Java tutorial
/** * 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.roihuapp; import javax.annotation.Nullable; import java.io.UnsupportedEncodingException; import java.util.HashMap; import java.util.Map; import android.graphics.Bitmap; import android.os.Build; import android.text.TextUtils; import android.webkit.WebView; import android.webkit.WebViewClient; 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.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.SystemClock; import com.facebook.react.common.build.ReactBuildConfig; 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.Event; import com.facebook.react.uimanager.events.EventDispatcher; public class CacheClearableWebViewManager extends SimpleViewManager<WebView> { private static final String REACT_CLASS = "RCTCacheClearableWebView"; private static final String HTML_ENCODING = "UTF-8"; private static final String HTML_MIME_TYPE = "text/html; charset=utf-8"; 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; // Use `webView.loadUrl("about:blank")` to reliably reset the view // state and release page resources (including any running JavaScript). private static final String BLANK_URL = "about:blank"; private WebViewConfig mWebViewConfig; private 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(); 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(), SystemClock.nanoTime(), createWebViewEvent(webView, url))); } @Override public void onReceivedError(WebView webView, int errorCode, String description, String failingUrl) { super.onReceivedError(webView, errorCode, description, failingUrl); mLastLoadFailed = true; // In case of an error JS side expect to get a finish event first, and then get an error event // Android WebView does it in the opposite way, so we need to simulate that behavior emitFinishEvent(webView, failingUrl); WritableMap eventData = createWebViewEvent(webView, failingUrl); eventData.putDouble("code", errorCode); eventData.putString("description", description); dispatchEvent(webView, new TopLoadingErrorEvent(webView.getId(), SystemClock.nanoTime(), eventData)); } @Override public void doUpdateVisitedHistory(WebView webView, String url, boolean isReload) { super.doUpdateVisitedHistory(webView, url, isReload); dispatchEvent(webView, new TopLoadingStartEvent(webView.getId(), SystemClock.nanoTime(), createWebViewEvent(webView, url))); } private void emitFinishEvent(WebView webView, String url) { dispatchEvent(webView, new TopLoadingFinishEvent(webView.getId(), SystemClock.nanoTime(), createWebViewEvent(webView, url))); } private static void dispatchEvent(WebView webView, Event event) { ReactContext reactContext = (ReactContext) webView.getContext(); EventDispatcher eventDispatcher = reactContext.getNativeModule(UIManagerModule.class) .getEventDispatcher(); eventDispatcher.dispatchEvent(event); } private WritableMap createWebViewEvent(WebView webView, String url) { WritableMap event = Arguments.createMap(); event.putDouble("target", webView.getId()); // Don't use webView.getUrl() here, the URL isn't updated to the new value yet in callbacks // like onPageFinished 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; } } /** * Subclass of {@link WebView} that implements {@link LifecycleEventListener} interface in order * to call {@link WebView#destroy} on activty destroy event and also to clear the client */ private static class ReactWebView extends WebView implements LifecycleEventListener { private @Nullable String injectedJS; /** * WebView must be created with an context of the current activity * * Activity Context is required for creation of dialogs internally by WebView * Reactive Native needed for access to ReactNative internal system functionality * */ 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 callInjectedJavaScript() { if (getSettings().getJavaScriptEnabled() && injectedJS != null && !TextUtils.isEmpty(injectedJS)) { loadUrl("javascript:(function() {\n" + injectedJS + ";\n})();"); } } private void cleanupCallbacksAndDestroy() { setWebViewClient(null); destroy(); } } public CacheClearableWebViewManager() { mWebViewConfig = new WebViewConfig() { public void configWebView(WebView webView) { } }; } public CacheClearableWebViewManager(WebViewConfig webViewConfig) { mWebViewConfig = webViewConfig; } @Override public String getName() { return REACT_CLASS; } @Override protected WebView createViewInstance(ThemedReactContext reactContext) { ReactWebView webView = new ReactWebView(reactContext); reactContext.addLifecycleEventListener(webView); mWebViewConfig.configWebView(webView); if (ReactBuildConfig.DEBUG && Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) { WebView.setWebContentsDebuggingEnabled(true); } return webView; } @ReactProp(name = "clearCache", defaultBoolean = false) public void clearCache(WebView view, boolean includeDiskFiles) { view.clearCache(includeDiskFiles); } @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 = "injectedJavaScript") public void setInjectedJavaScript(WebView view, @Nullable String injectedJavaScript) { ((ReactWebView) view).setInjectedJavaScript(injectedJavaScript); } @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"); 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(); headerMap.put(key, headers.getString(key)); } } view.loadUrl(url, headerMap); return; } } view.loadUrl(BLANK_URL); } @Override protected void addEventEmitters(ThemedReactContext reactContext, WebView view) { // Do not register default touch emitter and let WebView implementation handle touches 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); } @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; } } @Override public void onDropViewInstance(WebView webView) { super.onDropViewInstance(webView); ((ThemedReactContext) webView.getContext()).removeLifecycleEventListener((ReactWebView) webView); ((ReactWebView) webView).cleanupCallbacksAndDestroy(); } }