C# Forms.TapGestureRecognizer类代码示例

        public static void AnimateWithAction(this Label label, Command command = null, ScaleType type = ScaleType.After)
        {
            var tapGesture = new TapGestureRecognizer ();
            tapGesture.Tapped += async (sender, args) => {
                switch (type) {
                case ScaleType.First:
                    command?.Execute (null);
                    await label.ScaleTo (0.75, 100, Easing.CubicOut);
                    await label.ScaleTo (1, 100, Easing.CubicIn);
                    break;
                case ScaleType.Midle:
                    await label.ScaleTo (0.75, 100, Easing.CubicOut);
                    command?.Execute (null);
                    await label.ScaleTo (1, 100, Easing.CubicIn);
                    break;
                case ScaleType.After:
                    await label.ScaleTo (0.75, 100, Easing.CubicOut);
                    await label.ScaleTo (1, 100, Easing.CubicIn);
                    command?.Execute (null);
                    break;
                default:
                    break;
                }

            };
            label.GestureRecognizers.Add (tapGesture);
        }

        public MyToolBar(string labelText, string leftIconText, string rightIconText)
        {
            _toolbarInfoLabel = new Label {
                Text = labelText,
                TextColor = Color.White,
                HorizontalOptions = LayoutOptions.StartAndExpand,
                VerticalOptions = LayoutOptions.Center,
            };

            LeftIcon = new Label {
                Text = leftIconText,
                TextColor = Color.White,
                HorizontalOptions = LayoutOptions.EndAndExpand,
            };
            LeftIconGestureRecognizer = new TapGestureRecognizer ();

            RightIcon = new Label {
                Text = rightIconText,
                TextColor = Color.White,
                HorizontalOptions = LayoutOptions.End
            };
            RightIconGestureRecognizer = new TapGestureRecognizer ();

            Children.Add (_toolbarInfoLabel);
            Children.Add (LeftIcon);
            Children.Add (RightIcon);

            BackgroundColor = Color.Silver;
            HeightRequest = 20;
            Orientation = StackOrientation.Horizontal;
            Padding = new Thickness (12, 12, 12, 12);
        }

        public ExpandableCell(Layout header, Layout body, Layout footer)
        {
            this.Padding = 0;
            this.Spacing = 0;
            this.Children.Add (header);
            this.Children.Add (body);
            this.Children.Add (footer);
            this.body = body;
            this.IsClippedToBounds = true;

            var gestureRecognizer = new TapGestureRecognizer () { };

            gestureRecognizer.Tapped += (sender, e) => {
                double start = expanded ? bodyHeight : 0; // the starting height
                double offset = expanded ? -bodyHeight : bodyHeight; // the change over the animation
                expanded = !expanded;
                this.body.Animate (
                    name: "set height",
                    animation: new Xamarin.Forms.Animation((val) => {
                        this.body.HeightRequest = start + offset*val;
                    }),
                    length: 250,
                    easing: Easing.CubicInOut
                );
            };
            header.GestureRecognizers.Add (gestureRecognizer);
        }

        public void BuildLayout()
        {
            mainStack.Spacing = 20;
            mainStack.Padding = 50;
            mainStack.VerticalOptions = LayoutOptions.Center;

            
            userNameEntry.Placeholder = "Username";
            
            passwordEntry.Placeholder = "Password";
            passwordEntry.IsPassword = true;

            Button loginButton = new Button();
            loginButton.Text = "Login";
            loginButton.TextColor = Color.Black;
            loginButton.BackgroundColor = Color.FromHex("77D065");
            var tapGesture = new TapGestureRecognizer { Command = new Command(LoginTap)};
            loginButton.GestureRecognizers.Add(tapGesture);

            mainStack.Children.Add(userNameEntry);
            mainStack.Children.Add(passwordEntry);
            mainStack.Children.Add(loginButton);

            
        }

        private void ActivateOrDeactivateMenu()
        {
            if (isMenuAnimationWorking)
                return;
            else
                isMenuAnimationWorking = true;
            Rectangle menuRectangle;
            Rectangle midRectangle;

            if (!IsMenuOpen) {
                menuRectangle = new Rectangle (new Point (MyDevice.GetScaledSize(mMenuWidth), 0), new Size (mMenuLayout.Bounds.Width, mMenuLayout.Bounds.Height));
                midRectangle = new Rectangle (new Point (MyDevice.GetScaledSize (mMenuWidth), 0), new Size (mMidLayout.Bounds.Width, mMidLayout.Bounds.Height));
                mainRelativeLayout.Children.Add (InputBlockerForSwipeMenu,
                    Constraint.Constant (MyDevice.GetScaledSize (mMenuWidth)),
                    Constraint.Constant (0)
                );

                var tapRecognizer = new TapGestureRecognizer ();
                if (InputBlockerForSwipeMenu.GestureRecognizers.Count == 0) {
                    tapRecognizer.Tapped += (sender, e) => {
                        ActivateOrDeactivateMenu();
                    };
                }
                InputBlockerForSwipeMenu.GestureRecognizers.Add(tapRecognizer);
            } else {
                menuRectangle = new Rectangle (new Point (MyDevice.GetScaledSize (0), 0), new Size (mMenuLayout.Bounds.Width, mMenuLayout.Bounds.Height));
                midRectangle = new Rectangle (new Point (0, 0), new Size (mMidLayout.Bounds.Width, mMidLayout.Bounds.Height));
                mainRelativeLayout.Children.Remove (InputBlockerForSwipeMenu);
            }

            mMenuLayout.TranslateTo (menuRectangle.X,menuRectangle.Y, MyDevice.AnimationTimer, Easing.Linear).ContinueWith(antecendent => isMenuAnimationWorking=false);
            mMidLayout.TranslateTo (midRectangle.X,midRectangle.Y, MyDevice.AnimationTimer, Easing.Linear);

            IsMenuOpen = !IsMenuOpen;
        }

        public HomeView()
        {
            InitializeComponent();

            #region ChooseView

            TapGestureRecognizer chooseTapGestureRecognizer = new TapGestureRecognizer();
            chooseTapGestureRecognizer.Tapped += (async (o2, e2) =>
            {
                App.MealManager.Reset();
                var page = new ChooseView();
                NavigationPage.SetHasBackButton(page, true);

                await Navigation.PushAsync(page, false);
            });

            ChooseStack.GestureRecognizers.Add(chooseTapGestureRecognizer);

            #endregion

            #region OverviewView

            TapGestureRecognizer overviewTapGestureRecognizer = new TapGestureRecognizer();
            overviewTapGestureRecognizer.Tapped += (async (o2, e2) =>
            {
                var page = new OverviewView();
                NavigationPage.SetHasBackButton(page, true);

                await Navigation.PushAsync(page, false);
            });

            OverviewStack.GestureRecognizers.Add(overviewTapGestureRecognizer);

            #endregion
        }

        private void CreateOrRemoveGestureRecognizer()
        {
            if (Command == null)
            {
                if (_tapGestureRecognizer == null) return;

                GestureRecognizers.Remove(_tapGestureRecognizer);
                _tapGestureRecognizer = null;
            }
            else
            {
                if (_tapGestureRecognizer != null) return;

                _tapGestureRecognizer = new TapGestureRecognizer
                {
                    Command = new RelayCommand(p =>
                    {
                        if (Command != null)
                            Command.Execute(CommandParameter ?? p);
                    }, p => Command == null || Command.CanExecute(CommandParameter ?? p))
                };

                GestureRecognizers.Add(_tapGestureRecognizer);
            }
        }

        public ConfigSpringboard()
        {
            NavigationPage.SetHasNavigationBar (this, false);

            Grid configGrid = new Grid {
                BackgroundColor = Colours.BG_DARK,
                Padding = new Thickness(10),
                RowDefinitions = {
                    new RowDefinition {
                        Height = new GridLength(150, GridUnitType.Absolute)
                    }
                },
                ColumnDefinitions = {
                    new ColumnDefinition {
                        Width = new GridLength(1, GridUnitType.Star)
                    },
                    new ColumnDefinition {
                        Width = new GridLength(1, GridUnitType.Star)
                    }
                }
            };

            HomeButton UC = new HomeButton (IconLabel.Icon.FAUser, "YOUR INFO", Colours.USERCONFIG_LIGHT, Colours.USERCONFIG_MEDIUM);
            HomeButton AC = new HomeButton (IconLabel.Icon.FABell, "ALERTS CONFIG", Colours.ALERTSCONFIG_LIGHT, Colours.ALERTSCONFIG_MEDIUM);

            var alertConfigTapGestureRecognizer = new TapGestureRecognizer ();
            alertConfigTapGestureRecognizer.Tapped += async (s, e) => {
                if (AC.IsEnabled) {
                    AC.IsEnabled = false;
                    await AC.ScaleTo(.8, 100);
                    await AC.ScaleTo(1, 100);
                    await Navigation.PushAsync (await AlertConfigContainer.CreateAlertConfigContainer());
                    AC.IsEnabled = true;
                }
            };
            AC.GestureRecognizers.Add (alertConfigTapGestureRecognizer);

            var userConfigTapGestureRecognizer = new TapGestureRecognizer ();
            userConfigTapGestureRecognizer.Tapped += async (s, e) => {
                if (UC.IsEnabled) {
                    UC.IsEnabled = false;
                    await UC.ScaleTo(.8, 100);
                    await UC.ScaleTo(1, 100);
                    await Navigation.PushAsync (await YourInfoPageContainer.CreateYourInfoPageContainer());
                    UC.IsEnabled = true;
                }
            };
            UC.GestureRecognizers.Add (userConfigTapGestureRecognizer);

            configGrid.Children.Add (UC, 0, 0);
            configGrid.Children.Add (AC, 1, 0);

            ScrollView scrollView = new ScrollView {
                Orientation = ScrollOrientation.Vertical,
                Content = configGrid,
                VerticalOptions = LayoutOptions.FillAndExpand
            };

            Content = scrollView;
        }

        public GridBarChartPage()
        {
            InitializeComponent();

            List<View> views = new List<View>();
            TapGestureRecognizer tapGesture = new TapGestureRecognizer();
            tapGesture.Tapped += OnBoxViewTapped;

            // Create BoxView elements and add to List.
            for (int i = 0; i < COUNT; i++)
            {
                BoxView boxView = new BoxView
                {
                    Color = Color.Accent,
                    HeightRequest = 300 * random.NextDouble(),
                    VerticalOptions = LayoutOptions.End,
                    StyleId = RandomNameGenerator()
                };
                boxView.GestureRecognizers.Add(tapGesture);
                views.Add(boxView);
            }

            // Add whole List of BoxView elements to Grid.
            grid.Children.AddHorizontal(views);

            // Start a timer at the frame rate.
            Device.StartTimer(TimeSpan.FromMilliseconds(15), OnTimerTick);
        }

		public ConnexionPage()
		{
			InitializeComponent ();

			personConnecte = "";

			Poster.Source = ImageSource.FromFile("NoOne.jpg");

			var profilImage = new TapGestureRecognizer ();
			profilImage.Tapped += async (sender, e) => {
				
				var action =  await DisplayActionSheet("Choisir une action", "Annuler", null, "Phototheque", "Prendre une photo");

				if (action == "Phototheque") 
				{
					await SelectPicture();
				}
				else if (action == "Prendre une photo") 
				{
					await TakePicture();
				} 
				else 
				{
					Poster.Source = ImageSource.FromFile ("NoOne.jpg");
				}
			};

			emailEntry.Text = "";

			Poster.GestureRecognizers.Add(profilImage);
		}

		public Springboard ()
		{
			InitializeComponent ();

			var tapFirst = new TapGestureRecognizer();
			tapFirst.Tapped += async (s, e) =>
			{
				//firstImage.Opacity = .5;  // dim the image for user feedback when tapped
				//await Task.Delay(100);
				//firstImage.Opacity = 1;
				await this.Navigation.PushAsync(new FirstPage());
			};
			FirstImage.GestureRecognizers.Add(tapFirst);

			var tapSecond = new TapGestureRecognizer();
			tapSecond.Tapped += async (s, e) =>
			{
				await this.Navigation.PushAsync(new SecondPage());
			};
			SecondImage.GestureRecognizers.Add(tapSecond);

			var tapThird = new TapGestureRecognizer();
			tapThird.Tapped += async (s, e) =>
			{
				await this.Navigation.PushAsync(new ThirdPage());
			};
			ThirdImage.GestureRecognizers.Add(tapThird);

		}

        private void SetupEventHandlers()
        {
            firstNameEntry.Completed += (object sender, EventArgs e) =>
            {
                lastNameEntry.Focus();
            };
            lastNameEntry.Completed += (object sender, EventArgs e) =>
            {
                lastNameEntry.Focus();
            };
            usernameEntry.Completed += (object sender, EventArgs e) =>
            {
                usernameEntry.Focus();
            };
            passwordEntry.Completed += (object sender, EventArgs e) =>
            {
                passwordEntry.Focus();
            };

            cancelButtonTapped = new TapGestureRecognizer();
            cancelButtonTapped.Tapped += (object sender, EventArgs e) =>
            {
                Navigation.PopModalAsync();
            };
            cancelButton.GestureRecognizers.Add(cancelButtonTapped);
        }

        public Option()
        {
            Label = new Label {
                Text = "Option",
                HorizontalOptions = LayoutOptions.StartAndExpand,
                VerticalOptions = LayoutOptions.Center
            };

            PagePanel = new PagePanel {
                HorizontalOptions = LayoutOptions.End,
                Pages = new List<View> {
                    new Image (),
                    new Image ()
                }
            };

            var layout = new StackLayout {
                Orientation = StackOrientation.Horizontal,
                Children = {
                    Label,
                    PagePanel
                }
            };

            var tapGestureRecognizer = new TapGestureRecognizer ();
            tapGestureRecognizer.Tapped += (sender, e) => OnTapped ();
            GestureRecognizers.Add (tapGestureRecognizer);

            Content = layout;

            SetImageState ();
            SetLabelState ();
        }

		public ArticlePage()
		{
			InitializeComponent();

			this.BackgroundColor = Color.White;
			BindingContext = new ArticleViewModel();

			var tgr = new TapGestureRecognizer ();
			tgr.Tapped +=(s,e)=>ExpandLabelClicked();
			lblExpand.GestureRecognizers.Add(tgr);

			artStackLayout.SizeChanged += ArticleStackLayout_SizeChanged;

			#region WebView Navigation

			webView1.Navigating += (s, e) =>
			{
				
			 if (e.Url.StartsWith("http") || e.Url.StartsWith("mailto"))
				{
					try
					{
						var uri = new Uri(e.Url);
						Device.OpenUri(uri);
					}
					catch (Exception)
					{
					}

					e.Cancel = true;
				}
			};
			#endregion

		}

        void AddMoodOptions()
        {
            //hardcoded to be 3x3
            int rows = 3;
            int cols = 3;
            //we get all the filenames to prepare to display the images
            var filenames = new List<string>(vm.moods.Keys);

            //images cannot handle taps out of the box
            var tapRecognizer = new TapGestureRecognizer();
            //tapRecognizer.NumberOfTapsRequired = 1;
            tapRecognizer.Tapped += OnTapGestureRecognizerTapped;

            //to iterate through every image
            int k = 0;
            for (int i = 0; i < rows; i++)
            {
                for (int j = 0; j < cols; j++, k++)
                {
                    var moodImg = new Image { Source = filenames[k], Opacity = CONST.DEFAULT_OPACITY };
                    moodImg.GestureRecognizers.Add(tapRecognizer);
                    grdMoods.Children.Add(moodImg, j, i);
                }
            }
        }