protected override void AddChildView(VisualElement childView)
{
_pageContainer = null;
Page page = childView as NavigationPage ?? (Page)(childView as TabbedPage);
if (page == null)
{
// Not a NavigationPage or TabbedPage? Just do the normal thing
base.AddChildView(childView);
}
else
{
// 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.BeginTransaction();
transaction.DisallowAddToBackStack();
transaction.Add(Id, fragment);
transaction.SetTransition((int)FragmentTransit.FragmentOpen);
transaction.Commit();
}
}
public override Fragment GetItem(int position)
{
var fragment = FragmentContainer.CreateInstance(_page.Children[position]);
_fragments.Add(fragment);
return(fragment);
}
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)
{
// But first, if the previous occupant of this container was a fragment, we need to remove it properly
FragmentTransaction transaction = FragmentManager.BeginTransaction();
transaction.DisallowAddToBackStack();
transaction.Remove(_currentFragment);
transaction.SetTransition((int)FragmentTransit.None);
transaction.Commit();
_currentFragment = null;
}
base.AddChildView(childView);
}
else
{
// 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.BeginTransaction();
transaction.DisallowAddToBackStack();
if (_currentFragment != null)
{
transaction.Remove(_currentFragment);
}
transaction.Add(Id, fragment);
transaction.SetTransition((int)FragmentTransit.None);
transaction.Commit();
_currentFragment = fragment;
new Handler(Looper.MainLooper).PostAtFrontOfQueue(() => FragmentManager.ExecutePendingTransactions());
}
}
void InsertPageBefore(Page page, Page before)
{
UpdateToolbar();
int index = Element.InternalChildren.IndexOf(before);
if (index == -1)
{
throw new InvalidOperationException("This should never happen, please file a bug");
}
Fragment fragment = FragmentContainer.CreateInstance(page);
_fragmentStack.Insert(index, fragment);
}
Fragment GetFragment(Page page, bool removed, bool popToRoot)
{
// pop
if (removed)
{
return(_fragmentStack[_fragmentStack.Count - 2]);
}
// pop to root
if (popToRoot)
{
return(_fragmentStack[0]);
}
// push
return(FragmentContainer.CreateInstance(page));
}
void InsertPageBefore(Page page, Page before)
{
if (!_isAttachedToWindow)
{
PushCurrentPages();
}
UpdateToolbar();
int index = PageController.InternalChildren.IndexOf(before);
if (index == -1)
{
throw new InvalidOperationException("This should never happen, please file a bug");
}
Fragment fragment = FragmentContainer.CreateInstance(page);
_fragmentStack.Insert(index, fragment);
}
Task <bool> SwitchContentAsync(Page view, bool animated, bool removed = false, bool popToRoot = false)
{
var activity = (FormsAppCompatActivity)Context;
var tcs = new TaskCompletionSource <bool>();
Fragment fragment = FragmentContainer.CreateInstance(view);
FragmentManager fm = FragmentManager;
List <Fragment> fragments = _fragmentStack;
Current = view;
FragmentTransaction transaction = fm.BeginTransaction();
if (animated)
{
SetupPageTransition(transaction, !removed);
}
transaction.DisallowAddToBackStack();
if (fragments.Count == 0)
{
transaction.Add(Id, fragment);
fragments.Add(fragment);
}
else
{
if (removed)
{
// pop only one page, or pop everything to the root
var popPage = true;
while (fragments.Count > 1 && popPage)
{
Fragment currentToRemove = fragments.Last();
fragments.RemoveAt(fragments.Count - 1);
transaction.Remove(currentToRemove);
popPage = popToRoot;
}
Fragment toShow = fragments.Last();
// Execute pending transactions so that we can be sure the fragment list is accurate.
fm.ExecutePendingTransactions();
if (fm.Fragments.Contains(toShow))
{
transaction.Show(toShow);
}
else
{
transaction.Add(Id, toShow);
}
}
else
{
// push
Fragment currentToHide = fragments.Last();
transaction.Hide(currentToHide);
transaction.Add(Id, fragment);
fragments.Add(fragment);
}
}
transaction.Commit();
// 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 && Element.StackDepth == 2)
{
AnimateArrowIn();
}
}
else if (_drawerToggle != null && Element.StackDepth == 2)
{
AnimateArrowOut();
}
Device.StartTimer(TimeSpan.FromMilliseconds(200), () =>
{
tcs.TrySetResult(true);
fragment.UserVisibleHint = true;
if (removed)
{
UpdateToolbar();
}
return(false);
});
}
else
{
Device.StartTimer(TimeSpan.FromMilliseconds(1), () =>
{
tcs.TrySetResult(true);
fragment.UserVisibleHint = true;
UpdateToolbar();
return(false);
});
}
Context.HideKeyboard(this);
// 200ms is how long the animations are, and they are "reversible" in the sense that starting another one slightly before it's done is fine
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)
{
// But first, if the previous occupant of this container was a fragment, we need to remove it properly
FragmentTransaction transaction = FragmentManager.BeginTransaction();
transaction.Remove(_currentFragment);
transaction.SetTransition((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.CommitAllowingStateLoss();
_currentFragment = null;
}
base.AddChildView(childView);
}
else
{
// 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.BeginTransaction();
if (_currentFragment != null)
{
transaction.Remove(_currentFragment);
}
transaction.Add(Id, fragment);
transaction.SetTransition((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.CommitAllowingStateLoss();
_currentFragment = fragment;
new Handler(Looper.MainLooper).PostAtFrontOfQueue(() =>
{
if (_pageContainer == null)
{
// The view we're hosting in the fragment was never created (possibly we're already
// navigating to another page?) so there's nothing to commit
return;
}
FragmentManager.ExecutePendingTransactions();
});
}
}
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;
}
}
public override Fragment GetItem(int position)
{
return(FragmentContainer.CreateInstance(_page.Children[position]));
}
Task <bool> SwitchContentAsync(Page view, bool animated, bool removed = false, bool popToRoot = false)
{
var tcs = new TaskCompletionSource <bool>();
Fragment fragment = FragmentContainer.CreateInstance(view);
FragmentManager fm = FragmentManager;
#if DEBUG
// Enables logging of moveToState operations to logcat
FragmentManager.EnableDebugLogging(true);
#endif
List <Fragment> fragments = _fragmentStack;
Current = view;
((Platform)Element.Platform).NavAnimationInProgress = true;
FragmentTransaction transaction = fm.BeginTransaction();
if (animated)
{
SetupPageTransition(transaction, !removed);
}
transaction.DisallowAddToBackStack();
if (fragments.Count == 0)
{
transaction.Add(Id, fragment);
fragments.Add(fragment);
}
else
{
if (removed)
{
// pop only one page, or pop everything to the root
var popPage = true;
while (fragments.Count > 1 && popPage)
{
Fragment currentToRemove = fragments.Last();
fragments.RemoveAt(fragments.Count - 1);
transaction.Remove(currentToRemove);
popPage = popToRoot;
}
Fragment toShow = fragments.Last();
// Execute pending transactions so that we can be sure the fragment list is accurate.
fm.ExecutePendingTransactions();
if (fm.Fragments.Contains(toShow))
{
transaction.Show(toShow);
}
else
{
transaction.Add(Id, toShow);
}
}
else
{
// push
Fragment currentToHide = fragments.Last();
transaction.Hide(currentToHide);
transaction.Add(Id, fragment);
fragments.Add(fragment);
}
}
// We don't currently support fragment restoration, so we don't need to worry about
// whether the commit loses state
transaction.CommitAllowingStateLoss();
// 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 && ((INavigationPageController)Element).StackDepth == 2)
{
AnimateArrowIn();
}
}
else if (_drawerToggle != null && ((INavigationPageController)Element).StackDepth == 2)
{
AnimateArrowOut();
}
Device.StartTimer(TimeSpan.FromMilliseconds(TransitionDuration), () =>
{
tcs.TrySetResult(true);
fragment.UserVisibleHint = true;
if (removed)
{
UpdateToolbar();
}
return(false);
});
}
else
{
Device.StartTimer(TimeSpan.FromMilliseconds(1), () =>
{
tcs.TrySetResult(true);
fragment.UserVisibleHint = true;
UpdateToolbar();
return(false);
});
}
Context.HideKeyboard(this);
((Platform)Element.Platform).NavAnimationInProgress = false;
// TransitionDuration is how long the built-in animations are, and they are "reversible" in the sense that starting another one slightly before it's done is fine
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;
UpdateFlowDirection();
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;
}
}
