内部AsyncTask类内部还是外部的AlertDialog.Builder声明？

Question

Consider this AsyncTask inside activity MyActivity :

private class MyTask extends AsyncTask<Void, Void, Void> {

    private ProgressDialog progressDialog;
    private AlertDialog.Builder alertDialog;

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        progressDialog = ProgressDialog.show(MyActivity.this, "MyApp", "Working...");
    }

    @Override
    protected Void doInBackground(Void... params) {
        // elaborate...
        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        super.onPostExecute(result);
        progressDialog.dismiss();

        alertDialog = new AlertDialog.Builder(MyActivity);
        alertDialog.setMessage("Done !");
        alertDialog.show();
    }
}

What happen if I declare

private ProgressDialog progressDialog;
private AlertDialog.Builder alertDialog;

outside the AsyncTask , in the activity scope?

Is it really the same (for memory leaks and other inner Java behaviours)? Is one better than the other?

Answer 1

Not quite sure what you mean by 'the same'. But if you are talking about the scope of both progressDialog and alertDialog then the answer would definitely be no. A variable belongs to the class that declares it.

Basically what both progressDialog and alertDialog actually need is just a reference to a Context instance(In your case is 'MyActivity') in order for it to be instantiated and displayed, hence it doesn't matter where they are created as long as that Context object is available.

Hope it helps.