async Task <bool> PopToNavigationState(NavigationState state)
{
int index = navigationStateStack.FindIndex((ns) => ns == state);
if (index == -1)
{
return(false);
}
for (int i = navigationStateStack.Count - 1; i > index; i--)
{
if (!await navigationStateStack [i].Hide())
{
return(false);
}
if (!await navigationStateStack [i].Unload())
{
return(false);
}
navigationStateStack [i].ScreenState.Dispose();
navigationStateStack.RemoveAt(i);
if (!await App.Current.Navigation.Pop(null))
{
return(false);
}
}
if (!await state.Show())
{
return(false);
}
await App.Current.EventsBroker.Publish(new NavigationEvent { Name = state.Name });
return(await App.Current.Navigation.Push(state.ScreenState.Panel));
}
async Task <bool> PushModalState(NavigationState state, IScreenState current)
{
modalStateStack.Add(state);
if (!await state.Show())
{
return(false);
}
await App.Current.EventsBroker.Publish(new NavigationEvent { Name = state.ScreenState.Name, IsModal = true });
await App.Current.Navigation.PushModal(state.ScreenState.Panel, current.Panel);
return(true);
}
/// <summary>
/// Moves Back to the previous transition Panel or Modal.
/// </summary>
/// <returns>True: If the transition could be performed. False Otherwise</returns>
public async Task <bool> MoveBack()
{
if (modalStateStack.Count == 0 && navigationStateStack.Count <= 1 && home == null)
{
Log.Debug("Moving back failed because is last transition and there isn't any home");
return(false);
}
try {
bool triggeredFromModal;
NavigationState current = LastState(out triggeredFromModal);
if (!CanMove(current))
{
return(false);
}
Log.Debug("Moving Back");
if (current != null)
{
if (!triggeredFromModal)
{
if (!await PopNavigationState())
{
return(false);
}
}
else
{
if (!await PopModalState(current))
{
return(false);
}
}
current = LastState();
if (triggeredFromModal)
{
return(await current.Unfreeze());
}
else
{
return(await current.Show());
}
}
return(true);
} catch (Exception ex) {
Log.Exception(ex);
throw;
}
}
/// <summary>
/// Moves to a Panel inside the main window. If it has some previous modal windows
/// It Pops them all.
/// </summary>
/// <returns>True if the move could be performed. False otherwise</returns>
/// <param name="transition">Transition.</param>
public async Task <bool> MoveTo(string transition, dynamic properties, bool emptyStack = false, bool forceMove = false)
{
Log.Debug("Moving to " + transition);
if (!destination.ContainsKey(transition))
{
Log.Debug("Moving failed because transition " + transition + " is not in destination dictionary.");
return(false);
}
try {
bool isModal = false;
NavigationState lastState = LastState(out isModal);
if (!forceMove && lastState != null && lastState.Name == transition)
{
Log.Debug("Not moved to " + transition + "because we're already there");
return(true);
}
if (!CanMove(lastState) && !forceMove)
{
return(false);
}
if (emptyStack)
{
if (!await EmptyStateStack())
{
return(false);
}
if (lastState == home && home.Name != transition)
{
if (!await lastState.Hide())
{
Log.Debug("Moving failed because home panel " + lastState.Name + " cannot move.");
return(false);
}
}
}
else if (isModal)
{
if (!await PopAllModalStates())
{
return(false);
}
}
else if (lastState != null)
{
if (!await lastState.Hide())
{
Log.Debug("Moving failed because panel " + lastState.Name + " cannot move.");
return(false);
}
}
IScreenState state;
bool isHome = transition == home?.Name;
if (isHome)
{
state = home.ScreenState;
}
else
{
state = destination [transition] ();
if (!await state.LoadState(properties))
{
// If the transition failed and the stack is empty, load the home,
// otherwise show again the last state that was hidden at the start of the
// MoveTo
if (emptyStack)
{
await PushNavigationState(home.Name, home.ScreenState);
}
else
{
if (!await lastState.Show())
{
// This shouldn't fail... but just in case
Log.Error("Last state couldn't be shown again, we'll move back home");
await PushNavigationState(home.Name, home.ScreenState);
}
}
return(false);
}
}
return(await PushNavigationState(transition, state));
} catch (Exception ex) {
Log.Exception(ex);
throw;
}
}