Question

I’ve been using Callable, but now I need the function to use a param in the call method. I get that this isn’t a capability of call so how can I do this?

What I currently have (wrong):

AsyncTask async = new MyAsyncTask();
async.finished(new Callable(param) {
    // the function called during async.onPostExecute;
    doSomething(param);
});
async.execute(url);

MyAsyncTask:

...
@Override
protected void onPostExecute(JSONObject result)  {
    //super.onPostExecute(result);
    if(result != null) {
        try {
            this._finished.call(result); // not valid because call accepts no params
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

public void finished(Callable<Void> func) {
    this._finished = func;
}
...

Answer 1

If you make param a final variable, you can just refer to it from within the Callable:

final String param = ...;
async.finished(new Callable() {
    // the function called during async.onPostExecute;
    doSomething(param);
});

You’ll have to do this when you create the Callable though – you can’t give it the value later. If you need that for some reason, you’ll have to basically use shared state – some “holder” which the Callable has access to, and which can have the value set into it before the Callable executes. That could probably just be the MyAsyncTask itself:

final MyAsyncTask async = new MyAsyncTask();
async.finished(new Callable() {
    // the function called during async.onPostExecute;
    doSomething(async.getResult());
});
async.execute(url);

Then:

private JSONObject result;
public JSONObject getResult() {
    return result;
}

@Override
protected void onPostExecute(JSONObject result)  {
    this.result = result;
    if(result != null) {
        try {
            this._finished.call();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}