private XamarinFormsPageEventsEmulatedNavigation(
IViewModelResolver viewModelResolver,
IHistoryStack historyStack,
IViewModelLifeCycleHandler viewModelLifeCycleHandler)
: base(viewModelResolver, historyStack, viewModelLifeCycleHandler)
{
HistoryStack = historyStack;
ViewModelLifeCycleHandler = viewModelLifeCycleHandler;
}
public Navigation(
IViewModelResolver viewModelResolver,
IHistoryStack historyStack,
IViewModelLifeCycleHandler viewModelLifeCycle)
{
_viewModelResolver = viewModelResolver;
_historyStack = historyStack;
_viewModelLifeCycle = viewModelLifeCycle;
}
/// <summary>
/// Determines whether the specified <paramref name="view"/> is a member of the stack.
/// </summary>
/// <param name="historyStack">The stack to check.</param>
/// <param name="view">The <see cref="IMXView"/> to check for.</param>
/// <returns><c>true</c> if the view exists in the history stack, or is being displayed; otherwise <c>false</c>.</returns>
public static bool Contains(this IHistoryStack historyStack, IMXView view)
{
var entry = view as IHistoryEntry;
return(historyStack != null && historyStack.Views.Any(v =>
{
var e = v as IHistoryEntry;
if (e != null && entry != null)
{
return e.StackID == entry.StackID;
}
return Equals(v, view);
}));
}
/// <summary>
/// Displays the specified view in the stack.
/// </summary>
/// <param name="stack">The stack to display the view.</param>
/// <param name="view">The view to be displayed.</param>
/// <param name="forceRoot"><c>true</c> to empty the history stack; otherwise <c>false</c></param>
public static void DisplayView(this IHistoryStack stack, IMXView view, bool forceRoot)
{
var entry = view as IHistoryEntry;
var behaviorOptions = Device.Reflector.GetCustomAttributes(view.GetType(), true).OfType <StackBehaviorAttribute>().Select(stackAtt => stackAtt.Options).FirstOrDefault();
var viewForcesRoot = (behaviorOptions & StackBehaviorOptions.ForceRoot) != 0;
if (viewForcesRoot || forceRoot)
{
var root = stack.Views.FirstOrDefault();
if (root == null)
{
stack.PushView(view);
}
else
{
var rootAtt = Device.Reflector.GetCustomAttribute <StackBehaviorAttribute>(root.GetType(), true);
if (!viewForcesRoot && rootAtt != null && (rootAtt.Options & StackBehaviorOptions.ForceRoot) != 0)
{
// If current root is already ForceRoot, let it be
stack.PopToRoot();
stack.PushView(view);
}
else
{
// Otherwise replace it
stack.ReplaceView(root, view);
stack.PopToView(view);
}
}
}
else
{
var current = entry == null ? null : stack.Views.OfType <IHistoryEntry>().FirstOrDefault(e => e.StackID == entry.StackID);
if (current != null)
{
if (current != entry)
{
stack.ReplaceView((IMXView)current, view);
}
stack.PopToView(view);
}
else
{
stack.PushView(view);
}
}
}
/// <summary>
/// Whether this stack can navigate back, given a back button
/// </summary>
public static bool DisplayBackButton(this IHistoryStack stack, Link backButton)
{
if (stack == null || ((backButton == null || backButton.Address == null) && stack.Views.Count() < 2))
{
return(false);
}
if (backButton != null)
{
return(backButton.Action != ActionType.None);
}
var previousView = stack.Views.ElementAtOrDefault(stack.Views.Count() - 2);
if (previousView == null)
{
return(false);
}
var viewAtt = Device.Reflector.GetCustomAttribute <StackBehaviorAttribute>(previousView.GetType(), true);
return(viewAtt == null || (viewAtt.Options & StackBehaviorOptions.HistoryShy) == 0);
}
/// <summary>
/// Executes the appropriate logic for the specified <see cref="Link"/> object, treating it as a back button.
/// </summary>
/// <param name="stack">The stack that contains the view the link object is a part of.</param>
/// <param name="backLink">The link object to be handled.</param>
/// <param name="pane">The pane in which the view containing the back link resides.</param>
public static void HandleBackLink(this IHistoryStack stack, Link backLink, Pane pane)
{
if (backLink == null || backLink.Address == null)
{
var views = stack.Views.ToList();
var view = views.ElementAtOrDefault(views.Count() - 2);
if (view != null && !PaneManager.Instance.ShouldNavigate(new Link(PaneManager.Instance.GetNavigatedURI(view),
new Dictionary <string, string>()), pane, NavigationType.Back))
{
return;
}
if (backLink != null)
{
if (backLink.Action == ActionType.None)
{
return;
}
if (string.IsNullOrEmpty(backLink.ConfirmationText))
{
if (view == null)
{
stack.PopView();
}
else
{
PaneManager.Instance.DisplayView(view);
}
}
else
{
var newLink = backLink.Clone();
newLink.ConfirmationText = null;
var alert = new Alert(backLink.ConfirmationText, iApp.Factory.GetResourceString("ConfirmTitle"), AlertButtons.OKCancel);
alert.Dismissed += (o, e) =>
{
if (e.Result == AlertResult.OK)
{
if (view == null)
{
stack.PopView();
}
else
{
PaneManager.Instance.DisplayView(view);
}
}
};
alert.Show();
}
}
else
{
if (view == null)
{
stack.PopView();
}
else
{
PaneManager.Instance.DisplayView(view);
}
}
}
else
{
iApp.Navigate(backLink, stack.CurrentView);
}
}
/// <summary>
/// Whether this stack can navigate back
/// </summary>
public static bool CanGoBack(this IHistoryStack stack)
{
var entry = stack.CurrentView as IHistoryEntry;
return(stack.DisplayBackButton(entry == null ? null : entry.BackLink));
}
/// <summary>
/// Finds the <see cref="Pane"/> in which the stack is displayed.
/// </summary>
/// <param name="stack">The stack displayed in a pane.</param>
/// <returns>The <see cref="Pane"/> in which the stack is displayed.</returns>
public static Pane FindPane(this IHistoryStack stack)
{
return(PaneManager.Instance.NavContextFromKey(PaneManager.Instance.HistoryStacks.First(s => s.Value == stack).Key).ActivePane);
}
/// <summary>
/// Determines whether the specified stack has views in its history.
/// </summary>
/// <param name="stack">The stack to check.</param>
/// <returns><c>true</c> if the <see cref="IHistoryStack.Views"/> collection contains more than one view; otherwise <c>false</c>.</returns>
public static bool HasHistory(this IHistoryStack stack)
{
return(stack.Views.Where(v => v != stack.CurrentView)
.Select(view => Device.Reflector.GetCustomAttribute <StackBehaviorAttribute>(view.GetType(), true))
.Any(behavior => behavior == null || (behavior.Options & StackBehaviorOptions.HistoryShy) == 0));
}
/// <summary>
/// Displays the specified view in the stack.
/// </summary>
/// <param name="stack">The stack to display the view.</param>
/// <param name="view">The view to be displayed.</param>
public static void DisplayView(this IHistoryStack stack, IMXView view)
{
stack.DisplayView(view, false);
}
