protected override void AddChildView(VisualElement childView)
{
_pageContainer = null;
Page page = childView as NavigationPage ?? (Page)(childView as TabbedPage);
if (page == null)
{
// The thing we're adding is not a NavigationPage or TabbedPage, so we can just use the old AddChildView
if (_currentFragment != null)
{
if (!_parent.IsAttachedToRoot())
{
return;
}
// But first, if the previous occupant of this container was a fragment, we need to remove it properly
FragmentTransaction transaction = FragmentManager.BeginTransactionEx();
transaction.RemoveEx(_currentFragment);
transaction.SetTransitionEx((int)FragmentTransit.None);
if (IsAttachedToWindow)
{
ExecuteTransaction(transaction);
}
else
{
_transaction = transaction;
}
_currentFragment = null;
}
base.AddChildView(childView);
}
else
{
if (!_parent.IsAttachedToRoot())
{
return;
}
// The renderers for NavigationPage and TabbedPage both host fragments, so they need to be wrapped in a
// FragmentContainer in order to get isolated fragment management
Fragment fragment = FragmentContainer.CreateInstance(page);
var fc = fragment as FragmentContainer;
fc?.SetOnCreateCallback(pc =>
{
_pageContainer = pc;
UpdateFlowDirection();
SetDefaultBackgroundColor(pc.Child);
});
FragmentTransaction transaction = FragmentManager.BeginTransactionEx();
if (_currentFragment != null)
{
transaction.RemoveEx(_currentFragment);
}
transaction.AddEx(Id, fragment);
transaction.SetTransitionEx((int)FragmentTransit.None);
if (IsAttachedToWindow)
{
ExecuteTransaction(transaction);
}
else
{
_transaction = transaction;
}
_currentFragment = fragment;
}
}
Task <bool> SwitchContentAsync(Page page, bool animated, bool removed = false, bool popToRoot = false)
{
if (!Element.IsAttachedToRoot())
{
return(Task.FromResult(false));
}
var tcs = new TaskCompletionSource <bool>();
Fragment fragment = GetFragment(page, removed, popToRoot);
#if DEBUG
// Enables logging of moveToState operations to logcat
FragmentManager.EnableDebugLogging(true);
#endif
Current?.SendDisappearing();
Current = page;
if (Platform != null)
{
Platform.NavAnimationInProgress = true;
}
FragmentTransaction transaction = FragmentManager.BeginTransactionEx();
if (animated)
{
SetupPageTransition(transaction, !removed);
}
var fragmentsToRemove = new List <Fragment>();
if (_fragmentStack.Count == 0)
{
transaction.AddEx(Id, fragment);
_fragmentStack.Add(fragment);
}
else
{
if (removed)
{
// pop only one page, or pop everything to the root
var popPage = true;
while (_fragmentStack.Count > 1 && popPage)
{
Fragment currentToRemove = _fragmentStack.Last();
_fragmentStack.RemoveAt(_fragmentStack.Count - 1);
transaction.HideEx(currentToRemove);
fragmentsToRemove.Add(currentToRemove);
popPage = popToRoot;
}
Fragment toShow = _fragmentStack.Last();
// Execute pending transactions so that we can be sure the fragment list is accurate.
FragmentManager.ExecutePendingTransactionsEx();
if (FragmentManager.Fragments.Contains(toShow))
{
transaction.ShowEx(toShow);
}
else
{
transaction.AddEx(Id, toShow);
}
}
else
{
// push
Fragment currentToHide = _fragmentStack.Last();
transaction.HideEx(currentToHide);
transaction.AddEx(Id, fragment);
_fragmentStack.Add(fragment);
}
}
// We don't currently support fragment restoration, so we don't need to worry about
// whether the commit loses state
transaction.CommitAllowingStateLossEx();
// The fragment transitions don't really SUPPORT telling you when they end
// There are some hacks you can do, but they actually are worse than just doing this:
if (animated)
{
if (!removed)
{
UpdateToolbar();
if (_drawerToggle != null && NavigationPageController.StackDepth == 2)
{
AnimateArrowIn();
}
}
else if (_drawerToggle != null && NavigationPageController.StackDepth == 2)
{
AnimateArrowOut();
}
AddTransitionTimer(tcs, fragment, FragmentManager, fragmentsToRemove, TransitionDuration, removed);
}
else
{
AddTransitionTimer(tcs, fragment, FragmentManager, fragmentsToRemove, 1, true);
}
Context.HideKeyboard(this);
if (Platform != null)
{
Platform.NavAnimationInProgress = false;
}
return(tcs.Task);
}
protected override void AddChildView(VisualElement childView)
{
_pageContainer = null;
Page page = childView as NavigationPage ?? (Page)(childView as TabbedPage);
if (page == null)
{
// The thing we're adding is not a NavigationPage or TabbedPage, so we can just use the old AddChildView
if (_currentFragment != null)
{
if (!_parent.IsAttachedToRoot())
{
return;
}
// But first, if the previous occupant of this container was a fragment, we need to remove it properly
FragmentTransaction transaction = FragmentManager.BeginTransactionEx();
transaction.RemoveEx(_currentFragment);
transaction.SetTransitionEx((int)FragmentTransit.None);
// This is a removal of a fragment that's not going on the back stack; there's no reason to care
// whether its state gets successfully saved, since we'll never restore it. Ergo, CommitAllowingStateLoss
transaction.CommitAllowingStateLossEx();
_currentFragment = null;
}
base.AddChildView(childView);
}
else
{
if (!_parent.IsAttachedToRoot())
{
return;
}
// The renderers for NavigationPage and TabbedPage both host fragments, so they need to be wrapped in a
// FragmentContainer in order to get isolated fragment management
Fragment fragment = FragmentContainer.CreateInstance(page);
var fc = fragment as FragmentContainer;
fc?.SetOnCreateCallback(pc =>
{
_pageContainer = pc;
SetDefaultBackgroundColor(pc.Child);
});
FragmentTransaction transaction = FragmentManager.BeginTransactionEx();
if (_currentFragment != null)
{
transaction.RemoveEx(_currentFragment);
}
transaction.AddEx(Id, fragment);
transaction.SetTransitionEx((int)FragmentTransit.None);
// We don't currently support fragment restoration
// So we don't need to worry about loss of this fragment's state
transaction.CommitAllowingStateLossEx();
_currentFragment = fragment;
}
}
