I have UWP app that implements the below code to wire up the system back button. My understanding is that this event is provided to capture hardware back buttons on Windows Phones, the back button in the title bar on Windows 10 and the back button on the task bar in Windows 10 tablet mode.
The hardware and title bar back buttons are working in my app, but when in tablet mode, pressing the back button on the task bar moves my app to the background and navigates to the Start Menu regardless of where I am in the app backstack. The BackRequested event IS firing in this case and my app is navigating back one page.
protected override async void OnLaunched(LaunchActivatedEventArgs args)
{
Windows.UI.Core.SystemNavigationManager.GetForCurrentView().BackRequested +=
App_BackRequested;
}
private void App_BackRequested(object sender, BackRequestedEventArgs e)
{
NavService.GoBack();
}
Any thoughts on why the tablet mode back button would behave this way? I'm seeing this behavior across many Windows 10 PCs, Surfaces, etc.
The default behavior of the Tablet mode back button is indeed to navigate out of the app. To prevent this you have to make sure that when you can navigate back in the app, you also mark the back navigation as handled.
private void App_BackRequested(object sender, BackRequestedEventArgs e)
{
if ( NavService.CanGoBack() )
{
NavService.GoBack();
e.Handled = true;
}
}
You will have to add a CanGoBack() method that will check the app Frame's CanGoBack property.
Related
I would like to create a function like in Whatsapp for a WPF App with Win10 and with C#. I habe a normal button with some Text on it. As long as the button is pressed with hand touch or a stylus pen, the applikation should record and as soon as the button is untouched, it should stop the recording.
thats my code so far: I may add the I always youse the Preview-Versions of these Events
private void ButtonLiveDown(object sender, touchEventArgs e)
{
ButtonLiveOn();
}
private void ButtonLiveUp(object sender, TouchEventArgs e)
{
ButtonLiveOff();
}
private void ButtonLiveOn()
{
SetMicVolume(100);
isRecording = true;
}
private void ButtonLiveOff()
{
SetMicVolume(0);
isRecording = false;
}
for the recording, or better live announcement I use function in Windows systemsettings where you can say which microphone input schould be sent directly to the speaker
Now my Problem: I can start the speaking as soon as I press the button, but it doesn't matter if I hold the button or release him just directly after, The untouch event seems not to work, the Microphone is not set to 0. So I can't stop the live announcement. I want the function like in WhatsApp, the voice message is recording untill the button is released. What do I do wrong?
I am developing a windows phone 8 app. I want to control the back button of the phone for doing specific task. I want that when user press the back button in specific page it will not navigate to the previous page but to the page which I want. Is their any way to control the hardware back button present in phone?
In Silverlight apps (WP7, WP8, WP8.1) you do this:
protected override void OnBackKeyPress(CancelEventArgs e)
{
// put any code you like here
MessageBox.Show("You pressed the Back button");
e.Cancel = true;
}
That will work in all Windows Phone versions if you're using Silverlight.
If you're using WinRT for Windows Phone 8.1, it is a bit different:
Open NavigationHelper.cs and make this modification:
private void HardwareButtons_BackPressed(object sender, Windows.Phone.UI.Input.BackPressedEventArgs e)
{
if (this.GoBackCommand.CanExecute(null) && !e.Handled)
{
e.Handled = true;
this.GoBackCommand.Execute(null);
}
}
Now in your app page (the page that will be open when the back button is pressed), add the following namespace:
using Windows.Phone.UI.Input;
Add this handler to the constructor method of your page:
HardwareButtons.BackPressed += OnBackPressed;
Then add this method:
private async void OnBackPressed(object sender, Windows.Phone.UI.Input.BackPressedEventArgs e)
{
e.Handled = true;
// add your own code here to run when Back is pressed
}
Note: in both cases, the 'e.Handled = true' line tells the OS that the back button press has been handled, and therefore the OS will not action the default behaviour. If you remove that line your own code will run, and the OS will also do its own backwards navigation.
Be mindful of Rowland's comment about overriding the Back button - if you're not navigating intuitively you will confuse the user and risk your game being rejected (if you just need to control a pause screen or menu it will be fine, but if you implement something gimmicky like using the Back button as a game control you'll be in trouble).
My blog has the same answer with a bit more detail if you need it:
http://grogansoft.com/blog/?p=572
Whilst it possible to cancel the navigation event, and permissable in a game to present a pause screen or similar, generally it is not allowed to use the back button for anything other than backward navigation in an app; Per requirement 5.2.4 of the Technical certification requirements for Windows Phone
To maintain a consistent user experience, the Back button must only be used for backwards navigation in the app.
If you are creating a XAML app where it is permissible to cancel a "back" operation, such as per 5.2.4.4 of the Technical certification requirements for Windows Phone
:
For games, when the Back button is pressed during gameplay, the game can choose to present a pause context menu or dialog, or it can navigate the user to the prior menu screen.
Then you can implement this by overriding the OnNavigatingFrom method on your page, and set the Cancel property of the NavigatingCancelEventArgs, so something like this example from Frame, page, and navigation features for Windows Phone 8:
protected override void OnNavigatingFrom(NavigatingCancelEventArgs e)
{
base.OnNavigatingFrom(e);
// If the navigation can be cancelled, ask the user if they want to cancel
if (e.IsCancelable)
{
MessageBoxResult result = MessageBox.Show("Do you want to stay here?", "Confirm Navigation from Page", MessageBoxButton.OKCancel);
if (result == MessageBoxResult.OK)
{
// User wants to stay here
e.Cancel = true;
return;
}
}
}
Of course, you may choose to implement the prompt differently, but that should illustrate how it is possible.
I am writing a universal app and when I am testing it on the windows phone emulator when the back key is pressed it just brings me back to the start screen instead of navigating back a page.
This is the first windows phone 8.1 app I have made and I need some help on how to set so that the back key takes you back an app page instead of bringing you out of the app.
You need to handle the HardwareButtons.BackPressed event and plug into your app's navigation system. Commonly you'll find the Frame object, check if frame.CanGoBack, and if so call frame.GoBack. If you're at the app's front page (frame.CanGoBack is false) then don't handle the event and let it back out of the application.
private void HardwareButtons_BackPressed(object sender, BackPressedEventArgs e)
{
Frame frame = Window.Current.Content as Frame;
if (frame == null)
{
return;
}
if (frame.CanGoBack)
{
frame.GoBack();
e.Handled = true;
}
}
See Handling the Back button in a Windows Phone app
The NavigationHelper.cs classes in the non-blank Windows Phone app templates will hook this up for you.
Currently I am working on windows phone 8.
When a textbox get focus in popup window it hide under the keyboard. I've tried subtracting the keyboard height from the VerticalOffset of popup window. But still the textbox is hiding under the keyboard because of the suggestion bar of the keyboard. Is there any way to get the height of keyboard's suggestion bar?
Thanks!!!
Not in a Windows Phone 8 Silverlight app
If you upgrade to a Windows Phone 8.1 Silverlight app (or Runtime, but that's a bigger update) then you can use the InputPane class and examine its OccludedRect property in the Showing event.
This will fire whenever the keyboard changes what it covers, so you'll get the event once when the keyboard first opens and then again when the suggestion bar slides up.
protected override void OnNavigatedTo(NavigationEventArgs e)
{
Windows.UI.ViewManagement.InputPane.GetForCurrentView().Showing += MainPage_Showing;
Windows.UI.ViewManagement.InputPane.GetForCurrentView().Hiding += MainPage_Hiding;
}
protected override void OnNavigatedFrom(NavigationEventArgs e)
{
Windows.UI.ViewManagement.InputPane.GetForCurrentView().Showing -= MainPage_Showing;
Windows.UI.ViewManagement.InputPane.GetForCurrentView().Hiding -= MainPage_Hiding;
}
void MainPage_Hiding(Windows.UI.ViewManagement.InputPane sender, Windows.UI.ViewManagement.InputPaneVisibilityEventArgs args)
{
Debug.WriteLine("Hiding and occluding {0}", sender.OccludedRect.Height);
}
void MainPage_Showing(Windows.UI.ViewManagement.InputPane sender, Windows.UI.ViewManagement.InputPaneVisibilityEventArgs args)
{
Debug.WriteLine("Showing and occluding {0}", sender.OccludedRect.Height);
}
Depending on your layout this may not be necessary on WP8.1. I tested a WP8 app on the WP8.1 emulator and the TextBoxes in my Popup slid out of the way of the suggestion bar as well as out of the way of the keyboard. If your layout is complex enough that doesn't work (e.g. if you need to move things below the focused TextBox as well) then you can handle Showing to move things yourself and then set InputPaneVisibilityEventArgs.EnsuredFocusedElementInView to let the InputPane not to also move things itself.
I've just installed Windows Phone 8.1 SDK, and had an application in mind. But I cant even navigate back and forth! Back button the phone exit the application by default, and since all the pages now inherits "Page" the override for the back button isnt exposed.
Read http://msdn.microsoft.com/en-us/library/windows/apps/xaml/dn639128.aspx but I don't understand it, how can I implement it?
Take a look at any of the WP Projects that are included with Visual Studio (eg: The Hub App project). Or add a new "BasicPage" to your application. You will notice that they are using a NAvigationHelper to subscribe to the BackPressed event for you already. The post you linked to explains it pretty well.
The most important thing to know about the BackPressed event that is raised when the user presses the back button is that if your app does not handle the event, by setting BackPressedEventArgs.Handled property to true, the operating system will suspend your app and return the user to the previous experience
The example is given in that post
private void HardwareButtons_BackPressed(object sender, BackPressedEventArgs e)
{
Frame frame = Window.Current.Content as Frame;
if (frame == null)
{
return;
}
if (frame.CanGoBack)
{
frame.GoBack();
e.Handled = true;
}
}
Notice it sets e.Handled = true; to indicate that the app should not "close". You are saying "Hey, I've got this handled already". In the example, it will navigate to the previous page.