Yet another coroutine question

Unity Engine
1

Hi.
I’ve read several topics about coroutines on the forum, and even though I understand the concept (or so I think), I’m having some troubles working with them.
What I’m trying to accomplish is to create a DownloadManager behaviour that could start and stop coroutines for downloading data over the Internet.

I successfully created and started the download of the WWW file, but I’m stuck with the Stop/Cancel function. Now, I know there is a StopCoroutine(“MyCoroutine”) that should match StartCoroutine(“MyCoroutine”, WWW myWWW) but unfortunately I can’t seem to get it to work. Here’s what I did so far :

using UnityEngine;
using System.Collections;

public class DownloadManager : MonoBehaviour {
    public int maxDownloads = 1;
    private GameObject[] downloads;

    void Start() {
        downloads = new GameObject[maxDownloads];
    }

    void Update() {
        if (Input.GetKeyDown("b")) {
            for (int i = 0; i < maxDownloads; i++) {
                downloads[i] = new GameObject();
                downloads[i].AddComponent<DownloadCoroutine>();
                downloads[i].GetComponent<DownloadCoroutine>().Url = "http://www.website.com/bigimages/" + i + ".jpg";
                downloads[i].GetComponent<DownloadCoroutine>().StartDownload();
            }
        }

        if (Input.GetKeyDown("e")) {
            for (int i = 0; i < maxDownloads; i++) {
                downloads[i].GetComponent<DownloadCoroutine>().StopDownload();
            }
        }
    }
}

Now, for stopping, I read several Dreamora’s posts about “state variables”.
So that’s what I’m trying to accomplish, but I’m not sure exactly how to do it correctly. I did that :

using UnityEngine;
using System.Collections;

public class DownloadCoroutine : MonoBehaviour {
    private string url = "";
    private bool inProgress = false;
    private bool cancelled = false;

    public string Url { get; set; }
	
    public void StartDownload() {
        inProgress = true;
        WWW www = new WWW(url);
        StartCoroutine("MyCoroutine", www);
    }

    public void StopDownload() {
        if (inProgress) cancelled = true;
    }

    IEnumerator MyCoroutine(WWW www) {
        yield return www;
        inProgress = false;
        if (!cancelled) {
            if (www.error == null) {
                Debug.Log("GOT IMAGE: " + url);
            }
            else {
                Debug.Log("ERROR FOR IMAGE : " + url);
            }
        }
    }
}

My question here is : how can setting my cancelled variable to “true” will stop the coroutine from running, cause from what I understood, the “if” statement will only be done once the download is already over ?
Thanks a lot.

2

I just noticed I posted in the wrong section of the forum yesterday. So I created a new thread, this time in the Scripting section.
Sorry.
Here is the link : http://forum.unity3d.com/threads/71739-Yet-another-coroutine-question-(this-time-in-the-correct-section)?p=458493#post458493