Android: Set WebViewManager methods/fields as protected instead of pr…

…ivate

Summary:
**Motivation**

See discussion in #10946. The motivation is to make `ReactWebViewManager` more extensible.

Re-using logic from the ReactWebViewManager when implementing your own custom WebView is a pain since so much of the logic is set as `private`.

This PR makes for easier extension/overriding of behavior, and less duplication of code, since most of the methods/fields are set as `protected` instead.

I've also made some "create" methods for the `WebView` and `WebViewBridge` so they can more easily be overridden.

**Test plan**
The test plan is the same as the other PR (#10946). I've made an simple test app which extends `RCTWebViewManager`: https://github.com/cbrevik/overrideWebview

See [CustomWebViewManager.java](https://github.com/cbrevik/overrideWebview/blob/master/android/app/src/main/java/com/overridewebview/CustomWebViewManager.java) for a simple implementation.

CC shergin (#10946 (comment))
Closes #14261

Differential Revision: D5413922

Pulled By: shergin

fbshipit-source-id: d2f6d478f2a147e2e7b5e05c195a8b28a0a3d576

ReactAndroid/src/main/java/com/facebook/react/views/webview/ReactWebViewManager.java

@@ -87,11 +87,11 @@ 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";
+ protected static final String HTML_ENCODING = "UTF-8";
+ protected static final String HTML_MIME_TYPE = "text/html; charset=utf-8";
+ protected static final String BRIDGE_NAME = "__REACT_WEB_VIEW_BRIDGE";
 
- private static final String HTTP_METHOD_POST = "POST";
+ protected static final String HTTP_METHOD_POST = "POST";
 
  public static final int COMMAND_GO_BACK = 1;
  public static final int COMMAND_GO_FORWARD = 2;
@@ -102,14 +102,14 @@ public class ReactWebViewManager extends SimpleViewManager<WebView> {
 
  // 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";
+ protected static final String BLANK_URL = "about:blank";
 
- private WebViewConfig mWebViewConfig;
- private @Nullable WebView.PictureListener mPictureListener;
+ protected WebViewConfig mWebViewConfig;
+ protected @Nullable WebView.PictureListener mPictureListener;
 
  protected static class ReactWebViewClient extends WebViewClient {
 
- private boolean mLastLoadFailed = false;
+ protected boolean mLastLoadFailed = false;
 
  @Override
  public void onPageFinished(WebView webView, String url) {
@@ -185,15 +185,15 @@ public void doUpdateVisitedHistory(WebView webView, String url, boolean isReload
  createWebViewEvent(webView, url)));
  }
 
- private void emitFinishEvent(WebView webView, String url) {
+ protected void emitFinishEvent(WebView webView, String url) {
  dispatchEvent(
  webView,
  new TopLoadingFinishEvent(
  webView.getId(),
  createWebViewEvent(webView, url)));
  }
 
- private WritableMap createWebViewEvent(WebView webView, String url) {
+ protected 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
@@ -212,10 +212,10 @@ private WritableMap createWebViewEvent(WebView webView, String url) {
  * to call {@link WebView#destroy} on activty destroy event and also to clear the client
  */
  protected static class ReactWebView extends WebView implements LifecycleEventListener {
- private @Nullable String injectedJS;
- private boolean messagingEnabled = false;
+ protected @Nullable String injectedJS;
+ protected boolean messagingEnabled = false;
 
- private class ReactWebViewBridge {
+ protected class ReactWebViewBridge {
  ReactWebView mContext;
 
  ReactWebViewBridge(ReactWebView c) {
@@ -258,14 +258,18 @@ public void setInjectedJavaScript(@Nullable String js) {
  injectedJS = js;
  }
 
+ protected ReactWebViewBridge createReactWebViewBridge(ReactWebView webView) {
+ return new ReactWebViewBridge(webView);
+ }
+
  public void setMessagingEnabled(boolean enabled) {
  if (messagingEnabled == enabled) {
  return;
  }
 
  messagingEnabled = enabled;
  if (enabled) {
- addJavascriptInterface(new ReactWebViewBridge(this), BRIDGE_NAME);
+ addJavascriptInterface(createReactWebViewBridge(this), BRIDGE_NAME);
  linkBridge();
  } else {
  removeJavascriptInterface(BRIDGE_NAME);
@@ -308,7 +312,7 @@ public void onMessage(String message) {
  dispatchEvent(this, new TopMessageEvent(this.getId(), message));
  }
 
- private void cleanupCallbacksAndDestroy() {
+ protected void cleanupCallbacksAndDestroy() {
  setWebViewClient(null);
  destroy();
  }
@@ -330,9 +334,13 @@ public String getName() {
  return REACT_CLASS;
  }
 
+ protected ReactWebView createReactWebViewInstance(ThemedReactContext reactContext) {
+ return new ReactWebView(reactContext);
+ }
+
  @Override
  protected WebView createViewInstance(ThemedReactContext reactContext) {
- ReactWebView webView = new ReactWebView(reactContext);
+ ReactWebView webView = createReactWebViewInstance(reactContext);
  webView.setWebChromeClient(new WebChromeClient() {
  @Override
  public boolean onConsoleMessage(ConsoleMessage message) {
@@ -568,7 +576,7 @@ public void onDropViewInstance(WebView webView) {
  ((ReactWebView) webView).cleanupCallbacksAndDestroy();
  }
 
- private WebView.PictureListener getPictureListener() {
+ protected WebView.PictureListener getPictureListener() {
  if (mPictureListener == null) {
  mPictureListener = new WebView.PictureListener() {
  @Override
@@ -585,7 +593,7 @@ public void onNewPicture(WebView webView, Picture picture) {
  return mPictureListener;
  }
 
- private static void dispatchEvent(WebView webView, Event event) {
+ protected static void dispatchEvent(WebView webView, Event event) {
  ReactContext reactContext = (ReactContext) webView.getContext();
  EventDispatcher eventDispatcher =
  reactContext.getNativeModule(UIManagerModule.class).getEventDispatcher();