When my Windows 8 app returns from snapped view, it sends the user to the first page of the app. I received a failure notice that my app fails to resume properly, however, Windows passed it before. Is it illegal to send the user to the first page, when the user resumes from snapped mode? How do I tell the app what page the user is located and to restore it?
When my app enter exits snapped mode, this code runs:
void ShowCurrentViewState()
{
//this.UpdateUnsnapButtonState();
// Query for the current view state
ApplicationViewState currentState = Windows.UI.ViewManagement.ApplicationView.Value;
if (currentState != ApplicationViewState.Snapped)
{
App.DataMode = Mode.Featured;
this.Frame.Navigate(typeof(RestaurantSearchDetails));
}
}
The Reading and writing data sample shows how you can navigate between two different screens and change the layout for each screen depending on the view state, snapped vs. filled.
Related
I have Two Screen A And Screen B
Screen A execute
sharedPrefs.setUserLatLng(CURRENT_LOCATION_LAT_KEY, CURRENT_LOCATION_LNG_KEY, LatLng(location.latitude, location.longitude))
commonViewModel.onLatLngChange(LatLng(location.latitude, location.longitude))
These Two Lines of code in Launch Effect
When a button click in Screen A It navigate to Screen B
Everything works fine.
When I Back press from Screen B.
Screen A execute above mention two lines of code. I want to prevent that execution when back press from Screen B
You can save a flag which will indicate if this side effect was already processed, like this:
var userLatLngUpdated by rememberSaveable { mutableStateOf(false) }
if (!userLatLngUpdated) {
LaunchedEffect(Unit) {
// your code
userLatLngUpdated = true
}
}
I have a Windows 10 Universal Windows Platform app with multiple pages, a main page, a list page and a details page and use the following to navigate to List page:
this.Frame.Navigate(typeof(ListPage), parameter);
When you are on the list page you can select an item which will launch a details page like so:
this.Frame.Navigate(typeof(DetailsPage), parameter);
Which works fine, the parameter is a selected Id or information then when using the Back button which on a Desktop app or Phone uses:
this.Frame.GoBack();
This always returns to the MainPage, that is when go from Main, to List to Details hitting back goes to Main, how do I get the GoBack to Go back to the previous page, it always seems to go home rather than the user expected behaviour, an ideas how to resolve this?
I’ve seen this before when you subscribe to the HardwareButtons.BackPressed event (or whatever the equivalent is in a Win10 UWP app) on a page, but then don’t unsubscribe from it. This means two event handlers get called when pressing Back, and both event handlers call Frame.GoBack().
I always subscribe to the event in the page’s NavigatedTo event, and unsubscribe in the NavigatedFrom event.
Could this be happening with your app?
If every page in your app should have the same behaviour, i.e. go back to the previous page, then subscribe to the back button event in the app class as suggested by #RoguePlanetoid in the comments:
SystemNavigationManager.GetForCurrentView().BackRequested += OnBackRequested;
The OnLaunched method would be a good place to do this. Don't forget to tell the OS to display the back button when the app is running on a desktop or tablet:
SystemNavigationManager.GetForCurrentView().AppViewBackButtonVisibility = AppViewBackButtonVisibility.Visible;
Then, add an event handler in the app class like this:
private void OnBackRequested(object sender, BackRequestedEventArgs e)
{
Frame rootFrame = Window.Current.Content as Frame;
if (rootFrame.CanGoBack)
{
e.Handled = true;
rootFrame.GoBack();
}
}
If you want different behaviour on different pages when back is pressed, i.e. ask the user to confirm losing their changes or something, then subscribe to the back button event in a pages OnNavigatedTo method (the code will be same as above), but make sure you unsubscribe in the page's OnNavigatedFrom event:
protected override void OnNavigatedFrom(NavigationEventArgs e)
{
SystemNavigationManager.GetForCurrentView().BackRequested -= this.OnBackPressed;
base.OnNavigatedFrom(e);
}
I had created mediaplayer using mediaelement in windows 8 C#,XAML.
Everything works fine.But there are critical questions I have as follows.
User Navigates to the PlayerPage.
Player starts playing the media.
Now user moves his mouse to left corner and switches to the another app.
My Questions are as follows.
How do I pause my mediaelement if user is switches to the another app?
If user presses windowsbutton + L the device goes in lock state How do I pause the mediaelement?
User presses only windowsbutton How do i pause the mediaelement?
Please give any suggestions/guidance so that I can complete my player.
In constructor assign this event. It will be called when your app's visibility gets collapsed.
Windows.UI.Core.CoreWindow.GetForCurrentThread().VisibilityChanged += MyPlayer_VisibilityChanged;
Here's event body.
async void MyPlayer_VisibilityChanged(Windows.UI.Core.CoreWindow sender, Windows.UI.Core.VisibilityChangedEventArgs args)
{
await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () =>
{
//TODO : First get args.Visible property. If it's false & media is playing, just pause it.
});
}
I have a MessageBox being shown in Application Closing/Deactivated methods in Windows Phone 7/8 application. It is used to warn the user for active timer being disabled because app is closing. The App Closing/Deactivated events are perfect for this, because putting logic in all application pages would be a killer - too many pages and paths for navigation. This works just fine - message box displays OK in WP7.
I also know for breaking changes in the API of WP8. There it is clearly stated that MessageBox.Show in Activated and Launching will cause exception.
The problem is that in WP8 the message box does not get shown on app closing. Code is executed without exception, but no message appears.
P.S. I've asked this on MS WP Dev forum but obviously no one knew.
Move the msgBox code from the app closing events and into your main page codebehind. Override the on back key press event and place your code there. This is how it was done on 7.x:
protected override void OnBackKeyPress(System.ComponentModel.CancelEventArgs e)
{
if (MessageBox.Show("Do you want to exit XXXXX?", "Application Closing", MessageBoxButton.OKCancel) == MessageBoxResult.Cancel)
{
// Cancel default navigation
e.Cancel = true;
}
}
FYI - On WP8 it looks like you have to dispatch the MsgBox Show to a new thread.
This prompts the user before the app ever actually starts to close in the event model. If the user accepts the back key press is allowed to happen, otherwise its canceled. You are not allowed to override the home button press, it must always go immediately to the home screen. You should look into background agents to persist your timer code through suspend / resume.
Register BackKeyPress event on RootFrame.
RootFrame.BackKeyPress += BackKeyPressed;
private void BackKeyPressed(object sender, CancelEventArgs e)
{
var result = (MessageBox.Show("Do you want to exit XXXXX?", "Application Closing", MessageBoxButton.OKCancel));
if (result == MessageBoxResult.Cancel)
{
// Cancel default navigation
e.Cancel = true;
}
}
I am creating a silver light application using Navigation app template. It is for internal use and hence uses windows authenticatoin. There is a dashboard page which shows couple of records filtered by logged in users id. To get the user id (which is an int) I call a web service by overriding the GetAuthenticatedUser and pass the username (from IPrincipal). This service takes some time to return the details.
When I navigate to dashboard app, it renders completely with no data because the user service is a async operation and I am not able to make the rendering wait till my GetAuthenticatedUser finishes completely. So I created a Login page which just shows a progress bar till I get the user object and then navigate to dashboard. If someone tries to access the dashboard directly by using the URL, i want them to navigate back to Login page.
So in the dashboard constructor I added the following code
if (!UserService.Current.User.IsAuthenticated)
{
MessageBox.Show("Navigating away");
Frame objContainer = this.Parent as Frame;
objContainer.Navigate(new Uri("/Views/Login.xaml", UriKind.Relative));
}
Thogh I get the message box prompt, it does not actually take me to Login page but stays in dashboard page. I also tried putting this code in OnNavigatedTo override with no luck.
I also tried using NavigationService instead of Frame as below, with no luck
if (!UserService.Current.User.IsAuthenticated)
{
MessageBox.Show("Navigating away");
this.NavigationService.Navigate(new Uri("/Views/Login.xaml", UriKind.Relative));
}
it still does not work. Does anyone know how to make some page accessible only if I have fully valid user object? if they try to access the restricted page without this, I want them to be able to redirected to Login page, how can this be achieved?
I am using Silverlight 3 Beta
Shreedhar
I finally found a way around this. In the Constructo i Hooked up the Loaded event handler and in the event handler I am navigating to a different page and it works fine now.
public Dashboard()
{
InitializeComponent();
this.Loaded += new RoutedEventHandler(Dashboard_Loaded);
}
void Dashboard_Loaded(object sender, RoutedEventArgs e)
{
if (!UserService.Current.User.IsAuthenticated)
{
Frame objContainer = this.Parent as Frame;
if (objContainer != null)
{
objContainer.Navigate(new Uri("/Views/Login.xaml", UriKind.Relative));
}
}
}
This piece of code works just fine!
Shreedhar