android - 为什么从不调用 AsyncTask<> 接口(interface)的 onProgressUpdate()？

Question

永远不会调用 onProgressUpdate()，您能告诉我为什么吗？

private class LoginMe extends AsyncTask<Context, Void, Boolean> {

    @Override
    protected Boolean doInBackground(Context... arg0) {
        doSomething();
        return true;
    }

    @Override
    protected void onProgressUpdate(Void... v) {
        super.onProgressUpdate(v);
        Log.d("Dev", "Im in onProgressUpdate()");
    }

    @Override
    protected void onPostExecute(Boolean result) {
        super.onPostExecute(result);
        if (result) {
            doOne();
        } else {
            doTwo();
        }
    }
}

Answer 1

您必须从 doInBackground 中手动调用 publishProgress。

doInBackground(Params...), invoked on the background thread immediately after onPreExecute() finishes executing. ... This step can also use publishProgress(Progress...) to publish one or more units of progress. These values are published on the UI thread, in the onProgressUpdate(Progress...) step.

http://developer.android.com/reference/android/os/AsyncTask.html