// This is used for cases where the user is navigating via native UI navigation i.e. clicking on Tabs // If the user defers this type of navigation we generate the equivalent GotoAsync call // so when the deferral is completed the same navigation can complete public bool ProposeNavigationOutsideGotoAsync( ShellNavigationSource source, ShellItem shellItem, ShellSection shellSection, ShellContent shellContent, IReadOnlyList <Page> stack, bool canCancel, bool isAnimated) { if (_accumulateNavigatedEvents) { return(true); } var proposedState = GetNavigationState(shellItem, shellSection, shellContent, stack, shellSection.Navigation.ModalStack); var navArgs = ProposeNavigation(source, proposedState, canCancel, isAnimated); if (navArgs.DeferralCount > 0) { navArgs.RegisterDeferralCompletedCallBack(async() => { if (navArgs.Cancelled) { return; } Func <Task> navigationTask = () => GoToAsync(navArgs.Target, navArgs.Animate, false, navArgs); if (Device.IsInvokeRequired) { await Device.InvokeOnMainThreadAsync(navigationTask); } else { await navigationTask(); } }); } return(!navArgs.NavigationDelayedOrCancelled); }
public async Task GoToAsync(ShellNavigationParameters shellNavigationParameters) { if (shellNavigationParameters.PagePushing != null) { Routing.RegisterImplicitPageRoute(shellNavigationParameters.PagePushing); } var state = shellNavigationParameters.TargetState ?? new ShellNavigationState(Routing.GetRoute(shellNavigationParameters.PagePushing), false); bool?animate = shellNavigationParameters.Animated; bool enableRelativeShellRoutes = shellNavigationParameters.EnableRelativeShellRoutes; ShellNavigatingEventArgs deferredArgs = shellNavigationParameters.DeferredArgs; var navigationRequest = ShellUriHandler.GetNavigationRequest(_shell, state.FullLocation, enableRelativeShellRoutes, shellNavigationParameters: shellNavigationParameters); bool isRelativePopping = ShellUriHandler.IsTargetRelativePop(shellNavigationParameters); ShellNavigationSource source = CalculateNavigationSource(_shell, _shell.CurrentState, navigationRequest); // If the deferredArgs are non null that means we are processing a delayed navigation // so the user has indicated they want to go forward with navigation // This scenario only comes up from UI iniated navigation (i.e. switching tabs) if (deferredArgs == null) { var navigatingArgs = ProposeNavigation(source, state, _shell.CurrentState != null, animate ?? true); if (navigatingArgs != null) { bool accept = !navigatingArgs.NavigationDelayedOrCancelled; if (navigatingArgs.DeferredTask != null) { accept = await navigatingArgs.DeferredTask; } if (!accept) { return; } } } Routing.RegisterImplicitPageRoutes(_shell); _accumulateNavigatedEvents = true; var uri = navigationRequest.Request.FullUri; var queryString = navigationRequest.Query; var queryData = ParseQueryString(queryString); ApplyQueryAttributes(_shell, queryData, false, false); var shellItem = navigationRequest.Request.Item; var shellSection = navigationRequest.Request.Section; var currentShellSection = _shell.CurrentItem?.CurrentItem; var nextActiveSection = shellSection ?? shellItem?.CurrentItem; ShellContent shellContent = navigationRequest.Request.Content; bool modalStackPreBuilt = false; // If we're replacing the whole stack and there are global routes then build the navigation stack before setting the shell section visible if (navigationRequest.Request.GlobalRoutes.Count > 0 && nextActiveSection != null && navigationRequest.StackRequest == NavigationRequest.WhatToDoWithTheStack.ReplaceIt) { modalStackPreBuilt = true; bool?isAnimated = (nextActiveSection != currentShellSection) ? false : animate; await nextActiveSection.GoToAsync(navigationRequest, queryData, isAnimated, isRelativePopping); } if (shellItem != null) { ApplyQueryAttributes(shellItem, queryData, navigationRequest.Request.Section == null, false); bool navigatedToNewShellElement = false; if (shellSection != null && shellContent != null) { ApplyQueryAttributes(shellContent, queryData, navigationRequest.Request.GlobalRoutes.Count == 0, isRelativePopping); if (shellSection.CurrentItem != shellContent) { shellSection.SetValueFromRenderer(ShellSection.CurrentItemProperty, shellContent); navigatedToNewShellElement = true; } } if (shellSection != null) { ApplyQueryAttributes(shellSection, queryData, navigationRequest.Request.Content == null, false); if (shellItem.CurrentItem != shellSection) { shellItem.SetValueFromRenderer(ShellItem.CurrentItemProperty, shellSection); navigatedToNewShellElement = true; } } if (_shell.CurrentItem != shellItem) { _shell.SetValueFromRenderer(Shell.CurrentItemProperty, shellItem); navigatedToNewShellElement = true; } if (!modalStackPreBuilt && currentShellSection?.Navigation.ModalStack.Count > 0) { // - navigating to new shell element so just pop everything // - or route contains no global route requests if (navigatedToNewShellElement || navigationRequest.Request.GlobalRoutes.Count == 0) { // remove all non visible pages first so the transition just smoothly goes from // currently visible modal to base page if (navigationRequest.Request.GlobalRoutes.Count == 0) { for (int i = currentShellSection.Stack.Count - 1; i >= 1; i--) { currentShellSection.Navigation.RemovePage(currentShellSection.Stack[i]); } } await currentShellSection.PopModalStackToPage(null, animate); } } if (navigationRequest.Request.GlobalRoutes.Count > 0 && navigationRequest.StackRequest != NavigationRequest.WhatToDoWithTheStack.ReplaceIt) { // TODO get rid of this hack and fix so if there's a stack the current page doesn't display await Device.InvokeOnMainThreadAsync(() => { return(_shell.CurrentItem.CurrentItem.GoToAsync(navigationRequest, queryData, animate, isRelativePopping)); }); } else if (navigationRequest.Request.GlobalRoutes.Count == 0 && navigationRequest.StackRequest == NavigationRequest.WhatToDoWithTheStack.ReplaceIt && currentShellSection?.Navigation?.NavigationStack?.Count > 1) { // TODO get rid of this hack and fix so if there's a stack the current page doesn't display await Device.InvokeOnMainThreadAsync(() => { return(_shell.CurrentItem.CurrentItem.GoToAsync(navigationRequest, queryData, animate, isRelativePopping)); }); } } else { await _shell.CurrentItem.CurrentItem.GoToAsync(navigationRequest, queryData, animate, isRelativePopping); } _accumulateNavigatedEvents = false; // this can be null in the event that no navigation actually took place! if (_accumulatedEvent != null) { HandleNavigated(_accumulatedEvent); } }