public settings_page()
        {
            this.InitializeComponent();

            this.navigationHelper = new NavigationHelper(this);
            this.navigationHelper.LoadState += this.NavigationHelper_LoadState;
            this.navigationHelper.SaveState += this.NavigationHelper_SaveState;
        }
        /* end geolocator / geoposition */
        public Tracking_Page()
        {
            this.InitializeComponent();
            HardwareButtons.BackPressed += HardwareButtons_BackPressed;

            this.navigationHelper = new NavigationHelper(this);
            this.navigationHelper.LoadState += this.NavigationHelper_LoadState;
            this.navigationHelper.SaveState += this.NavigationHelper_SaveState;
            
            
        }