Instantiate a prefab on button press and keep it dragged

Question

So far the gameObject is created, but I need to click on the object a second time, in order to start the Drag event. Here's the script where I use the button to spawn a prefab

public void SpawnPrefab(Transform prefab)
{
    clicked = false;
    Vector3 mousePosition, targetPosition;
    mousePosition = Input.mousePosition;
    targetPosition=Camera.main.ScreenToWorldPoint(new Vector3(mousePosition.x,mousePosition.y,distance));
    prefab.position=targetPosition;
    if(isAlreadyClicked == false)
    {
        Instantiate(prefab, prefab.transform.position, prefab.transform.rotation);
        isAlreadyClicked = true;
        Debug.Log(clicked);
    }
}

I call this Drag event from another script inside the spawned gameObject though

void OnMouseDrag() 
{
    cursor.setGrab(); 
    if(this.transform.parent == null || this.transform.parent != null)
    {
        //drag the component
        Vector3 curScreenPoint = new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPoint.z);
        Vector3 curPosition = Camera.main.ScreenToWorldPoint(curScreenPoint) + offset;
        transform.position = curPosition;
        if(this.gameObject.CompareTag("Component"))
        {
            mainCanvas.transform.GetChild(1).gameObject.transform.GetChild(0).gameObject.transform.GetChild(4).gameObject.SetActive(false);
        }
        if(this.gameObject.CompareTag("NewComponent"))
        {
            mainCanvas.transform.GetChild(1).gameObject.transform.GetChild(0).gameObject.transform.GetChild(4).gameObject.SetActive(true);
        }  
    }
}

Hope it's clear enough. Any ideas? Thanks in advance!

EDIT: So I found out that the SpawnPrefab() only works when mouse button is released. Is there any way I can make the buttons work on mouse pressed?

Answer 1

When you spawn the element, set the isDragging to true.

---

using UnityEngine;
using UnityEngine.EventSystems;

public class Draggable : MonoBehaviour , IPointerUpHandler, IBeginDragHandler {

    public bool isDragging;

    void Update () {
        if (!isDragging)
            return;
        // Put you dragging logic here
    }

    public void OnBeginDrag(PointerEventData data){
        isDragging = true;
    }

    public void OnPointerUp (PointerEventData data){
        isDragging = false;
    }


}