessageNative, new ValueCallback<String>() {
                        @Override
                        public void onReceiveValue(String value) {
                            if (value.equals("true")) {
                                FLog.w(ReactConstants.TAG, "Setting onMessage on a WebView overrides existing values of window.postMessage, but a previous value was defined");
                            }
                        }
                    });
                }

                loadUrl("javascript:(" +
                        "window.originalPostMessage = window.postMessage," +
                        "window.postMessage = function(data) {" +
                        BRIDGE_NAME + ".postMessage(String(data));" +
                        "}" +
                        ")");
            }
        }

        public void onMessage(String message) {
            dispatchEvent(this, new TopMessageEvent(this.getId(), message));
        }

        private void cleanupCallbacksAndDestroy() {
            setWebViewClient(null);
            destroy();
        }
    }

    public ReactWebViewManager() {
        mWebViewConfig = new WebViewConfig() {
            public void configWebView(WebView webView) {
            }
        };
    }

    public ReactWebViewManager(WebViewConfig webViewConfig) {
        mWebViewConfig = webViewConfig;
    }

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

    @Override
    protected WebView createViewInstance(final ThemedReactContext reactContext) {
        ReactWebView webView = new ReactWebView(reactContext);
        webView.setWebChromeClient(new WebChromeClient() {
            @Override
            public boolean onConsoleMessage(ConsoleMessage message) {
                if (ReactBuildConfig.DEBUG) {
                    return super.onConsoleMessage(message);
                }
                return true;
            }

            @Override
            public void onGeolocationPermissionsShowPrompt(String origin, GeolocationPermissions.Callback callback) {
                callback.invoke(origin, true, false);
            }

            private File createImageFile() throws IOException {
                String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
                String imageFileName = "JPEG_" + timeStamp + "_";
                File storageDir = Environment.getExternalStoragePublicDirectory(
                        Environment.DIRECTORY_PICTURES);
                File imageFile = new File(
                        storageDir,
                        imageFileName + ".jpg"
                );

                return imageFile;
            }


            private Intent getVideoCaptureIntent() {
                Intent recordVideoIntent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);
                recordVideoIntent
                        .resolveActivity(
                                reactContext
                                    .getCurrentActivity()
                                    .getPackageManager()
                        );

                recordVideoIntent.putExtra("type", "foobar");
                return recordVideoIntent;
            }

            public boolean onShowFileChooser(
                    WebView webView,
                    ValueCallback<Uri[]> filePathCallback,
                    WebChromeClient.FileChooserParams fileChooserParams
            ) {
                if (mFilePathCallbackArr != null) {
                    mFilePathCallbackArr.onReceiveValue(null);
                }
                mFilePathCallbackArr = filePathCallback;

                Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
                ComponentName comp = takePictureIntent
                                        .resolveActivity(
                                                reactContext
                                                        .getCurrentActivity()
                                                        .getPackageManager()
                                        );
                if (comp != null) {
                    File photoFile = null;
                    try {
                        photoFile = createImageFile();
                        takePictureIntent.putExtra("PhotoPath", mCameraPhotoPath);
                    } catch (IOException ex) {
                        FLog.e(ReactConstants.TAG, "Unable to create Image File", ex);
                    }

                    if (photoFile != null) {
                        mCameraPhotoPath = "file:" + photoFile.getAbsolutePath();
                        takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT,
                                Uri.fromFile(photoFile));
                    } else {
                        takePictureIntent = null;
                    }
                }

                Intent contentSelectionIntent = new Intent(Intent.ACTION_GET_CONTENT);
                contentSelectionIntent.addCategory(Intent.CATEGORY_OPENABLE);
                contentSelectionIntent.setType("*/*");

                Intent videoCaptureIntent = getVideoCaptureIntent();

                Intent[] intentArray;
                if (takePictureIntent != null) {
                    intentArray = new Intent[]{takePictureIntent};
                } else {
                    intentArray = new Intent[0];
                }

                intentArray = new Intent[]{
                        intentArray[0],
                        videoCaptureIntent
                };

                Intent chooserIntent = new Intent(Intent.ACTION_CHOOSER);
                chooserIntent.putExtra(Intent.EXTRA_INTENT, contentSelectionIntent);
                chooserIntent.putExtra(Intent.EXTRA_TITLE, "Image Chooser");
                chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS, intentArray);

                reactContext.getCurrentActivity().startActivityForResult(chooserIntent, INPUT_FILE_REQUEST_GALLERY_IMAGE);

                return true;
            }
        });


        reactContext.addLifecycleEventListener(webView);

        reactContext.addActivityEventListener(new ActivityEventListener() {

            // Android 5+
            @Override
            public void onActivityResult (Activity activity, int requestCode, int resultCode, Intent data) {
                if(requestCode != INPUT_FILE_REQUEST_GALLERY_IMAGE || mFilePathCallbackArr == null) {
                    return;
                }
                Uri[] results = null;

                if(resultCode == Activity.RESULT_OK) {
                    if(data == null || data.getData() == null) {
                        if(mCameraPhotoPath != null) {
                            results = new Uri[]{Uri.parse(mCameraPhotoPath)};
                        }
                    } else {
                        String dataString = data.getDataString();
                        if (dataString != null) {
                            results = new Uri[]{Uri.parse(dataString)};
                        }
                    }
                }

                if(results == null) {
                    mFilePathCallbackArr.onReceiveValue(new Uri[]{});
                }
                else {
                    mFilePathCallbackArr.onReceiveValue(results);
                }
                mFilePathCallbackArr = null;
                return;
            }

            @Override
            public void onNewIntent(Intent intent) {}
        });

        mWebViewConfig.configWebView(webView);
        webView.getSettings().setBuiltInZoomControls(true);
        webView.getSettings().setDisplayZoomControls(false);
        webView.getSettings().setDomStorageEnabled(true);
        webView.setLayoutParams(
                new LayoutParams(LayoutParams.MATCH_PARENT,
                        LayoutParams.MATCH_PARENT));

        if (ReactBuildConfig.DEBUG && Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            WebView.setWebContentsDebuggingEnabled(true);
        }

        return webView;
    }

    @ReactProp(name = "javaScriptEnabled")
    public void setJavaScriptEnabled(WebView view, boolean enabled) {
        view.getSettings().setJavaScriptEnabled(enabled);
    }

    @ReactProp(name = "scalesPageToFit")
    public void setScalesPageToFit(WebView view, boolean enabled) {
        view.getSettings().setUseWideViewPort(!enabled);
    }

    @ReactProp(name = "domStorageEnabled")
    public void setDomStorageEnabled(WebView view, boolean enabled) {
        view.getSettings().setDomStorageEnabled(enabled);
    }

    @ReactProp(name = "userAgent")
    public void setUserAgent(WebView view, @Nullable String userAgent) {
        if (userAgent != null) {
            // TODO(8496850): Fix incorrect behavior when property is unset (uA == null)
            view.getSettings().setUserAgentString(userAgent);
        }
    }

    @ReactProp(name = "mediaPlaybackRequiresUserAction")
    public void setMediaPlaybackRequiresUserAction(WebView view, boolean requires) {
        view.getSettings().setMediaPlaybackRequiresUserGesture(requires);
    }

    @ReactProp(name = "allowUniversalAccessFromFileURLs")
    public void setAllowUniversalAccessFromFileURLs(WebView view, boolean allow) {
        view.getSettings().setAllowUniversalAccessFromFileURLs(allow);
    }

    @ReactProp(name = "injectedJavaScript")
    public void setInjectedJavaScript(WebView view, @Nullable String injectedJavaScript) {
        ((ReactWebView) view).setInjectedJavaScript(injectedJavaScript);
    }

    @ReactProp(name = "messagingEnabled")
    public void setMessagingEnabled(WebView view, boolean enabled) {
        ((ReactWebView) view).setMessagingEnabled(enabled);
    }

    @ReactProp(name = "source")
    public void setSource(WebView view, @Nullable ReadableMap source) {
    if (source != null) {
        if (source.hasKey("html")) {
            String html = source.getString("html");
            if (source.hasKey("baseUrl")) {
                view.loadDataWithBaseURL(
                        source.getString("baseUrl"), html, HTML_MIME_TYPE, HTML_ENCODING, null);
            } else {
                view.loadData(html, HTML_MIME_TYPE, HTML_ENCODING);
            }
            return;
        }
        if (source.hasKey("uri")) {
            String url = source.getString("uri");
            String previousUrl = view.getUrl();
            if (previousUrl != null && previousUrl.equals(url)) {
                return;
            }
            if (source.hasKey("method")) {
                String method = source.getString("method");
                if (method.equals(HTTP_METHOD_POST)) {
                    byte[] postData = null;
                    if (source.hasKey("body")) {
                        String body = source.getString("body");
                        try {
                            postData = body.getBytes("UTF-8");
                        } catch (UnsupportedEncodingException e) {
                            postData = body.getBytes();
                        }
                    }
                    if (postData == null) {
                        postData = new byte[0];
                    }
                    view.postUrl(url, postData);
                    return;
                }
            }
            HashMap<String, String> headerMap = new HashMap<>();
            if (source.hasKey("headers")) {
                ReadableMap headers = source.getMap("headers");
                ReadableMapKeySetIterator iter = headers.keySetIterator();
                while (iter.hasNextKey()) {
                    String key = iter.nextKey();
                    if ("user-agent".equals(key.toLowerCase(Locale.ENGLISH))) {
                        if (view.getSettings() != null) {
                            view.getSettings().setUserAgentString(headers.getString(key));
                        }
                    } else {
                        headerMap.put(key, headers.getString(key));
                    }
                }
            }
            view.loadUrl(url, headerMap);
            return;
        }
    }
    view.loadUrl(BLANK_URL);
    }

    @ReactProp(name = "onContentSizeChange")
    public void setOnContentSizeChange(WebView view, boolean sendContentSizeChangeEvents) {
        if (sendContentSizeChangeEvents) {
            view.setPictureListener(getPictureListener());
        } else {
            view.setPictureListener(null);
        }
    }

    @ReactProp(name = "mixedContentMode")
    public void setMixedContentMode(WebView view, @Nullable String mixedContentMode) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            if (mixedContentMode == null || "never".equals(mixedContentMode)) {
                view.getSettings().setMixedContentMode(WebSettings.MIXED_CONTENT_NEVER_ALLOW);
            } else if ("always".equals(mixedContentMode)) {
                view.getSettings().setMixedContentMode(WebSettings.MIXED_CONTENT_ALWAYS_ALLOW);
            } else if ("compatibility".equals(mixedContentMode)) {
                view.getSettings().setMixedContentMode(WebSettings.MIXED_CONTENT_COMPATIBILITY_MODE);
            }
        }
    }

    @Override
    protected void addEventEmitters(ThemedReactContext reactContext, WebView view) {
        view.setWebViewClient(new ReactWebViewClient());
    }
    @Override
    public
    @Nullable
    Map<String, Integer> getCommandsMap() {
        return MapBuilder.of(
                "goBack", COMMAND_GO_BACK,
                "goForward", COMMAND_GO_FORWARD,
                "reload", COMMAND_RELOAD,
                "stopLoading", COMMAND_STOP_LOADING,
                "postMessage", COMMAND_POST_MESSAGE,
                "injectJavaScript", COMMAND_INJECT_JAVASCRIPT
        );
    }

    @Override
    public void receiveCommand(WebView root, int commandId, @Nullable ReadableArray args) {
        switch (commandId) {
            case COMMAND_GO_BACK:
                root.goBack();
                break;
            case COMMAND_GO_FORWARD:
                root.goForward();
                break;
            case COMMAND_RELOAD:
                root.reload();
                break;
            case COMMAND_STOP_LOADING:
                root.stopLoading();
                break;
            case COMMAND_POST_MESSAGE:
                try {
                    JSONObject eventInitDict = new JSONObject();
                    eventInitDict.put("data", args.getString(0));
                    root.loadUrl("javascript:(function () {" +
                            "var event;" +
                            "var data = " + eventInitDict.toString() + ";" +
                            "try {" +
                            "event = new MessageEvent('message', data);" +
                            "} catch (e) {" +
                            "event = document.createEvent('MessageEvent');" +
                            "event.initMessageEvent('message', true, true, data.data, data.origin, data.lastEventId, data.source);" +
                            "}" +
                            "document.dispatchEvent(event);" +
                            "})();");
                } catch (JSONException e) {
                    throw new RuntimeException(e);
                }
                break;
            case COMMAND_INJECT_JAVASCRIPT:
                root.loadUrl("javascript:" + args.getString(0));
                break;
        }
    }

    @Override
    public void onDropViewInstance(WebView webView) {
        super.onDropViewInstance(webView);
        ((ThemedReactContext) webView.getContext()).removeLifecycleEventListener((ReactWebView) webView);
        ((ReactWebView) webView).cleanupCallbacksAndDestroy();
    }

    private WebView.PictureListener getPictureListener() {
        if (mPictureListener == null) {
            mPictureListener = new WebView.PictureListener() {
                @Override
                public void onNewPicture(WebView webView, Picture picture) {
                    dispatchEvent(
                            webView,
                            new ContentSizeChangeEvent(
                                    webView.getId(),
                                    webView.getWidth(),
                                    webView.getContentHeight()));
                }
            };
        }
        return mPictureListener;
    }
    private static void dispatchEvent(WebView webView, Event event) {
        ReactContext reactContext = (ReactContext) webView.getContext();
        EventDispatcher eventDispatcher =
                reactContext.getNativeModule(UIManagerModule.class).getEventDispatcher();
        eventDispatcher.dispatchEvent(event);
    }
}

Answer 3

我在任何地方都找不到这个解决方案，所以我想我会分享一下，希望对您有所帮助...

要使浏览按钮能够工作并随后允许文件访问，您可以用这些修改版本替换上面和这个 react-native 文件：

node_modules/react-native/ReactAndroid/src/main/java/com/facebook/react/uimanager/ThemedReactContext.java

/**
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */

package com.facebook.react.uimanager;

import javax.annotation.Nullable;

import android.app.Activity;
import android.content.Context;

import com.facebook.react.bridge.ActivityEventListener;
import com.facebook.react.bridge.ReactApplicationContext;
import com.facebook.react.bridge.ReactContext;
import com.facebook.react.bridge.LifecycleEventListener;

//

/**
 * Wraps {@link ReactContext} with the base {@link Context} passed into the constructor.
 * It provides also a way to start activities using the viewContext to which RN native views belong.
 * It delegates lifecycle listener registration to the original instance of {@link ReactContext}
 * which is supposed to receive the lifecycle events. At the same time we disallow receiving
 * lifecycle events for this wrapper instances.
 * TODO: T7538544 Rename ThemedReactContext to be in alignment with name of ReactApplicationContext
 */
public class ThemedReactContext extends ReactContext {

    private final ReactApplicationContext mReactApplicationContext;

    public ThemedReactContext(ReactApplicationContext reactApplicationContext, Context base) {
        super(base);
        initializeWithInstance(reactApplicationContext.getCatalystInstance());
        mReactApplicationContext = reactApplicationContext;
    }

    @Override
    public void addLifecycleEventListener(LifecycleEventListener listener) {
        mReactApplicationContext.addLifecycleEventListener(listener);
    }

    @Override
    public void removeLifecycleEventListener(LifecycleEventListener listener) {
        mReactApplicationContext.removeLifecycleEventListener(listener);
    }

    @Override
    public void addActivityEventListener(ActivityEventListener listener) {
        mReactApplicationContext.addActivityEventListener(listener);
    }


    @Override
    public void removeActivityEventListener(ActivityEventListener listener) {
        mReactApplicationContext.removeActivityEventListener(listener);
    }

    @Override
    public boolean hasCurrentActivity() {
        return mReactApplicationContext.hasCurrentActivity();
    }

    @Override
    public
    @Nullable
    Activity getCurrentActivity() {
        return mReactApplicationContext.getCurrentActivity();
    }
}

上面列出了第二个文件