如何从ASyncTask调用父活动功能？

Question

setAccountAuthenticatorResult可以从Activity中调用,它可以扩展AccountAuthenticatorActivity.我的活动扩展了,但是启动了ASyncTask,因此setAccountAuthenticatorResult应该从ASyncTask调用(或者,ASyncTask的结果应该传递回主线程).

怎么做？

下面的代码有什么问题？

AsyncTask<Uri, Void, Bundle> task = new RetrieveAccessTokenTask(this, consumer, provider, prefs).execute(uri);

public class RetrieveAccessTokenTask extends AsyncTask<Uri, Void, Bundle> {
    private Context context;

    public RetrieveAccessTokenTask(Context context, OAuthConsumer consumer,
            OAuthProvider provider, SharedPreferences prefs) {
        this.context = context;
    }

    @Override
    protected void onPostExecute(Bundle result) {
        context.setAccountAuthenticatorResult(); // doesn't work

    }

Answer 1

创建AsyncTask时,可以向其添加新的构造函数,并传入对Activity的引用:

AsyncTask myTask = new MyTask(this);

然后从AsyncTask中的onPostExecute()方法中可以调用Activity上的方法.

public class MyTask extends AsyncTask<String, String, String>
{
    public MyActivity activity;

    public MyTask(MyActivity a)
    {
        this.activity = a;
    }

    //  ......

    protected void onPostExecute(String result)
    {
        activity.myMethod();
    }
}