Windows Phone 7: Navigating Between Pages
5 likes7,757 views
The document discusses the programming environments and frameworks used for developing Windows Phone apps. There are two main environments: XNA for games and Silverlight for other apps. Silverlight uses a combination of XAML markup and code-behind files. Apps are structured with an App class that launches the app and handles navigation between pages using a PhoneApplicationFrame. Data can be passed between pages or stored longer term using IsolatedStorage.
![App.g.cs
namespace PhoneApp8 {
public partial class App : System.Windows.Application {
private bool _contentLoaded;
[System.Diagnostics.DebuggerNonUserCodeAttribute()]
public void InitializeComponent() {
if (_contentLoaded) {
return;
}
_contentLoaded = true;
System.Windows.Application.LoadComponent(this, new System.Uri("/
PhoneApp8;component/App.xaml", System.UriKind.Relative));
}
}
}](https://image.slidesharecdn.com/wp7-hello-world-120110130642-phpapp01/85/Windows-Phone-7-Navigating-Between-Pages-8-320.jpg)
![To
receive
the
parameters
protected override void
OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
{
IDictionary<string, string> parameters =
NavigationContext.QueryString;
if (parameters.ContainsKey("name"))
{
PageTitle.Text = parameters["name"];
}
base.OnNavigatedTo(e);
}](https://image.slidesharecdn.com/wp7-hello-world-120110130642-phpapp01/85/Windows-Phone-7-Navigating-Between-Pages-23-320.jpg)
![Example
protected override void OnNavigatedFrom(System.Windows.Navigation.NavigationEventArgs e)
{
PhoneApplicationService.Current.State["key"] = "arvo";
base.OnNavigatedFrom(e);
}
protected override void
OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
{
if (PhoneApplicationService.Current.State.ContainsKey("key"))
{
string value = (string) PhoneApplicationService.Current.State["key"];
}
base.OnNavigatedTo(e);
}](https://image.slidesharecdn.com/wp7-hello-world-120110130642-phpapp01/85/Windows-Phone-7-Navigating-Between-Pages-28-320.jpg)
![App.xaml.cs:
void SaveSettings()
{
IsolatedStorageSettings settings = IsolatedStorageSettings.ApplicationSettings;
settings["savedValue"] = CommonValue;
settings.Save();
}
void LoadSettings()
{
string mydefault = "0";
IsolatedStorageSettings settings = IsolatedStorageSettings.ApplicationSettings;
if(settings.TryGetValue<string>("savedValue", out mydefault))
CommonValue = (string) settings["savedValue"];
}](https://image.slidesharecdn.com/wp7-hello-world-120110130642-phpapp01/85/Windows-Phone-7-Navigating-Between-Pages-33-320.jpg)
Windows Phone 7: Navigating Between Pages
- 1. Windows Phone: Naviga1on between Pages Jussi Pohjolainen Tampere University of Applied Sciences
- 2. Programming Environments • Two programming environments – XNA – for games – Silverlight – non-‐games • You can mix some of the libraries • When crea1ng a project, you must decide if you are doing a XNA or Silverlight
- 3. Silverlight: for apps and u1li1es • Silverlight apps are combina1on of code and markup • Extensible markup language (XAML), pronounced “zammel”
- 4. XNA: for games • High performance games: 2D and 3D • Sprites and backgrounds based on bitmaps • Moving objects around screen, polling user input, built-‐in XNA loop
- 5. Silverlight files • Markup files and “code behind” files: – App.xaml – App.xaml.cs – MainPage.xaml – MainPage.xaml.cs
- 6. App.xaml.cs: App wide init, startup and shutdown namespace PhoneApp8 { public partial class App : Application { Par1al class! So public App() another App-‐ class must be { somewhere! ... InitializeComponent(); ...
- 7. App.xaml • App.xaml and App.xaml.cs files together are the App-‐class • How can .xaml file be part of .cs? – During compila1on • App.xaml -‐> App.g.cs ! • g stands for generated
- 8. App.g.cs namespace PhoneApp8 { public partial class App : System.Windows.Application { private bool _contentLoaded; [System.Diagnostics.DebuggerNonUserCodeAttribute()] public void InitializeComponent() { if (_contentLoaded) { return; } _contentLoaded = true; System.Windows.Application.LoadComponent(this, new System.Uri("/ PhoneApp8;component/App.xaml", System.UriKind.Relative)); } } }
- 9. App.xaml <Application x:Class="PhoneApp8.App" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone" xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"> <!--Application Resources--> <Application.Resources> Store </Application.Resources> resources: colors, styles.. <Application.ApplicationLifetimeObjects> <!--Required object that handles lifetime events for the application--> <shell:PhoneApplicationService Launching="Application_Launching" Closing="Application_Closing" Activated="Application_Activated" Deactivated="Application_Deactivated"/> </Application.ApplicationLifetimeObjects> </Application>
- 10. MainPage.xaml.cs • When app is ini1alized the App class opens the Main Page • Again par1al class! The other half is in MainPage.xaml.cs namespace PhoneApp8 { public partial class MainPage : PhoneApplicationPage { // Constructor public MainPage() { InitializeComponent(); } }
- 11. MainPage.cs • Contains visual elements of the main page PhoneApplicationFrame PhoneApplicationPage Grid named “LayoutRoot” StackPanel named “TitlePanel” TextBlock named “ApplicationTitle” TextBlock named “PageTitle” Grid named “ContentPanel”
- 13. Xap is Zip • binDebug dir has .xap file – Pronounced “zap” • This is the file to be deployed to phone or emulator
- 15. Basic Structure • App class starts the app • PhoneApplicationFrame instance can host one or more pages • PhoneApplicationPage instances are the pages
- 16. MainPage namespace PhoneApp8 { public partial class MainPage : PhoneApplicationPage { // Constructor public MainPage() { InitializeComponent(); } … }
- 17. Navigate • Naviga1on is based on XAML-‐files (like .html files in Web) • Use Naviga1on Service to navigate – Naviga1onService.Navigate(new Uri("/ SecondPage.xaml", UriKind.Rela1ve)); – Naviga1onService.GoBack();
- 18. public partial class MainPage : PhoneApplicationPage { // Constructor public MainPage() { InitializeComponent(); } private void navigateButton_Click(object sender, RoutedEventArgs e) { NavigationService.Navigate(new Uri("/SecondPage.xaml", UriKind.Relative)); } }
- 19. About Naviga1on • Last-‐in-‐first-‐out => Stack • Phones back bueon is the same than – Naviga1onService.GoBack(); • To create new instance of the page: – Naviga1onService.Navigate(new Uri("/ MainPage.xaml", UriKind.Rela1ve));
- 20. RETAIN DATA ACROSS PAGES
- 21. Possibili1es • Every 1me you navigate to new page, a new instance is created => data loss • Solu1ons – 1) Just pass data across pages – 2) PhoneApplica1onService: data in memory while app running – 3) IsolatedStorage: persistant storage
- 22. Page 1 to Page 2 • Pass values like in Web! – NavigationService.Navigate(new Uri("/ SecondPage.xaml?name=Jussi", UriKind.Relative));
- 23. To receive the parameters protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e) { IDictionary<string, string> parameters = NavigationContext.QueryString; if (parameters.ContainsKey("name")) { PageTitle.Text = parameters["name"]; } base.OnNavigatedTo(e); }
- 24. Give values back protected override void OnNavigatedFrom(System.Windows.Navigation.NavigationEventArgs e) { if (e.Content is MainPage) { MainPage reference = (e.Content as MainPage); reference.PageTitle.Text = "And we are back!"; } base.OnNavigatedFrom(e); }
- 25. Basics • When app is opened from Start screen – App is launched • When app is terminated as result of Back – App is closed • When program is running and user presses start – App is deac1vated -‐> tombstoned state • When program is navigated back – App is ac1vated -‐> back from tombstoned state
- 26. public partial class App : Application { ... private void Application_Launching(object sender, LaunchingEventArgs e) { Debug.WriteLine("* Launch! *"); } private void Application_Activated(object sender, ActivatedEventArgs e) { Debug.WriteLine("* Activate! *"); } private void Application_Deactivated(object sender, DeactivatedEventArgs e) { Debug.WriteLine("* Deactivate! *"); } private void Application_Closing(object sender, ClosingEventArgs e) { Debug.WriteLine("* Closed! *"); }
- 27. PhoneApplica1onService: Store Data while App in Memory • You can use PhoneApplica1onService to store data in RAM while app is in use or tombstoned • Really easy to implement store key value pairs in PhoneApplica1onService.Current.State
- 28. Example protected override void OnNavigatedFrom(System.Windows.Navigation.NavigationEventArgs e) { PhoneApplicationService.Current.State["key"] = "arvo"; base.OnNavigatedFrom(e); } protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e) { if (PhoneApplicationService.Current.State.ContainsKey("key")) { string value = (string) PhoneApplicationService.Current.State["key"]; } base.OnNavigatedTo(e); }
- 29. When values are lost? • Open app, press back -‐> app is closed -‐> data lost • Open app, press start -‐> press back -‐> data is there • Open app, press start -‐> open app again from menu -‐> data lost • Open app, long press back -‐> switch apps -‐> long press back to switch back -‐> data is there
- 30. Persistant Storage: Isolated Storage • Load seings when app launching or ac1va1ng • Save seings when app deac1va1ng or closing • Why? – program should also save applica1on seings during the Deac%vated event because the program really doesn’t know if it will ever be resurrected. And if it is resurrected, it should load applica1on seings during the Ac%vated event because otherwise it won’t know about those seings.
- 31. Common value for All public partial class App : Application { private String commonValue = "Default"; public String CommonValue { set { commonValue = value; } get { return commonValue; } }
- 32. Usage of Common Value private void button1_Click(object sender, RoutedEventArgs e) { App appRef = Application.Current as App; PageTitle.Text = appRef.CommonValue; }
- 33. App.xaml.cs: void SaveSettings() { IsolatedStorageSettings settings = IsolatedStorageSettings.ApplicationSettings; settings["savedValue"] = CommonValue; settings.Save(); } void LoadSettings() { string mydefault = "0"; IsolatedStorageSettings settings = IsolatedStorageSettings.ApplicationSettings; if(settings.TryGetValue<string>("savedValue", out mydefault)) CommonValue = (string) settings["savedValue"]; }
- 34. App.xaml.cs: private void Application_Launching(object sender, LaunchingEventArgs e) { LoadSettings(); } private void Application_Activated(object sender, ActivatedEventArgs e) { LoadSettings(); } private void Application_Deactivated(object sender, DeactivatedEventArgs e) { SaveSettings(); } private void Application_Closing(object sender, ClosingEventArgs e) { SaveSettings(); }