Viewmodels are now maintained throughout the app lifecycle

This commit is contained in:
watsonb8 2019-07-15 15:03:59 -04:00
parent 00b39b1d84
commit a3937e78da
9 changed files with 70 additions and 15 deletions

View File

@ -17,5 +17,7 @@ namespace Aurora.Design.Components.NavigationMenu
public string Group { get; set; }
public Type TargetType { get; set; }
public Type TargetViewModelType { get; set; }
}
}

View File

@ -1,7 +1,7 @@
using System;
namespace Aurora.Design.Views.Artists
{
public class ArtistsViewModel
public class ArtistsViewModel : BaseViewModel
{
public ArtistsViewModel()
{

View File

@ -1,6 +1,7 @@
using System;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Threading.Tasks;
namespace Aurora.Design.Views
{
@ -10,6 +11,13 @@ namespace Aurora.Design.Views
{
}
#region Lifecycle
public virtual void OnActive() { }
public virtual void OnInactive() { }
#endregion
#region INotifyPropertyChanged Implementation
public bool SetProperty<T>(ref T storage, T value, [CallerMemberName] string propertyName = null)
{

View File

@ -1,5 +1,6 @@
using System;
using System.Collections.ObjectModel;
using System.Collections.Generic;
using System.Linq;
using Aurora.Design.Components.NavigationMenu;
using Aurora.Design.Views.MainView;
@ -11,10 +12,14 @@ namespace Aurora.Design.Views.Main
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class MainView : MasterDetailPage
{
private Dictionary<int, BaseViewModel> _viewModels;
private BaseViewModel _lastViewModel;
public MainView()
{
InitializeComponent();
BindingContext = new MainViewModel();
_viewModels = new Dictionary<int, BaseViewModel>();
MasterPage.ListView.ItemSelected += ListView_ItemSelected;
Appearing += OnAppearing;
@ -32,6 +37,33 @@ namespace Aurora.Design.Views.Main
var view = (View)Activator.CreateInstance(item.TargetType);
//Check if we have an instantiated viewModel
BaseViewModel vm = new BaseViewModel();
if (_viewModels.ContainsKey(item.Id))
{
_viewModels.TryGetValue(item.Id, out vm);
}
else
{
if (item.TargetViewModelType.BaseType != typeof(BaseViewModel))
{
throw new InvalidOperationException("TargetViewModel field must be of type BaseViewModel");
}
//Instantiate new view model
vm = (BaseViewModel)Activator.CreateInstance(item.TargetViewModelType);
_viewModels.Add(item.Id, vm);
}
//Activate viewmodel
vm.OnActive();
//Deactivate last viewModel
_lastViewModel.OnInactive();
//Assign viewModel
_lastViewModel = vm;
view.BindingContext = vm;
ContentPresenter viewContent = (ContentPresenter)ContentPage.Content.FindByName("ViewContent");
viewContent.Content = view;
@ -47,7 +79,26 @@ namespace Aurora.Design.Views.Main
{
//Set initial view from first item in list
ObservableCollection<NavigationGroupItem> screenList = (ObservableCollection<NavigationGroupItem>)MasterPage.ListView.ItemsSource;
var view = (View)Activator.CreateInstance(screenList.FirstOrDefault().FirstOrDefault().TargetType);
//Assign viewModel
NavigationItem firstNavItem = screenList.FirstOrDefault().FirstOrDefault();
var view = (View)Activator.CreateInstance(firstNavItem.TargetType);
BaseViewModel vm = new BaseViewModel();
if (_viewModels.ContainsKey(firstNavItem.Id))
{
_viewModels.TryGetValue(firstNavItem.Id, out vm);
}
else
{
//Instantiate new view model
vm = (BaseViewModel)Activator.CreateInstance(firstNavItem.TargetViewModelType);
_viewModels.Add(firstNavItem.Id, vm);
}
view.BindingContext = vm;
_lastViewModel = vm;
vm.OnActive();
ContentPresenter viewContent = (ContentPresenter)ContentPage.Content.FindByName("ViewContent");
viewContent.Content = view;

View File

@ -32,12 +32,12 @@ namespace Aurora.Design.Views.MainView
{
_pages = new ObservableCollection<NavigationItem>(new[]
{
new NavigationItem { Id = 4, Title = "Party", Group="Social", TargetType = typeof(PartyView)},
new NavigationItem { Id = 5, Title = "Profile", Group="Social", TargetType = typeof(ProfileView)},
new NavigationItem { Id = 0, Title = "Songs", Group="Library", TargetType = typeof(SongsView) },
new NavigationItem { Id = 1, Title = "Artists", Group="Library", TargetType = typeof(ArtistsView)},
new NavigationItem { Id = 2, Title = "Albums", Group="Library", TargetType = typeof(AlbumsView)},
new NavigationItem { Id = 3, Title = "Stations", Group="Library", TargetType = typeof(StationsView)},
new NavigationItem { Id = 0, Title = "Songs", Group="Library", TargetType = typeof(SongsView), TargetViewModelType = typeof(SongsViewModel) },
new NavigationItem { Id = 1, Title = "Artists", Group="Library", TargetType = typeof(ArtistsView), TargetViewModelType = typeof(ArtistsViewModel)},
new NavigationItem { Id = 2, Title = "Albums", Group="Library", TargetType = typeof(AlbumsView), TargetViewModelType = typeof(AlbumsViewModel)},
new NavigationItem { Id = 3, Title = "Stations", Group="Library", TargetType = typeof(StationsView), TargetViewModelType = typeof(StationsViewModel)},
new NavigationItem { Id = 4, Title = "Party", Group="Social", TargetType = typeof(PartyView), TargetViewModelType = typeof(PartyViewModel)},
new NavigationItem { Id = 5, Title = "Profile", Group="Social", TargetType = typeof(ProfileView), TargetViewModelType = typeof(ProfileViewModel)},
});
}

View File

@ -8,7 +8,6 @@ namespace Aurora.Design.Views.Party
public PartyView()
{
InitializeComponent();
BindingContext = new PartyViewModel();
}
}
}

View File

@ -9,7 +9,6 @@ namespace Aurora.Design.Views.Profile
public ProfileView()
{
InitializeComponent();
BindingContext = new ProfileViewModel();
}
}
}

View File

@ -5,10 +5,6 @@
xmlns:songs="clr-namespace:Aurora.Design.Views.Songs"
xmlns:dg="clr-namespace:Xamarin.Forms.DataGrid;assembly=Xamarin.Forms.DataGrid"
x:Class="Aurora.Design.Views.Songs.SongsView">
<ContentPage.BindingContext>
<songs:SongsViewModel
x:Name="songsViewModel"/>
</ContentPage.BindingContext>
<ContentPage.Content>
<dg:DataGrid
ItemsSource="{Binding SongsList}"

View File

@ -1,7 +1,7 @@
using System;
namespace Aurora.Design.Views.Stations
{
public class StationsViewModel
public class StationsViewModel : BaseViewModel
{
public StationsViewModel()
{