void nextPage_Clicked(object sender, EventArgs e)
{
ContentPage page = null;
page = new ContentPage()
{
Title = "second page",
Content = new StackLayout()
{
Children =
{
new Button()
{
Text = "Toggle Back Button",
Command = new Command(() =>
{
NavigationPage.SetHasBackButton(page, !NavigationPage.GetHasBackButton(page));
})
},
new Button()
{
Text = "Toggle Title View",
Command = new Command(() =>
{
changeTitleView_Clicked(page, EventArgs.Empty);
})
}
}
}
};
NavigationPage.SetTitleView(page, createGrid());
Navigation.PushAsync(page);
}
public override void RequestNavigation(NavigationRequest e)
{
NavAnimationInProgress = true;
base.RequestNavigation(e);
NavAnimationInProgress = false;
var currentStack = NavigationStack;
var newStackSize = e.NavigationStack.Count;
bool animated = e.Animated;
bool removed = currentStack.Count > newStackSize;
if (animated)
{
var page = (Page)e.NavigationStack[newStackSize - 1];
if (!removed)
{
UpdateToolbar();
if (_drawerToggle != null && NavigationPageController.StackDepth == 2 &&
NavigationPage.GetHasBackButton(page))
{
AnimateArrowIn();
}
}
else if (_drawerToggle != null && NavigationPageController.StackDepth == 2 &&
NavigationPage.GetHasBackButton(page))
{
AnimateArrowOut();
}
}
}
protected override Task <bool> PushRoot(NavigationPushInfo pushInfo)
{
var newPage = GetInitializedPage(pushInfo);
var navigation = GetRootNavigation();
Device.BeginInvokeOnMainThread(async() => {
try {
if (navigation.NavigationStack.Any())
{
while (navigation.ModalStack.Count > 0)
{
var page = await navigation.PopModalAsync(true);
DisposeModalPage(page);
}
var hasBackButton = NavigationPage.GetHasBackButton(newPage);
NavigationPage.SetHasBackButton(newPage, false);
await navigation.PushAsync(newPage);
foreach (var page in navigation.NavigationStack.Where(p => p != newPage).ToList())
{
navigation.RemovePage(page);
}
NavigationPage.SetHasBackButton(newPage, hasBackButton);
}
pushInfo.OnCompletedTask?.TrySetResult(true);
}
catch (Exception e) {
Console.WriteLine(e);
pushInfo.OnCompletedTask?.TrySetResult(false);
}
});
return(pushInfo.OnCompletedTask?.Task);
}
public DetailPage()
{
var button = new Button {
Text = "Click me", AutomationId = NavButton
};
button.Clicked += async(o, s) =>
{
var button2 = new Button {
Text = "Toggle back button", AutomationId = ToggleBackButton
};
var page = new ContentPage {
Content = new StackLayout {
Children =
{
new Label {
Text = "If there is no hamburger button, this test has failed. If you cannot toggle the back arrow, this test has failed."
},
button2
}
}
};
button2.Clicked += (o2, s2) =>
{
NavigationPage.SetHasBackButton(page, !NavigationPage.GetHasBackButton(page));
};
NavigationPage.SetHasBackButton(page, false);
await ParentPage.PushAsync(page);
};
Content = button;
}
bool ShowBackButton(bool forceShowBackButton)
{
if (_navigation == null)
{
return(false);
}
return(NavigationPage.GetHasBackButton(_navigation.CurrentPage) && (forceShowBackButton || !IsRootPage()));
}
void UpdateHasBackButton()
{
if (Child == null)
{
return;
}
NavigationItem.HidesBackButton = !NavigationPage.GetHasBackButton(Child);
}
private bool ShowBackButton()
{
if (_navigation == null)
{
return(false);
}
return(NavigationPage.GetHasBackButton(_navigation.CurrentPage) &&
!IsRootPage());
}
void UpdateBackButton()
{
bool showBackButton = PageController.InternalChildren.Count > 1 && NavigationPage.GetHasBackButton(_currentPage);
_container.ShowBackButton = showBackButton;
if (_navManager != null)
{
_navManager.AppViewBackButtonVisibility = showBackButton ? AppViewBackButtonVisibility.Visible : AppViewBackButtonVisibility.Collapsed;
}
}
void UpdateBackButton()
{
if (_navManager == null)
{
return;
}
bool showBackButton = Element.InternalChildren.Count > 1 && NavigationPage.GetHasBackButton(_currentPage);
_navManager.AppViewBackButtonVisibility = showBackButton ? AppViewBackButtonVisibility.Visible : AppViewBackButtonVisibility.Collapsed;
}
public void UpdateMenu()
{
if (NavigationPage.GetHasBackButton(Element.CurrentPage))
{
_toolbar.SetNavigationOnClickListener(_navigationBackListener);
}
else
{
_toolbar.SetNavigationOnClickListener(null);
}
foreach (ToolbarItem item in _toolbarTracker.ToolbarItems)
{
item.PropertyChanged -= HandleToolbarItemPropertyChanged;
}
IMenu menu = _toolbar.Menu;
for (var i = 0; i < _toolbarTracker.ToolbarItems.Count(); i++)
{
var item = _toolbarTracker.ToolbarItems.ElementAt(i);
item.PropertyChanged += HandleToolbarItemPropertyChanged;
var menuItem = menu.GetItem(i);
if (item.Order == ToolbarItemOrder.Secondary)
{
continue;
}
var itemEx = item as ToolbarItemEx;
if (itemEx == null)
{
continue;
}
if (!itemEx.IsVisible)
{
menuItem.SetVisible(false);
continue;
}
//左側のアイコン設定。NavigationIconを使うためBackButtonとの併用は不可
//BackButtonよりも優先される。
//複数の左アイコンが指定されても最後の一つだけが有効となる
//今の所modalのみで使う方が良い
if (itemEx.IsLeftIcon)
{
UpdateLeftIcon(itemEx, menuItem);
continue;
}
UpdateRightIcon(itemEx, menuItem);
}
}
bool UpButtonShouldNavigate()
{
if (CurrentNavigationPage == null)
{
return(false);
}
bool pagePushed = ((INavigationPageController)CurrentNavigationPage).StackDepth > 1;
bool pushedPageHasBackButton = NavigationPage.GetHasBackButton(CurrentNavigationPage.CurrentPage);
return(pagePushed && pushedPageHasBackButton);
}
void UpdateBackButton()
{
bool showBackButton = Element.InternalChildren.Count > 1 && NavigationPage.GetHasBackButton(_currentPage);
_container.ShowBackButton = showBackButton;
#if WINDOWS_UWP
if (_navManager != null)
{
_navManager.AppViewBackButtonVisibility = showBackButton ? AppViewBackButtonVisibility.Visible : AppViewBackButtonVisibility.Collapsed;
}
#endif
}
protected override void OnAppearing()
{
base.OnAppearing();
Application.Current.Properties["LoginUtc"] = DateTime.UtcNow;
Note.ValueChanged += (s, e) =>
{
if (NavigationPage.GetHasBackButton(this))
{
NavigationPage.SetHasBackButton(this, false); // Hide back button because of that users want to back with this button even if not saved
}
};
}
void UpdateLeftBarButtonItem(ParentingViewController containerController, Page pageBeingRemoved = null)
{
if (containerController == null)
{
return;
}
var currentChild = containerController.Child;
var firstPage = ((NavigationPage)Element).Pages.FirstOrDefault();
if ((firstPage != pageBeingRemoved && currentChild != firstPage && NavigationPage.GetHasBackButton(currentChild)) || _parentMasterDetailPage == null)
{
return;
}
SetMasterLeftBarButton(containerController, _parentMasterDetailPage);
}
void UpdateLeftBarButtonItem(ParentingViewController containerController, Page pageBeingRemoved = null)
{
if (containerController == null)
{
return;
}
var currentChild = containerController.Child;
var firstPage = ((INavigationPageController)Element).Pages.FirstOrDefault();
if ((firstPage != pageBeingRemoved && currentChild != firstPage && NavigationPage.GetHasBackButton(currentChild)) || _parentMasterDetailPage == null)
{
return;
}
if (!_parentMasterDetailPage.ShouldShowToolbarButton())
{
containerController.NavigationItem.LeftBarButtonItem = null;
return;
}
var shouldUseIcon = _parentMasterDetailPage.Master.Icon != null;
if (shouldUseIcon)
{
try
{
containerController.NavigationItem.LeftBarButtonItem =
new UIBarButtonItem(new UIImage(_parentMasterDetailPage.Master.Icon), UIBarButtonItemStyle.Plain,
(o, e) => _parentMasterDetailPage.IsPresented = !_parentMasterDetailPage.IsPresented);
}
catch (Exception)
{
// Throws Exception otherwise would catch more specific exception type
shouldUseIcon = false;
}
}
if (!shouldUseIcon)
{
containerController.NavigationItem.LeftBarButtonItem = new UIBarButtonItem(_parentMasterDetailPage.Master.Title,
UIBarButtonItemStyle.Plain,
(o, e) => _parentMasterDetailPage.IsPresented = !_parentMasterDetailPage.IsPresented);
}
}
void ToggleBackButton(object sender, EventArgs e)
{
NavigationPage.SetHasBackButton(this, !NavigationPage.GetHasBackButton(this));
}
void UpdateBackButton()
{
this.Control.HasBackButton = NavigationPage.GetHasBackButton(Element);
}
protected virtual void UpdateToolbar()
{
ActionBarDrawerToggle toggle = _drawerToggle;
if (Toolbar == null || NavigationStack.Count == 0 || CurrentPage == null || VirtualView == null)
{
return;
}
bool isNavigated = NavigationStack.Count > 1;
Page currentPage = CurrentPage;
_defaultNavigationIcon ??= Toolbar.NavigationIcon;
if (isNavigated)
{
if (NavigationPage.GetHasBackButton(currentPage))
{
Toolbar.NavigationIcon ??= _defaultNavigationIcon;
if (toggle != null)
{
toggle.DrawerIndicatorEnabled = false;
toggle.SyncState();
}
var prevPage = (Page)NavigationStack[NavigationStack.Count - 2];
var backButtonTitle = NavigationPage.GetBackButtonTitle(prevPage);
ImageSource image = NavigationPage.GetTitleIconImageSource(currentPage);
if (!string.IsNullOrEmpty(backButtonTitle))
{
Toolbar.NavigationContentDescription = backButtonTitle;
}
else if (image == null ||
Toolbar.SetNavigationContentDescription(image) == null)
{
Toolbar.SetNavigationContentDescription(Resource.String.nav_app_bar_navigate_up_description);
}
}
else if (toggle != null && _flyoutPage != null)
{
toggle.DrawerIndicatorEnabled = _flyoutPage.ShouldShowToolbarButton();
toggle.SyncState();
}
else
{
Toolbar.NavigationIcon = null;
}
}
else
{
if (toggle != null && _flyoutPage != null)
{
toggle.DrawerIndicatorEnabled = _flyoutPage.ShouldShowToolbarButton();
toggle.SyncState();
Toolbar.SetNavigationContentDescription(Resource.String.nav_app_bar_open_drawer_description);
}
}
Color tintColor = NavigationView.BarBackgroundColor;
if (tintColor == null)
{
Toolbar.BackgroundTintMode = null;
}
else
{
Toolbar.BackgroundTintMode = PorterDuff.Mode.Src;
Toolbar.BackgroundTintList = ColorStateList.ValueOf(tintColor.ToNative());
}
Brush barBackground = NavigationView.BarBackground;
Toolbar.UpdateBackground(barBackground);
Color textColor = NavigationView.BarTextColor;
if (textColor != null)
{
Toolbar.SetTitleTextColor(textColor.ToNative().ToArgb());
}
Color navIconColor = NavigationPage.GetIconColor(CurrentPage);
if (navIconColor != null && Toolbar.NavigationIcon != null)
{
DrawableExtensions.SetColorFilter(Toolbar.NavigationIcon, navIconColor, FilterMode.SrcAtop);
}
Toolbar.Title = currentPage?.Title ?? string.Empty;
if (Toolbar.NavigationIcon != null && textColor != null)
{
var icon = this.Toolbar.NavigationIcon as DrawerArrowDrawable;
if (icon != null)
{
icon.Color = textColor.ToNative().ToArgb();
}
}
UpdateTitleIcon();
UpdateTitleView();
UpdateToolbarVisibility();
}
void UpdateBackButton()
{
bool showBackButton = Element.InternalChildren.Count > 1 && NavigationPage.GetHasBackButton(_currentPage);
_container.ShowBackButton = showBackButton;
}
public NavigationPropertiesGallery()
{
var noBack = new ContentPage
{
Title = "No back button",
};
NavigationPage.SetHasBackButton(noBack, false);
var toggleBackButton = new Button {
Text = "Toggle Back Button"
};
toggleBackButton.Clicked += (sender, e) =>
{
var hasBack = NavigationPage.GetHasBackButton(noBack);
if (hasBack)
{
NavigationPage.SetHasBackButton(noBack, false);
}
else
{
NavigationPage.SetHasBackButton(noBack, true);
}
};
noBack.Content = toggleBackButton;
var noBar = new ContentPage
{
Title = "No bar",
Content = new Label
{
Text = "No bar content",
Style = Device.Styles.TitleStyle
}
};
var backTitle = new ContentPage
{
Title = "Back button title"
};
NavigationPage.SetHasNavigationBar(noBar, false);
Content = new ListView
{
ItemsSource = new[] {
noBack,
noBar,
backTitle
},
ItemTemplate = new DataTemplate(typeof(TextCell))
{
Bindings =
{
{ TextCell.TextProperty, new Binding("Title") }
}
}
};
((ListView)Content).ItemTapped += async(sender, args) =>
{
await Navigation.PushAsync((Page)args.Item);
};
NavigationPage.SetBackButtonTitle(this, "Back Title");
}
