只需将AsyncTask创建为Activity的内部类,或将Context传递给AsyncTask的构造函数.

内部类：MyActivity.java

public class MyActivity extends Activity {

// your other methods of the activity here...

private class MyTask extends AsyncTask {

protected Void doInBackground(Void... param) {

publishProgress(...); // this will call onProgressUpdate();

}

protected Void onProgressUpdate(Void... prog) {

Toast.makeText(getActivity(), "text", 1000).show();

}

}

}

构造函数：MyTask.java

public class MyTask extends AsyncTask {

Context c;

public MyTask(Context c) {

this.c = c;

}

protected Void doInBackground(Void... param) {

publishProgress(...); // this will call onProgressUpdate();

}

protected Void onProgressUpdate(Void... prog) {

Toast.makeText(c, "text", 1000).show();

}

}

此外,请不要忘记在对话框上调用.show().

AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());

builder.show();