protected override void OnCreate (Bundle savedInstanceState)
        {
            base.OnCreate (savedInstanceState);

            // Set our view from the "main" layout resource
            SetContentView (Resource.Layout.Main);
          
            // Get our button from the layout resource,
            // and attach an event to it
            Button button = FindViewById<Button> (Resource.Id.myButton);
            
            button.Click += delegate {
                button.Text = string.Format ("{0} clicks!", count++);
            };
            Android.Util.Log.Info ("normal", "日志zzl");
            var loginBtn = FindViewById<Button> (Resource.Id.loginBtn);
            var username = FindViewById<TextView> (Resource.Id.username);
            var password = FindViewById<TextView> (Resource.Id.password);
            var result = FindViewById<TextView> (Resource.Id.result);
            loginBtn.Click += delegate {

                string url = "//api.xuexiba.com/v1/User/Login";
                //創建HttpClient（注意傳入(ru)HttpClientHandler）
                using (var http = new HttpClient ()) {
                    var content = new FormUrlEncodedContent (new Dictionary<string, string> () { 
                        { "username",username.Text },
                        { "password",password.Text }
                        
                    });

                    var response = http.PostAsync (url, content);
                    result.Text = response.Result.Content.ReadAsStringAsync ().Result;
                 Intent intent = new Intent(this, typeof(ViewPageActivity));
                 StartActivity(intent);
 
                }
            };
        }

    protected override void OnCreate (Bundle savedInstanceState)
        {
            base.OnCreate (savedInstanceState);
            SetContentView (Resource.Layout.ViewPage);
            var webView = FindViewById<WebView> (Resource.Id.webView);
            //啟用Javascript Enable
            webView.Settings.JavaScriptEnabled = true;
            //載(zai)入網址(zhi)
            webView.LoadUrl ("//www.sina.com");
            //直接(jie)在當(dang)前webView上打開
             webView.SetWebViewClient (new CustWebViewClient ());

        }

public class CustWebViewClient : WebViewClient
    {
        public override bool ShouldOverrideUrlLoading (WebView view, string url)
        {
            view.LoadUrl (url);
            return true;
        }

    }