public async Task BackButtonExecutesCommand()
{
var pushedPage = new ContentPage();
TestShell testShell = new TestShell(new ContentPage());
var window = new Window()
{
Page = testShell
};
bool commandExecuted = false;
string parameter = String.Empty;
var command = new Command((p) =>
{
parameter = $"{p}";
commandExecuted = true;
});
var backButtonBehavior = new BackButtonBehavior()
{
Command = command,
CommandParameter = "PARAMETER"
};
await testShell.Navigation.PushAsync(pushedPage);
Shell.SetBackButtonBehavior(pushedPage, backButtonBehavior);
(window as IWindow).BackButtonClicked();
// Validate that we didn't navigate back and only the
// Command was executed
Assert.AreEqual(pushedPage, testShell.CurrentPage);
Assert.IsTrue(commandExecuted);
Assert.AreEqual("PARAMETER", parameter);
}
public async Task SetHasBackButton()
{
SetupBuilder();
var shell = await InvokeOnMainThreadAsync <Shell>(() =>
{
return(new Shell()
{
Items = { new ContentPage() }
});
});
await CreateHandlerAndAddToWindow <ShellHandler>(shell, async (handler) =>
{
Assert.False(IsBackButtonVisible(shell.Handler));
await shell.Navigation.PushAsync(new ContentPage());
Assert.True(IsBackButtonVisible(shell.Handler));
BackButtonBehavior behavior = new BackButtonBehavior()
{
IsVisible = false
};
Shell.SetBackButtonBehavior(shell.CurrentPage, behavior);
Assert.False(IsBackButtonVisible(shell.Handler));
behavior.IsVisible = true;
NavigationPage.SetHasBackButton(shell.CurrentPage, true);
});
}
protected override void Init()
{
_behavior = new BackButtonBehavior();
var page = GetContentPage(title);
Shell.SetBackButtonBehavior(page, _behavior);
AddContentPage(page).Title = title;
}
public OrderPageViewModel()
{
Console.WriteLine("Created new OrderPage");
Title = "Your order";
backButton = new BackButtonBehavior();
//Customers = sipItService.GetCustomers();
}
protected override void Init()
{
_behavior = new BackButtonBehavior();
var page = GetContentPage(title);
Shell.SetBackButtonBehavior(page, _behavior);
AddContentPage(page).Title = FlyoutItem;
Shell.SetFlyoutBehavior(this.CurrentItem, FlyoutBehavior.Disabled);
}
public void BackButtonBehaviorBindingContextPropagationWithExistingBindingContext()
{
object bindingContext = new object();
var page = new ContentPage();
var backButtonBehavior = new BackButtonBehavior();
page.BindingContext = bindingContext;
Shell.SetBackButtonBehavior(page, backButtonBehavior);
Assert.AreEqual(page.BindingContext, backButtonBehavior.BindingContext);
}
public void BackButtonBehaviorSet()
{
var page = new ContentPage();
Assert.IsNull(Shell.GetBackButtonBehavior(page));
var backButtonBehavior = new BackButtonBehavior();
Shell.SetBackButtonBehavior(page, backButtonBehavior);
Assert.AreEqual(backButtonBehavior, Shell.GetBackButtonBehavior(page));
}
void OnBackButtonCommandCanExecuteChanged(object sender, EventArgs e)
{
if (NavigationItem?.LeftBarButtonItem == null)
return;
bool isEnabled = BackButtonBehavior.GetPropertyIfSet<bool>(BackButtonBehavior.IsEnabledProperty, true);
if (isEnabled && sender is ICommand command)
isEnabled = command.CanExecute(BackButtonBehavior?.CommandParameter);
NavigationItem.LeftBarButtonItem.Enabled = isEnabled;
}
void ToggleFlyoutBehavior(object obj)
{
var behavior = (int)(Shell.Current.FlyoutBehavior);
behavior++;
if (Enum.GetValues(typeof(FlyoutBehavior)).Length <= behavior)
{
behavior = 0;
}
Shell.Current.FlyoutBehavior = (FlyoutBehavior)behavior;
}
void ToggleFlyoutBehavior(object obj, Button btn)
{
var behavior = (int)(Shell.Current.FlyoutBehavior);
behavior++;
if (Enum.GetValues(typeof(FlyoutBehavior)).Length <= behavior)
{
behavior = 0;
}
Shell.Current.FlyoutBehavior = (FlyoutBehavior)behavior;
btn.Text = $"Flyout Behavior: {(FlyoutBehavior)behavior}";
}
public async Task ShellToolbarUpdatesFromNewBackButtonBehavior()
{
var page = new ContentPage();
TestShell testShell = new TestShell(new ContentPage());
await testShell.Navigation.PushAsync(page);
Assert.IsTrue(testShell.Toolbar.BackButtonVisible);
var backButtonBehavior = new BackButtonBehavior()
{
IsVisible = false,
};
Shell.SetBackButtonBehavior(page, backButtonBehavior);
Assert.IsFalse(testShell.Toolbar.BackButtonVisible);
}
async void SetBackButtonBehavior(BackButtonBehavior value)
{
if (BackButtonBehavior == value)
return;
if (BackButtonBehavior != null)
BackButtonBehavior.PropertyChanged -= OnBackButtonBehaviorPropertyChanged;
BackButtonBehavior = value;
if (BackButtonBehavior != null)
BackButtonBehavior.PropertyChanged += OnBackButtonBehaviorPropertyChanged;
await UpdateToolbarItems().ConfigureAwait(false);
}
public async Task BackButtonDisabledWhenCommandDisabled()
{
var page = new ContentPage();
TestShell testShell = new TestShell(new ContentPage());
await testShell.Navigation.PushAsync(page);
var backButtonBehavior = new BackButtonBehavior();
Shell.SetBackButtonBehavior(page, backButtonBehavior);
Assert.IsTrue(testShell.Toolbar.BackButtonEnabled);
bool canExecute = false;
backButtonBehavior.Command = new Command(() => { }, () => canExecute);
Assert.IsFalse(testShell.Toolbar.BackButtonEnabled);
canExecute = true;
(backButtonBehavior.Command as Command).ChangeCanExecute();
Assert.IsTrue(testShell.Toolbar.BackButtonEnabled);
}
public Task NavigateTo <T>(object parameter = null, bool modal = false) where T : BasePageModel
{
var pageModel = Activator.CreateInstance <T>();
var pageType = GetPageTypeName(pageModel.GetType());
var page = (Page)Activator.CreateInstance(pageType);
pageModel.Parameter = parameter;
pageModel.CurrentPage = page;
pageModel.Initialize();
page.BindingContext = pageModel;
if (pageModel.HandleBackCommandImpl)
{
var backButtonBehavior = new BackButtonBehavior();
backButtonBehavior.SetBinding(BackButtonBehavior.CommandProperty, new Binding
{
Path = nameof(BasePageModel.BackCommand),
Source = page.BindingContext,
Mode = BindingMode.OneWay
});
Shell.SetBackButtonBehavior(page, backButtonBehavior);
}
if (modal)
{
Shell.Current.Navigation.PushModalAsync(page, animated: false);
}
else
{
Shell.Current.Navigation.PushAsync(page, animated: false);
}
return(Task.CompletedTask);
}
void SetBackButtonBehavior(BackButtonBehavior value)
{
if (BackButtonBehavior == value)
{
return;
}
if (BackButtonBehavior != null)
{
BackButtonBehavior.PropertyChanged -= OnBackButtonBehaviorPropertyChanged;
}
BackButtonBehavior = value;
if (BackButtonBehavior != null)
{
BackButtonBehavior.PropertyChanged += OnBackButtonBehaviorPropertyChanged;
}
UpdateToolbarItems();
}
