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IDragHandler

interface in UnityEngine.EventSystems


Implements interfaces: IEventSystemHandler

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Description

Interface to implement if you wish to receive OnDrag callbacks.

#pragma strict
@RequireComponent(Image)
public class DragMe extends MonoBehaviour {
	public var dragOnSurfaces: boolean = true;
	private var m_DraggingIcon: GameObject;
	private var m_DraggingPlane: RectTransform;
	public function OnBeginDrag(eventData: PointerEventData) {
		var canvas: var = FindInParents.<Canvas>(gameObject);
		if (canvas == null)return ;
		// What we want to do is create an icon for this.
		m_DraggingIcon = new GameObject("icon");
		m_DraggingIcon.transform.SetParent(canvas.transform, false);
		m_DraggingIcon.transform.SetAsLastSibling();
		var image: var = m_DraggingIcon.AddComponent.<Image>();
		// We want it to be ignored by the event system.
		m_DraggingIcon.AddComponent.<IgnoreRaycast>();
		image.sprite = GetComponent.<Image>().sprite;
		image.SetNativeSize();
		if (dragOnSurfaces)
			m_DraggingPlane = transform as RectTransform;
		else
			m_DraggingPlane = canvas.transform as RectTransform;
		SetDraggedPosition(eventData);
	}
	public function OnDrag(data: PointerEventData) {
		if (m_DraggingIcon != null)
			SetDraggedPosition(data);
	}
	private function SetDraggedPosition(data: PointerEventData) {
		if (dragOnSurfaces && data.pointerEnter != null && data.pointerEnter.transform as RectTransform != null)
			m_DraggingPlane = data.pointerEnter.transform as RectTransform;
		var rt: var = m_DraggingIcon.GetComponent.<RectTransform>();
		var globalMousePos: Vector3;
		if (RectTransformUtility.ScreenPointToWorldPointInRectangle(m_DraggingPlane, data.position, data.pressEventCamera, globalMousePos)) {
			rt.position = globalMousePos;
			rt.rotation = m_DraggingPlane.rotation;
		}
	}
	public function OnEndDrag(eventData: PointerEventData) {
		if (m_DraggingIcon != null)
			Destroy(m_DraggingIcon);
	}
	public static function FindInParents(go: GameObject) {
		if (go == null)return null;
		var comp: var = go.GetComponent.<T>();
		if (comp != null)return comp;
		var t: Transform = go.transform.parent;
		while ( t != null && comp == null ) {
			comp = t.gameObject.GetComponent.<T>();
			t = t.parent;
		}
		return comp;
	}
}
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

[RequireComponent(typeof(Image))] public class DragMe : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler { public bool dragOnSurfaces = true; private GameObject m_DraggingIcon; private RectTransform m_DraggingPlane;

public void OnBeginDrag(PointerEventData eventData) { var canvas = FindInParents<Canvas>(gameObject); if (canvas == null) return;

// We have clicked something that can be dragged. // What we want to do is create an icon for this. m_DraggingIcon = new GameObject("icon");

m_DraggingIcon.transform.SetParent (canvas.transform, false); m_DraggingIcon.transform.SetAsLastSibling(); var image = m_DraggingIcon.AddComponent<Image>(); // The icon will be under the cursor. // We want it to be ignored by the event system. m_DraggingIcon.AddComponent<IgnoreRaycast>();

image.sprite = GetComponent<Image>().sprite; image.SetNativeSize(); if (dragOnSurfaces) m_DraggingPlane = transform as RectTransform; else m_DraggingPlane = canvas.transform as RectTransform; SetDraggedPosition(eventData); }

public void OnDrag(PointerEventData data) { if (m_DraggingIcon != null) SetDraggedPosition(data); }

private void SetDraggedPosition(PointerEventData data) { if (dragOnSurfaces && data.pointerEnter != null && data.pointerEnter.transform as RectTransform != null) m_DraggingPlane = data.pointerEnter.transform as RectTransform; var rt = m_DraggingIcon.GetComponent<RectTransform>(); Vector3 globalMousePos; if (RectTransformUtility.ScreenPointToWorldPointInRectangle(m_DraggingPlane, data.position, data.pressEventCamera, out globalMousePos)) { rt.position = globalMousePos; rt.rotation = m_DraggingPlane.rotation; } }

public void OnEndDrag(PointerEventData eventData) { if (m_DraggingIcon != null) Destroy(m_DraggingIcon); }

static public T FindInParents<T>(GameObject go) where T : Component { if (go == null) return null; var comp = go.GetComponent<T>();

if (comp != null) return comp; Transform t = go.transform.parent; while (t != null && comp == null) { comp = t.gameObject.GetComponent<T>(); t = t.parent; } return comp; } }

Public Functions

OnDragWhen draging is occuring this will be called every time the cursor is moved.