Android中webview的DoUpdateVisitedHistory()

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using Android.App;
using Android.Content;
using Android.Content.PM;
using Android.OS;
using Android.Webkit;
using Android.Runtime;
using Android.Views;
using Android.Widget;

namespace Test.Droid
{
    [Activity(Name = "test.droid.TestWebViewActivity", ScreenOrientation = ScreenOrientation.Portrait, ConfigurationChanges = ConfigChanges.KeyboardHidden | ConfigChanges.Orientation, Theme = "@style/CustomActivityTheme", AllowTaskReparenting = true)] 
    public classTestWebViewActivity : BaseActivity,View.IOnTouchListener
    {
        /// <summary>
        /// key
        /// </summary>
        public const string ExtraPathKey = "path";

        public const string FromWhere = "FromWhere";

        private WebView webView;

        private string url;

        private int type;

        private bool needClearHistory = false;

        public enum FromType
        {
            Type1 = 0,
            Type2 = 1,
            Type3 = 2
        }

        protected override void OnCreate (Bundle savedInstanceState)
        {
            base.OnCreate (savedInstanceState);
            SetContentView (Resource.Layout.LoginWebView);
            ActionBar.SetDisplayHomeAsUpEnabled (false);
            ActionBar.SetDisplayShowHomeEnabled (true);
            ActionBar.SetDisplayUseLogoEnabled (true);
            ActionBar.SetHomeButtonEnabled (true);
            ActionBar.SetLogo (Resource.Drawable.MenuBackButton);

          
            ActionBar.Title = "";

            type = Intent.GetIntExtra (FromWhere, 3);

            webView = FindViewById<WebView> (Resource.Id.TestWebView);
            webView.Settings.JavaScriptEnabled = true;
            JSBridge jsBridge = new JSBridge ();
            webView.AddJavascriptInterface (jsBridge, "JSBridge");

            TestWebViewClient webViewClient = new TestWebViewClient (this);
            webViewClient.LoadingMessage = GetString (Resource.String.common_progress_dialog_message);
            webViewClient.ClearHistory += ClearHistory;
            webViewClient.OnLoadFinished += OnLoadFinished;
            webView.SetWebViewClient (webViewClient);
            webView.SetVerticalScrollbarOverlay (true);
            webView.SetOnTouchListener (this);
#if DEBUG
            webView.SetWebChromeClient (new WebChromeClient ());
#endif
          
            url = Intent.GetStringExtra (ExtraPathKey);
            webView.LoadUrl (url);
        }

        /// <summary>
        /// menu项目选择
        /// </summary>
        public override bool OnOptionsItemSelected (IMenuItem item)
        {
            switch (item.ItemId) {
            case global::Android.Resource.Id.Home:
              

                //当是error画面时，再次点击画面，做刷新操作，此时有一个重定向，使得按下返回按钮时，有history存在，不能直接返回上一个画面。此时做出判  断，若为error画面，则直接finifsh(),返回上一页面

                if(webView.CanGoBack () && (webView.Url != GetString (Resource.String.common_webview_error_url)))

                {
                    webView.GoBack ();
                }else
                {

                   if (type.Equals ((int)FromType.Type1)) {
                        GATrackEvent ();
                    } else if (type.Equals ((int)FromType.Type2)) {
                        GATrackEvent ();
                    } else {
                        GATrackEvent ();
                    }

                    Finish ();

                }
                break;
            }
            return true;
        }

      
        protected override void OnDestroy ()
        {
            webView.StopLoading ();
           
            webView.ClearCache (false);
            webView.SetWebViewClient (null);
            webView.SetWebChromeClient (null);
            webView.Destroy ();
            base.OnDestroy ();
        }

        /// <summary>
        /// error画面
        /// </summary>
        /// <param name="v">V.</param>
        /// <param name="e">E.</param>
        public bool OnTouch (View v, MotionEvent e)
        {
            if (webView.Url == GetString (Resource.String.common_webview_error_url) && e.Action == MotionEventActions.Up) {
                needClearHistory = true;
                webView.LoadUrl (url);
                return true;
            }
            return false;
        }

        public void OnLoadFinished (object sender, ErrorEventArgs e)
        {
            WebView senderWebView = sender as WebView;
            if (e.IsErrorOccurred) {
                senderWebView.StopLoading ();
                senderWebView.LoadUrl (GetString (Resource.String.common_webview_error_url));
                return;
            }
           
            if (senderWebView != null) {
                if (type.Equals ((int)FromWhereType.SettingLogin)) {
                    ActionBar.Title = "aaaaa";
                    GAManager.GetInstance (this).TrackingView ("");
                }else{
                    ActionBar.Title = "bbbbb";
                    GAManager.GetInstance (this).TrackingView ("");
                }
            }
        }

        public void ClearHistory (object sender, EventArgs e)
        {
            if (needClearHistory) {
                needClearHistory = false;
                webView.ClearHistory ();
            }
        }
    }

    public classTestWebViewClient : WebViewClient
    {
        private ProgressDialog progressDialog;

        public string LoadingMessage { get; set; }

        public event EventHandler<EventArgs> OnLoadStarted;
      
        public event EventHandler ClearHistory;
       
        public event EventHandler<ErrorEventArgs> OnLoadFinished;

        private Context context;
       
        private bool isErrorOccurred = false;

        private bool loadingFinished = true;
        private bool redirect = false;

        public LoginWebViewClient (Context context)
        {
            this.context = context;
            progressDialog = new ProgressDialog (context);
            progressDialog.SetProgressStyle (ProgressDialogStyle.Spinner);
            progressDialog.SetCancelable (false);
        }

        public override void OnPageStarted (WebView view, string url, Android.Graphics.Bitmap favicon)
        {
            loadingFinished = false;
            if (!progressDialog.IsShowing) {
                if (LoadingMessage != null) {
                    progressDialog.SetMessage (LoadingMessage);
                    progressDialog.Show ();
                }
            }
            if (OnLoadStarted != null) {
                OnLoadStarted (view, null);
            }
            base.OnPageStarted (view, url, favicon);
        }

        public override void OnPageFinished (WebView view, string url)
        {
            if(!redirect) {
                loadingFinished = true;
            }
            if(loadingFinished && !redirect){
                progressDialog.Dismiss ();
                if (OnLoadFinished != null) {
                    ErrorEventArgs args = new ErrorEventArgs ();
                    args.IsErrorOccurred = isErrorOccurred;
                    isErrorOccurred = false;
                    OnLoadFinished (view, args);
                }
            } else {
                redirect = false;
            }

            base.OnPageFinished (view, url);
        }

        /// <summary>
        /// error发生时
        /// </summary>
        /// <param name="view">View.</param>
        /// <param name="errorCode">Error code.</param>
        /// <param name="description">Description.</param>
        /// <param name="failingUrl">Failing URL.</param>
        public override void OnReceivedError (WebView view, ClientError errorCode, string description, string failingUrl)
        {
            isErrorOccurred = true;
            base.OnReceivedError (view, errorCode, description, failingUrl);
        }

        /// <summary>
        /// 读入新的url时
        /// </summary>
        public override bool ShouldOverrideUrlLoading (WebView view, string url)
        {
            if(!loadingFinished){
                redirect = true;
            }
            loadingFinished = false;
            if (url.Contains ("testSchema")) {
                var intent = new Intent (Intent.ActionView, Android.Net.Uri.Parse (url));
                context.StartActivity (intent);
                return true;
            }

            view.LoadUrl (url);
            return true;

        }

        /// <summary>
        /// 更新历史记录
        /// </summary>

        public override void DoUpdateVisitedHistory (WebView view, string url, bool isReload)

        {

            base.DoUpdateVisitedHistory (view, url, isReload);

            //清除历史记录

            if (ClearHistory != null) {
                ClearHistory (view, null);
            }
        }
    }

}