TouchBehavior

Artikel
04/04/2024

The TouchBehavior is a Behavior that provides the ability to interact with any VisualElement based on touch, mouse click and hover events. The TouchBehavior implementation makes it possible to customize many different visual properties of the VisualElement that it is attached to such as the BackgroundColor, Opacity, Rotation and Scale, as well as many other properties.

Note

The toolkit also provides the ImageTouchBehavior implementation that extends this TouchBehavior by also providing the ability to customize the Source of an Image element.

Important

The .NET MAUI Community Toolkit Behaviors do not set the BindingContext of a behavior, because behaviors can be shared and applied to multiple controls through styles. For more information refer to .NET MAUI Behaviors

Syntax

The following examples show how to add the TouchBehavior to a parent HorizontalStackLayout and perform the following animations when a user touches or clicks on the HorizontalStackLayout or any of its children:

animates over a period of 250 milliseconds
applies the CubicInOut Easing
changes the Opacity to 0.6
changes the Scale to 0.8

XAML

Including the XAML namespace

In order to use the toolkit in XAML the following xmlns needs to be added into your page or view:

xmlns:toolkit="http://schemas.microsoft.com/dotnet/2022/maui/toolkit"

Therefore the following:

<ContentPage
    x:Class="CommunityToolkit.Maui.Sample.Pages.MyPage"
    xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml">

</ContentPage>

Would be modified to include the xmlns as follows:

<ContentPage
    x:Class="CommunityToolkit.Maui.Sample.Pages.MyPage"
    xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    xmlns:toolkit="http://schemas.microsoft.com/dotnet/2022/maui/toolkit">

</ContentPage>

Using the TouchBehavior

<ContentPage 
    xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    xmlns:toolkit="http://schemas.microsoft.com/dotnet/2022/maui/toolkit"
    x:Class="CommunityToolkit.Maui.Sample.Pages.Behaviors.TouchBehaviorPage">

   <HorizontalStackLayout HorizontalOptions="Center" VerticalOptions="Center">
        <HorizontalStackLayout.Behaviors>
            <toolkit:TouchBehavior
                DefaultAnimationDuration="250"
                DefaultAnimationEasing="{x:Static Easing.CubicInOut}"
                PressedOpacity="0.6"
                PressedScale="0.8" />
        </HorizontalStackLayout.Behaviors>

        <ContentView
            HeightRequest="100"
            WidthRequest="10"
            BackgroundColor="Gold" />
        <Label Text="The entire layout receives touches" VerticalOptions="Center" LineBreakMode="TailTruncation"/>
        <ContentView
            HeightRequest="100"
            WidthRequest="10"
            BackgroundColor="Gold" />
    </HorizontalStackLayout>

</ContentPage>

C#

The TouchBehavior can be used as follows in C#:

class TouchBehaviorPage : ContentPage
{
    public TouchBehaviorPage()
    {
        var firstContent = new ContentView
        {
            HeightRequest = 100,
            WidthRequest = 10,
            BackgroundColor = Colors.Gold
        };

        var label = new Label
        {
            Text = "The entire layout receives touches",
            VerticalOptions = LayoutOptions.Center,
            LineBreakMode = LineBreakMode.TailTruncation
        };

        var secondContent = new ContentView
        {
            HeightRequest = 100,
            WidthRequest = 10,
            BackgroundColor = Colors.Gold
        };

        var layout = new HorizontalStackLayout
        {
            HorizontalOptions = LayoutOptions.Center,
            VerticalOptions = LayoutOptions.Center,
            Children = 
            {
                firstContent,
                label,
                secondContent
            }
        }

        var touchBehavior = new TouchBehavior
        {
            DefaultAnimationDuration = 250,
            DefaultAnimationEasing = Easing.CubicInOut,
            PressedOpacity = 0.6,
            PressedScale = 0.8
        };

        layout.Behaviors.Add(touchBehavior);

        Content = layout;
    }
}

C# Markup

Our CommunityToolkit.Maui.Markup package provides a much more concise way to use this Behavior in C#.

using CommunityToolkit.Maui.Markup;

class TouchBehaviorPage : ContentPage
{
    public TouchBehaviorPage()
    {
        Content = new HorizontalStackLayout
        {
            HorizontalOptions = LayoutOptions.Center,
            VerticalOptions = LayoutOptions.Center,
            Children = 
            {
                new ContentView()
                    .Size(10, 100)
                    .BackgroundColor(Colors.Gold),

                new Label
                {
                    LineBreakMode = LineBreakMode.TailTruncation
                }
                    .Text("The entire layout receives touches"
                    .CenterVertical(),

                new ContentView()
                    .Size(10, 100)
                    .BackgroundColor(Colors.Gold)
            }
        }
            .Behaviors(new TouchBehavior
            {
                DefaultAnimationDuration = 250,
                DefaultAnimationEasing = Easing.CubicInOut,
                PressedOpacity = 0.6,
                PressedScale = 0.8
            });
    }
}

Additional examples

Handling hover interaction

The TouchBehavior provides the ability to customize the properties of the attached VisualElement based on whether the mouse it hovering over the element.

The following example shows how to attach the TouchBehavior to a HorizontalStackLayout and change the BackgroundColor and Scale of the HorizontalStackLayout when a user hovers their mouse cursor over the layout and any child elements.

<HorizontalStackLayout
    Padding="20"
    Background="Black"
    HorizontalOptions="Center">
    <HorizontalStackLayout.Behaviors>
        <toolkit:TouchBehavior
            HoveredBackgroundColor="{StaticResource Gray900}"
            HoveredScale="1.2" />
    </HorizontalStackLayout.Behaviors>
</HorizontalStackLayout>

Handling long press interaction

The TouchBehavior provides the ability to handle the scenario when a user presses for a long period of time. This period of time can be defined by the LongPressDuration which is in units of milliseconds.

The following example shows how to add the TouchBehavior to a HorizontalStackLayout, bind the LongPressCommand to the IncreaseLongPressCountCommand defined in the backing view model and set the LongPressDuration to 750 milliseconds.

<HorizontalStackLayout
    Padding="20"
    Background="Black"
    HorizontalOptions="Center">
    <HorizontalStackLayout.Behaviors>
        <toolkit:TouchBehavior
            LongPressDuration="750"
            LongPressCommand="{Binding Source={x:Reference Page}, Path=BindingContext.IncreaseLongPressCountCommand}"/>
    </HorizontalStackLayout.Behaviors>
</HorizontalStackLayout>

Properties

Property	Type	Description
Command	`ICommand`	Gets or sets the `ICommand` to invoke when the user has completed a touch gesture.
CommandParameter	`object`	Gets or sets the parameter to pass to the `Command` property.
CurrentHoverState	`HoverState`	Gets or sets the current `HoverState` of the behavior.
CurrentHoverStatus	`HoverStatus`	Gets or sets the current `HoverStatus` of the behavior.
CurrentInteractionStatus	`TouchInteractionStatus`	Gets or sets the current `TouchInteractionStatus` of the behavior.
CurrentTouchState	`TouchState`	Gets or sets the current `TouchState` of the behavior.
CurrentTouchStatus	`TouchStatus`	Gets or sets the current `TouchStatus` of the behavior.
DefaultAnimationDuration	`int`	Gets or sets the duration of the animation when the `CurrentTouchState` property is `TouchState.Default`.
DefaultAnimationEasing	`Easing`	Gets or sets the easing of the animation when the `CurrentTouchState` property is `TouchState.Default`.
DefaultBackgroundColor	`Color`	Gets or sets the background color of the element when the `CurrentTouchState` property is `TouchState.Default`.
DefaultOpacity	`double`	Gets or sets the opacity of the element when the `CurrentTouchState` property is `TouchState.Default`.
DefaultRotation	`double`	Gets or sets the rotation around both the X and Y axes of the element when the `CurrentTouchState` property is `TouchState.Default`.
DefaultRotationX	`double`	Gets or sets the rotation around the X axis of the element when the `CurrentTouchState` property is `TouchState.Default`.
DefaultRotationY	`double`	Gets or sets the rotation around the Y axis of the element when the `CurrentTouchState` property is `TouchState.Default`.
DefaultScale	`double`	Gets or sets the scale of the element when the `CurrentTouchState` property is `TouchState.Default`.
DefaultTranslationX	`double`	Gets or sets the X translation of the element when the `CurrentTouchState` property is `TouchState.Default`.
DefaultTranslationY	`double`	Gets or sets the Y translation of the element when the `CurrentTouchState` property is `TouchState.Default`.
DisallowTouchThreshold	`int`	Gets or sets the threshold for disallowing touch.
HoveredAnimationDuration	`int`	Gets or sets the duration of the animation when the `CurrentHoverState` property is `HoverState.Hovered`.
HoveredAnimationEasing	`Easing`	Gets or sets the easing of the animation when the `CurrentHoverState` property is `HoverState.Hovered`.
HoveredBackgroundColor	`Color`	Gets or sets the background color of the element when the `CurrentHoverState` property is `HoverState.Hovered`.
HoveredOpacity	`double`	Gets or sets the opacity of the element when the `CurrentHoverState` property is `HoverState.Hovered`.
HoveredRotation	`double`	Gets or sets the rotation around both the X and Y axes of the element when the `CurrentHoverState` property is `HoverState.Hovered`.
HoveredRotationX	`double`	Gets or sets the rotation around the X axis of the element when the `CurrentHoverState` property is `HoverState.Hovered`.
HoveredRotationY	`double`	Gets or sets the rotation around the Y axis of the element when the `CurrentHoverState` property is `HoverState.Hovered`.
HoveredScale	`double`	Gets or sets the scale of the element when the `CurrentHoverState` property is `HoverState.Hovered`.
HoveredTranslationX	`double`	Gets or sets the X translation of the element when the `CurrentHoverState` property is `HoverState.Hovered`.
HoveredTranslationY	`double`	Gets or sets the Y translation of the element when the `CurrentHoverState` property is `HoverState.Hovered`.
IsEnabled	`bool`	Gets or sets a value indicating whether the behavior is enabled.
LongPressCommand	`ICommand`	Gets or sets the `ICommand` to invoke when the user has completed a long press.
LongPressCommandParameter	`object`	Gets or sets the parameter to pass to the `LongPressCommand` property.
LongPressDuration	`int`	Gets or sets the duration in milliseconds required to trigger the long press gesture.
PressedAnimationDuration	`int`	Gets or sets the duration of the animation when the `CurrentTouchState` property is `TouchState.Pressed`.
PressedAnimationEasing	`Easing`	Gets or sets the easing of the animation when the `CurrentTouchState` property is `TouchState.Pressed`.
PressedBackgroundColor	`Color`	Gets or sets the background color of the element when the `CurrentTouchState` property is `TouchState.Pressed`.
PressedOpacity	`double`	Gets or sets the opacity of the element when the `CurrentTouchState` property is `TouchState.Pressed`.
PressedRotation	`double`	Gets or sets the rotation around both the X and Y axes of the element when the `CurrentTouchState` property is `TouchState.Pressed`.
PressedRotationX	`double`	Gets or sets the rotation around the X axis of the element when the `CurrentTouchState` property is `TouchState.Pressed`.
PressedRotationY	`double`	Gets or sets the rotation around the Y axis of the element when the `CurrentTouchState` property is `TouchState.Pressed`.
PressedScale	`double`	Gets or sets the scale of the element when the `CurrentTouchState` property is `TouchState.Pressed`.
PressedTranslationX	`double`	Gets or sets the X translation of the element when the `CurrentTouchState` property is `TouchState.Pressed`.
PressedTranslationY	`double`	Gets or sets the Y translation of the element when the `CurrentTouchState` property is `TouchState.Pressed`.
ShouldMakeChildrenInputTransparent	`bool`	Gets or sets a value indicating whether the children of the element should be made input transparent.

Events

Event	Description
`CurrentTouchStateChanged`	Fires when `CurrentTouchState` changes.
`CurrentTouchStatusChanged`	Fires when `CurrentTouchStatus` changes.
`HoverStateChanged`	Fires when `CurrentHoverState` changes.
`HoverStatusChanged`	Fires when `CurrentHoverStatus` changes.
`InteractionStatusChanged`	Fires when `CurrentInteractionStatus` changes.
`LongPressCompleted`	Fires when a long press gesture has completed.
`TouchGestureCompleted`	Fires when a touch gesture has completed.

Examples

You can find an example of this behavior in action in the .NET MAUI Community Toolkit Sample Application.

API

You can find the source code for TouchBehavior over on the .NET MAUI Community Toolkit GitHub repository.

Migrating From Xamarin Community Toolkit

In the Xamarin Community Toolkit, there was the TouchEffect if you are upgrading an app from Xamarin.Forms to .NET MAUI there are some breaking changes that you should be aware of:

API Name Changes
TouchBehavior is now implemented as a PlatformBehavior

API Name Changes

Name In Xamarin Community Toolkit	Name In MAUI Community Toolkit
TouchEffect	TouchBehavior
NormalBackgroundColor	DefaultBackgroundColor
NormalScale	DefaultScale
NormalOpacity	DefaultOpacity
NormalTranslationX	DefaultTranslationX
NormalTranslationY	DefaultTranslationY
NormalRotation	DefaultRotation
NormalRotationX	DefaultRotationX
NormalRotationY	DefaultRotationY
NormalAnimationDuration	DefaultAnimationDuration
NormalAnimationEasing	DefaultAnimationEasing
NormalBackgroundImageSource	DefaultImageSource (Moved to `ImageTouchBehavior`)
NormalBackgroundImageAspect	DefaultImageAspect (Moved to `ImageTouchBehavior` )

TouchBehavior is now implemented as a `PlatformBehavior`

In the Xamarin Community Toolkit the TouchEffect was implemented as an AttachedEffect. To use the effect you would use the attached properties and apply to any VisualElement

In .NET MAUI the TouchBehavior is implemented as a PlatformBehavior which is now applied to the elements behavior collection, see Platform Behaviors for more information.

Note: By default in .NET MAUI PlatformBehaviors will not set the BindingContext property, this is because Behaviors can be shared in styles. The TouchBehavior will set the BindingContext property equal to the VisualElement it is applied to. This means that you should not share the TouchBehavior between elements via styles.

Below is an example of a TouchEffect being applied to a view in Xamarin.Forms:

XAML
C#

<StackLayout Orientation="Horizontal"
            HorizontalOptions="CenterAndExpand"
            xct:TouchEffect.AnimationDuration="250"
            xct:TouchEffect.AnimationEasing="{x:Static Easing.CubicInOut}"
            xct:TouchEffect.PressedScale="0.8"
            xct:TouchEffect.PressedOpacity="0.6"
            xct:TouchEffect.Command="{Binding Command}">
    <BoxView Color="Gold" />
    <Label Text="The entire layout receives touches" />
    <BoxView Color="Gold"/>
</StackLayout>

var stackLayout = new StackLayout()
{
    HorizontalOptions = LayoutOptions.CenterAndExpand,
    Orientation = StackOrientation.Horizontal,
    Children =
    {
        new BoxView() { Color = Color.Gold, },
        new Label() { Text = "The entire layout receives touches", },
        new BoxView() { Color = Color.Gold, },
    }
};

TouchEffect.SetAnimationDuration(stackLayout, 250);
TouchEffect.SetAnimationEasing(stackLayout, Easing.CubicInOut);
TouchEffect.SetPressedScale(stackLayout, 0.8);
TouchEffect.SetPressedOpacity(stackLayout, 0.6);
TouchEffect.SetCommand(stackLayout, command);

The equivalent TouchBehavior in .NET MAUI would look like this:

XAML
C#

<HorizontalStackLayout HorizontalOptions="Center" VerticalOptions="Center">
    <HorizontalStackLayout.Behaviors>
        <toolkit:TouchBehavior
            DefaultAnimationDuration="250"
            DefaultAnimationEasing="{x:Static Easing.CubicInOut}"
            PressedOpacity="0.6"
            PressedScale="0.8"
            Command="{Binding Command}" />
    </HorizontalStackLayout.Behaviors>

    <ContentView
        BackgroundColor="Gold"
        HeightRequest="100"
        WidthRequest="10" />
    <Label
        LineBreakMode="TailTruncation"
        Text="The entire layout receives touches"
        VerticalOptions="Center" />
    <ContentView
        BackgroundColor="Gold"
        HeightRequest="100"
        WidthRequest="10" />
</HorizontalStackLayout>

var stackLayout = new HorizontalStackLayout()
{
    HorizontalOptions = LayoutOptions.Center,
    VerticalOptions = LayoutOptions.Center,
    Children =
    {
        new ContentView()
        {
            BackgroundColor = Colors.Gold,
            HeightRequest = 100,
            WidthRequest = 10,
        },
        new Label()
        {
            LineBreakMode = LineBreakMode.TailTruncation,
            Text = "The entire layout receives touches",
            VerticalOptions = LayoutOptions.Center,
        },
        new ContentView()
        {
            BackgroundColor = Colors.Gold,
            HeightRequest = 100,
            WidthRequest = 10,
        },
    },
    Behaviors =
    {
        new TouchBehavior()
        {
            DefaultAnimationDuration = 250,
            DefaultAnimationEasing = Easing.CubicInOut,
            PressedOpacity = 0.6,
            PressedScale = 0.8,
            Command = command,
        }
    }
};

Dela via

TouchBehavior

Syntax

XAML

Including the XAML namespace

Using the TouchBehavior

C#

C# Markup

Additional examples

Handling hover interaction

Handling long press interaction

Properties

Events

Examples

API

Migrating From Xamarin Community Toolkit

API Name Changes

TouchBehavior is now implemented as a `PlatformBehavior`

Ytterligare resurser

Dela via

TouchBehavior

Syntax

XAML

Including the XAML namespace

Using the TouchBehavior

C#

C# Markup

Additional examples

Handling hover interaction

Handling long press interaction

Properties

Events

Examples

API

Migrating From Xamarin Community Toolkit

API Name Changes

TouchBehavior is now implemented as a PlatformBehavior

Ytterligare resurser

TouchBehavior is now implemented as a `PlatformBehavior`