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

WebChromeClient
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.Nullable;
import android.annotation.SystemApi;
import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Message;
import android.view.View;

public class WebChromeClient {

    Tell the host application the current progress of loading a page.
Params: view – The WebView that initiated the callback.
newProgress – Current page loading progress, represented by
                   an integer between 0 and 100./**
     * Tell the host application the current progress of loading a page.
     * @param view The WebView that initiated the callback.
     * @param newProgress Current page loading progress, represented by
     *                    an integer between 0 and 100.
     */
    public void onProgressChanged(WebView view, int newProgress) {}

    Notify the host application of a change in the document title.
Params: view – The WebView that initiated the callback.
title – A String containing the new title of the document./**
     * Notify the host application of a change in the document title.
     * @param view The WebView that initiated the callback.
     * @param title A String containing the new title of the document.
     */
    public void onReceivedTitle(WebView view, String title) {}

    Notify the host application of a new favicon for the current page.
Params: view – The WebView that initiated the callback.
icon – A Bitmap containing the favicon for the current page./**
     * Notify the host application of a new favicon for the current page.
     * @param view The WebView that initiated the callback.
     * @param icon A Bitmap containing the favicon for the current page.
     */
    public void onReceivedIcon(WebView view, Bitmap icon) {}

    Notify the host application of the url for an apple-touch-icon.
Params: view – The WebView that initiated the callback.
url – The icon url.
precomposed – true if the url is for a precomposed touch icon./**
     * Notify the host application of the url for an apple-touch-icon.
     * @param view The WebView that initiated the callback.
     * @param url The icon url.
     * @param precomposed {@code true} if the url is for a precomposed touch icon.
     */
    public void onReceivedTouchIconUrl(WebView view, String url,
            boolean precomposed) {}

    A callback interface used by the host application to notify
the current page that its custom view has been dismissed.
/**
     * A callback interface used by the host application to notify
     * the current page that its custom view has been dismissed.
     */
    public interface CustomViewCallback {
        Invoked when the host application dismisses the
custom view.
/**
         * Invoked when the host application dismisses the
         * custom view.
         */
        public void onCustomViewHidden();
    }

    Notify the host application that the current page has entered full screen mode. The host application must show the custom View which contains the web contents — video or other HTML content — in full screen mode. Also see "Full screen support" documentation on WebView. 
Params: view – is the View object to be shown.
callback – invoke this callback to request the page to exit
full screen mode./**
     * Notify the host application that the current page has entered full
     * screen mode. The host application must show the custom View which
     * contains the web contents &mdash; video or other HTML content &mdash;
     * in full screen mode. Also see "Full screen support" documentation on
     * {@link WebView}.
     * @param view is the View object to be shown.
     * @param callback invoke this callback to request the page to exit
     * full screen mode.
     */
    public void onShowCustomView(View view, CustomViewCallback callback) {};

    Notify the host application that the current page would
like to show a custom View in a particular orientation.
Params: view – is the View object to be shown.
requestedOrientation – An orientation constant as used in ActivityInfo.screenOrientation.
callback – is the callback to be invoked if and when the view
is dismissed.
Deprecated: This method supports the obsolete plugin mechanism,
and will not be invoked in future/**
     * Notify the host application that the current page would
     * like to show a custom View in a particular orientation.
     * @param view is the View object to be shown.
     * @param requestedOrientation An orientation constant as used in
     * {@link ActivityInfo#screenOrientation ActivityInfo.screenOrientation}.
     * @param callback is the callback to be invoked if and when the view
     * is dismissed.
     * @deprecated This method supports the obsolete plugin mechanism,
     * and will not be invoked in future
     */
    @Deprecated
    public void onShowCustomView(View view, int requestedOrientation,
            CustomViewCallback callback) {};

    Notify the host application that the current page has exited full screen mode. The host application must hide the custom View, ie. the View passed to onShowCustomView when the content entered fullscreen. Also see "Full screen support" documentation on WebView. /**
     * Notify the host application that the current page has exited full
     * screen mode. The host application must hide the custom View, ie. the
     * View passed to {@link #onShowCustomView} when the content entered fullscreen.
     * Also see "Full screen support" documentation on {@link WebView}.
     */
    public void onHideCustomView() {}

    Request the host application to create a new window. If the host application chooses to honor this request, it should return true from this method, create a new WebView to host the window, insert it into the View system and send the supplied resultMsg message to its target with the new WebView as an argument. If the host application chooses not to honor the request, it should return false from this method. The default implementation of this method does nothing and hence returns false.  Applications should typically not allow windows to be created when the isUserGesture flag is false, as this may be an unwanted popup. 

Applications should be careful how they display the new window: don't simply
overlay it over the existing WebView as this may mislead the user about which
site they are viewing. If your application displays the URL of the main page,
make sure to also display the URL of the new window in a similar fashion. If
your application does not display URLs, consider disallowing the creation of
new windows entirely.
Note: There is no trustworthy way to tell which page
requested the new window: the request might originate from a third-party iframe
inside the WebView.
Params: view – The WebView from which the request for a new window
            originated.
isDialog – true if the new window should be a dialog, rather than a full-size window.
isUserGesture – true if the request was initiated by a user gesture, such as the user clicking a link.
resultMsg – The message to send when once a new WebView has been created. resultMsg.obj is a WebViewTransport object. This should be used to transport the new WebView, by calling 
                 WebView.WebViewTransport.setWebView(WebView).
Returns: This method should return true if the host application will create a new window, in which case resultMsg should be sent to its target. Otherwise, this method should return false. Returning false from this method but also sending resultMsg will result in undefined behavior./**
     * Request the host application to create a new window. If the host
     * application chooses to honor this request, it should return {@code true} from
     * this method, create a new WebView to host the window, insert it into the
     * View system and send the supplied resultMsg message to its target with
     * the new WebView as an argument. If the host application chooses not to
     * honor the request, it should return {@code false} from this method. The default
     * implementation of this method does nothing and hence returns {@code false}.
     * <p>
     * Applications should typically not allow windows to be created when the
     * {@code isUserGesture} flag is false, as this may be an unwanted popup.
     * <p>
     * Applications should be careful how they display the new window: don't simply
     * overlay it over the existing WebView as this may mislead the user about which
     * site they are viewing. If your application displays the URL of the main page,
     * make sure to also display the URL of the new window in a similar fashion. If
     * your application does not display URLs, consider disallowing the creation of
     * new windows entirely.
     * <p class="note"><b>Note:</b> There is no trustworthy way to tell which page
     * requested the new window: the request might originate from a third-party iframe
     * inside the WebView.
     *
     * @param view The WebView from which the request for a new window
     *             originated.
     * @param isDialog {@code true} if the new window should be a dialog, rather than
     *                 a full-size window.
     * @param isUserGesture {@code true} if the request was initiated by a user gesture,
     *                      such as the user clicking a link.
     * @param resultMsg The message to send when once a new WebView has been
     *                  created. resultMsg.obj is a
     *                  {@link WebView.WebViewTransport} object. This should be
     *                  used to transport the new WebView, by calling
     *                  {@link WebView.WebViewTransport#setWebView(WebView)
     *                  WebView.WebViewTransport.setWebView(WebView)}.
     * @return This method should return {@code true} if the host application will
     *         create a new window, in which case resultMsg should be sent to
     *         its target. Otherwise, this method should return {@code false}. Returning
     *         {@code false} from this method but also sending resultMsg will result in
     *         undefined behavior.
     */
    public boolean onCreateWindow(WebView view, boolean isDialog,
            boolean isUserGesture, Message resultMsg) {
        return false;
    }

    Request display and focus for this WebView. This may happen due to
another WebView opening a link in this WebView and requesting that this
WebView be displayed.
Params: view – The WebView that needs to be focused./**
     * Request display and focus for this WebView. This may happen due to
     * another WebView opening a link in this WebView and requesting that this
     * WebView be displayed.
     * @param view The WebView that needs to be focused.
     */
    public void onRequestFocus(WebView view) {}

    Notify the host application to close the given WebView and remove it
from the view system if necessary. At this point, WebCore has stopped
any loading in this window and has removed any cross-scripting ability
in javascript.
 As with onCreateWindow, the application should ensure that any URL or security indicator displayed is updated so that the user can tell that the page they were interacting with has been closed. 
Params: window – The WebView that needs to be closed./**
     * Notify the host application to close the given WebView and remove it
     * from the view system if necessary. At this point, WebCore has stopped
     * any loading in this window and has removed any cross-scripting ability
     * in javascript.
     * <p>
     * As with {@link #onCreateWindow}, the application should ensure that any
     * URL or security indicator displayed is updated so that the user can tell
     * that the page they were interacting with has been closed.
     *
     * @param window The WebView that needs to be closed.
     */
    public void onCloseWindow(WebView window) {}

    Tell the client to display a javascript alert dialog. If the client returns true, WebView will assume that the client will handle the dialog. If the client returns false, it will continue execution. 
Params: view – The WebView that initiated the callback.
url – The url of the page requesting the dialog.
message – Message to be displayed in the window.
result – A JsResult to confirm that the user hit enter.
Returns: boolean Whether the client will handle the alert dialog./**
     * Tell the client to display a javascript alert dialog.  If the client
     * returns {@code true}, WebView will assume that the client will handle the
     * dialog.  If the client returns {@code false}, it will continue execution.
     * @param view The WebView that initiated the callback.
     * @param url The url of the page requesting the dialog.
     * @param message Message to be displayed in the window.
     * @param result A JsResult to confirm that the user hit enter.
     * @return boolean Whether the client will handle the alert dialog.
     */
    public boolean onJsAlert(WebView view, String url, String message,
            JsResult result) {
        return false;
    }

    Tell the client to display a confirm dialog to the user. If the client returns true, WebView will assume that the client will handle the confirm dialog and call the appropriate JsResult method. If the client returns false, a default value of false will be returned to javascript. The default behavior is to return false. 
Params: view – The WebView that initiated the callback.
url – The url of the page requesting the dialog.
message – Message to be displayed in the window.
result – A JsResult used to send the user's response to
              javascript.
Returns: boolean Whether the client will handle the confirm dialog./**
     * Tell the client to display a confirm dialog to the user. If the client
     * returns {@code true}, WebView will assume that the client will handle the
     * confirm dialog and call the appropriate JsResult method. If the
     * client returns false, a default value of {@code false} will be returned to
     * javascript. The default behavior is to return {@code false}.
     * @param view The WebView that initiated the callback.
     * @param url The url of the page requesting the dialog.
     * @param message Message to be displayed in the window.
     * @param result A JsResult used to send the user's response to
     *               javascript.
     * @return boolean Whether the client will handle the confirm dialog.
     */
    public boolean onJsConfirm(WebView view, String url, String message,
            JsResult result) {
        return false;
    }

    Tell the client to display a prompt dialog to the user. If the client returns true, WebView will assume that the client will handle the prompt dialog and call the appropriate JsPromptResult method. If the client returns false, a default value of false will be returned to to javascript. The default behavior is to return false. 
Params: view – The WebView that initiated the callback.
url – The url of the page requesting the dialog.
message – Message to be displayed in the window.
defaultValue – The default value displayed in the prompt dialog.
result – A JsPromptResult used to send the user's reponse to
              javascript.
Returns: boolean Whether the client will handle the prompt dialog./**
     * Tell the client to display a prompt dialog to the user. If the client
     * returns {@code true}, WebView will assume that the client will handle the
     * prompt dialog and call the appropriate JsPromptResult method. If the
     * client returns false, a default value of {@code false} will be returned to to
     * javascript. The default behavior is to return {@code false}.
     * @param view The WebView that initiated the callback.
     * @param url The url of the page requesting the dialog.
     * @param message Message to be displayed in the window.
     * @param defaultValue The default value displayed in the prompt dialog.
     * @param result A JsPromptResult used to send the user's reponse to
     *               javascript.
     * @return boolean Whether the client will handle the prompt dialog.
     */
    public boolean onJsPrompt(WebView view, String url, String message,
            String defaultValue, JsPromptResult result) {
        return false;
    }

    Tell the client to display a dialog to confirm navigation away from the current page. This is the result of the onbeforeunload javascript event. If the client returns true, WebView will assume that the client will handle the confirm dialog and call the appropriate JsResult method. If the client returns false, a default value of true will be returned to javascript to accept navigation away from the current page. The default behavior is to return false. Setting the JsResult to true will navigate away from the current page, false will cancel the navigation. 
Params: view – The WebView that initiated the callback.
url – The url of the page requesting the dialog.
message – Message to be displayed in the window.
result – A JsResult used to send the user's response to
              javascript.
Returns: boolean Whether the client will handle the confirm dialog./**
     * Tell the client to display a dialog to confirm navigation away from the
     * current page. This is the result of the onbeforeunload javascript event.
     * If the client returns {@code true}, WebView will assume that the client will
     * handle the confirm dialog and call the appropriate JsResult method. If
     * the client returns {@code false}, a default value of {@code true} will be returned to
     * javascript to accept navigation away from the current page. The default
     * behavior is to return {@code false}. Setting the JsResult to {@code true} will navigate
     * away from the current page, {@code false} will cancel the navigation.
     * @param view The WebView that initiated the callback.
     * @param url The url of the page requesting the dialog.
     * @param message Message to be displayed in the window.
     * @param result A JsResult used to send the user's response to
     *               javascript.
     * @return boolean Whether the client will handle the confirm dialog.
     */
    public boolean onJsBeforeUnload(WebView view, String url, String message,
            JsResult result) {
        return false;
    }

   Tell the client that the quota has been exceeded for the Web SQL Database API for a particular origin and request a new quota. The client must respond by invoking the updateQuota(long) method of the supplied QuotaUpdater instance. The minimum value that can be set for the new quota is the current quota. The default implementation responds with the current quota, so the quota will not be increased. 
Params: url – The URL of the page that triggered the notification
databaseIdentifier – The identifier of the database where the quota
                          was exceeded.
quota – The quota for the origin, in bytes
estimatedDatabaseSize – The estimated size of the offending
                             database, in bytes
totalQuota – The total quota for all origins, in bytes
quotaUpdater – An instance of QuotaUpdater which must be used to inform the WebView of the new quota.
Deprecated: This method is no longer called; WebView now uses the HTML5 / JavaScript Quota
            Management API./**
    * Tell the client that the quota has been exceeded for the Web SQL Database
    * API for a particular origin and request a new quota. The client must
    * respond by invoking the
    * {@link WebStorage.QuotaUpdater#updateQuota(long) updateQuota(long)}
    * method of the supplied {@link WebStorage.QuotaUpdater} instance. The
    * minimum value that can be set for the new quota is the current quota. The
    * default implementation responds with the current quota, so the quota will
    * not be increased.
    * @param url The URL of the page that triggered the notification
    * @param databaseIdentifier The identifier of the database where the quota
    *                           was exceeded.
    * @param quota The quota for the origin, in bytes
    * @param estimatedDatabaseSize The estimated size of the offending
    *                              database, in bytes
    * @param totalQuota The total quota for all origins, in bytes
    * @param quotaUpdater An instance of {@link WebStorage.QuotaUpdater} which
    *                     must be used to inform the WebView of the new quota.
    * @deprecated This method is no longer called; WebView now uses the HTML5 / JavaScript Quota
    *             Management API.
    */
    @Deprecated
    public void onExceededDatabaseQuota(String url, String databaseIdentifier,
            long quota, long estimatedDatabaseSize, long totalQuota,
            WebStorage.QuotaUpdater quotaUpdater) {
        // This default implementation passes the current quota back to WebCore.
        // WebCore will interpret this that new quota was declined.
        quotaUpdater.updateQuota(quota);
    }

   Notify the host application that the Application Cache has reached the maximum size. The client must respond by invoking the updateQuota(long) method of the supplied QuotaUpdater instance. The minimum value that can be set for the new quota is the current quota. The default implementation responds with the current quota, so the quota will not be increased. 
Params: requiredStorage – The amount of storage required by the Application
                       Cache operation that triggered this notification,
                       in bytes.
quota – the current maximum Application Cache size, in bytes
quotaUpdater – An instance of QuotaUpdater which must be used to inform the WebView of the new quota.
Deprecated: This method is no longer called; WebView now uses the HTML5 / JavaScript Quota
            Management API./**
    * Notify the host application that the Application Cache has reached the
    * maximum size. The client must respond by invoking the
    * {@link WebStorage.QuotaUpdater#updateQuota(long) updateQuota(long)}
    * method of the supplied {@link WebStorage.QuotaUpdater} instance. The
    * minimum value that can be set for the new quota is the current quota. The
    * default implementation responds with the current quota, so the quota will
    * not be increased.
    * @param requiredStorage The amount of storage required by the Application
    *                        Cache operation that triggered this notification,
    *                        in bytes.
    * @param quota the current maximum Application Cache size, in bytes
    * @param quotaUpdater An instance of {@link WebStorage.QuotaUpdater} which
    *                     must be used to inform the WebView of the new quota.
    * @deprecated This method is no longer called; WebView now uses the HTML5 / JavaScript Quota
    *             Management API.
    */
    @Deprecated
    public void onReachedMaxAppCacheSize(long requiredStorage, long quota,
            WebStorage.QuotaUpdater quotaUpdater) {
        quotaUpdater.updateQuota(quota);
    }

    Notify the host application that web content from the specified origin is attempting to use the Geolocation API, but no permission state is currently set for that origin. The host application should invoke the specified callback with the desired permission state. See GeolocationPermissions for details. Note that for applications targeting Android N and later SDKs (API level > VERSION_CODES.M) this method is only called for requests originating from secure origins such as https. On non-secure origins geolocation requests are automatically denied. 
Params: origin – The origin of the web content attempting to use the
              Geolocation API.
callback – The callback to use to set the permission state for the
                origin./**
     * Notify the host application that web content from the specified origin
     * is attempting to use the Geolocation API, but no permission state is
     * currently set for that origin. The host application should invoke the
     * specified callback with the desired permission state. See
     * {@link GeolocationPermissions} for details.
     *
     * <p>Note that for applications targeting Android N and later SDKs
     * (API level > {@link android.os.Build.VERSION_CODES#M})
     * this method is only called for requests originating from secure
     * origins such as https. On non-secure origins geolocation requests
     * are automatically denied.
     *
     * @param origin The origin of the web content attempting to use the
     *               Geolocation API.
     * @param callback The callback to use to set the permission state for the
     *                 origin.
     */
    public void onGeolocationPermissionsShowPrompt(String origin,
            GeolocationPermissions.Callback callback) {}

    Notify the host application that a request for Geolocation permissions, made with a previous call to onGeolocationPermissionsShowPrompt() has been canceled. Any related UI should therefore be hidden. /**
     * Notify the host application that a request for Geolocation permissions,
     * made with a previous call to
     * {@link #onGeolocationPermissionsShowPrompt(String,GeolocationPermissions.Callback) onGeolocationPermissionsShowPrompt()}
     * has been canceled. Any related UI should therefore be hidden.
     */
    public void onGeolocationPermissionsHidePrompt() {}

    Notify the host application that web content is requesting permission to access the specified resources and the permission currently isn't granted or denied. The host application must invoke PermissionRequest.grant(String[]) or PermissionRequest.deny(). If this method isn't overridden, the permission is denied. 
Params: request – the PermissionRequest from current web content./**
     * Notify the host application that web content is requesting permission to
     * access the specified resources and the permission currently isn't granted
     * or denied. The host application must invoke {@link PermissionRequest#grant(String[])}
     * or {@link PermissionRequest#deny()}.
     *
     * If this method isn't overridden, the permission is denied.
     *
     * @param request the PermissionRequest from current web content.
     */
    public void onPermissionRequest(PermissionRequest request) {
        request.deny();
    }

    Notify the host application that the given permission request
has been canceled. Any related UI should therefore be hidden.
Params: request – the PermissionRequest that needs be canceled./**
     * Notify the host application that the given permission request
     * has been canceled. Any related UI should therefore be hidden.
     *
     * @param request the PermissionRequest that needs be canceled.
     */
    public void onPermissionRequestCanceled(PermissionRequest request) {}

    Tell the client that a JavaScript execution timeout has occured. And the client may decide whether or not to interrupt the execution. If the client returns true, the JavaScript will be interrupted. If the client returns false, the execution will continue. Note that in the case of continuing execution, the timeout counter will be reset, and the callback will continue to occur if the script does not finish at the next check point. 
Returns: boolean Whether the JavaScript execution should be interrupted.
Deprecated: This method is no longer supported and will not be invoked./**
     * Tell the client that a JavaScript execution timeout has occured. And the
     * client may decide whether or not to interrupt the execution. If the
     * client returns {@code true}, the JavaScript will be interrupted. If the client
     * returns {@code false}, the execution will continue. Note that in the case of
     * continuing execution, the timeout counter will be reset, and the callback
     * will continue to occur if the script does not finish at the next check
     * point.
     * @return boolean Whether the JavaScript execution should be interrupted.
     * @deprecated This method is no longer supported and will not be invoked.
     */
    // This method was only called when using the JSC javascript engine. V8 became
    // the default JS engine with Froyo and support for building with JSC was
    // removed in b/5495373. V8 does not have a mechanism for making a callback such
    // as this.
    @Deprecated
    public boolean onJsTimeout() {
        return true;
    }

    Report a JavaScript error message to the host application. The ChromeClient
should override this to process the log message as they see fit.
Params: message – The error message to report.
lineNumber – The line number of the error.
sourceID – The name of the source file that caused the error.
Deprecated: Use onConsoleMessage(ConsoleMessage) instead./**
     * Report a JavaScript error message to the host application. The ChromeClient
     * should override this to process the log message as they see fit.
     * @param message The error message to report.
     * @param lineNumber The line number of the error.
     * @param sourceID The name of the source file that caused the error.
     * @deprecated Use {@link #onConsoleMessage(ConsoleMessage) onConsoleMessage(ConsoleMessage)}
     *      instead.
     */
    @Deprecated
    public void onConsoleMessage(String message, int lineNumber, String sourceID) { }

    Report a JavaScript console message to the host application. The ChromeClient
should override this to process the log message as they see fit.
Params: consoleMessage – Object containing details of the console message.
Returns: true if the message is handled by the client./**
     * Report a JavaScript console message to the host application. The ChromeClient
     * should override this to process the log message as they see fit.
     * @param consoleMessage Object containing details of the console message.
     * @return {@code true} if the message is handled by the client.
     */
    public boolean onConsoleMessage(ConsoleMessage consoleMessage) {
        // Call the old version of this function for backwards compatability.
        onConsoleMessage(consoleMessage.message(), consoleMessage.lineNumber(),
                consoleMessage.sourceId());
        return false;
    }

    When not playing, video elements are represented by a 'poster' image. The
image to use can be specified by the poster attribute of the video tag in
HTML. If the attribute is absent, then a default poster will be used. This
method allows the ChromeClient to provide that default image.
Returns: Bitmap The image to use as a default poster, or null if no such image is available./**
     * When not playing, video elements are represented by a 'poster' image. The
     * image to use can be specified by the poster attribute of the video tag in
     * HTML. If the attribute is absent, then a default poster will be used. This
     * method allows the ChromeClient to provide that default image.
     *
     * @return Bitmap The image to use as a default poster, or {@code null} if no such image is
     * available.
     */
    @Nullable
    public Bitmap getDefaultVideoPoster() {
        return null;
    }

    Obtains a View to be displayed while buffering of full screen video is taking
place. The host application can override this method to provide a View
containing a spinner or similar.
Returns: View The View to be displayed whilst the video is loading./**
     * Obtains a View to be displayed while buffering of full screen video is taking
     * place. The host application can override this method to provide a View
     * containing a spinner or similar.
     *
     * @return View The View to be displayed whilst the video is loading.
     */
    @Nullable
    public View getVideoLoadingProgressView() {
        return null;
    }

    Obtains a list of all visited history items, used for link coloring
/** Obtains a list of all visited history items, used for link coloring
     */
    public void getVisitedHistory(ValueCallback<String[]> callback) {
    }

    Tell the client to show a file chooser.
This is called to handle HTML forms with 'file' input type, in response to the
user pressing the "Select File" button.
To cancel the request, call filePathCallback.onReceiveValue(null) and return true. 
Params: webView – The WebView instance that is initiating the request.
filePathCallback – Invoke this callback to supply the list of paths to files to upload, or null to cancel. Must only be called if the onShowFileChooser implementation returns true.
fileChooserParams – Describes the mode of file chooser to be opened, and options to be
                         used with it.
See Also: FileChooserParams
Returns: true if filePathCallback will be invoked, false to use default handling./**
     * Tell the client to show a file chooser.
     *
     * This is called to handle HTML forms with 'file' input type, in response to the
     * user pressing the "Select File" button.
     * To cancel the request, call <code>filePathCallback.onReceiveValue(null)</code> and
     * return {@code true}.
     *
     * @param webView The WebView instance that is initiating the request.
     * @param filePathCallback Invoke this callback to supply the list of paths to files to upload,
     *                         or {@code null} to cancel. Must only be called if the
     *                         {@link #onShowFileChooser} implementation returns {@code true}.
     * @param fileChooserParams Describes the mode of file chooser to be opened, and options to be
     *                          used with it.
     * @return {@code true} if filePathCallback will be invoked, {@code false} to use default
     *         handling.
     *
     * @see FileChooserParams
     */
    public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> filePathCallback,
            FileChooserParams fileChooserParams) {
        return false;
    }

    Parameters used in the onShowFileChooser method. /**
     * Parameters used in the {@link #onShowFileChooser} method.
     */
    public static abstract class FileChooserParams {
        Open single file. Requires that the file exists before allowing the user to pick it. /** Open single file. Requires that the file exists before allowing the user to pick it. */
        public static final int MODE_OPEN = 0;
        Like Open but allows multiple files to be selected. /** Like Open but allows multiple files to be selected. */
        public static final int MODE_OPEN_MULTIPLE = 1;
        Like Open but allows a folder to be selected. The implementation should enumerate
all files selected by this operation.
This feature is not supported at the moment.
@hide /** Like Open but allows a folder to be selected. The implementation should enumerate
            all files selected by this operation.
            This feature is not supported at the moment.
            @hide */
        public static final int MODE_OPEN_FOLDER = 2;
         Allows picking a nonexistent file and saving it. /**  Allows picking a nonexistent file and saving it. */
        public static final int MODE_SAVE = 3;

        Parse the result returned by the file picker activity. This method should be used with createIntent. Refer to createIntent for how to use it. 
Params: resultCode – the integer result code returned by the file picker activity.
data – the intent returned by the file picker activity.
Returns: the Uris of selected file(s) or null if the resultCode indicates activity canceled or any other error./**
         * Parse the result returned by the file picker activity. This method should be used with
         * {@link #createIntent}. Refer to {@link #createIntent} for how to use it.
         *
         * @param resultCode the integer result code returned by the file picker activity.
         * @param data the intent returned by the file picker activity.
         * @return the Uris of selected file(s) or {@code null} if the resultCode indicates
         *         activity canceled or any other error.
         */
        @Nullable
        public static Uri[] parseResult(int resultCode, Intent data) {
            return WebViewFactory.getProvider().getStatics().parseFileChooserResult(resultCode, data);
        }

        Returns file chooser mode.
/**
         * Returns file chooser mode.
         */
        public abstract int getMode();

        Returns an array of acceptable MIME types. The returned MIME type
could be partial such as audio/*. The array will be empty if no
acceptable types are specified.
/**
         * Returns an array of acceptable MIME types. The returned MIME type
         * could be partial such as audio/*. The array will be empty if no
         * acceptable types are specified.
         */
        public abstract String[] getAcceptTypes();

        Returns preference for a live media captured value (e.g. Camera, Microphone). True indicates capture is enabled, false disabled. Use getAcceptTypes to determine suitable capture devices.
/**
         * Returns preference for a live media captured value (e.g. Camera, Microphone).
         * True indicates capture is enabled, {@code false} disabled.
         *
         * Use <code>getAcceptTypes</code> to determine suitable capture devices.
         */
        public abstract boolean isCaptureEnabled();

        Returns the title to use for this file selector. If null a default title should be used. /**
         * Returns the title to use for this file selector. If {@code null} a default title should
         * be used.
         */
        @Nullable
        public abstract CharSequence getTitle();

        The file name of a default selection if specified, or null. /**
         * The file name of a default selection if specified, or {@code null}.
         */
        @Nullable
        public abstract String getFilenameHint();

        Creates an intent that would start a file picker for file selection.
The Intent supports choosing files from simple file sources available
on the device. Some advanced sources (for example, live media capture)
may not be supported and applications wishing to support these sources
or more advanced file operations should build their own Intent.
How to use: 1. Build an intent using createIntent 2. Fire the intent using Activity.startActivityForResult. 3. Check for ActivityNotFoundException and take a user friendly action if thrown. 4. Listen the result using Activity.onActivityResult 5. Parse the result using parseResult only if media capture was not requested. 6. Send the result using filePathCallback of WebChromeClient.onShowFileChooser 
Returns: an Intent that supports basic file chooser sources./**
         * Creates an intent that would start a file picker for file selection.
         * The Intent supports choosing files from simple file sources available
         * on the device. Some advanced sources (for example, live media capture)
         * may not be supported and applications wishing to support these sources
         * or more advanced file operations should build their own Intent.
         *
         * <pre>
         * How to use:
         * 1. Build an intent using {@link #createIntent}
         * 2. Fire the intent using {@link android.app.Activity#startActivityForResult}.
         * 3. Check for ActivityNotFoundException and take a user friendly action if thrown.
         * 4. Listen the result using {@link android.app.Activity#onActivityResult}
         * 5. Parse the result using {@link #parseResult} only if media capture was not requested.
         * 6. Send the result using filePathCallback of {@link WebChromeClient#onShowFileChooser}
         * </pre>
         *
         * @return an Intent that supports basic file chooser sources.
         */
        public abstract Intent createIntent();
    }

    Tell the client to open a file chooser.
Params: uploadFile – A ValueCallback to set the URI of the file to upload.
     onReceiveValue must be called to wake up the thread.a
acceptType – The value of the 'accept' attribute of the input tag
        associated with this file picker.
capture – The value of the 'capture' attribute of the input tag
        associated with this file picker.
Deprecated: Use onShowFileChooser instead.
@hide This method was not published in any SDK version./**
     * Tell the client to open a file chooser.
     * @param uploadFile A ValueCallback to set the URI of the file to upload.
     *      onReceiveValue must be called to wake up the thread.a
     * @param acceptType The value of the 'accept' attribute of the input tag
     *         associated with this file picker.
     * @param capture The value of the 'capture' attribute of the input tag
     *         associated with this file picker.
     *
     * @deprecated Use {@link #onShowFileChooser} instead.
     * @hide This method was not published in any SDK version.
     */
    @SystemApi
    @Deprecated
    public void openFileChooser(ValueCallback<Uri> uploadFile, String acceptType, String capture) {
        uploadFile.onReceiveValue(null);
    }
}
Params:	view – is the View object to be shown. requestedOrientation – An orientation constant as used in `ActivityInfo.screenOrientation`. callback – is the callback to be invoked if and when the view is dismissed.
Deprecated:	This method supports the obsolete plugin mechanism, and will not be invoked in future
Params:	view – The WebView that initiated the callback. url – The url of the page requesting the dialog. message – Message to be displayed in the window. result – A JsResult to confirm that the user hit enter.
Returns:	boolean Whether the client will handle the alert dialog.
Params:	requiredStorage – The amount of storage required by the Application Cache operation that triggered this notification, in bytes. quota – the current maximum Application Cache size, in bytes quotaUpdater – An instance of `QuotaUpdater` which must be used to inform the WebView of the new quota.
Deprecated:	This method is no longer called; WebView now uses the HTML5 / JavaScript Quota Management API.
Returns:	boolean Whether the JavaScript execution should be interrupted.
Deprecated:	This method is no longer supported and will not be invoked.
Params:	message – The error message to report. lineNumber – The line number of the error. sourceID – The name of the source file that caused the error.
Deprecated:	Use `onConsoleMessage(ConsoleMessage)` instead.
Params:	consoleMessage – Object containing details of the console message.
Returns:	`true` if the message is handled by the client.
Params:	webView – The WebView instance that is initiating the request. filePathCallback – Invoke this callback to supply the list of paths to files to upload, or `null` to cancel. Must only be called if the `onShowFileChooser` implementation returns `true`. fileChooserParams – Describes the mode of file chooser to be opened, and options to be used with it.
See Also:	FileChooserParams
Returns:	`true` if filePathCallback will be invoked, `false` to use default handling.
Params:	resultCode – the integer result code returned by the file picker activity. data – the intent returned by the file picker activity.
Returns:	the Uris of selected file(s) or `null` if the resultCode indicates activity canceled or any other error.
Params:	uploadFile – A ValueCallback to set the URI of the file to upload. onReceiveValue must be called to wake up the thread.a acceptType – The value of the 'accept' attribute of the input tag associated with this file picker. capture – The value of the 'capture' attribute of the input tag associated with this file picker.
Deprecated:	Use `onShowFileChooser` instead.
@hide	This method was not published in any SDK version.
/

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