WindowsPhone/WP8/WeatherInformation/WeatherInformation/MainPage.xaml.cs

   1 using Microsoft.Phone.Controls;
   2 using System;
   3 using System.Linq;
   4 using System.Globalization;
   5 using System.Windows;
   6 using System.Windows.Controls;
   7 using System.Windows.Navigation;
   8 using WeatherInformation.Model;
   9 using WeatherInformation.Model.Services;
  10 using WeatherInformation.Resources;
  11 using WeatherInformation.ViewModels;
  12 using System.Threading.Tasks;
  13 using WeatherInformation.Model.JsonDataParser;
  14
  15 namespace WeatherInformation
  16 {
  17     public partial class MainPage : PhoneApplicationPage
  18     {
  19         private MainViewModel _mainViewModel;
  20         private bool _isNewPageInstance = false;
  21
  22         // Constructor
  23         public MainPage()
  24         {
  25             InitializeComponent();
  26
  27             _isNewPageInstance = true;
  28
  29             // Código de ejemplo para traducir ApplicationBar
  30             //BuildLocalizedApplicationBar();
  31         }
  32
  33
  34         // Cargar datos para los elementos MainViewModel
  35         protected override void OnNavigatedTo(NavigationEventArgs e)
  36         {
  37             base.OnNavigatedTo(e);
  38
  39             // If _isNewPageInstance is true, the page constuctor has been called, so
  40             // state may need to be restored.
  41             if (_isNewPageInstance)
  42             {
  43                 if (_mainViewModel == null)
  44                 {
  45                     _mainViewModel = new MainViewModel(new SettingsViewModel());
  46                 }
  47
  48                 DataContext = _mainViewModel;
  49             }
  50             // Set _isNewPageInstance to false. If the user navigates back to this page
  51             // and it has remained in memory, this value will continue to be false.
  52             _isNewPageInstance = false;
  53
  54             UpdateApplicationDataUI();
  55         }
  56
  57         async private void UpdateApplicationDataUI()
  58         {
  59             Location locationItem = null;
  60             using (var db = new LocationDataContext(LocationDataContext.DBConnectionString))
  61             {
  62                 locationItem = db.Locations.Where(location => location.IsSelected).FirstOrDefault();
  63             }
  64
  65             // Empty UI
  66             this.CurrentData.Visibility = Visibility.Collapsed;
  67             this.ForecastData.Visibility = Visibility.Collapsed;
  68             this.ProgressBarRemoteData.Visibility = Visibility.Collapsed;
  69             this.NoDataAvailable.Visibility = Visibility.Collapsed;
  70
  71             if (locationItem == null)
  72             {
  73                 // Nothing to do.
  74                 // Show error message.
  75                 this.CurrentData.Visibility = Visibility.Collapsed;
  76                 this.ForecastData.Visibility = Visibility.Collapsed;
  77                 this.ProgressBarRemoteData.Visibility = Visibility.Collapsed;
  78                 this.NoDataAvailable.Visibility = Visibility.Visible;
  79                 return;
  80             }
  81
  82             // If the application member variable is not empty,
  83             // set the page's data object from the application member variable.
  84             WeatherData weatherData = (Application.Current as WeatherInformation.App).ApplicationDataObject;
  85             if (!IsDataFresh(locationItem.LastRemoteDataUpdate) || weatherData == null)
  86             {
  87                 // Gets the data from the web.
  88                 this.CurrentData.Visibility = Visibility.Collapsed;
  89                 this.ForecastData.Visibility = Visibility.Collapsed;
  90                 this.ProgressBarRemoteData.Visibility = Visibility.Visible;
  91                 this.NoDataAvailable.Visibility = Visibility.Collapsed;
  92
  93                 await GetRemoteDataAndUpdateUI(locationItem);
  94             }
  95             else
  96             {
  97                 this.CurrentData.Visibility = Visibility.Visible;
  98                 this.ForecastData.Visibility = Visibility.Visible;
  99                 this.ProgressBarRemoteData.Visibility = Visibility.Collapsed;
 100                 this.NoDataAvailable.Visibility = Visibility.Collapsed;
 101
 102                 UpdateUI(weatherData);
 103             }
 104         }
 105
 106         private void UpdateUI(WeatherData weatherData)
 107         {
 108             if (weatherData != null)
 109             {
 110                 _mainViewModel.LoadData(weatherData);
 111             }
 112         }
 113
 114         async private Task GetRemoteDataAndUpdateUI(Location locationItem)
 115         {
 116             // Load remote data (aynchronous way by means of async/await)
 117             try
 118             {
 119                 // Without ConfigureAwait(false) await returns data on the calling thread.
 120                 WeatherData weatherData = await GetRemoteDataAsync(locationItem);
 121
 122                 this.CurrentData.Visibility = Visibility.Visible;
 123                 this.ForecastData.Visibility = Visibility.Visible;
 124                 this.ProgressBarRemoteData.Visibility = Visibility.Collapsed;
 125                 this.NoDataAvailable.Visibility = Visibility.Collapsed;
 126
 127                 UpdateUI(weatherData);
 128
 129                 (Application.Current as WeatherInformation.App).ApplicationDataObject = weatherData;
 130
 131                 using (var db = new LocationDataContext(LocationDataContext.DBConnectionString))
 132                 {
 133                     locationItem = db.Locations.Where(location => location.IsSelected).FirstOrDefault();
 134                     locationItem.LastRemoteDataUpdate = DateTime.UtcNow;
 135                     db.SubmitChanges();
 136                 }
 137             }
 138             catch(Exception e)
 139             {
 140                 // Empty UI and show error message
 141                 this.CurrentData.Visibility = Visibility.Collapsed;
 142                 this.ForecastData.Visibility = Visibility.Collapsed;
 143                 this.ProgressBarRemoteData.Visibility = Visibility.Collapsed;
 144                 this.NoDataAvailable.Visibility = Visibility.Visible;
 145             }
 146
 147         }
 148
 149         private void LongListSelector_SelectionChanged(object sender, SelectionChangedEventArgs e)
 150         {
 151             LongListSelector longListSelector = sender as LongListSelector;
 152
 153             // TODO: with LINQ :(
 154             ItemViewModel element = longListSelector.SelectedItem as ItemViewModel;
 155             int index = longListSelector.ItemsSource.IndexOf(element);
 156             String uri = string.Format(CultureInfo.InvariantCulture, "/SelectedDatePage.xaml?parameter={0}", index);
 157             NavigationService.Navigate(new Uri(uri, UriKind.Relative));
 158         }
 159
 160         /// <summary>
 161         /// Retrieve remote weather data.
 162         /// </summary>
 163         async public Task<WeatherData> GetRemoteDataAsync(Location locationItem)
 164         {
 165             double latitude = locationItem.Latitude;
 166             double longitude = locationItem.Longitude;
 167             int resultsNumber = Convert.ToInt32(AppResources.APIOpenWeatherMapResultsNumber);
 168
 169             CustomHTTPClient httpClient = new CustomHTTPClient();
 170
 171             string formattedForecastURL = String.Format(
 172                 CultureInfo.InvariantCulture, AppResources.URIAPIOpenWeatherMapForecast,
 173                 AppResources.APIVersionOpenWeatherMap, latitude, longitude, resultsNumber);
 174             string jsonForecast = await httpClient.GetWeatherDataAsync(formattedForecastURL).ConfigureAwait(false);
 175
 176             string formattedCurrentURL = String.Format(
 177                 CultureInfo.InvariantCulture, AppResources.URIAPIOpenWeatherMapCurrent,
 178                 AppResources.APIVersionOpenWeatherMap, latitude, longitude, resultsNumber);
 179             string jsonCurrent = await httpClient.GetWeatherDataAsync(formattedCurrentURL).ConfigureAwait(false);
 180
 181             var parser = new ServiceParser(new JsonParser());
 182             var weatherData = parser.WeatherDataParser(jsonForecast, jsonCurrent, locationItem.City, locationItem.Country);
 183
 184             return weatherData;
 185         }
 186
 187         private bool IsDataFresh(DateTime? lastUpdate)
 188         {
 189             if (lastUpdate == null)
 190             {
 191                 return false;
 192             }
 193
 194             // Check the time elapsed since data was last saved to isolated storage.
 195             TimeSpan TimeSinceLastSave = DateTime.UtcNow - lastUpdate.Value;
 196
 197             if (TimeSinceLastSave.TotalSeconds < 30)
 198             {
 199                 return true;
 200             }
 201
 202             return false;
 203         }
 204
 205         private void Location_Click(object sender, EventArgs e)
 206         {
 207             NavigationService.Navigate(new Uri("/MapPage.xaml", UriKind.Relative));
 208         }
 209
 210         private void Settings_Click(object sender, EventArgs e)
 211         {
 212             NavigationService.Navigate(new Uri("/SettingsPage.xaml", UriKind.Relative));
 213         }
 214
 215         // Código de ejemplo para compilar una ApplicationBar traducida
 216         //private void BuildLocalizedApplicationBar()
 217         //{
 218         //    // Establecer ApplicationBar de la página en una nueva instancia de ApplicationBar.
 219         //    ApplicationBar = new ApplicationBar();
 220
 221         //    // Crear un nuevo botón y establecer el valor de texto en la cadena traducida de AppResources.
 222         //    ApplicationBarIconButton appBarButton = new ApplicationBarIconButton(new Uri("/Assets/AppBar/appbar.add.rest.png", UriKind.Relative));
 223         //    appBarButton.Text = AppResources.AppBarButtonText;
 224         //    ApplicationBar.Buttons.Add(appBarButton);
 225
 226         //    // Crear un nuevo elemento de menú con la cadena traducida de AppResources.
 227         //    ApplicationBarMenuItem appBarMenuItem = new ApplicationBarMenuItem(AppResources.AppBarMenuItemText);
 228         //    ApplicationBar.MenuItems.Add(appBarMenuItem);
 229         //}
 230     }
 231 }