Merge pull request PrismLibrary#77 from almirvuk/feature/ConfirmNavig…

…ation

ConfirmNavigation Sample implementation.

20-ConfirmNavigation/ReadMe.md

@@ -1,6 +1,7 @@
 # Confirm Navigation
 
-TODO
+* **ViewAPage** is tab page, and it contains `Switch` and `Button` control, `Switch` is binding to `CanNavigateAway` property. `ViewAPageViewModel ` is implementing `IConfirmNavigation` interface and `CanNavigateAway` is used for returning value in `CanNavigate` method.
 
-- Show use of IConfirmNavigation
-- Show use of IConfirmNavigationAsync
+* **ViewBPage** is tab page, and it contains `Button`, `Button` and `Command` property is binding to `NavigateAwayCommand`. `ViewBPageViewModel` is implementing `IConfirmNavigationAsync` interface and I am using `IPageDialogService` to ask user for confirm to navigate away, response from `DisplayAlertAsync` is used for return value of `CanNavigateAsync` method.
+
+* **ViewCPage** is only used for navigating to it, and to show some kind of message with `Label` control. It also has `Button` to navigate back (GoBacAsync).

20-ConfirmNavigation/src/PrismSample/App.xaml.cs

@@ -1,5 +1,4 @@
-using System;
-using Prism.Ioc;
+using Prism.Ioc;
 using PrismSample.ViewModels;
 using PrismSample.Views;
 using Xamarin.Forms;
@@ -16,7 +15,7 @@ protected override async void OnInitialized()
         {
             InitializeComponent();
 
-            var result = await NavigationService.NavigateAsync("MainPage");
+            var result = await NavigationService.NavigateAsync("TabbedPage?createTab=NonAsyncExamplePage&createTab=AsyncExamplePage");
 
             if(!result.Success)
             {
@@ -27,7 +26,10 @@ protected override async void OnInitialized()
         protected override void RegisterTypes(IContainerRegistry containerRegistry)
         {
             containerRegistry.RegisterForNavigation<NavigationPage>();
-            containerRegistry.RegisterForNavigation<MainPage, MainPageViewModel>();
+            containerRegistry.RegisterForNavigation<TabbedPage>();
+            containerRegistry.RegisterForNavigation<NonAsyncExamplePage, NonAsyncExamplePageViewModel>();
+            containerRegistry.RegisterForNavigation<AsyncExamplePage, AsyncExamplePageViewModel>();
+            containerRegistry.RegisterForNavigation<ResultPage, ResultPageViewModel>();
         }
     }
 }

20-ConfirmNavigation/src/PrismSample/ViewModels/AsyncExamplePageViewModel.cs

@@ -0,0 +1,34 @@
+using System.Threading.Tasks;
+using Prism.Navigation;
+using Prism.Commands;
+using Prism.Services;
+
+namespace PrismSample.ViewModels
+{
+    public class AsyncExamplePageViewModel : IConfirmNavigationAsync
+    {
+        private readonly INavigationService _navigationService;
+        private readonly IPageDialogService _pageDialogService;
+
+        public DelegateCommand NavigateAwayCommand { get; private set; }
+
+        public AsyncExamplePageViewModel(INavigationService navigationService, 
+            IPageDialogService pageDialogService)
+        {
+            _navigationService = navigationService;
+            _pageDialogService = pageDialogService;
+
+            NavigateAwayCommand = new DelegateCommand(NavigateAway);
+        }
+
+        private async void NavigateAway()
+        {
+            await _navigationService.NavigateAsync("ResultPage");
+        }
+
+        public Task<bool> CanNavigateAsync(INavigationParameters parameters)
+        {
+            return _pageDialogService.DisplayAlertAsync(string.Empty, "Are you sure you want to navigate away?", "Yes", "No");
+        }
+    }
+}

20-ConfirmNavigation/src/PrismSample/ViewModels/NonAsyncExamplePageViewModel.cs

@@ -0,0 +1,37 @@
+using Prism.Navigation;
+using Prism.Commands;
+using Prism.Mvvm;
+
+namespace PrismSample.ViewModels
+{
+    public class NonAsyncExamplePageViewModel : BindableBase, IConfirmNavigation
+    {
+        private readonly INavigationService _navigationService;
+
+        private bool _canNavigateAway;
+        public bool CanNavigateAway
+        {
+            get { return _canNavigateAway; }
+            set { SetProperty(ref _canNavigateAway, value); }
+        }
+
+        public DelegateCommand NavigateAwayCommand { get; private set; }
+
+        public NonAsyncExamplePageViewModel(INavigationService navigationService)
+        {
+            _navigationService = navigationService;
+
+            NavigateAwayCommand = new DelegateCommand(NavigateAway);
+        }
+
+        private async void NavigateAway()
+        {
+            await _navigationService.NavigateAsync("ResultPage");
+        }
+
+        public bool CanNavigate(INavigationParameters parameters)
+        {
+            return CanNavigateAway;
+        }
+    }
+}

20-ConfirmNavigation/src/PrismSample/ViewModels/ResultPageViewModel.cs

@@ -0,0 +1,24 @@
+using Prism.Navigation;
+using Prism.Commands;
+
+namespace PrismSample.ViewModels
+{
+    public class ResultPageViewModel
+    {
+        private readonly INavigationService _navigationService;
+
+        public DelegateCommand GoBackCommand { get; private set; }
+
+        public ResultPageViewModel(INavigationService navigationService) 
+        {
+            _navigationService = navigationService;
+
+            GoBackCommand = new DelegateCommand(GoBack);
+        }
+
+        private async void GoBack()
+        {
+            await _navigationService.GoBackAsync();
+        }
+    }
+}

20-ConfirmNavigation/src/PrismSample/Views/AsyncExamplePage.xaml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             x:Class="PrismSample.Views.AsyncExamplePage"
+             Title="Async">
+  <StackLayout VerticalOptions="Center" Margin="16">
+
+    <Label Text="IConfirmNavigationAsync Example" 
+           HorizontalOptions="Center"/>
+
+    <Button Text="Navigate away"
+            Command="{Binding NavigateAwayCommand}"
+            HorizontalOptions="Center"/>
+
+  </StackLayout>
+
+</ContentPage>

20-ConfirmNavigation/src/PrismSample/Views/AsyncExamplePage.xaml.cs

@@ -0,0 +1,12 @@
+using Xamarin.Forms;
+
+namespace PrismSample.Views
+{
+    public partial class AsyncExamplePage : ContentPage
+    {
+        public AsyncExamplePage()
+        {
+            InitializeComponent();
+        }
+    }
+}

20-ConfirmNavigation/src/PrismSample/Views/NonAsyncExamplePage.xaml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             x:Class="PrismSample.Views.NonAsyncExamplePage"
+             Title="Non-Async">
+
+  <StackLayout VerticalOptions="Center" 
+               Margin="16">
+
+    <Label Text="Can navigate?" 
+           HorizontalOptions="Center"/>
+
+    <Switch IsToggled="{Binding CanNavigateAway}" 
+            HorizontalOptions="Center"/>
+
+    <Button Text="Navigate away" 
+            HorizontalOptions="Center"
+            Command="{Binding NavigateAwayCommand}"/>
+
+  </StackLayout>
+
+</ContentPage>

20-ConfirmNavigation/src/PrismSample/Views/NonAsyncExamplePage.xaml.cs

@@ -0,0 +1,12 @@
+using Xamarin.Forms;
+
+namespace PrismSample.Views
+{
+    public partial class NonAsyncExamplePage : ContentPage
+    {
+        public NonAsyncExamplePage()
+        {
+            InitializeComponent();
+        }
+    }
+}

20-ConfirmNavigation/src/PrismSample/Views/ResultPage.xaml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             x:Class="PrismSample.Views.ResultPage">
+
+  <StackLayout VerticalOptions="Center" Margin="16">
+
+    <Label Text="Congratulations! You did it!"
+           FontAttributes="Bold" 
+           HorizontalOptions="Center"/>
+
+    <Button Text="Go back" 
+            HorizontalOptions="Center"
+            Command="{Binding GoBackCommand}" />
+
+  </StackLayout>
+
+</ContentPage>

20-ConfirmNavigation/src/PrismSample/Views/ResultPage.xaml.cs

@@ -0,0 +1,12 @@
+using Xamarin.Forms;
+
+namespace PrismSample.Views
+{
+    public partial class ResultPage : ContentPage
+    {
+        public ResultPage()
+        {
+            InitializeComponent();
+        }
+    }
+}