Share button AR

Hi guys, i'm a complete noob in Unity and have no programming knowledge. Nevertheless i did an AR app with Unity and Vuforia that for now is working. I found a C# script to take a screenshot of the screen and call the default Android sharing options. I'm now trying to implement that script into a Button but the script calls for a GUITexture. I had it working with the GUITexture but i'd want it to worrk with the button. So here's the script, what needs to change for it to work with the onClick() event of the button?

 using UnityEngine;
 using System.Collections;
 using System.IO;
 
 public class Share : MonoBehaviour {
 
     /*    Daniele Olivieri
      * www.daniel4d.com
      * 
      * I really hope this could help you out!
      * If you want to share the code please link to my blog! :-)
      * If you use the code in your app, it would be much  appreciated to give me credit somehow :-)
      * 
      * 
      * 
      * 
      * 
      * 
      * -------------------------------------- ***********************
      *  IMPORTANT !!!!! READ THIS
     * -------------------------------------- ***********************
      *  Grant the Writing Access to External (SDCard) in PlayerSettings ;-) Otherwise you won't be able to share pictures!!!!
      * 
      * 
      * 
      * 
      * 
      * */
 
 
     //Selectable GUITexture;
 
     private bool isProcessing = false;
 
     void Update ()
     {
         //GUITexture = gameObject.GetComponent<Selectable>();
         if (Input.touches.Length > 0 && GetComponent<GUITexture>().HitTest(Input.touches[0].position))
         {
             if(Input.touches[0].phase == TouchPhase.Began)
             {
                 GetComponent<GUITexture>().enabled = false;
             }
             else if (Input.touches[0].phase == TouchPhase.Ended)
             {
                 if(!isProcessing)
                     StartCoroutine( ShareScreenshot() );
             }
         }
     }
 
 
     public IEnumerator ShareScreenshot()
     {
         isProcessing = true;
 
         // wait for graphics to render
         yield return new WaitForEndOfFrame();
         //----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- PHOTO
         // create the texture
         Texture2D screenTexture = new Texture2D(Screen.width, Screen.height,TextureFormat.RGB24,true);
         
         // put buffer into texture
         screenTexture.ReadPixels(new Rect(0f, 0f, Screen.width, Screen.height),0,0);
 
         // apply
         screenTexture.Apply();
         //----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- PHOTO
 
         byte[] dataToSave = screenTexture.EncodeToPNG();
         
         string destination = Path.Combine(Application.persistentDataPath,System.DateTime.Now.ToString("yyyy-MM-dd-HHmmss") + ".png");
 
         File.WriteAllBytes(destination, dataToSave);
 
         if(!Application.isEditor)
         {
             // block to open the file and share it ------------START
             AndroidJavaClass intentClass = new AndroidJavaClass("android.content.Intent");
             AndroidJavaObject intentObject = new AndroidJavaObject("android.content.Intent");
             intentObject.Call<AndroidJavaObject>("setAction", intentClass.GetStatic<string>("ACTION_SEND"));
             AndroidJavaClass uriClass = new AndroidJavaClass("android.net.Uri");
             AndroidJavaObject uriObject = uriClass.CallStatic<AndroidJavaObject>("parse","file://" + destination);
             intentObject.Call<AndroidJavaObject>("putExtra", intentClass.GetStatic<string>("EXTRA_STREAM"), uriObject);
             //intentObject.Call<AndroidJavaObject>("putExtra", intentClass.GetStatic<string>("EXTRA_TEXT"), "testo");
             //intentObject.Call<AndroidJavaObject>("putExtra", intentClass.GetStatic<string>("EXTRA_SUBJECT"), "SUBJECT");
             intentObject.Call<AndroidJavaObject>("setType", "image/jpeg");
             AndroidJavaClass unity = new AndroidJavaClass("com.unity3d.player.UnityPlayer");
             AndroidJavaObject currentActivity = unity.GetStatic<AndroidJavaObject>("currentActivity");
 
             // option one WITHOUT chooser:
             //currentActivity.Call("startActivity", intentObject);
 
             // option two WITH chooser:
             AndroidJavaObject jChooser = intentClass.CallStatic<AndroidJavaObject>("createChooser", intentObject, "Share this...");
             currentActivity.Call("startActivity", jChooser);
 
             // block to open the file and share it ------------END
 
         }
         isProcessing = false;
         GetComponent<GUITexture>().enabled = true;
     }
 }