Xamarin.forms: How detect pressed software button NavigationBack?

[scriptBoris]

No way how catch pressed software button NavigationBack.

[VladislavAntonyuk]

you can override OnAppearing, OnDisappearing in code behind

[scriptBoris]

you can override OnAppearing, OnDisappearing in code behind

Override OnAppearing and OnDisappearing - can not break action NavigationBack, when user taped button (software) Back.

[scriptBoris]

The question is still relevant.

[KSemenenko]

@scriptBoris you need override OnBackButtonPressed() in your page.

protected override bool OnBackButtonPressed()
{
    //put your logic here
}

And you need to return true or false depending on whether you want to do the navigation back or not.

[VladislavAntonyuk]

@KSemenenko this code is not executed

[KSemenenko]

https://docs.microsoft.com/en-us/dotnet/api/xamarin.forms.navigationpage.onbackbuttonpressed?view=xamarin-forms

@VladislavAntonyuk you can try next code, and put break point.

protected override bool OnBackButtonPressed()
{
    return OnBackButtonPressed();
}

If you return true from then you will not go back to the previous page, unless you also call the base method in your override.

[VladislavAntonyuk]

@Ksemenenko if you press back button of android the code is executed, but the question is about arrow. See screenshot

[KSemenenko]

https://theconfuzedsourcecode.wordpress.com/2017/03/12/lets-override-navigation-bar-back-button-click-in-xamarin-forms/
@VladislavAntonyuk

[KSemenenko]

@VladislavAntonyuk @scriptBoris also if you check https://github.com/xamarin/Xamarin.Forms/blob/master/Xamarin.Forms.Platform.Android/AppCompat/FormsAppCompatActivity.cs then find that the code is already there and my code should work. But it is not. What version of Xamarin.Forms are you using?
Are you using NavigationPage or MasterDetailPage?

[scriptBoris]

https://theconfuzedsourcecode.wordpress.com/2017/03/12/lets-override-navigation-bar-back-button-click-in-xamarin-forms/
@VladislavAntonyuk

Xamarin Forms 4.1
MasterPage, MasterDetail - NavigationPage ...

[scriptBoris]

The problem is not solved. Help please!

[KSemenenko]

Seems it's a bug, I will look for a solution to the problem

[hartez]

There is no simple way to do this. As pointed out upthread, there are some hacks and tricks you can employ to do this (see: https://xamarinhelp.com/xamarin-forms-back-navigation-pitfalls/).

If this is a feature you would like, I suggest opening a feature request.

[hartez]

@scriptBoris Another option would be to move your application to use Xamarin.Forms Shell - Shell has a Navigating event that you can intercept and cancel: https://docs.microsoft.com/en-us/xamarin/xamarin-forms/app-fundamentals/shell/navigation#navigation-events