View source for Type:ButtonEventHandler

'''ButtonEventHandler''' is a delegate type for methods that react to a button event. A method that can be bound to it takes the [[Type:IButton|button]] that raised the event and a ButtonEventData that describes where the button was touched, and returns nothing. Its generic form, <code>ButtonEventHandler<T></code>, takes one extra argument of type T after those two.

The type is used for the synced delegate fields of buttons (<code>Pressed</code>, <code>Pressing</code>, <code>Released</code> and, on some, the hover events) and of the relay components that call a method when a button is pressed. Such a field is a [[Type:SyncDelegate`1|SyncDelegate]] of this type, so it can point at any method with a matching signature on any component in the world, and the target is saved with the world. The same type is also used for the local-only events of the C# side of a button, which cannot be saved.

== Signature ==
{| class="wikitable"
! Parameter !! Type !! Description
|-
| button || [[Type:IButton|IButton]] || The button that raised the event.
|-
| eventData || ButtonEventData || Where and by what the button was touched.
|-
| argument || T || Only on <code>ButtonEventHandler<T></code>. The value stored in the Argument field of the relay that calls the method.
|}

=== ButtonEventData ===
{| class="wikitable"
! Member !! Type !! Description
|-
| source || [[Type:Component|Component]] || The component that caused the event, such as the touching laser or finger.
|-
| globalPoint || Float3 || Point of the touch in global space.
|-
| localPoint || Float2 || Point of the touch in the local space of the button.
|-
| normalizedPressPoint || Float2 || Point of the touch relative to the size of the button.
|}

== Where it is used ==
=== Button events (<code>ButtonEventHandler</code>) ===
{| class="wikitable"
! Component !! Fields of this type
|-
| [[Component:Button|Button]] || Pressed, Pressing, Released, HoverEnter, HoverStay, HoverLeave
|-
| [[Component:LegacyButton|LegacyButton]] || Pressed, Pressing, Released
|-
| [[Component:PhysicalButton|PhysicalButton]] || Pressed, Pressing, Released
|-
| [[Component:TouchButton|TouchButton]] || Pressed, Pressing, Released
|-
| [[Component:ContextMenuItemSource|ContextMenuItemSource]] || Pressed, Pressing, Released
|}
These components all implement [[Type:IButton|IButton]], which declares Pressed, Pressing and Released as synced delegates of this type.

=== Relays (<code>ButtonEventHandler</code>) ===
{| class="wikitable"
! Component !! Fields of this type !! Behavior
|-
| [[Component:ButtonRelay|ButtonRelay]] || ButtonPressed || Calls the target when a button it is attached to is pressed.
|-
| [[Component:ButtonHoverRelay|ButtonHoverRelay]] || OnHoverEnter, OnHoverStay, OnHoverLeave || Calls the targets for the hover events.
|}

=== Relays with an argument (<code>ButtonEventHandler<T></code>) ===
All of these call <code>ButtonPressed</code> when pressed and pass the value of their <code>Argument</code> as the third parameter.
{| class="wikitable"
! Component !! Type of Argument
|-
| [[Component:ButtonRelay`1|ButtonRelay<T>]] || T (a value type)
|-
| [[Component:ButtonRefRelay`1|ButtonRefRelay<T>]] || A reference to a T (any world element)
|-
| [[Component:ButtonDelegateRelay`1|ButtonDelegateRelay<T>]] || A delegate of type T
|}
The relays also share the <code>DoublePressDelay</code> and <code>ReleasePressInterval</code> fields, which delay or filter when the target is called.

=== ProtoFlux ===
The [[ProtoFlux:ButtonEvents|ButtonEvents]] node subscribes to the Pressed, Pressing, Released, HoverEnter, HoverStay and HoverLeave events of a button and gives out the data of the event (source, global point, local point and normalized point) as outputs.

== See also ==
* [[Type:IButton]]
* [[Type:SyncDelegate`1]]
* [[Type:Delegate]]
* [[Component:Button]]
* [[Component:LegacyButton]]
* [[Component:PhysicalButton]]
* [[Component:TouchButton]]
* [[Component:ContextMenuItemSource]]
* [[Component:ButtonRelay]]
* [[Component:ButtonRelay`1]]
* [[Component:ButtonRefRelay`1]]
* [[Component:ButtonDelegateRelay`1]]
* [[Component:ButtonHoverRelay]]
* [[ProtoFlux:ButtonEvents]]

[[Category:Type]]