protected virtual void OnPopToRoot(IPageViewModel viewModel, bool animated)
{
var except = PageReferences.FirstOrDefault();
PageReferences.RemoveAll(p => p != except);
PopToRootAsync(animated);
}
/// <summary>
/// Add an imported page to our output
/// @throws IOException, BadPdfFormatException
/// </summary>
/// <param name="iPage">an imported page</param>
public void AddPage(PdfImportedPage iPage)
{
var pageNum = SetFromIPage(iPage);
var thePage = Reader.GetPageN(pageNum);
var origRef = Reader.GetPageOrigRef(pageNum);
Reader.ReleasePage(pageNum);
var key = new RefKey(origRef);
PdfIndirectReference pageRef;
var iRef = (IndirectReferences)Indirects[key];
if (iRef != null && !iRef.Copied)
{
PageReferences.Add(iRef.Ref);
iRef.SetCopied();
}
pageRef = CurrentPage;
if (iRef == null)
{
iRef = new IndirectReferences(pageRef);
Indirects[key] = iRef;
}
iRef.SetCopied();
var newPage = CopyDictionary(thePage);
Root.AddPage(newPage);
++currentPageNumber;
}
protected void OnPopToNewRoot(IPageViewModel viewModel, bool animated)
{
var pref = createPageFor(viewModel);
PageReferences.Clear();
PageReferences.Add(pref);
popToNewRootAsync(pref.View, animated);
}
protected void RemoveReferenceFromStack(ViewLinkHelper reference)
{
if (reference != null)
{
PageReferences.Remove(reference);
ViewModel.EnforcePageDisappearsNotification(reference.Model, true);
}
}
protected void PageDisappears(ViewLinkHelper viewLinkHelper)
{
var removingFromStack = ViewModel.Pages.LastOrDefault() == viewLinkHelper.Model;
if (removingFromStack)
{
PageReferences.Remove(viewLinkHelper);
}
ViewModel.EnforcePageDisappearsNotification(viewLinkHelper.Model, removingFromStack);
}
protected virtual void OnPushViewModel(IPageViewModel viewModel, bool animated)
{
if (PageReferences.Any(p => p.Model == viewModel))
{
throw new Exception(String.Format("The navigation stack already contains the viewModel: {0}", viewModel));
}
var pref = createPageFor(viewModel);
PageReferences.Add(pref);
PushAsync(pref.View, animated);
}
protected virtual void OnPopViewModel(IPageViewModel viewModel, bool animated)
{
if (PageReferences.LastOrDefault()?.Model != viewModel)
{
throw new Exception(String.Format("The viewModel is not the last in the stack: {0}", viewModel));
}
var pageReference = PageReferences.LastOrDefault();
PageReferences.RemoveAt(PageReferences.Count - 1);
if (this.Navigation.NavigationStack.LastOrDefault() == pageReference.View)
{
PopAsync();
}
}
async void updatePages()
{
if (_pages != null && _pages.Count > 0)
{
foreach (var pref in PageReferences.Where(p => !_pages.Contains(p.Model)).ToList())
{
PageReferences.Remove(pref);
}
if (new[] { this.Navigation.NavigationStack.FirstOrDefault(), this.Navigation.NavigationStack.LastOrDefault(), PageReferences.LastOrDefault()?.View }
.All(v => v == PageReferences.FirstOrDefault()?.View))
{
OnPopToRoot(Pages.LastOrDefault(), TransitionAnimationEnabled);
}
else
{
if (Navigation.NavigationStack.Count > 0)
{
var pref = createPageFor(Pages.LastOrDefault());
PageReferences.Clear();
PageReferences.Add(pref);
await popToNewRootAsync(pref.View, TransitionAnimationEnabled);
}
else
{
OnPushViewModel(Pages.LastOrDefault(), TransitionAnimationEnabled);
}
}
}
else
{
//At least on page should be displayed
PageReferences.Clear();
var blankPage = new ContentPage {
BackgroundColor = Color.Transparent
};
if (Navigation.NavigationStack.Count > 0)
{
await popToNewRootAsync(blankPage, TransitionAnimationEnabled);
}
else
{
await PushAsync(blankPage, TransitionAnimationEnabled);
}
}
}
void _pages_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
{
bool wasResetting = resetting;
resetting = false;
if (e.Action == NotifyCollectionChangedAction.Add)
{
if (wasResetting && e.NewItems.OfType <IPageViewModel> ().FirstOrDefault() == PageReferences.FirstOrDefault()?.Model)
{
OnPopToRoot(Pages.LastOrDefault(), TransitionAnimationEnabled);
}
else if (wasResetting)
{
OnPopToNewRoot(e.NewItems.OfType <IPageViewModel> ().LastOrDefault(), TransitionAnimationEnabled);
}
else
{
OnPushViewModel(e.NewItems.OfType <IPageViewModel> ().LastOrDefault(), TransitionAnimationEnabled);
}
}
else if (e.Action == NotifyCollectionChangedAction.Remove)
{
if (PageReferences.LastOrDefault()?.Model == e.OldItems.OfType <IPageViewModel> ().LastOrDefault() && e.OldItems.Count == 1)
{
OnPopViewModel(e.OldItems.OfType <IPageViewModel> ().LastOrDefault(), TransitionAnimationEnabled);
}
else
{
PageReferences.RemoveAll(r => e.OldItems.Contains(r.Model));
}
}
else if (e.Action == NotifyCollectionChangedAction.Reset)
{
resetting = true;
}
}
