Cant Exit the App After Make BackButton Override Method in Xamarin Forms

Question

So Previously I wanted to make my app to go back to MainPage after the Pyshical BackButton is pressed. I've already done that but the problem is when I am on MainPage and press the Pyhsical Button, instead of closing the App it doesn't go anywhere. The second problem is when the page stack is 2 (MainPage > News > NewsDetail) it goes directly to MainPage (DetailNews > MainPage). What I want to do is to pop to previouse Page (DetailNews > News > MainPage > ). Here is my full code for overide the backbutton

  public bool DoBack
        {
            get
            {
                MasterDetailPage mainPage = App.Current.MainPage as MasterDetailPage;

                if (mainPage != null)
                {
                    bool canDoBack = mainPage.Detail.Navigation.NavigationStack.Count > 1 || mainPage.IsPresented;

                    // we are on a top level page and the Master menu is NOT showing
                    if (!canDoBack)
                    {
                        // don't exit the app just show Dashboard
                        //mainPage.IsPresented = true;

                        Type page = typeof(DrawerPage);

                        mainPage.Detail = new NavigationPage((Page)Activator.CreateInstance(page));
                        return false;
                    }
                    else
                    {
                        return true;
                    }
                }
                return true;
            }
        }

What Code should i Add or change here to do that, Any Sugestion ?

Answer 1

Im Already Found the solution im override OnBackButtonPressed in every Detail Page

  protected override bool OnBackButtonPressed()
            {
                Device.BeginInvokeOnMainThread(async () => {
                    Application.Current.MainPage = new DrawerPage();
                });

                return true;
            }

Answer 2

The first problem: You logic is wrong. You need to return true if you want to stay on MainPage.

  public bool DoBack
        {
            get
            {
                MasterDetailPage mainPage = App.Current.MainPage as MasterDetailPage;

                if (mainPage != null)
                {
                    bool canDoBack = mainPage.Detail.Navigation.NavigationStack.Count > 1 || mainPage.IsPresented;

                    // we are on a top level page and the Master menu is NOT showing
                    if (!canDoBack)
                    {
                        // don't exit the app just show Dashboard
                        //mainPage.IsPresented = true;

                        Type page = typeof(DrawerPage);

                        mainPage.Detail = new NavigationPage((Page)Activator.CreateInstance(page));
                        return true;
                    }
                    else
                    {
                        return false;
                    }
                }
                return true;
            }
        }

The second problem: The reason why it goes directly to MainPage from DetailsNews is because you call PopToRoot instead of Pop. Read this article.