/// <summary>
/// Calls <see cref="StackNavigatorExtensions.Navigate{TViewModel}(IStackNavigator, CancellationToken, Func{TViewModel}, bool)"/> on this <see cref="ISectionsNavigator"/>'s active stack navigator.
/// </summary>
/// <param name="sectionsNavigator">The sections navigator.</param>
/// <param name="ct">The cancellation token.</param>
/// <param name="viewModelProvider">The method to invoke to instanciate the ViewModel.</param>
/// <param name="suppressTransition">Whether to suppress the navigation transition.</param>
public static async Task <TViewModel> Navigate <TViewModel>(this ISectionsNavigator sectionsNavigator, CancellationToken ct, Func <TViewModel> viewModelProvider, bool suppressTransition = false)
where TViewModel : INavigableViewModel
{
var navigator = GetActiveStackNavigator(sectionsNavigator);
return(await navigator.Navigate(ct, viewModelProvider, suppressTransition));
}
/// <summary>
/// Opens a new modal.
/// </summary>
/// <typeparam name="TViewModel">The type of the view model.</typeparam>
/// <param name="sectionsNavigator">The sections navigator.</param>
/// <param name="ct"></param>
/// <param name="viewModelProvider">The method invoked to instanciate the new ViewModel.</param>
/// <param name="priority">The modal's priority.</param>
/// <param name="name">The modal's name.</param>
/// <returns>The newly created ViewModel instance.</returns>
public static async Task <TViewModel> OpenModal <TViewModel>(this ISectionsNavigator sectionsNavigator, CancellationToken ct, Func <TViewModel> viewModelProvider, int?priority = null, string name = null)
where TViewModel : INavigableViewModel
{
var modalNavigator = await sectionsNavigator.OpenModal(ct, SectionsNavigatorRequest.GetOpenModalRequest(StackNavigatorRequest.GetNavigateRequest(viewModelProvider, suppressTransition: true), name, priority));
// Note that modalNavigator can be null if the OpenModal gets cancelled.
return((TViewModel)modalNavigator?.GetActiveViewModel());
}
/// <summary>
/// Gets an observable of the last page type from currently active section.
/// The observable pushes a value whenever a navigation request is processed with the type of the last page ViewModel.
/// </summary>
/// <returns>An observable of types.</returns>
public static IObservable <Type> ObserveActiveSectionLastPageType(this ISectionsNavigator sectionsNavigator)
{
return(sectionsNavigator
.ObserveStateChanged()
.Where(args => args.EventArgs.CurrentState.LastRequestState == NavigatorRequestState.Processed)
.Select(args =>
{
var state = args.EventArgs.CurrentState;
return state.ActiveSection?.State.Stack.LastOrDefault()?.ViewModel.GetType();
})
.StartWith(sectionsNavigator.State.ActiveSection?.State.Stack.LastOrDefault()?.ViewModel.GetType()));
}
/// <summary>
/// Executes back action depending on top-most frame state.
/// </summary>
/// <remarks>
/// Priorities:
/// <list type="number">
/// <item>Navigates back within the modal, if possible.</item>
/// <item>Closes the modal, if possible.</item>
/// <item>Navigates back within a section.</item>
/// </list>
/// This is useful when dealing with hardware back buttons.
/// </remarks>
/// <param name="sectionsNavigator">The sections navigator.</param>
/// <param name="ct">The cancellation token.</param>
public static async Task NavigateBackOrCloseModal(this ISectionsNavigator sectionsNavigator, CancellationToken ct)
{
if (sectionsNavigator.State.ActiveModal?.CanNavigateBack() ?? false)
{
await sectionsNavigator.State.ActiveModal.NavigateBack(ct);
}
else if (sectionsNavigator.State.ActiveModal != null)
{
await sectionsNavigator.CloseModal(ct);
}
else if (sectionsNavigator.State.ActiveSection?.CanNavigateBack() ?? false)
{
await sectionsNavigator.State.ActiveSection.NavigateBack(ct);
}
else
{
throw new InvalidOperationException($"Failed to NavigateBack or CloseModal. The active section '{sectionsNavigator.State.ActiveSection?.Name ?? "null"}' can't currently navigate back and there are no modals to close.");
}
}
/// <summary>
/// Creates a new instance of <see cref="SectionsNavigatorToStackNavigatorAdapter"/> from the specified adaptee.
/// </summary>
/// <param name="sectionsNavigator">The sections navigator to adapt into a <see cref="IStackNavigator"/>.</param>
public SectionsNavigatorToStackNavigatorAdapter(ISectionsNavigator sectionsNavigator)
{
_sectionsNavigator = sectionsNavigator;
}
/// <summary>
/// Gets an observable sequence that produces values whenever <see cref="ISectionsNavigator.StateChanged"/> is raised, pushing only the <see cref="SectionsNavigatorEventArgs.CurrentState"/> value.
/// </summary>
/// <param name="navigator">The sections navigator.</param>
/// <returns>An observable sequence of <see cref="SectionsNavigatorState"/>.</returns>
public static IObservable <SectionsNavigatorState> ObserveCurrentState(this ISectionsNavigator navigator)
{
return(navigator
.ObserveStateChanged()
.Select(pattern => pattern.EventArgs.CurrentState));
}
/// <summary>
/// Gets an observable sequence that produces values whenever <see cref="ISectionsNavigator.StateChanged"/> is raised.
/// </summary>
/// <param name="navigator">The sections navigator.</param>
/// <returns>An observable sequence of <see cref="EventPattern{SectionsNavigatorEventArgs}"/>.</returns>
public static IObservable <EventPattern <SectionsNavigatorEventArgs> > ObserveStateChanged(this ISectionsNavigator navigator)
{
return(Observable
.FromEventPattern <SectionsNavigatorStateChangedEventHandler, SectionsNavigatorEventArgs>(
handler => navigator.StateChanged += handler,
handler => navigator.StateChanged -= handler
));
}
/// <summary>
/// Closes the top-most modal.
/// </summary>
/// <param name="sectionsNavigator">The sections navigator.</param>
/// <param name="ct">The cancellation token.</param>
public static async Task CloseModal(this ISectionsNavigator sectionsNavigator, CancellationToken ct)
{
await sectionsNavigator.CloseModal(ct, SectionsNavigatorRequest.GetCloseModalRequest(modalPriority: null));
}
/// <summary>
/// Sets the active section using the provided section name and navigates.
/// </summary>
/// <typeparam name="TViewModel">The type of the view model.</typeparam>
/// <param name="sectionsNavigator">The sections navigator.</param>
/// <param name="ct">The cancellation token.</param>
/// <param name="sectionName">The name of the section to set as active.</param>
/// <param name="viewModelProvider">The method to make the view model instance. It will be invoked only if necessary.</param>
/// <param name="returnToRoot">When this is true, the navigator will navigate back to the view model matching the type <typeparamref name="TViewModel"/>.</param>
/// <returns>The stack navigator of the active section.</returns>
public static async Task <ISectionStackNavigator> SetActiveSection <TViewModel>(this ISectionsNavigator sectionsNavigator,
CancellationToken ct,
string sectionName,
Func <TViewModel> viewModelProvider,
bool returnToRoot = false)
where TViewModel : INavigableViewModel
{
if (ct.IsCancellationRequested)
{
typeof(SectionsNavigatorExtensions).Log().LogWarning($"Canceled 'SetActiveSection' operation to '{typeof(TViewModel).Name}' because of cancellation token.");
return(null);
}
// No cancellation beyond this point.
ct = CancellationToken.None;
var sectionNavigator = sectionsNavigator.State.Sections[sectionName];
if (sectionNavigator.State.Stack.LastOrDefault() == null)
{
// Create the default page if there's nothing in the section.
await sectionNavigator.Navigate(ct, StackNavigatorRequest.GetNavigateRequest(viewModelProvider, suppressTransition: true));
}
else if (returnToRoot && sectionNavigator.State.Stack.Last().ViewModel.GetType() != typeof(TViewModel))
{
if (sectionNavigator.State.Stack.Any(e => e.ViewModel.GetType() == typeof(TViewModel)))
{
// If the stack contains the root page of the section, remove all other entries and navigate back to it.
var indexesToRemove = sectionNavigator.State.Stack
.Select((entry, index) => (entry, index))
.Where(t => t.entry.ViewModel.GetType() != typeof(TViewModel) && t.index < sectionNavigator.State.Stack.Count - 1)
.Select(t => t.index)
.ToList();
await sectionNavigator.RemoveEntries(ct, indexesToRemove);
await sectionNavigator.NavigateBack(ct);
}
else
{
// If the section root page isn't in the stack, clear everything and navigate to it.
await sectionNavigator.Navigate(ct, StackNavigatorRequest.GetNavigateRequest(viewModelProvider, suppressTransition: true, clearBackStack: true));
}
}
return(await sectionsNavigator.SetActiveSection(ct, SectionsNavigatorRequest.GetSetActiveSectionRequest(sectionName)));
}
/// <summary>
/// Sets the active section using the provided section name.
/// </summary>
/// <param name="sectionsNavigator">The sections navigator.</param>
/// <param name="ct">The cancellation token.</param>
/// <param name="sectionName">The name of the section to set as active.</param>
/// <returns>The stack navigator of the active section.</returns>
public static Task <ISectionStackNavigator> SetActiveSection(this ISectionsNavigator sectionsNavigator, CancellationToken ct, string sectionName)
{
return(sectionsNavigator.SetActiveSection(ct, SectionsNavigatorRequest.GetSetActiveSectionRequest(sectionName)));
}
/// <summary>
/// Calls <see cref="StackNavigatorExtensions.GetActiveViewModel(IStackNavigator)"/> on this <see cref="ISectionsNavigator"/>'s active stack navigator.
/// </summary>
/// <param name="sectionsNavigator">The sections navigator.</param>
public static INavigableViewModel GetActiveViewModel(this ISectionsNavigator sectionsNavigator)
{
var navigator = GetActiveStackNavigator(sectionsNavigator);
return(navigator.GetActiveViewModel());
}
/// <summary>
/// Calls <see cref="StackNavigatorExtensions.RemovePrevious(IStackNavigator, CancellationToken)"/> on this <see cref="ISectionsNavigator"/>'s active stack navigator.
/// </summary>
/// <param name="sectionsNavigator">The sections navigator.</param>
/// <param name="ct">The cancellation token.</param>
public static async Task RemovePrevious(this ISectionsNavigator sectionsNavigator, CancellationToken ct)
{
var navigator = GetActiveStackNavigator(sectionsNavigator);
await navigator.RemovePrevious(ct);
}
/// <summary>
/// Calls <see cref="IStackNavigator.NavigateBack(CancellationToken)"/> on this <see cref="ISectionsNavigator"/>'s active stack navigator.
/// </summary>
/// <param name="sectionsNavigator">The sections navigator.</param>
/// <param name="ct">The cancellation token.</param>
public static async Task NavigateBack(this ISectionsNavigator sectionsNavigator, CancellationToken ct)
{
var navigator = GetActiveStackNavigator(sectionsNavigator);
await navigator.NavigateBack(ct);
}
/// <summary>
/// Gets the active <see cref="IStackNavigator"/> of this <see cref="ISectionsNavigator"/>.
/// </summary>
/// <remarks>
/// The result can be null if no navigator is active.
/// </remarks>
/// <param name="sectionsNavigator">The sections navigator.</param>
public static IStackNavigator GetActiveStackNavigator(this ISectionsNavigator sectionsNavigator)
{
return(sectionsNavigator.State.GetActiveStackNavigator());
}
/// <summary>
/// Gets whether the <see cref="ISectionsNavigator"/> can navigate back or close a modal.
/// </summary>
/// <remarks>
/// This is useful when dealing with hardware back buttons.
/// </remarks>
/// <param name="sectionsNavigator">The sections navigator.</param>
/// <returns>True if the navigator can navigate back or close a modal. False otherwise.</returns>
public static bool CanNavigateBackOrCloseModal(this ISectionsNavigator sectionsNavigator)
{
return((sectionsNavigator.State.ActiveSection?.CanNavigateBack() ?? false) || sectionsNavigator.State.Modals.Any());
}
