Move an object by touch in x,z (need fast help)

Unity Engine
1

i need a script to move an object by touch in x,z coordinates.
i have some objects on the ground and i want to move them by touch on ground.
help me please.

2

Im working on a augmented reality program and i need to move objects by touch in x and z coordinates. i have found a code in vuforia site to move objects. i tested this code but there are some problems, like object moving in Y so it goes to air !!!
but i want to move my object only in x z (on ground scene)
i tried to change code to do myself but it hasn’t any result.
please help me if you got it.

Im working on a augmented reality program and i need to move objects by touch in x and z coordinates. i have found a code in vuforia site to move objects. i tested this code but there are some problems, like object moving in Y so it goes to air !!!!!
but i want to move my object only in x z (on ground scene)
i tried to change code to do myself but it hasn't any result.
please help me if you got it.

using UnityEngine;
using System.Collections;

public class MyDragBehaviour : MonoBehaviour
{
    private float maxPickingDistance = 2000;// increase if needed, depending on your scene size

    private Transform pickedObject = null;

    // Use this for initialization
    void Start()
    {
    }

    // Update is called once per frame
    void Update()
    {
        foreach (Touch touch in Input.touches)
        {
            Debug.Log("Touching at: " + touch.position);

            //Gets the ray at position where the screen is touched
            Ray ray = Camera.main.ScreenPointToRay(touch.position);

            if (touch.phase == TouchPhase.Began)
            {
                Debug.Log("Touch phase began at: " + touch.position);

                RaycastHit hit = new RaycastHit();
                if (Physics.Raycast(ray, out hit, maxPickingDistance))
                {
                    pickedObject = hit.transform;
                }
                else
                {
                    pickedObject = null;
                }
            }
            else if (touch.phase == TouchPhase.Moved)
            {
                Debug.Log("Touch phase Moved");

                if (pickedObject != null)
                {
                    Vector2 screenDelta = touch.deltaPosition;

                    float halfScreenWidth = 0.5f * Screen.width;
                    float halfScreenHeight = 0.5f * Screen.height;

                    float dx = screenDelta.x / halfScreenWidth;
                    float dy = screenDelta.y / halfScreenHeight;

                    Vector3 objectToCamera =
                        pickedObject.transform.position - Camera.main.transform.position;
                    float distance = objectToCamera.magnitude;

                    float fovRad = Camera.main.fieldOfView * Mathf.Deg2Rad;
                    float motionScale = distance * Mathf.Tan(fovRad / 2);

                    Vector3 translationInCameraRef =
                        new Vector3( motionScale * dy,0, motionScale * dx);

                    Vector3 translationInWorldRef =
                        Camera.main.transform.TransformDirection(translationInCameraRef);

                    pickedObject.position += translationInWorldRef;
                }
            }
            else if (touch.phase == TouchPhase.Ended)
            {
                Debug.Log("Touch phase Ended");

                pickedObject = null;
            }
        }
    }
}
3

You can parent the object to the player to keep it at the exact x and z position relative to the player. Then you can manually set the Y so it never changes on that axis.