PointerEventData.dragging

Descripción

Determines whether the user is dragging the mouse or trackpad.

PointerEventData.dragging returns true when the user is moving the mouse or trackpad pointer. Returns false when the mouse or trackpad pointer is not moving. The dragging uses the move of the mouse or trackpad finger. OnDrag includes the dragging event.

The example below uses the IBeginDragHandler, IDragHandler, and IEndDragHandler interfaces. They provide EventTrigger.OnBeginDrag, EventTrigger.OnDrag, and EventTrigger.OnEndDrag event handlers respectively. IDragHandler.OnDrag queries when the pointer starts moving, and only sends a message when the user drags the pointer.

using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

// PointerEventDrag.dragging example.

// PointerEventData.dragging is set to true when the object is moving.
// Otherwise dragging is set to false.
//
// Create a 2D Project and add a Canvas and an Image as a child. Position the Image in the center
// of the Canvas. Resize the Image to approximately a quarter of the height and width. Create a
// Resources folder and add a sprite. Set the sprite to the Image component. Then add this script
// to the Image. Then press the Play button. The Image should be clickable and moved with the
// mouse or trackpad.

public class Example : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler
{
    private Vector3 position;
    private float timeCount = 0.0f;

    public void OnBeginDrag(PointerEventData eventData)
    {
        position = transform.position;
        Debug.Log("OnBeginDrag: " + position);
    }

    // Drag the selected item.
    public void OnDrag(PointerEventData data)
    {
        if (data.dragging)
        {
            // Object is being dragged.
            timeCount += Time.deltaTime;
            if (timeCount > 0.25f)
            {
                Debug.Log("Dragging:" + data.position);
                timeCount = 0.0f;
            }
        }
        transform.position = data.position;
    }

    public void OnEndDrag(PointerEventData eventData)
    {
        transform.position = position;
        Debug.Log("OnEndDrag: " + position);
    }
}