gestures

Cross-platform, multi-touch gesture and input recognition for Android, iOS, macOS, UWP and WPF.

• Supports tap, long-press, swipe, pan, pinch and hover gestures on all platforms
• Supports key listeners on desktop platforms (macOS, UWP, WPF)
• Xamarin support for Android, iOS and macOS.
• Xamarin.Forms support for all platforms.

Recognizers

Overview

All recognizers fire TouchesBegan and TouchesEnded. They may fire additional events dependent on their designated behavior.

Tap

Multi-touch, multi-tap gesture recognizer.

• NumberOfTouchesRequired: The number of touches required.
• NumberOfTapsRequired: The number of taps required.
• Tapped: The tapped event.

Long-press

Multi-touch, long-press gesture recognizer.

• NumberOfTouchesRequired: The number of touches required.
• LongPressed: The long-pressed event.

Swipe

Multi-touch, swipe gesture recognizer.

• NumberOfTouchesRequired: The number of touches required.
• SwipeDirectionMask: The swipe direction mask. Sets the allowable directions.
• Swiped: The swiped event with the direction.

Pan

Pan gesture recognizer.

• NumberOfTouchesRequired: The number of touches required.
• Panning: The panning event with the current state and delta position.

Pinch

Pinch gesture recognizer.

• NumberOfTouchesRequired: The number of touches required.
• Pinching: The pinching event with the current state and scale.

Hover

Hover gesture recognizer. For desktop platforms, this is triggered by mouseover.

• LongPressed: The hovering event.

Listeners

Key

Key event listener (desktop platforms only). Supports multiple concurrent keys and key combinations.

• Pressed: The key(s) pressed event.
• KeyDown: The key down event.
• KeyUp: The key up event.

Platforms

Xamarin

Type	Android	iOS	macOS
TapRecognizer	✅	✅	✅
LongPressRecognizer	✅	✅	✅
SwipeRecognizer	✅	✅	✅
PanRecognizer	✅	✅	✅
PinchRecognizer	✅	✅	✅
HoverRecognizer	✅	✅	✅
KeyListener	-	-	✅

Xamarin.Forms

Type	Android	iOS	macOS	UWP	WPF
TapGestureRecognizer	✅	✅	✅	✅	✅
LongPressGestureRecognizer	✅	✅	✅	✅	✅
SwipeGestureRecognizer	✅	✅	✅	✅	✅
PanGestureRecognizer	✅	✅	✅	✅	✅
PinchGestureRecognizer	✅	✅	✅	✅	✅
HoverGestureRecognizer	✅	✅	✅	✅	✅
KeyGestureListener	-	-	✅	✅	✅

Windows

Type	UWP	WPF
TapRecognizer	✅	✅
LongPressRecognizer	✅	✅
SwipeRecognizer	✅	✅
PanRecognizer	✅	✅
PinchRecognizer	✅	✅
HoverRecognizer	✅	✅
KeyListener	✅	✅

Xamarin

Usage

Recognizers can be attached to a native view by passing in a reference during construction. They may be subsequently detached by calling the Dispose method. For example:

Android

var view = FindViewById<View>(Resource.Id.SomeView);
var recognizer = new TapGestureRecognizer(Context, view);
recognizer.Tapped.Subscribe(e => {
    ...
});

iOS

var view = new UIView();
var recognizer = new TapGestureRecognizer(view);
recognizer.Tapped.Subscribe(e => {
    ...
});

macOS

var view = new NSView();
var recognizer = new TapGestureRecognizer(view);
recognizer.Tapped.Subscribe(e => {
    ...
});

Xamarin.Forms

Usage

Recognizers or listeners can be attached to a View by adding them to the GestureRecognizers collection. For example:

var recognizer = new TapGestureRecognizer();
recognizer.Tapped += (sender, e) => {
    ...
};

View.GestureRecognizers.Add(recognizer);

Platform support is enabled by adding a RecognizerEffect or ListenerEffect to the Effects collection. For example:

View.Effects.Add(Effect.Resolve($"Velocity.{nameof(RecognizerEffect)}"));

View.Effects.Add(Effect.Resolve($"Velocity.{nameof(ListenerEffect)}"));

Note: If the effect is not added, the gesture or listener will not be handled by Xamarin.Forms.

Supported Elements

Element	Android	iOS	macOS	UWP	WPF
AbsoluteLayout	-	-	-	-	-
ActivityIndicator	-	-	-	-	-
BoxView	-	-	-	-	-
Button	-	-	-	-	-
ContentPage	-	-	-	-	-
ContentView	-	-	-	-	-
DatePicker	-	-	-	-	-
Editor	-	-	-	-	-
Entry	-	-	-	-	-
Frame	-	-	-	-	-
Grid	-	-	-	-	-
Image	-	-	-	-	-
ImageButton	-	-	-	-	-
Label	-	-	-	-	-
ListView	-	-	-	-	-
Picker	-	-	-	-	-
ProgressBar	-	-	-	-	-
RelativeLayout	-	-	-	-	-
ScrollView	-	-	-	-	-
SearchBar	-	-	-	-	-
Slider	-	-	-	-	-
StackLayout	-	-	-	-	-
Stepper	-	-	-	-	-
Switch	-	-	-	-	-
TabbedPage	-	-	-	-	-
TableView	-	-	-	-	-
TimePicker	-	-	-	-	-
WebView	-	-	-	-	-

Windows

Recognizers can be attached to a native view by passing in a reference during construction. They may be subsequently detached by calling the Dispose method. For example:

UWP/WPF

var view = new Canvas();
var recognizer = new TapGestureRecognizer(view);
recognizer.Tapped.Subscribe(e => {
    ...
});

Lifecycle Events

Recognizers and listeners may be attached and detached 'on-the-fly'. It is recommended that for managing the lifecycle of multiple recognizers, a CompositeDisposable is used. For example:

var view = FindViewById<View>(Resource.Id.SomeView);
var disposable = new CompositeDisposable();

disposable.Add(new TapGestureRecognizer(Context, view));
disposable.Add(new LongPressRecognizer(Context, view));
disposable.Add(new SwipeGestureRecognizer(Context, view));

When required to detach the recognizers, we can call:

disposable.Clear();

Or, if the CompositeDisposable is no longer required:

disposable.Dispose();

Advanced Scenarios

Multiple Recognizers

Not all recognizers may work together concurrently. For example, you cannot use a SwipeRecognizer and PanRecognizer simulataneously.

Support Notes

Android

1. Hover recognizer requires hardware support.

iOS

1. Hover recognizer requires iOS 13 and above.

UWP

1. Long-press recognizer is triggered by right-click.
2. Hover recognizer triggered by mouseover.

WPF

1. For gestures to work in Xamarin.Forms, they must be attached to a view where the background color is opaque (not transparent).
2. Long-press recognizer is triggered by right-click.
3. Hover recognizer triggered by mouseover.

Remaining Work

• Migrate to AndroidX
• Add detection algorithms for platforms which do not offer native recognition.
• Add unit tests for shared behavior
• Add delay-based long-press recognition on macOS, UWP and WPF.
• Add multi-touch support for platforms which do not offer native recognition.
• Add platform sample pages (non-Xamarin.Forms)
• Unify values returned by PinchGestureRecognizer across all platforms.
• Implement YAML build script