android/android-9.0.0_r35 : android/webkit/WebViewClient.java

WebViewClient
https://source.android.com/
/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.webkit;

import android.annotation.IntDef;
import android.annotation.Nullable;
import android.graphics.Bitmap;
import android.net.http.SslError;
import android.os.Message;
import android.view.InputEvent;
import android.view.KeyEvent;
import android.view.ViewRootImpl;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

public class WebViewClient {

    Give the host application a chance to take control when a URL is about to be loaded in the current WebView. If a WebViewClient is not provided, by default WebView will ask Activity Manager to choose the proper handler for the URL. If a WebViewClient is provided, returning true causes the current WebView to abort loading the URL, while returning false causes the WebView to continue loading the URL as usual. Note: Do not call WebView.loadUrl(String) with the same URL and then return true. This unnecessarily cancels the current load and starts a new load with the same URL. The correct way to continue loading a given URL is to simply return false, without calling WebView.loadUrl(String). 
Note: This method is not called for POST requests.
Note: This method may be called for subframes and with non-HTTP(S) schemes; calling WebView.loadUrl(String) with such a URL will fail. 
Params: view – The WebView that is initiating the callback.
url – The URL to be loaded.
Returns: true to cancel the current load, otherwise return false.
Deprecated: Use 
            shouldOverrideUrlLoading(WebView, WebResourceRequest) instead./**
     * Give the host application a chance to take control when a URL is about to be loaded in the
     * current WebView. If a WebViewClient is not provided, by default WebView will ask Activity
     * Manager to choose the proper handler for the URL. If a WebViewClient is provided, returning
     * {@code true} causes the current WebView to abort loading the URL, while returning
     * {@code false} causes the WebView to continue loading the URL as usual.
     *
     * <p class="note"><b>Note:</b> Do not call {@link WebView#loadUrl(String)} with the same
     * URL and then return {@code true}. This unnecessarily cancels the current load and starts a
     * new load with the same URL. The correct way to continue loading a given URL is to simply
     * return {@code false}, without calling {@link WebView#loadUrl(String)}.
     *
     * <p class="note"><b>Note:</b> This method is not called for POST requests.
     *
     * <p class="note"><b>Note:</b> This method may be called for subframes and with non-HTTP(S)
     * schemes; calling {@link WebView#loadUrl(String)} with such a URL will fail.
     *
     * @param view The WebView that is initiating the callback.
     * @param url The URL to be loaded.
     * @return {@code true} to cancel the current load, otherwise return {@code false}.
     * @deprecated Use {@link #shouldOverrideUrlLoading(WebView, WebResourceRequest)
     *             shouldOverrideUrlLoading(WebView, WebResourceRequest)} instead.
     */
    @Deprecated
    public boolean shouldOverrideUrlLoading(WebView view, String url) {
        return false;
    }

    Give the host application a chance to take control when a URL is about to be loaded in the current WebView. If a WebViewClient is not provided, by default WebView will ask Activity Manager to choose the proper handler for the URL. If a WebViewClient is provided, returning true causes the current WebView to abort loading the URL, while returning false causes the WebView to continue loading the URL as usual. Note: Do not call WebView.loadUrl(String) with the request's URL and then return true. This unnecessarily cancels the current load and starts a new load with the same URL. The correct way to continue loading a given URL is to simply return false, without calling WebView.loadUrl(String). 
Note: This method is not called for POST requests.
Note: This method may be called for subframes and with non-HTTP(S) schemes; calling WebView.loadUrl(String) with such a URL will fail. 
Params: view – The WebView that is initiating the callback.
request – Object containing the details of the request.
Returns: true to cancel the current load, otherwise return false./**
     * Give the host application a chance to take control when a URL is about to be loaded in the
     * current WebView. If a WebViewClient is not provided, by default WebView will ask Activity
     * Manager to choose the proper handler for the URL. If a WebViewClient is provided, returning
     * {@code true} causes the current WebView to abort loading the URL, while returning
     * {@code false} causes the WebView to continue loading the URL as usual.
     *
     * <p class="note"><b>Note:</b> Do not call {@link WebView#loadUrl(String)} with the request's
     * URL and then return {@code true}. This unnecessarily cancels the current load and starts a
     * new load with the same URL. The correct way to continue loading a given URL is to simply
     * return {@code false}, without calling {@link WebView#loadUrl(String)}.
     *
     * <p class="note"><b>Note:</b> This method is not called for POST requests.
     *
     * <p class="note"><b>Note:</b> This method may be called for subframes and with non-HTTP(S)
     * schemes; calling {@link WebView#loadUrl(String)} with such a URL will fail.
     *
     * @param view The WebView that is initiating the callback.
     * @param request Object containing the details of the request.
     * @return {@code true} to cancel the current load, otherwise return {@code false}.
     */
    public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
        return shouldOverrideUrlLoading(view, request.getUrl().toString());
    }

    Notify the host application that a page has started loading. This method
is called once for each main frame load so a page with iframes or
framesets will call onPageStarted one time for the main frame. This also
means that onPageStarted will not be called when the contents of an
embedded frame changes, i.e. clicking a link whose target is an iframe,
it will also not be called for fragment navigations (navigations to
#fragment_id).
Params: view – The WebView that is initiating the callback.
url – The url to be loaded.
favicon – The favicon for this page if it already exists in the
           database./**
     * Notify the host application that a page has started loading. This method
     * is called once for each main frame load so a page with iframes or
     * framesets will call onPageStarted one time for the main frame. This also
     * means that onPageStarted will not be called when the contents of an
     * embedded frame changes, i.e. clicking a link whose target is an iframe,
     * it will also not be called for fragment navigations (navigations to
     * #fragment_id).
     *
     * @param view The WebView that is initiating the callback.
     * @param url The url to be loaded.
     * @param favicon The favicon for this page if it already exists in the
     *            database.
     */
    public void onPageStarted(WebView view, String url, Bitmap favicon) {
    }

    Notify the host application that a page has finished loading. This method is called only for main frame. When onPageFinished() is called, the rendering picture may not be updated yet. To get the notification for the new Picture, use PictureListener.onNewPicture. 
Params: view – The WebView that is initiating the callback.
url – The url of the page./**
     * Notify the host application that a page has finished loading. This method
     * is called only for main frame. When onPageFinished() is called, the
     * rendering picture may not be updated yet. To get the notification for the
     * new Picture, use {@link WebView.PictureListener#onNewPicture}.
     *
     * @param view The WebView that is initiating the callback.
     * @param url The url of the page.
     */
    public void onPageFinished(WebView view, String url) {
    }

    Notify the host application that the WebView will load the resource
specified by the given url.
Params: view – The WebView that is initiating the callback.
url – The url of the resource the WebView will load./**
     * Notify the host application that the WebView will load the resource
     * specified by the given url.
     *
     * @param view The WebView that is initiating the callback.
     * @param url The url of the resource the WebView will load.
     */
    public void onLoadResource(WebView view, String url) {
    }

    Notify the host application that WebView content left over from previous page navigations will no longer be drawn. This callback can be used to determine the point at which it is safe to make a recycled WebView visible, ensuring that no stale content is shown. It is called at the earliest point at which it can be guaranteed that WebView.onDraw will no longer draw any content from previous navigations. The next draw will display either the background color of the WebView, or some of the contents of the newly loaded page. 
This method is called when the body of the HTTP response has started loading, is reflected
in the DOM, and will be visible in subsequent draws. This callback occurs early in the
document loading process, and as such you should expect that linked resources (for example,
CSS and images) may not be available.
For more fine-grained notification of visual state updates, see WebView.postVisualStateCallback. 
Please note that all the conditions and recommendations applicable to WebView.postVisualStateCallback also apply to this API. 
This callback is only called for main frame navigations.
Params: view – The WebView for which the navigation occurred.
url –  The URL corresponding to the page navigation that triggered this callback./**
     * Notify the host application that {@link android.webkit.WebView} content left over from
     * previous page navigations will no longer be drawn.
     *
     * <p>This callback can be used to determine the point at which it is safe to make a recycled
     * {@link android.webkit.WebView} visible, ensuring that no stale content is shown. It is called
     * at the earliest point at which it can be guaranteed that {@link WebView#onDraw} will no
     * longer draw any content from previous navigations. The next draw will display either the
     * {@link WebView#setBackgroundColor background color} of the {@link WebView}, or some of the
     * contents of the newly loaded page.
     *
     * <p>This method is called when the body of the HTTP response has started loading, is reflected
     * in the DOM, and will be visible in subsequent draws. This callback occurs early in the
     * document loading process, and as such you should expect that linked resources (for example,
     * CSS and images) may not be available.
     *
     * <p>For more fine-grained notification of visual state updates, see {@link
     * WebView#postVisualStateCallback}.
     *
     * <p>Please note that all the conditions and recommendations applicable to
     * {@link WebView#postVisualStateCallback} also apply to this API.
     *
     * <p>This callback is only called for main frame navigations.
     *
     * @param view The {@link android.webkit.WebView} for which the navigation occurred.
     * @param url  The URL corresponding to the page navigation that triggered this callback.
     */
    public void onPageCommitVisible(WebView view, String url) {
    }

    Notify the host application of a resource request and allow the application to return the data. If the return value is null, the WebView will continue to load the resource as usual. Otherwise, the return response and data will be used. This callback is invoked for a variety of URL schemes (e.g., http(s):, 
data:, file:, etc.), not only those schemes which send requests over the network. This is not called for javascript: URLs, blob: URLs, or for assets accessed via file:///android_asset/ or file:///android_res/ URLs. 
In the case of redirects, this is only called for the initial resource URL, not any
subsequent redirect URLs.
Note: This method is called on a thread
other than the UI thread so clients should exercise caution
when accessing private data or the view system.
Note: When Safe Browsing is enabled, these URLs still undergo Safe Browsing checks. If this is undesired, whitelist the URL with WebView.setSafeBrowsingWhitelist or ignore the warning with onSafeBrowsingHit. 
Params: view – The WebView that is requesting the resource.
url – The raw url of the resource.
Returns: A WebResourceResponse containing the response information or null if the WebView should load the resource itself.
Deprecated: Use 
            shouldInterceptRequest(WebView, WebResourceRequest) instead./**
     * Notify the host application of a resource request and allow the
     * application to return the data.  If the return value is {@code null}, the WebView
     * will continue to load the resource as usual.  Otherwise, the return
     * response and data will be used.
     *
     * <p>This callback is invoked for a variety of URL schemes (e.g., {@code http(s):}, {@code
     * data:}, {@code file:}, etc.), not only those schemes which send requests over the network.
     * This is not called for {@code javascript:} URLs, {@code blob:} URLs, or for assets accessed
     * via {@code file:///android_asset/} or {@code file:///android_res/} URLs.
     *
     * <p>In the case of redirects, this is only called for the initial resource URL, not any
     * subsequent redirect URLs.
     *
     * <p class="note"><b>Note:</b> This method is called on a thread
     * other than the UI thread so clients should exercise caution
     * when accessing private data or the view system.
     *
     * <p class="note"><b>Note:</b> When Safe Browsing is enabled, these URLs still undergo Safe
     * Browsing checks. If this is undesired, whitelist the URL with {@link
     * WebView#setSafeBrowsingWhitelist} or ignore the warning with {@link #onSafeBrowsingHit}.
     *
     * @param view The {@link android.webkit.WebView} that is requesting the
     *             resource.
     * @param url The raw url of the resource.
     * @return A {@link android.webkit.WebResourceResponse} containing the
     *         response information or {@code null} if the WebView should load the
     *         resource itself.
     * @deprecated Use {@link #shouldInterceptRequest(WebView, WebResourceRequest)
     *             shouldInterceptRequest(WebView, WebResourceRequest)} instead.
     */
    @Deprecated
    @Nullable
    public WebResourceResponse shouldInterceptRequest(WebView view,
            String url) {
        return null;
    }

    Notify the host application of a resource request and allow the application to return the data. If the return value is null, the WebView will continue to load the resource as usual. Otherwise, the return response and data will be used. This callback is invoked for a variety of URL schemes (e.g., http(s):, 
data:, file:, etc.), not only those schemes which send requests over the network. This is not called for javascript: URLs, blob: URLs, or for assets accessed via file:///android_asset/ or file:///android_res/ URLs. 
In the case of redirects, this is only called for the initial resource URL, not any
subsequent redirect URLs.
Note: This method is called on a thread
other than the UI thread so clients should exercise caution
when accessing private data or the view system.
Note: When Safe Browsing is enabled, these URLs still undergo Safe Browsing checks. If this is undesired, whitelist the URL with WebView.setSafeBrowsingWhitelist or ignore the warning with onSafeBrowsingHit. 
Params: view – The WebView that is requesting the resource.
request – Object containing the details of the request.
Returns: A WebResourceResponse containing the response information or null if the WebView should load the resource itself./**
     * Notify the host application of a resource request and allow the
     * application to return the data.  If the return value is {@code null}, the WebView
     * will continue to load the resource as usual.  Otherwise, the return
     * response and data will be used.
     *
     * <p>This callback is invoked for a variety of URL schemes (e.g., {@code http(s):}, {@code
     * data:}, {@code file:}, etc.), not only those schemes which send requests over the network.
     * This is not called for {@code javascript:} URLs, {@code blob:} URLs, or for assets accessed
     * via {@code file:///android_asset/} or {@code file:///android_res/} URLs.
     *
     * <p>In the case of redirects, this is only called for the initial resource URL, not any
     * subsequent redirect URLs.
     *
     * <p class="note"><b>Note:</b> This method is called on a thread
     * other than the UI thread so clients should exercise caution
     * when accessing private data or the view system.
     *
     * <p class="note"><b>Note:</b> When Safe Browsing is enabled, these URLs still undergo Safe
     * Browsing checks. If this is undesired, whitelist the URL with {@link
     * WebView#setSafeBrowsingWhitelist} or ignore the warning with {@link #onSafeBrowsingHit}.
     *
     * @param view The {@link android.webkit.WebView} that is requesting the
     *             resource.
     * @param request Object containing the details of the request.
     * @return A {@link android.webkit.WebResourceResponse} containing the
     *         response information or {@code null} if the WebView should load the
     *         resource itself.
     */
    @Nullable
    public WebResourceResponse shouldInterceptRequest(WebView view,
            WebResourceRequest request) {
        return shouldInterceptRequest(view, request.getUrl().toString());
    }

    Notify the host application that there have been an excessive number of
HTTP redirects. As the host application if it would like to continue
trying to load the resource. The default behavior is to send the cancel
message.
Params: view – The WebView that is initiating the callback.
cancelMsg – The message to send if the host wants to cancel
continueMsg – The message to send if the host wants to continue
Deprecated: This method is no longer called. When the WebView encounters
            a redirect loop, it will cancel the load./**
     * Notify the host application that there have been an excessive number of
     * HTTP redirects. As the host application if it would like to continue
     * trying to load the resource. The default behavior is to send the cancel
     * message.
     *
     * @param view The WebView that is initiating the callback.
     * @param cancelMsg The message to send if the host wants to cancel
     * @param continueMsg The message to send if the host wants to continue
     * @deprecated This method is no longer called. When the WebView encounters
     *             a redirect loop, it will cancel the load.
     */
    @Deprecated
    public void onTooManyRedirects(WebView view, Message cancelMsg,
            Message continueMsg) {
        cancelMsg.sendToTarget();
    }

    // These ints must match up to the hidden values in EventHandler.
    Generic error /** Generic error */
    public static final int ERROR_UNKNOWN = -1;
    Server or proxy hostname lookup failed /** Server or proxy hostname lookup failed */
    public static final int ERROR_HOST_LOOKUP = -2;
    Unsupported authentication scheme (not basic or digest) /** Unsupported authentication scheme (not basic or digest) */
    public static final int ERROR_UNSUPPORTED_AUTH_SCHEME = -3;
    User authentication failed on server /** User authentication failed on server */
    public static final int ERROR_AUTHENTICATION = -4;
    User authentication failed on proxy /** User authentication failed on proxy */
    public static final int ERROR_PROXY_AUTHENTICATION = -5;
    Failed to connect to the server /** Failed to connect to the server */
    public static final int ERROR_CONNECT = -6;
    Failed to read or write to the server /** Failed to read or write to the server */
    public static final int ERROR_IO = -7;
    Connection timed out /** Connection timed out */
    public static final int ERROR_TIMEOUT = -8;
    Too many redirects /** Too many redirects */
    public static final int ERROR_REDIRECT_LOOP = -9;
    Unsupported URI scheme /** Unsupported URI scheme */
    public static final int ERROR_UNSUPPORTED_SCHEME = -10;
    Failed to perform SSL handshake /** Failed to perform SSL handshake */
    public static final int ERROR_FAILED_SSL_HANDSHAKE = -11;
    Malformed URL /** Malformed URL */
    public static final int ERROR_BAD_URL = -12;
    Generic file error /** Generic file error */
    public static final int ERROR_FILE = -13;
    File not found /** File not found */
    public static final int ERROR_FILE_NOT_FOUND = -14;
    Too many requests during this load /** Too many requests during this load */
    public static final int ERROR_TOO_MANY_REQUESTS = -15;
    Resource load was canceled by Safe Browsing /** Resource load was canceled by Safe Browsing */
    public static final int ERROR_UNSAFE_RESOURCE = -16;

    @hide /** @hide */
    @IntDef(prefix = { "SAFE_BROWSING_THREAT_" }, value = {
            SAFE_BROWSING_THREAT_UNKNOWN,
            SAFE_BROWSING_THREAT_MALWARE,
            SAFE_BROWSING_THREAT_PHISHING,
            SAFE_BROWSING_THREAT_UNWANTED_SOFTWARE
    })
    @Retention(RetentionPolicy.SOURCE)
    public @interface SafeBrowsingThreat {}

    The resource was blocked for an unknown reason /** The resource was blocked for an unknown reason */
    public static final int SAFE_BROWSING_THREAT_UNKNOWN = 0;
    The resource was blocked because it contains malware /** The resource was blocked because it contains malware */
    public static final int SAFE_BROWSING_THREAT_MALWARE = 1;
    The resource was blocked because it contains deceptive content /** The resource was blocked because it contains deceptive content */
    public static final int SAFE_BROWSING_THREAT_PHISHING = 2;
    The resource was blocked because it contains unwanted software /** The resource was blocked because it contains unwanted software */
    public static final int SAFE_BROWSING_THREAT_UNWANTED_SOFTWARE = 3;

    Report an error to the host application. These errors are unrecoverable (i.e. the main resource is unavailable). The errorCode parameter corresponds to one of the ERROR_* constants. 
Params: view – The WebView that is initiating the callback.
errorCode – The error code corresponding to an ERROR_* value.
description – A String describing the error.
failingUrl – The url that failed to load.
Deprecated: Use 
            onReceivedError(WebView, WebResourceRequest, WebResourceError) instead./**
     * Report an error to the host application. These errors are unrecoverable
     * (i.e. the main resource is unavailable). The {@code errorCode} parameter
     * corresponds to one of the {@code ERROR_*} constants.
     * @param view The WebView that is initiating the callback.
     * @param errorCode The error code corresponding to an ERROR_* value.
     * @param description A String describing the error.
     * @param failingUrl The url that failed to load.
     * @deprecated Use {@link #onReceivedError(WebView, WebResourceRequest, WebResourceError)
     *             onReceivedError(WebView, WebResourceRequest, WebResourceError)} instead.
     */
    @Deprecated
    public void onReceivedError(WebView view, int errorCode,
            String description, String failingUrl) {
    }

    Report web resource loading error to the host application. These errors usually indicate
inability to connect to the server. Note that unlike the deprecated version of the callback,
the new version will be called for any resource (iframe, image, etc.), not just for the main
page. Thus, it is recommended to perform minimum required work in this callback.
Params: view – The WebView that is initiating the callback.
request – The originating request.
error – Information about the error occurred./**
     * Report web resource loading error to the host application. These errors usually indicate
     * inability to connect to the server. Note that unlike the deprecated version of the callback,
     * the new version will be called for any resource (iframe, image, etc.), not just for the main
     * page. Thus, it is recommended to perform minimum required work in this callback.
     * @param view The WebView that is initiating the callback.
     * @param request The originating request.
     * @param error Information about the error occurred.
     */
    public void onReceivedError(WebView view, WebResourceRequest request, WebResourceError error) {
        if (request.isForMainFrame()) {
            onReceivedError(view,
                    error.getErrorCode(), error.getDescription().toString(),
                    request.getUrl().toString());
        }
    }

    Notify the host application that an HTTP error has been received from the server while loading a resource. HTTP errors have status codes >= 400. This callback will be called for any resource (iframe, image, etc.), not just for the main page. Thus, it is recommended to perform minimum required work in this callback. Note that the content of the server response may not be provided within the errorResponse parameter. 
Params: view – The WebView that is initiating the callback.
request – The originating request.
errorResponse – Information about the error occurred./**
     * Notify the host application that an HTTP error has been received from the server while
     * loading a resource.  HTTP errors have status codes &gt;= 400.  This callback will be called
     * for any resource (iframe, image, etc.), not just for the main page. Thus, it is recommended
     * to perform minimum required work in this callback. Note that the content of the server
     * response may not be provided within the {@code errorResponse} parameter.
     * @param view The WebView that is initiating the callback.
     * @param request The originating request.
     * @param errorResponse Information about the error occurred.
     */
    public void onReceivedHttpError(
            WebView view, WebResourceRequest request, WebResourceResponse errorResponse) {
    }

    As the host application if the browser should resend data as the
requested page was a result of a POST. The default is to not resend the
data.
Params: view – The WebView that is initiating the callback.
dontResend – The message to send if the browser should not resend
resend – The message to send if the browser should resend data/**
     * As the host application if the browser should resend data as the
     * requested page was a result of a POST. The default is to not resend the
     * data.
     *
     * @param view The WebView that is initiating the callback.
     * @param dontResend The message to send if the browser should not resend
     * @param resend The message to send if the browser should resend data
     */
    public void onFormResubmission(WebView view, Message dontResend,
            Message resend) {
        dontResend.sendToTarget();
    }

    Notify the host application to update its visited links database.
Params: view – The WebView that is initiating the callback.
url – The url being visited.
isReload – true if this url is being reloaded./**
     * Notify the host application to update its visited links database.
     *
     * @param view The WebView that is initiating the callback.
     * @param url The url being visited.
     * @param isReload {@code true} if this url is being reloaded.
     */
    public void doUpdateVisitedHistory(WebView view, String url,
            boolean isReload) {
    }

    Notify the host application that an SSL error occurred while loading a
resource. The host application must call either handler.cancel() or
handler.proceed(). Note that the decision may be retained for use in
response to future SSL errors. The default behavior is to cancel the
load.

Applications are advised not to prompt the user about SSL errors, as
the user is unlikely to be able to make an informed security decision
and WebView does not provide any UI for showing the details of the
error in a meaningful way.

Application overrides of this method may display custom error pages or
silently log issues, but it is strongly recommended to always call
handler.cancel() and never allow proceeding past errors.
Params: view – The WebView that is initiating the callback.
handler – An SslErrorHandler object that will handle the user's
           response.
error – The SSL error object./**
     * Notify the host application that an SSL error occurred while loading a
     * resource. The host application must call either handler.cancel() or
     * handler.proceed(). Note that the decision may be retained for use in
     * response to future SSL errors. The default behavior is to cancel the
     * load.
     * <p>
     * Applications are advised not to prompt the user about SSL errors, as
     * the user is unlikely to be able to make an informed security decision
     * and WebView does not provide any UI for showing the details of the
     * error in a meaningful way.
     * <p>
     * Application overrides of this method may display custom error pages or
     * silently log issues, but it is strongly recommended to always call
     * handler.cancel() and never allow proceeding past errors.
     *
     * @param view The WebView that is initiating the callback.
     * @param handler An SslErrorHandler object that will handle the user's
     *            response.
     * @param error The SSL error object.
     */
    public void onReceivedSslError(WebView view, SslErrorHandler handler,
            SslError error) {
        handler.cancel();
    }

    Notify the host application to handle a SSL client certificate request. The host application is responsible for showing the UI if desired and providing the keys. There are three ways to respond: ClientCertRequest.proceed, ClientCertRequest.cancel, or ClientCertRequest.ignore. Webview stores the response in memory (for the life of the application) if ClientCertRequest.proceed or ClientCertRequest.cancel is called and does not call onReceivedClientCertRequest() again for the same host and port pair. Webview does not store the response if ClientCertRequest.ignore is called. Note that, multiple layers in chromium network stack might be caching the responses, so the behavior for ignore is only a best case effort. This method is called on the UI thread. During the callback, the connection is suspended. For most use cases, the application program should implement the KeyChainAliasCallback interface and pass it to KeyChain.choosePrivateKeyAlias to start an activity for the user to choose the proper alias. The keychain activity will provide the alias through the callback method in the implemented interface. Next the application should create an async task to call KeyChain.getPrivateKey to receive the key. An example implementation of client certificates can be seen at 
AOSP Browser
The default behavior is to cancel, returning no client certificate.
Params: view – The WebView that is initiating the callback
request – An instance of a ClientCertRequest/**
     * Notify the host application to handle a SSL client certificate request. The host application
     * is responsible for showing the UI if desired and providing the keys. There are three ways to
     * respond: {@link ClientCertRequest#proceed}, {@link ClientCertRequest#cancel}, or {@link
     * ClientCertRequest#ignore}. Webview stores the response in memory (for the life of the
     * application) if {@link ClientCertRequest#proceed} or {@link ClientCertRequest#cancel} is
     * called and does not call {@code onReceivedClientCertRequest()} again for the same host and
     * port pair. Webview does not store the response if {@link ClientCertRequest#ignore}
     * is called. Note that, multiple layers in chromium network stack might be
     * caching the responses, so the behavior for ignore is only a best case
     * effort.
     *
     * This method is called on the UI thread. During the callback, the
     * connection is suspended.
     *
     * For most use cases, the application program should implement the
     * {@link android.security.KeyChainAliasCallback} interface and pass it to
     * {@link android.security.KeyChain#choosePrivateKeyAlias} to start an
     * activity for the user to choose the proper alias. The keychain activity will
     * provide the alias through the callback method in the implemented interface. Next
     * the application should create an async task to call
     * {@link android.security.KeyChain#getPrivateKey} to receive the key.
     *
     * An example implementation of client certificates can be seen at
     * <A href="https://android.googlesource.com/platform/packages/apps/Browser/+/android-5.1.1_r1/src/com/android/browser/Tab.java">
     * AOSP Browser</a>
     *
     * The default behavior is to cancel, returning no client certificate.
     *
     * @param view The WebView that is initiating the callback
     * @param request An instance of a {@link ClientCertRequest}
     *
     */
    public void onReceivedClientCertRequest(WebView view, ClientCertRequest request) {
        request.cancel();
    }

    Notifies the host application that the WebView received an HTTP authentication request. The host application can use the supplied HttpAuthHandler to set the WebView's response to the request. The default behavior is to cancel the request. 
Params: view – the WebView that is initiating the callback
handler – the HttpAuthHandler used to set the WebView's response
host – the host requiring authentication
realm – the realm for which authentication is required
See Also: WebView.getHttpAuthUsernamePassword/**
     * Notifies the host application that the WebView received an HTTP
     * authentication request. The host application can use the supplied
     * {@link HttpAuthHandler} to set the WebView's response to the request.
     * The default behavior is to cancel the request.
     *
     * @param view the WebView that is initiating the callback
     * @param handler the HttpAuthHandler used to set the WebView's response
     * @param host the host requiring authentication
     * @param realm the realm for which authentication is required
     * @see WebView#getHttpAuthUsernamePassword
     */
    public void onReceivedHttpAuthRequest(WebView view,
            HttpAuthHandler handler, String host, String realm) {
        handler.cancel();
    }

    Give the host application a chance to handle the key event synchronously. e.g. menu shortcut key events need to be filtered this way. If return true, WebView will not handle the key event. If return false, WebView will always handle the key event, so none of the super in the view chain will see the key event. The default behavior returns false. 
Params: view – The WebView that is initiating the callback.
event – The key event.
Returns: true if the host application wants to handle the key event itself, otherwise return false/**
     * Give the host application a chance to handle the key event synchronously.
     * e.g. menu shortcut key events need to be filtered this way. If return
     * true, WebView will not handle the key event. If return {@code false}, WebView
     * will always handle the key event, so none of the super in the view chain
     * will see the key event. The default behavior returns {@code false}.
     *
     * @param view The WebView that is initiating the callback.
     * @param event The key event.
     * @return {@code true} if the host application wants to handle the key event
     *         itself, otherwise return {@code false}
     */
    public boolean shouldOverrideKeyEvent(WebView view, KeyEvent event) {
        return false;
    }

    Notify the host application that a key was not handled by the WebView. Except system keys, WebView always consumes the keys in the normal flow or if shouldOverrideKeyEvent returns true. This is called asynchronously from where the key is dispatched. It gives the host application a chance to handle the unhandled key events. 
Params: view – The WebView that is initiating the callback.
event – The key event./**
     * Notify the host application that a key was not handled by the WebView.
     * Except system keys, WebView always consumes the keys in the normal flow
     * or if {@link #shouldOverrideKeyEvent} returns {@code true}. This is called asynchronously
     * from where the key is dispatched. It gives the host application a chance
     * to handle the unhandled key events.
     *
     * @param view The WebView that is initiating the callback.
     * @param event The key event.
     */
    public void onUnhandledKeyEvent(WebView view, KeyEvent event) {
        onUnhandledInputEventInternal(view, event);
    }

    Notify the host application that a input event was not handled by the WebView. Except system keys, WebView always consumes input events in the normal flow or if shouldOverrideKeyEvent returns true. This is called asynchronously from where the event is dispatched. It gives the host application a chance to handle the unhandled input events. Note that if the event is a MotionEvent, then it's lifetime is only that of the function call. If the WebViewClient wishes to use the event beyond that, then it must create a copy of the event. It is the responsibility of overriders of this method to call onUnhandledKeyEvent(WebView, KeyEvent) when appropriate if they wish to continue receiving events through it. 
Params: view – The WebView that is initiating the callback.
event – The input event.
@removed /**
     * Notify the host application that a input event was not handled by the WebView.
     * Except system keys, WebView always consumes input events in the normal flow
     * or if {@link #shouldOverrideKeyEvent} returns {@code true}. This is called asynchronously
     * from where the event is dispatched. It gives the host application a chance
     * to handle the unhandled input events.
     *
     * Note that if the event is a {@link android.view.MotionEvent}, then it's lifetime is only
     * that of the function call. If the WebViewClient wishes to use the event beyond that, then it
     * <i>must</i> create a copy of the event.
     *
     * It is the responsibility of overriders of this method to call
     * {@link #onUnhandledKeyEvent(WebView, KeyEvent)}
     * when appropriate if they wish to continue receiving events through it.
     *
     * @param view The WebView that is initiating the callback.
     * @param event The input event.
     * @removed
     */
    public void onUnhandledInputEvent(WebView view, InputEvent event) {
        if (event instanceof KeyEvent) {
            onUnhandledKeyEvent(view, (KeyEvent) event);
            return;
        }
        onUnhandledInputEventInternal(view, event);
    }

    private void onUnhandledInputEventInternal(WebView view, InputEvent event) {
        ViewRootImpl root = view.getViewRootImpl();
        if (root != null) {
            root.dispatchUnhandledInputEvent(event);
        }
    }

    Notify the host application that the scale applied to the WebView has
changed.
Params: view – The WebView that is initiating the callback.
oldScale – The old scale factor
newScale – The new scale factor/**
     * Notify the host application that the scale applied to the WebView has
     * changed.
     *
     * @param view The WebView that is initiating the callback.
     * @param oldScale The old scale factor
     * @param newScale The new scale factor
     */
    public void onScaleChanged(WebView view, float oldScale, float newScale) {
    }

    Notify the host application that a request to automatically log in the
user has been processed.
Params: view – The WebView requesting the login.
realm – The account realm used to look up accounts.
account – An optional account. If not null, the account should be checked against accounts on the device. If it is a valid account, it should be used to log in the user.
args – Authenticator specific arguments used to log in the user./**
     * Notify the host application that a request to automatically log in the
     * user has been processed.
     * @param view The WebView requesting the login.
     * @param realm The account realm used to look up accounts.
     * @param account An optional account. If not {@code null}, the account should be
     *                checked against accounts on the device. If it is a valid
     *                account, it should be used to log in the user.
     * @param args Authenticator specific arguments used to log in the user.
     */
    public void onReceivedLoginRequest(WebView view, String realm,
            @Nullable String account, String args) {
    }

    Notify host application that the given WebView's render process has exited. Multiple WebView instances may be associated with a single render process; onRenderProcessGone will be called for each WebView that was affected. The application's implementation of this callback should only attempt to clean up the specific WebView given as a parameter, and should not assume that other WebView instances are affected. The given WebView can't be used, and should be removed from the view hierarchy, all references to it should be cleaned up, e.g any references in the Activity or other classes saved using View.findViewById and similar calls, etc. To cause an render process crash for test purpose, the application can call loadUrl("chrome://crash") on the WebView. Note that multiple WebView instances may be affected if they share a render process, not just the specific WebView which loaded chrome://crash. 
Params: view – The WebView which needs to be cleaned up.
detail – the reason why it exited.
Returns: true if the host application handled the situation that process has exited, otherwise, application will crash if render process crashed, or be killed if render process was killed by the system./**
     * Notify host application that the given WebView's render process has exited.
     *
     * Multiple WebView instances may be associated with a single render process;
     * onRenderProcessGone will be called for each WebView that was affected.
     * The application's implementation of this callback should only attempt to
     * clean up the specific WebView given as a parameter, and should not assume
     * that other WebView instances are affected.
     *
     * The given WebView can't be used, and should be removed from the view hierarchy,
     * all references to it should be cleaned up, e.g any references in the Activity
     * or other classes saved using {@link android.view.View#findViewById} and similar calls, etc.
     *
     * To cause an render process crash for test purpose, the application can
     * call {@code loadUrl("chrome://crash")} on the WebView. Note that multiple WebView
     * instances may be affected if they share a render process, not just the
     * specific WebView which loaded chrome://crash.
     *
     * @param view The WebView which needs to be cleaned up.
     * @param detail the reason why it exited.
     * @return {@code true} if the host application handled the situation that process has
     *         exited, otherwise, application will crash if render process crashed,
     *         or be killed if render process was killed by the system.
     */
    public boolean onRenderProcessGone(WebView view, RenderProcessGoneDetail detail) {
        return false;
    }

    Notify the host application that a loading URL has been flagged by Safe Browsing. The application must invoke the callback to indicate the preferred response. The default behavior is to show an interstitial to the user, with the reporting checkbox visible. If the application needs to show its own custom interstitial UI, the callback can be invoked asynchronously with SafeBrowsingResponse.backToSafety or SafeBrowsingResponse.proceed, depending on user response. 
Params: view – The WebView that hit the malicious resource.
request – Object containing the details of the request.
threatType – The reason the resource was caught by Safe Browsing, corresponding to a SAFE_BROWSING_THREAT_* value.
callback – Applications must invoke one of the callback methods./**
     * Notify the host application that a loading URL has been flagged by Safe Browsing.
     *
     * The application must invoke the callback to indicate the preferred response. The default
     * behavior is to show an interstitial to the user, with the reporting checkbox visible.
     *
     * If the application needs to show its own custom interstitial UI, the callback can be invoked
     * asynchronously with {@link SafeBrowsingResponse#backToSafety} or {@link
     * SafeBrowsingResponse#proceed}, depending on user response.
     *
     * @param view The WebView that hit the malicious resource.
     * @param request Object containing the details of the request.
     * @param threatType The reason the resource was caught by Safe Browsing, corresponding to a
     *                   {@code SAFE_BROWSING_THREAT_*} value.
     * @param callback Applications must invoke one of the callback methods.
     */
    public void onSafeBrowsingHit(WebView view, WebResourceRequest request,
            @SafeBrowsingThreat int threatType, SafeBrowsingResponse callback) {
        callback.showInterstitial(/* allowReporting */ true);
    }
}
Params:	view – The WebView that is initiating the callback. url – The URL to be loaded.
Returns:	`true` to cancel the current load, otherwise return `false`.
Deprecated:	Use `shouldOverrideUrlLoading(WebView, WebResourceRequest)` instead.
Params:	view – The `WebView` that is requesting the resource. url – The raw url of the resource.
Returns:	A `WebResourceResponse` containing the response information or `null` if the WebView should load the resource itself.
Deprecated:	Use `shouldInterceptRequest(WebView, WebResourceRequest)` instead.
Params:	view – the WebView that is initiating the callback handler – the HttpAuthHandler used to set the WebView's response host – the host requiring authentication realm – the realm for which authentication is required
See Also:	WebView.getHttpAuthUsernamePassword
Params:	view – The WebView that is initiating the callback. event – The input event.
@removed
Params:	view – The WebView which needs to be cleaned up. detail – the reason why it exited.
Returns:	`true` if the host application handled the situation that process has exited, otherwise, application will crash if render process crashed, or be killed if render process was killed by the system.
/

android/ android-9.0.0_r35/ android/webkit/WebViewClient.java
