/// <summary>
        /// 启动 progress dialog.
        /// </summary>
        /// <param name="context">Context.</param>
        /// <param name="msg">Message.</param>
        public static void StartProgressDialog(Activity _activity, string msg, bool canceleable = false)
        {
//			if(progressDialog == null)
            progressDialog = CustomProgressDialog.createDialog(_activity);
            progressDialog.Window.SetGravity(GravityFlags.Center);
            progressDialog.SetMessage(msg);
            progressDialog.Show();
            progressDialog.SetCancelable(canceleable);
        }
		/// <summary>
		/// 启动 progress dialog.
		/// </summary>
		/// <param name="context">Context.</param>
		/// <param name="msg">Message.</param>
		public static void StartProgressDialog(Activity _activity,string msg,bool canceleable =false)
		{

//			if(progressDialog == null)
				progressDialog = CustomProgressDialog.createDialog (_activity);
			progressDialog.Window.SetGravity (GravityFlags.Center); 
			progressDialog.SetMessage (msg);
			progressDialog.Show ();
			progressDialog.SetCancelable (canceleable);

		}