I'm trying to close my Wp7 app when the back is pressed in emulator.I have tried the code on that page from which I would close the whole app.the code is given below:
protected override void OnBackKeyPress(System.ComponentModel.CancelEventArgs e)
{
base.OnBackKeyPress(e);
if (NavigationService.CanGoBack)
{
while (NavigationService.RemoveBackEntry() != null)
{
NavigationService.RemoveBackEntry();
}
}
}
Help needed !
Thanks in advance!
First of all, There is no way to close wp7 application programatically.
And to do this you need not override back key press. When in the first page(ideally the home page or main page), pressing back key automatically closes the application.
Related
Is there any way to detect the press of the back button of the Navigation Page in Xamarin forms?
You can override your navigation page "OnBackButtonPressed" method:
protected override bool OnBackButtonPressed()
{
Device.BeginInvokeOnMainThread(async () =>
{
if (await DisplayAlert("Exit?", "Are you sure you want to exit from this page?", "Yes", "No"))
{
base.OnBackButtonPressed();
await App.Navigation.PopAsync();
}
});
return true;
}
If you are using the shell, you can override the Shell's OnNavigating event:
void OnNavigating(object sender, ShellNavigatingEventArgs e)
{
// Cancel back navigation if data is unsaved
if (e.Source == ShellNavigationSource.Pop && !dataSaved)
{
e.Cancel();
}
}
Update:
OnBackButtonPressed event will get fired ONLY on Android when user press the Hardware back button.
Seems like you are more interested to implement when any page get disappeared you want to do something!
In that case:
You have the page's two methods -
protected override void OnAppearing()
{
base.OnAppearing();
Console.WriteLine("Hey, Im coming to your screen");
}
protected override void OnDisappearing()
{
base.OnDisappearing();
Console.WriteLine("Hey, Im going from your screen");
}
You can override those 2 methods on any page to track when they appear and disappear.
Recent updates to Xamarin forms mean you can now do this in an application made with Shell Navigation for navigation back arrow on both platforms.
Use the Shell.SetBackButtonBehavior method, for example running this code in the constructor of your page object will allow the back navigation to take place only when the bound viewmodel is not busy:
Shell.SetBackButtonBehavior(this, new BackButtonBehavior
{
Command = new Command(async() =>
{
if (ViewModel.IsNotBusy)
{
await Shell.Current.Navigation.PopAsync();
}
})
});
In the body of the Command you can do whatever you need to do when you are intercepting the click of the back button.
Note that this will affect only the navigation back button, not the Android hardware back button - that will need handling separately as per the answers above. You could write a shared method called from both the back button pressed override and the command on shell back button behaviour places to share the logic.
You must override native navigationbar button behavior with custom renderer. OnBackButtonPressed triggers only physical device button. You can read good article how to achive this here
I want to do some work if user presses back key on the phone with navigating back How to do it?
With following code it cancel navigation to back page & do some stuff but i want to do stuff while going back please help...
protected override void OnBackKeyPress(System.ComponentModel.CancelEventArgs e)
{
// do some stuff...
e.Cancel = true;
}
I am working on WP7 Phonegap app. I have used below code to handle back button, but whenever I click back button , back button event is not cancelled and application gets exited.
void OnBackKeyPressed(object sender, CancelEventArgs e)
{
var result = MessageBox.Show("Dof fd fd you want to exit?", "Attention!",
MessageBoxButton.OKCancel);
if (result == MessageBoxResult.OK)
{
// Do not cancel navigation
return;
}
e.Cancel = true;
}
Please helpme on same.
Thanks in advance.
One of the lead devs for the Windows Phone implementation of PhoneGap recently wrote about correctly handling the back button.
See his article at http://www.risingj.com/archives/493
I have a main page with some options. One of them is to navigate to page 1 where there are two arrows. One that navigates to page2, page3, and the other arrow page3, page2, page1 like a loop. There is also an arrow that navigates to main page.
I want to ask if there is a way when the user presses the back button to terminate the app from whatever page the user is currently at and not to navigate through all pages.
edit
if i want when i press the back to always navigate to the mainpage what i have to do ?
clear the back stack inside the onbackkeypress function where you want to exit the app. And it will exit the app normally.
[Updated]
1) after clearing back stack. Use NavigationService.Navigate(new Uri("MainPage.xaml",UriKind.Relative)); to traverse to mainpage and do e.Cancel = true in the next statement.
2) Or clear the back stack upto the mainpage. and automatically the back press will take you to the mainpage. inside the mainpage clear the back stack fully inside the OnNavigatedTo function so that the first item is always your mainpage and user can exit easily.
protected override void OnBackKeyPress(System.ComponentModel.CancelEventArgs e)
{
while (NavigationService.CanGoBack)
NavigationService.RemoveBackEntry();
e.Cancel = true;
return;
}
protected override void OnBackKeyPress(System.ComponentModel.CancelEventArgs e)
{
while (NavigationService.CanGoBack)
NavigationService.RemoveBackEntry();
}
Throw an exception in OnBackKeyPress which terminates the app.
protected override void OnBackKeyPress(System.ComponentModel.CancelEventArgs e)
{
throw an exception();
}
You can also do like this,
check
e.NavigationMode == System.Windows.Navigation.NavigationMode.Back
in OnNavigatedTo event (you need to override this every page) and call
NavigationService.GoBack();
there is no direct way of exiting an app.. see here
hope this will work. If its XNA
if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
this.Exit();
I have an application, the main page contains few functions. To explain in detail - I have save, color palette button in my main page. When any of these buttons are clicked, save pop up or color palette appears. How to handle back button of the device, when color palette or save pop up is opened. When back button is pressed at these scenario it should just make them invisible and stay on the main page. When nothing is being performed in the main page, then it should come out of the app. I tried to make their visibility collapsed on back button press. But it still is coming out of the application.
Please, guide me in this. Thanks in advance.
Override PhoneApplicationPage.OnBackKeyPress and then set CancelEventArgs.Cancel to true if you want to stop it from actually going back.
protected override void OnBackKeyPress(CancelEventArgs args)
{
if (PanelIsShowing)
{
HidePanel();
args.Cancel = true;
}
}
The back button behaves as is intended by Microsoft.
If you change its behavior you risk your application not being certified for the Marketplace.
If you want the back button to close the popups, turn the popups into pages so the back button navigates back to the main page..
You need to use
protected override void OnBackKeyPress(CancelEventArgs e)
{
if (_popup.IsOpen)
{
_popup.IsOpen= false;
e.Cancel = true;
}
else
{
base.OnBackKeyPress(e);
}
}
That should do the trick.