Untitled

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Drag_Drop : MonoBehaviour
{
    private bool isDragging = false;
    private bool isOverplayerdropZone = false;
    private GameObject playerdropZone;
    private Vector2 startPosition;


    // Update is called once per frame
    void Update()
    {
        if (isDragging)
        {
            transform.position = new Vector2(Input.mousePosition.x, Input.mousePosition.y);
        }
    }

    private void OnCollisionEnter2D(Collision2D collision)
    {
        playerdropZone = collision.gameObject;
    }

    private void OnCollisionExit2D(Collision2D collision)
    {
        isOverplayerdropZone = false;
        playerdropZone = null;
    }
    public void StartDrag()
    {
        startPosition = transform.position;
        isDragging = true;
    }

    public void EndDrag()
    {
        isDragging = false;
        if (isOverplayerdropZone)
        {
            transform.SetParent(playerdropZone.transform, false);
        }
        else
        {
            transform.position = startPosition;
        }
    }
}

using UnityEngine;

public class Drag_Drop : MonoBehaviour
{
    public bool isDragging = false;
    public Vector2 offset;
    public Vector2 startPosition;
    public Camera cam;

    public GameObject playerdropZone;
    public bool isOverplayerdropZone = false;
    public bool dropInOther = true;


    private void Start()
    {
        startPosition = transform.position;
    }

    private void OnMouseDown()
    {
        isDragging = true;
        offset = GetMousePos() - (Vector2)transform.position;
    }

    private void OnMouseDrag()
    {
        Vector2 targetPos = GetMousePos() - offset;
        transform.position = targetPos;
    }

    private void OnMouseUp()
    {
        isDragging = false;
    }

    private void OnTriggerEnter2D(Collider2D other)
    {
        playerdropZone = other.gameObject;
        isOverplayerdropZone = true;
    }

    private void OnTriggerExit2D(Collider2D other)
    {
        isOverplayerdropZone = false;
        playerdropZone = null;
    }


    private void Update()
    {
        if (isDragging)
        {
            if (isOverplayerdropZone)
            {
                transform.SetParent(playerdropZone.transform,false);
                transform.localPosition = Vector3.zero;
            }
        }
        else
        {
            if (!dropInOther)
            {
                transform.SetParent(null);
                transform.position = startPosition;
            }
        }
    }

    private Vector2 GetMousePos()
    {
        var flippedCamZ = -cam.transform.position.z;
        return cam.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, flippedCamZ));
    }
}