com.creativtrendz.folio.ui.FolioWebViewScroll.java Source code

Java tutorial

Introduction

Here is the source code for com.creativtrendz.folio.ui.FolioWebViewScroll.java

Source

package com.creativtrendz.folio.ui;

/**
 * Copyright 2015 delight.im <info@delight.im>
 * <p/>
 * 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
 * <p/>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p/>
 * 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.
 */

import android.support.v4.view.MotionEventCompat;
import android.support.v4.view.NestedScrollingChild;
import android.support.v4.view.NestedScrollingChildHelper;
import android.support.v4.view.ViewCompat;
import android.view.ContextMenu;
import android.view.MotionEvent;
import android.view.ViewGroup;
import android.app.DownloadManager;
import android.app.DownloadManager.Request;
import android.os.Environment;
import android.webkit.CookieManager;

import java.util.Arrays;

import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;

import java.util.HashMap;

import android.net.http.SslError;
import android.view.InputEvent;
import android.view.KeyEvent;
import android.webkit.ClientCertRequest;
import android.webkit.HttpAuthHandler;
import android.webkit.SslErrorHandler;
import android.webkit.WebResourceRequest;
import android.webkit.WebResourceResponse;
import android.os.Message;
import android.view.View;
import android.webkit.ConsoleMessage;
import android.webkit.GeolocationPermissions.Callback;
import android.webkit.JsPromptResult;
import android.webkit.JsResult;
import android.webkit.PermissionRequest;
import android.webkit.WebStorage.QuotaUpdater;
import android.app.Fragment;
import android.util.Base64;
import android.os.Build;
import android.webkit.DownloadListener;
import android.graphics.Bitmap;
import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.webkit.ValueCallback;
import android.webkit.WebChromeClient;
import android.webkit.WebViewClient;
import android.webkit.WebSettings;
import android.annotation.SuppressLint;
import android.content.Context;
import android.util.AttributeSet;
import android.webkit.WebView;

import java.util.MissingResourceException;
import java.util.Locale;
import java.util.LinkedList;
import java.util.Collection;
import java.util.List;
import java.io.UnsupportedEncodingException;
import java.lang.ref.WeakReference;
import java.util.Map;

/**
 * Advanced WebView component for Android that works as intended out of the box
 */
@SuppressWarnings("deprecation")
public class FolioWebViewScroll extends WebView implements NestedScrollingChild {

    public interface Listener {
        void onPageStarted(String url, Bitmap favicon);

        void onPageFinished(String url);

        void onPageError(int errorCode, String description, String failingUrl);

        void onDownloadRequested(String url, String userAgent, String contentDisposition, String mimetype,
                long contentLength);

        void onExternalPageRequest(String url);

        /**
         * Called when the scroll position of a view changes.
         *
         * @param scrollX    Current horizontal scroll origin.
         * @param scrollY    Current vertical scroll origin.
         * @param oldScrollX Previous horizontal scroll origin.
         * @param oldScrollY Previous vertical scroll origin.
         */
        void onScrollChange(int scrollX, int scrollY, int oldScrollX, int oldScrollY);

        void onCreateContextMenu(ContextMenu menu);
    }

    private int mLastY;
    private final int[] mScrollOffset = new int[2];
    private final int[] mScrollConsumed = new int[2];
    private int mNestedOffsetY;
    private NestedScrollingChildHelper mChildHelper;

    public static final String PACKAGE_NAME_DOWNLOAD_MANAGER = "com.android.providers.downloads";
    protected static final int REQUEST_CODE_FILE_PICKER = 51426;
    protected static final String DATABASES_SUB_FOLDER = "/databases";
    protected static final String LANGUAGE_DEFAULT_ISO3 = "eng";
    protected static final String CHARSET_DEFAULT = "UTF-8";
    /**
     * Alternative browsers that have their own rendering engine and *may* be installed on this device
     */
    protected static final String[] ALTERNATIVE_BROWSERS = new String[] { "org.mozilla.firefox",
            "com.android.chrome", "com.opera.browser", "org.mozilla.firefox_beta", "com.chrome.beta",
            "com.opera.browser.beta" };
    protected WeakReference<Activity> mActivity;
    protected WeakReference<Fragment> mFragment;
    protected Listener mListener;
    protected final List<String> mPermittedHostnames = new LinkedList<>();
    /**
     * File upload callback for platform versions prior to Android 5.0
     */
    protected ValueCallback<Uri> mFileUploadCallbackFirst;
    /**
     * File upload callback for Android 5.0+
     */
    protected ValueCallback<Uri[]> mFileUploadCallbackSecond;
    protected long mLastError;
    protected String mLanguageIso3;
    protected int mRequestCodeFilePicker = REQUEST_CODE_FILE_PICKER;
    protected WebViewClient mCustomWebViewClient;
    protected WebChromeClient mCustomWebChromeClient;
    protected boolean mGeolocationEnabled;
    protected String mUploadableFileTypes = "*/*";
    protected final Map<String, String> mHttpHeaders = new HashMap<>();

    public FolioWebViewScroll(Context context) {
        this(context, null);
    }

    public FolioWebViewScroll(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public FolioWebViewScroll(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init(context);
        mChildHelper = new NestedScrollingChildHelper(this);
        setNestedScrollingEnabled(true);
    }

    public void setListener(final Activity activity, final Listener listener) {
        setListener(activity, listener, REQUEST_CODE_FILE_PICKER);
    }

    public void setListener(final Activity activity, final Listener listener, final int requestCodeFilePicker) {
        if (activity != null) {
            mActivity = new WeakReference<>(activity);
        } else {
            mActivity = null;
        }

        setListener(listener, requestCodeFilePicker);
    }

    public void setListener(final Fragment fragment, final Listener listener) {
        setListener(fragment, listener, REQUEST_CODE_FILE_PICKER);
    }

    public void setListener(final Fragment fragment, final Listener listener, final int requestCodeFilePicker) {
        if (fragment != null) {
            mFragment = new WeakReference<>(fragment);
        } else {
            mFragment = null;
        }

        setListener(listener, requestCodeFilePicker);
    }

    protected void setListener(final Listener listener, final int requestCodeFilePicker) {
        mListener = listener;
        mRequestCodeFilePicker = requestCodeFilePicker;
    }

    @Override
    public void setWebViewClient(final WebViewClient client) {
        mCustomWebViewClient = client;
    }

    @Override
    public void setWebChromeClient(final WebChromeClient client) {
        mCustomWebChromeClient = client;
    }

    @SuppressLint("SetJavaScriptEnabled")
    public void setGeolocationEnabled(final boolean enabled) {
        if (enabled) {
            getSettings().setJavaScriptEnabled(true);
            getSettings().setGeolocationEnabled(true);
            setGeolocationDatabasePath();
        }

        mGeolocationEnabled = enabled;
    }

    @SuppressLint("NewApi")
    protected void setGeolocationDatabasePath() {
        final Activity activity;

        if (mFragment != null && mFragment.get() != null && Build.VERSION.SDK_INT >= 11
                && mFragment.get().getActivity() != null) {
            activity = mFragment.get().getActivity();
        } else if (mActivity != null && mActivity.get() != null) {
            activity = mActivity.get();
        } else {
            return;
        }

        getSettings().setGeolocationDatabasePath(activity.getFilesDir().getPath());
    }

    public void setUploadableFileTypes(final String mimeType) {
        mUploadableFileTypes = mimeType;
    }

    @SuppressLint("NewApi")
    @SuppressWarnings("all")
    public void onResume() {
        if (Build.VERSION.SDK_INT >= 11) {
            super.onResume();
        }
        resumeTimers();
    }

    @SuppressLint("NewApi")
    @SuppressWarnings("all")
    public void onPause() {
        pauseTimers();
        if (Build.VERSION.SDK_INT >= 11) {
            super.onPause();
        }
    }

    public void onDestroy() {
        // try to remove this view from its parent first
        try {
            ((ViewGroup) getParent()).removeView(this);
        } catch (Exception ignored) {
        }

        // then try to remove all child views from this view
        try {
            removeAllViews();
        } catch (Exception ignored) {
        }

        // and finally destroy this view
        destroy();
    }

    public void onActivityResult(final int requestCode, final int resultCode, final Intent intent) {
        if (requestCode == mRequestCodeFilePicker) {
            if (resultCode == Activity.RESULT_OK) {
                if (intent != null) {
                    if (mFileUploadCallbackFirst != null) {
                        mFileUploadCallbackFirst.onReceiveValue(intent.getData());
                        mFileUploadCallbackFirst = null;
                    } else if (mFileUploadCallbackSecond != null) {
                        Uri[] dataUris;
                        try {
                            dataUris = new Uri[] { Uri.parse(intent.getDataString()) };
                        } catch (Exception e) {
                            dataUris = null;
                        }

                        mFileUploadCallbackSecond.onReceiveValue(dataUris);
                        mFileUploadCallbackSecond = null;
                    }
                }
            } else {
                if (mFileUploadCallbackFirst != null) {
                    mFileUploadCallbackFirst.onReceiveValue(null);
                    mFileUploadCallbackFirst = null;
                } else if (mFileUploadCallbackSecond != null) {
                    mFileUploadCallbackSecond.onReceiveValue(null);
                    mFileUploadCallbackSecond = null;
                }
            }
        }
    }

    /**
     * Adds an additional HTTP header that will be sent along with every request
     * <p/>
     * If you later want to delete an HTTP header that was previously added this way, call `removeHttpHeader()`
     * <p/>
     * The `WebView` implementation may in some cases overwrite headers that you set or unset
     *
     * @param name  the name of the HTTP header to add
     * @param value the value of the HTTP header to send
     */
    public void addHttpHeader(final String name, final String value) {
        mHttpHeaders.put(name, value);
    }

    /**
     * Removes one of the HTTP headers that have previously been added via `addHttpHeader()`
     * <p/>
     * If you want to unset a pre-defined header, set it to an empty string with `addHttpHeader()` instead
     * <p/>
     * The `WebView` implementation may in some cases overwrite headers that you set or unset
     *
     * @param name the name of the HTTP header to remove
     */
    public void removeHttpHeader(final String name) {
        mHttpHeaders.remove(name);
    }

    public void addPermittedHostname(String hostname) {
        mPermittedHostnames.add(hostname);
    }

    public void addPermittedHostnames(Collection<? extends String> collection) {
        mPermittedHostnames.addAll(collection);
    }

    public List<String> getPermittedHostnames() {
        return mPermittedHostnames;
    }

    public void removePermittedHostname(String hostname) {
        mPermittedHostnames.remove(hostname);
    }

    public void clearPermittedHostnames() {
        mPermittedHostnames.clear();
    }

    public boolean onBackPressed() {
        if (canGoBack()) {
            goBack();
            return false;
        } else {
            return true;
        }
    }

    @SuppressLint("NewApi")
    protected static void setAllowAccessFromFileUrls(final WebSettings webSettings, final boolean allowed) {
        if (Build.VERSION.SDK_INT >= 16) {
            webSettings.setAllowFileAccessFromFileURLs(allowed);
            webSettings.setAllowUniversalAccessFromFileURLs(allowed);
        }
    }

    @SuppressWarnings("static-method")
    public void setCookiesEnabled(final boolean enabled) {
        CookieManager.getInstance().setAcceptCookie(enabled);
    }

    @SuppressLint("NewApi")
    public void setThirdPartyCookiesEnabled(final boolean enabled) {
        if (Build.VERSION.SDK_INT >= 21) {
            CookieManager.getInstance().setAcceptThirdPartyCookies(this, enabled);
        }
    }

    public void setMixedContentAllowed(final boolean allowed) {
        setMixedContentAllowed(getSettings(), allowed);
    }

    @SuppressWarnings("static-method")
    @SuppressLint("NewApi")
    protected void setMixedContentAllowed(final WebSettings webSettings, final boolean allowed) {
        if (Build.VERSION.SDK_INT >= 21) {
            webSettings.setMixedContentMode(
                    allowed ? WebSettings.MIXED_CONTENT_ALWAYS_ALLOW : WebSettings.MIXED_CONTENT_NEVER_ALLOW);
        }
    }

    @SuppressLint({ "SetJavaScriptEnabled" })
    protected void init(Context context) {
        if (context instanceof Activity) {
            mActivity = new WeakReference<>((Activity) context);
        }

        mLanguageIso3 = getLanguageIso3();

        setFocusable(true);
        setFocusableInTouchMode(true);

        setSaveEnabled(true);

        final String filesDir = context.getFilesDir().getPath();
        final String databaseDir = filesDir.substring(0, filesDir.lastIndexOf("/")) + DATABASES_SUB_FOLDER;

        final WebSettings webSettings = getSettings();
        webSettings.setAllowFileAccess(false);
        setAllowAccessFromFileUrls(webSettings, false);
        webSettings.setBuiltInZoomControls(false);
        webSettings.setJavaScriptEnabled(true);
        webSettings.setDomStorageEnabled(true);
        if (Build.VERSION.SDK_INT < 18) {
            webSettings.setRenderPriority(WebSettings.RenderPriority.HIGH);
        }
        webSettings.setDatabaseEnabled(true);
        if (Build.VERSION.SDK_INT < 19) {
            webSettings.setDatabasePath(databaseDir);
        }
        setMixedContentAllowed(webSettings, true);

        setThirdPartyCookiesEnabled(true);

        super.setWebViewClient(new WebViewClient() {

            @Override
            public void onPageStarted(WebView view, String url, Bitmap favicon) {
                if (!hasError()) {
                    if (mListener != null) {
                        mListener.onPageStarted(url, favicon);
                    }
                }

                if (mCustomWebViewClient != null) {
                    mCustomWebViewClient.onPageStarted(view, url, favicon);
                }
            }

            @Override
            public void onPageFinished(WebView view, String url) {
                if (!hasError()) {
                    if (mListener != null) {
                        mListener.onPageFinished(url);
                    }
                }

                if (mCustomWebViewClient != null) {
                    mCustomWebViewClient.onPageFinished(view, url);
                }
            }

            @Override
            public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
                setLastError();

                if (mListener != null) {
                    mListener.onPageError(errorCode, description, failingUrl);
                }

                if (mCustomWebViewClient != null) {
                    mCustomWebViewClient.onReceivedError(view, errorCode, description, failingUrl);
                }
            }

            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                if (isHostnameAllowed(url)) {
                    return mCustomWebViewClient != null && mCustomWebViewClient.shouldOverrideUrlLoading(view, url);
                } else {
                    if (mListener != null) {
                        mListener.onExternalPageRequest(url);
                    }

                    return true;
                }
            }

            @Override
            public void onLoadResource(WebView view, String url) {
                if (mCustomWebViewClient != null) {
                    mCustomWebViewClient.onLoadResource(view, url);
                } else {
                    super.onLoadResource(view, url);
                }
            }

            @SuppressLint("NewApi")
            @SuppressWarnings("all")
            public WebResourceResponse shouldInterceptRequest(WebView view, String url) {
                if (Build.VERSION.SDK_INT >= 11) {
                    if (mCustomWebViewClient != null) {
                        return mCustomWebViewClient.shouldInterceptRequest(view, url);
                    } else {
                        return super.shouldInterceptRequest(view, url);
                    }
                } else {
                    return null;
                }
            }

            @SuppressLint("NewApi")
            @SuppressWarnings("all")
            public WebResourceResponse shouldInterceptRequest(WebView view, WebResourceRequest request) {
                if (Build.VERSION.SDK_INT >= 21) {
                    if (mCustomWebViewClient != null) {
                        return mCustomWebViewClient.shouldInterceptRequest(view, request);
                    } else {
                        return super.shouldInterceptRequest(view, request);
                    }
                } else {
                    return null;
                }
            }

            @Override
            public void onFormResubmission(WebView view, Message dontResend, Message resend) {
                if (mCustomWebViewClient != null) {
                    mCustomWebViewClient.onFormResubmission(view, dontResend, resend);
                } else {
                    super.onFormResubmission(view, dontResend, resend);
                }
            }

            @Override
            public void doUpdateVisitedHistory(WebView view, String url, boolean isReload) {
                if (mCustomWebViewClient != null) {
                    mCustomWebViewClient.doUpdateVisitedHistory(view, url, isReload);
                } else {
                    super.doUpdateVisitedHistory(view, url, isReload);
                }
            }

            @Override
            public void onReceivedSslError(WebView view, SslErrorHandler handler, SslError error) {
                if (mCustomWebViewClient != null) {
                    mCustomWebViewClient.onReceivedSslError(view, handler, error);
                } else {
                    super.onReceivedSslError(view, handler, error);
                }
            }

            @SuppressLint("NewApi")
            @SuppressWarnings("all")
            public void onReceivedClientCertRequest(WebView view, ClientCertRequest request) {
                if (Build.VERSION.SDK_INT >= 21) {
                    if (mCustomWebViewClient != null) {
                        mCustomWebViewClient.onReceivedClientCertRequest(view, request);
                    } else {
                        super.onReceivedClientCertRequest(view, request);
                    }
                }
            }

            @Override
            public void onReceivedHttpAuthRequest(WebView view, HttpAuthHandler handler, String host,
                    String realm) {
                if (mCustomWebViewClient != null) {
                    mCustomWebViewClient.onReceivedHttpAuthRequest(view, handler, host, realm);
                } else {
                    super.onReceivedHttpAuthRequest(view, handler, host, realm);
                }
            }

            @Override
            public boolean shouldOverrideKeyEvent(WebView view, KeyEvent event) {
                if (mCustomWebViewClient != null) {
                    return mCustomWebViewClient.shouldOverrideKeyEvent(view, event);
                } else {
                    return super.shouldOverrideKeyEvent(view, event);
                }
            }

            @Override
            public void onUnhandledKeyEvent(WebView view, KeyEvent event) {
                if (mCustomWebViewClient != null) {
                    mCustomWebViewClient.onUnhandledKeyEvent(view, event);
                } else {
                    super.onUnhandledKeyEvent(view, event);
                }
            }

            @SuppressLint("NewApi")
            @SuppressWarnings("all")
            public void onUnhandledInputEvent(WebView view, InputEvent event) {
                if (Build.VERSION.SDK_INT >= 21) {
                    if (mCustomWebViewClient != null) {
                        mCustomWebViewClient.onUnhandledInputEvent(view, event);
                    } else {
                        super.onUnhandledInputEvent(view, event);
                    }
                }
            }

            @Override
            public void onScaleChanged(WebView view, float oldScale, float newScale) {
                if (mCustomWebViewClient != null) {
                    mCustomWebViewClient.onScaleChanged(view, oldScale, newScale);
                } else {
                    super.onScaleChanged(view, oldScale, newScale);
                }
            }

            @SuppressLint("NewApi")
            @SuppressWarnings("all")
            public void onReceivedLoginRequest(WebView view, String realm, String account, String args) {
                if (Build.VERSION.SDK_INT >= 12) {
                    if (mCustomWebViewClient != null) {
                        mCustomWebViewClient.onReceivedLoginRequest(view, realm, account, args);
                    } else {
                        super.onReceivedLoginRequest(view, realm, account, args);
                    }
                }
            }

        });

        super.setWebChromeClient(new WebChromeClient() {

            // file upload callback (Android 2.2 (API level 8) -- Android 2.3 (API level 10)) (hidden method)
            @SuppressWarnings("unused")
            public void openFileChooser(ValueCallback<Uri> uploadMsg) {
                openFileChooser(uploadMsg, null);
            }

            // file upload callback (Android 3.0 (API level 11) -- Android 4.0 (API level 15)) (hidden method)
            public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType) {
                openFileChooser(uploadMsg, acceptType, null);
            }

            // file upload callback (Android 4.1 (API level 16) -- Android 4.3 (API level 18)) (hidden method)
            @SuppressWarnings("unused")
            public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType, String capture) {
                openFileInput(uploadMsg, null);
            }

            // file upload callback (Android 5.0 (API level 21) -- current) (public method)
            @SuppressWarnings("all")
            public boolean onShowFileChooser(WebView webView, ValueCallback<Uri[]> filePathCallback,
                    WebChromeClient.FileChooserParams fileChooserParams) {
                openFileInput(null, filePathCallback);
                return true;
            }

            @Override
            public void onProgressChanged(WebView view, int newProgress) {
                if (mCustomWebChromeClient != null) {
                    mCustomWebChromeClient.onProgressChanged(view, newProgress);
                } else {
                    super.onProgressChanged(view, newProgress);
                }
            }

            @Override
            public void onReceivedTitle(WebView view, String title) {
                if (mCustomWebChromeClient != null) {
                    mCustomWebChromeClient.onReceivedTitle(view, title);
                } else {
                    super.onReceivedTitle(view, title);
                }
            }

            @Override
            public void onReceivedIcon(WebView view, Bitmap icon) {
                if (mCustomWebChromeClient != null) {
                    mCustomWebChromeClient.onReceivedIcon(view, icon);
                } else {
                    super.onReceivedIcon(view, icon);
                }
            }

            @Override
            public void onReceivedTouchIconUrl(WebView view, String url, boolean precomposed) {
                if (mCustomWebChromeClient != null) {
                    mCustomWebChromeClient.onReceivedTouchIconUrl(view, url, precomposed);
                } else {
                    super.onReceivedTouchIconUrl(view, url, precomposed);
                }
            }

            @Override
            public void onShowCustomView(View view, CustomViewCallback callback) {
                if (mCustomWebChromeClient != null) {
                    mCustomWebChromeClient.onShowCustomView(view, callback);
                } else {
                    super.onShowCustomView(view, callback);
                }
            }

            @SuppressLint("NewApi")
            @SuppressWarnings("all")
            public void onShowCustomView(View view, int requestedOrientation, CustomViewCallback callback) {
                if (Build.VERSION.SDK_INT >= 14) {
                    if (mCustomWebChromeClient != null) {
                        mCustomWebChromeClient.onShowCustomView(view, requestedOrientation, callback);
                    } else {
                        super.onShowCustomView(view, requestedOrientation, callback);
                    }
                }
            }

            @Override
            public void onHideCustomView() {
                if (mCustomWebChromeClient != null) {
                    mCustomWebChromeClient.onHideCustomView();
                } else {
                    super.onHideCustomView();
                }
            }

            @Override
            public boolean onCreateWindow(WebView view, boolean isDialog, boolean isUserGesture,
                    Message resultMsg) {
                if (mCustomWebChromeClient != null) {
                    return mCustomWebChromeClient.onCreateWindow(view, isDialog, isUserGesture, resultMsg);
                } else {
                    return super.onCreateWindow(view, isDialog, isUserGesture, resultMsg);
                }
            }

            @Override
            public void onRequestFocus(WebView view) {
                if (mCustomWebChromeClient != null) {
                    mCustomWebChromeClient.onRequestFocus(view);
                } else {
                    super.onRequestFocus(view);
                }
            }

            @Override
            public void onCloseWindow(WebView window) {
                if (mCustomWebChromeClient != null) {
                    mCustomWebChromeClient.onCloseWindow(window);
                } else {
                    super.onCloseWindow(window);
                }
            }

            @Override
            public boolean onJsAlert(WebView view, String url, String message, JsResult result) {
                if (mCustomWebChromeClient != null) {
                    return mCustomWebChromeClient.onJsAlert(view, url, message, result);
                } else {
                    return super.onJsAlert(view, url, message, result);
                }
            }

            @Override
            public boolean onJsConfirm(WebView view, String url, String message, JsResult result) {
                if (mCustomWebChromeClient != null) {
                    return mCustomWebChromeClient.onJsConfirm(view, url, message, result);
                } else {
                    return super.onJsConfirm(view, url, message, result);
                }
            }

            @Override
            public boolean onJsPrompt(WebView view, String url, String message, String defaultValue,
                    JsPromptResult result) {
                if (mCustomWebChromeClient != null) {
                    return mCustomWebChromeClient.onJsPrompt(view, url, message, defaultValue, result);
                } else {
                    return super.onJsPrompt(view, url, message, defaultValue, result);
                }
            }

            @Override
            public boolean onJsBeforeUnload(WebView view, String url, String message, JsResult result) {
                if (mCustomWebChromeClient != null) {
                    return mCustomWebChromeClient.onJsBeforeUnload(view, url, message, result);
                } else {
                    return super.onJsBeforeUnload(view, url, message, result);
                }
            }

            @Override
            public void onGeolocationPermissionsShowPrompt(String origin, Callback callback) {
                if (mGeolocationEnabled) {
                    callback.invoke(origin, true, false);
                } else {
                    if (mCustomWebChromeClient != null) {
                        mCustomWebChromeClient.onGeolocationPermissionsShowPrompt(origin, callback);
                    } else {
                        super.onGeolocationPermissionsShowPrompt(origin, callback);
                    }
                }
            }

            @Override
            public void onGeolocationPermissionsHidePrompt() {
                if (mCustomWebChromeClient != null) {
                    mCustomWebChromeClient.onGeolocationPermissionsHidePrompt();
                } else {
                    super.onGeolocationPermissionsHidePrompt();
                }
            }

            @SuppressLint("NewApi")
            @SuppressWarnings("all")
            public void onPermissionRequest(PermissionRequest request) {
                if (Build.VERSION.SDK_INT >= 21) {
                    if (mCustomWebChromeClient != null) {
                        mCustomWebChromeClient.onPermissionRequest(request);
                    } else {
                        super.onPermissionRequest(request);
                    }
                }
            }

            @SuppressLint("NewApi")
            @SuppressWarnings("all")
            public void onPermissionRequestCanceled(PermissionRequest request) {
                if (Build.VERSION.SDK_INT >= 21) {
                    if (mCustomWebChromeClient != null) {
                        mCustomWebChromeClient.onPermissionRequestCanceled(request);
                    } else {
                        super.onPermissionRequestCanceled(request);
                    }
                }
            }

            @Override
            public boolean onJsTimeout() {
                if (mCustomWebChromeClient != null) {
                    return mCustomWebChromeClient.onJsTimeout();
                } else {
                    return super.onJsTimeout();
                }
            }

            @Override
            public void onConsoleMessage(String message, int lineNumber, String sourceID) {
                if (mCustomWebChromeClient != null) {
                    mCustomWebChromeClient.onConsoleMessage(message, lineNumber, sourceID);
                } else {
                    super.onConsoleMessage(message, lineNumber, sourceID);
                }
            }

            @Override
            public boolean onConsoleMessage(ConsoleMessage consoleMessage) {
                if (mCustomWebChromeClient != null) {
                    return mCustomWebChromeClient.onConsoleMessage(consoleMessage);
                } else {
                    return super.onConsoleMessage(consoleMessage);
                }
            }

            @Override
            public Bitmap getDefaultVideoPoster() {
                if (mCustomWebChromeClient != null) {
                    return mCustomWebChromeClient.getDefaultVideoPoster();
                } else {
                    return super.getDefaultVideoPoster();
                }
            }

            @Override
            public View getVideoLoadingProgressView() {
                if (mCustomWebChromeClient != null) {
                    return mCustomWebChromeClient.getVideoLoadingProgressView();
                } else {
                    return super.getVideoLoadingProgressView();
                }
            }

            @Override
            public void getVisitedHistory(ValueCallback<String[]> callback) {
                if (mCustomWebChromeClient != null) {
                    mCustomWebChromeClient.getVisitedHistory(callback);
                } else {
                    super.getVisitedHistory(callback);
                }
            }

            @Override
            public void onExceededDatabaseQuota(String url, String databaseIdentifier, long quota,
                    long estimatedDatabaseSize, long totalQuota, QuotaUpdater quotaUpdater) {
                if (mCustomWebChromeClient != null) {
                    mCustomWebChromeClient.onExceededDatabaseQuota(url, databaseIdentifier, quota,
                            estimatedDatabaseSize, totalQuota, quotaUpdater);
                } else {
                    super.onExceededDatabaseQuota(url, databaseIdentifier, quota, estimatedDatabaseSize, totalQuota,
                            quotaUpdater);
                }
            }

            @Override
            public void onReachedMaxAppCacheSize(long requiredStorage, long quota, QuotaUpdater quotaUpdater) {
                if (mCustomWebChromeClient != null) {
                    mCustomWebChromeClient.onReachedMaxAppCacheSize(requiredStorage, quota, quotaUpdater);
                } else {
                    super.onReachedMaxAppCacheSize(requiredStorage, quota, quotaUpdater);
                }
            }

        });

        setDownloadListener(new DownloadListener() {

            @Override
            public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimetype,
                    long contentLength) {
                if (mListener != null) {
                    mListener.onDownloadRequested(url, userAgent, contentDisposition, mimetype, contentLength);
                }
            }

        });
    }

    @Override
    public void loadUrl(final String url, Map<String, String> additionalHttpHeaders) {
        if (additionalHttpHeaders == null) {
            additionalHttpHeaders = mHttpHeaders;
        } else if (mHttpHeaders.size() > 0) {
            additionalHttpHeaders.putAll(mHttpHeaders);
        }

        super.loadUrl(url, additionalHttpHeaders);
    }

    @Override
    public void loadUrl(final String url) {
        if (mHttpHeaders.size() > 0) {
            super.loadUrl(url, mHttpHeaders);
        } else {
            super.loadUrl(url);
        }
    }

    public void loadUrl(String url, final boolean preventCaching) {
        if (preventCaching) {
            url = makeUrlUnique(url);
        }

        loadUrl(url);
    }

    public void loadUrl(String url, final boolean preventCaching, final Map<String, String> additionalHttpHeaders) {
        if (preventCaching) {
            url = makeUrlUnique(url);
        }

        loadUrl(url, additionalHttpHeaders);
    }

    protected static String makeUrlUnique(final String url) {
        StringBuilder unique = new StringBuilder();
        unique.append(url);

        if (url.contains("?")) {
            unique.append('&');
        } else {
            if (url.lastIndexOf('/') <= 7) {
                unique.append('/');
            }
            unique.append('?');
        }

        unique.append(System.currentTimeMillis());
        unique.append('=');
        unique.append(1);

        return unique.toString();
    }

    protected boolean isHostnameAllowed(String url) {
        if (mPermittedHostnames.size() == 0) {
            return true;
        }

        String url_host = Uri.parse(url).getHost();

        for (String hostname : mPermittedHostnames) {
            if (url_host.startsWith(hostname)) {
                return true;
            } else if (hostname.startsWith("*.") && url_host.endsWith(hostname.substring(2))) {
                // Allow wildcards for base domain support (*.example.com)
                return true;
            }
        }

        return false;
    }

    protected void setLastError() {
        mLastError = System.currentTimeMillis();
    }

    protected boolean hasError() {
        return (mLastError + 500) >= System.currentTimeMillis();
    }

    protected static String getLanguageIso3() {
        try {
            return Locale.getDefault().getISO3Language().toLowerCase(Locale.US);
        } catch (MissingResourceException e) {
            return LANGUAGE_DEFAULT_ISO3;
        }
    }

    /**
     * Provides localizations for the 25 most widely spoken languages that have a ISO 639-2/T code
     */
    protected String getFileUploadPromptLabel() {
        try {
            switch (mLanguageIso3) {
            case "zho":
                return decodeBase64("6YCJ5oup5LiA5Liq5paH5Lu2");
            case "spa":
                return decodeBase64("RWxpamEgdW4gYXJjaGl2bw==");
            case "hin":
                return decodeBase64("4KSP4KSVIOCkq+CkvOCkvuCkh+CksiDgpJrgpYHgpKjgpYfgpII=");
            case "ben":
                return decodeBase64("4KaP4KaV4Kaf4Ka/IOCmq+CmvuCmh+CmsiDgpqjgpr/gprDgp43gpqzgpr7gpprgpqg=");
            case "ara":
                return decodeBase64("2KfYrtiq2YrYp9ixINmF2YTZgSDZiNin2K3Yrw==");
            case "por":
                return decodeBase64("RXNjb2xoYSB1bSBhcnF1aXZv");
            case "rus":
                return decodeBase64("0JLRi9Cx0LXRgNC40YLQtSDQvtC00LjQvSDRhNCw0LnQuw==");
            case "jpn":
                return decodeBase64("MeODleOCoeOCpOODq+OCkumBuOaKnuOBl+OBpuOBj+OBoOOBleOBhA==");
            case "pan":
                return decodeBase64("4KiH4Kmx4KiVIOCoq+CovuCoh+CosiDgqJrgqYHgqKPgqYs=");
            case "deu":
                return decodeBase64("V8OkaGxlIGVpbmUgRGF0ZWk=");
            case "jav":
                return decodeBase64("UGlsaWggc2lqaSBiZXJrYXM=");
            case "msa":
                return decodeBase64("UGlsaWggc2F0dSBmYWls");
            case "tel":
                return decodeBase64("4LCS4LCVIOCwq+CxhuCxluCwsuCxjeCwqOCxgSDgsI7gsILgsJrgsYHgsJXgsYvgsILgsKHgsL8=");
            case "vie":
                return decodeBase64("Q2jhu41uIG3hu5l0IHThuq1wIHRpbg==");
            case "kor":
                return decodeBase64("7ZWY64KY7J2YIO2MjOydvOydhCDshKDtg50=");
            case "fra":
                return decodeBase64("Q2hvaXNpc3NleiB1biBmaWNoaWVy");
            case "mar":
                return decodeBase64("4KSr4KS+4KSH4KSyIOCkqOCkv+CkteCkoeCkvg==");
            case "tam":
                return decodeBase64("4K6S4K6w4K+BIOCuleCvh+CuvuCuquCvjeCuquCviCDgrqTgr4fgrrDgr43grrXgr4E=");
            case "urd":
                return decodeBase64("2KfbjNqpINmB2KfYptmEINmF24zauiDYs9uSINin2YbYqtiu2KfYqCDaqdix24zaug==");
            case "fas":
                return decodeBase64("2LHYpyDYp9mG2KrYrtin2Kgg2qnZhtuM2K8g24zaqSDZgdin24zZhA==");
            case "tur":
                return decodeBase64("QmlyIGRvc3lhIHNlw6dpbg==");
            case "ita":
                return decodeBase64("U2NlZ2xpIHVuIGZpbGU=");
            case "tha":
                return decodeBase64("4LmA4Lil4Li34Lit4LiB4LmE4Lif4Lil4LmM4Lir4LiZ4Li24LmI4LiH");
            case "guj":
                return decodeBase64("4KqP4KqVIOCqq+CqvuCqh+CqsuCqqOCrhyDgqqrgqrjgqoLgqqY=");
            }
        } catch (Exception ignored) {
        }

        // return English translation by default
        return "Choose a file";
    }

    protected static String decodeBase64(final String base64)
            throws IllegalArgumentException, UnsupportedEncodingException {
        final byte[] bytes = Base64.decode(base64, Base64.DEFAULT);
        return new String(bytes, CHARSET_DEFAULT);
    }

    @SuppressLint("NewApi")
    protected void openFileInput(final ValueCallback<Uri> fileUploadCallbackFirst,
            final ValueCallback<Uri[]> fileUploadCallbackSecond) {
        if (mFileUploadCallbackFirst != null) {
            mFileUploadCallbackFirst.onReceiveValue(null);
        }
        mFileUploadCallbackFirst = fileUploadCallbackFirst;

        if (mFileUploadCallbackSecond != null) {
            mFileUploadCallbackSecond.onReceiveValue(null);
        }
        mFileUploadCallbackSecond = fileUploadCallbackSecond;

        Intent i = new Intent(Intent.ACTION_GET_CONTENT);
        i.addCategory(Intent.CATEGORY_OPENABLE);
        i.setType(mUploadableFileTypes);

        if (mFragment != null && mFragment.get() != null && Build.VERSION.SDK_INT >= 11) {
            mFragment.get().startActivityForResult(Intent.createChooser(i, getFileUploadPromptLabel()),
                    mRequestCodeFilePicker);
        } else if (mActivity != null && mActivity.get() != null) {
            mActivity.get().startActivityForResult(Intent.createChooser(i, getFileUploadPromptLabel()),
                    mRequestCodeFilePicker);
        }
    }

    /**
     * Returns whether file uploads can be used on the current device (generally all platform versions except for 4.4)
     *
     * @return whether file uploads can be used
     */
    public static boolean isFileUploadAvailable() {
        return isFileUploadAvailable(false);
    }

    /**
     * Returns whether file uploads can be used on the current device (generally all platform versions except for 4.4)
     * <p/>
     * On Android 4.4.3/4.4.4, file uploads may be possible but will come with a wrong MIME type
     *
     * @param needsCorrectMimeType whether a correct MIME type is required for file uploads or `application/octet-stream` is acceptable
     * @return whether file uploads can be used
     */
    public static boolean isFileUploadAvailable(final boolean needsCorrectMimeType) {
        if (Build.VERSION.SDK_INT == 19) {
            final String platformVersion = (Build.VERSION.RELEASE == null) ? "" : Build.VERSION.RELEASE;

            return !needsCorrectMimeType
                    && (platformVersion.startsWith("4.4.3") || platformVersion.startsWith("4.4.4"));
        } else {
            return true;
        }
    }

    /**
     * Handles a download by loading the file from `fromUrl` and saving it to `toFilename` on the external storage
     * <p/>
     * This requires the two permissions `android.permission.INTERNET` and `android.permission.WRITE_EXTERNAL_STORAGE`
     * <p/>
     * Only supported on API level 9 (Android 2.3) and above
     *
     * @param context    a valid `Context` reference
     * @param fromUrl    the URL of the file to download, e.g. the one from `AdvancedWebView.onDownloadRequested(...)`
     * @param toFilename the name of the destination file where the download should be saved, e.g. `myImage.jpg`
     * @return whether the download has been successfully handled or not
     */
    @SuppressLint("NewApi")
    public static boolean handleDownload(final Context context, final String fromUrl, final String toFilename) {
        if (Build.VERSION.SDK_INT < 9) {
            throw new RuntimeException("Method requires API level 9 or above");
        }

        final Request request = new Request(Uri.parse(fromUrl));
        if (Build.VERSION.SDK_INT >= 11) {
            request.allowScanningByMediaScanner();
            request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
        }
        request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, toFilename);

        final DownloadManager dm = (DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE);
        try {
            try {
                dm.enqueue(request);
            } catch (SecurityException e) {
                if (Build.VERSION.SDK_INT >= 11) {
                    request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE);
                }
                dm.enqueue(request);
            }

            return true;
        }
        // if the download manager app has been disabled on the device
        catch (IllegalArgumentException e) {
            // show the settings screen where the user can enable the download manager app again
            openAppSettings(context, FolioWebViewScroll.PACKAGE_NAME_DOWNLOAD_MANAGER);

            return false;
        }
    }

    @SuppressLint("NewApi")
    private static boolean openAppSettings(final Context context, final String packageName) {
        if (Build.VERSION.SDK_INT < 9) {
            throw new RuntimeException("Method requires API level 9 or above");
        }

        try {
            final Intent intent = new Intent(android.provider.Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
            intent.setData(Uri.parse("package:" + packageName));
            intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

            context.startActivity(intent);

            return true;
        } catch (Exception e) {
            return false;
        }
    }

    /**
     * Wrapper for methods related to alternative browsers that have their own rendering engines
     */
    public static class Browsers {

        /**
         * Package name of an alternative browser that is installed on this device
         */
        private static String mAlternativePackage;

        /**
         * Returns whether there is an alternative browser with its own rendering engine currently installed
         *
         * @param context a valid `Context` reference
         * @return whether there is an alternative browser or not
         */
        public static boolean hasAlternative(final Context context) {
            return getAlternative(context) != null;
        }

        /**
         * Returns the package name of an alternative browser with its own rendering engine or `null`
         *
         * @param context a valid `Context` reference
         * @return the package name or `null`
         */
        public static String getAlternative(final Context context) {
            if (mAlternativePackage != null) {
                return mAlternativePackage;
            }

            final List<String> alternativeBrowsers = Arrays.asList(ALTERNATIVE_BROWSERS);
            final List<ApplicationInfo> apps = context.getPackageManager()
                    .getInstalledApplications(PackageManager.GET_META_DATA);

            for (ApplicationInfo app : apps) {
                if (!app.enabled) {
                    continue;
                }

                if (alternativeBrowsers.contains(app.packageName)) {
                    mAlternativePackage = app.packageName;

                    return app.packageName;
                }
            }

            return null;
        }

        /**
         * Opens the given URL in an alternative browser
         *
         * @param context a valid `Activity` reference
         * @param url     the URL to open
         */
        public static void openUrl(final Activity context, final String url) {
            openUrl(context, url, false);
        }

        /**
         * Opens the given URL in an alternative browser
         *
         * @param context           a valid `Activity` reference
         * @param url               the URL to open
         * @param withoutTransition whether to switch to the browser `Activity` without a transition
         */
        public static void openUrl(final Activity context, final String url, final boolean withoutTransition) {
            final Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
            intent.setPackage(getAlternative(context));
            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

            context.startActivity(intent);

            if (withoutTransition) {
                context.overridePendingTransition(0, 0);
            }
        }
    }

    @Override
    protected void onScrollChanged(final int l, final int t, final int oldl, final int oldt) {
        super.onScrollChanged(l, t, oldl, oldt);
        mListener.onScrollChange(l, t, oldl, oldt);
    }

    @Override
    protected void onCreateContextMenu(ContextMenu menu) {
        super.onCreateContextMenu(menu);
        mListener.onCreateContextMenu(menu);
    }

    @Override
    public void setNestedScrollingEnabled(boolean enabled) {
        mChildHelper.setNestedScrollingEnabled(enabled);
    }

    @Override
    public boolean isNestedScrollingEnabled() {
        return mChildHelper.isNestedScrollingEnabled();
    }

    @Override
    public boolean startNestedScroll(int axes) {
        return mChildHelper.startNestedScroll(axes);
    }

    @Override
    public void stopNestedScroll() {
        mChildHelper.stopNestedScroll();
    }

    @Override
    public boolean hasNestedScrollingParent() {
        return mChildHelper.hasNestedScrollingParent();
    }

    @Override
    public boolean dispatchNestedScroll(int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed,
            int[] offsetInWindow) {
        return mChildHelper.dispatchNestedScroll(dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed,
                offsetInWindow);
    }

    @Override
    public boolean dispatchNestedPreScroll(int dx, int dy, int[] consumed, int[] offsetInWindow) {
        return mChildHelper.dispatchNestedPreScroll(dx, dy, consumed, offsetInWindow);
    }

    @Override
    public boolean dispatchNestedFling(float velocityX, float velocityY, boolean consumed) {
        return mChildHelper.dispatchNestedFling(velocityX, velocityY, consumed);
    }

    @Override
    public boolean dispatchNestedPreFling(float velocityX, float velocityY) {
        return mChildHelper.dispatchNestedPreFling(velocityX, velocityY);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        boolean rs = false;
        final int action = MotionEventCompat.getActionMasked(event);
        if (action == MotionEvent.ACTION_DOWN) {
            mNestedOffsetY = 0;
        }
        int y = (int) event.getY();
        event.offsetLocation(0, mNestedOffsetY);
        switch (action) {
        case MotionEvent.ACTION_DOWN:
            rs = super.onTouchEvent(event);
            mLastY = y;
            break;
        case MotionEvent.ACTION_MOVE:
            int dy = mLastY - y;
            int oldY = getScrollY();
            startNestedScroll(ViewCompat.SCROLL_AXIS_VERTICAL);
            if (dispatchNestedPreScroll(0, dy, mScrollConsumed, mScrollOffset)) {
                dy -= mScrollConsumed[1];
                event.offsetLocation(0, -mScrollOffset[1]);
                mNestedOffsetY += mScrollOffset[1];
            }
            rs = super.onTouchEvent(event);
            mLastY = y - mScrollOffset[1];
            if (dy < 0) {
                int newScrollY = Math.max(0, oldY + dy);
                dy -= newScrollY - oldY;
                if (dispatchNestedScroll(0, newScrollY - dy, 0, dy, mScrollOffset)) {
                    event.offsetLocation(0, mScrollOffset[1]);
                    mNestedOffsetY += mScrollOffset[1];
                    mLastY -= mScrollOffset[1];
                }
            }
            break;
        case MotionEvent.ACTION_UP:
        case MotionEvent.ACTION_CANCEL:
            rs = super.onTouchEvent(event);
            stopNestedScroll();
            break;
        }
        return rs;
    }
}