Android: override onPostExecute() if AsyncTask.execute(new Runnable()) is invoked in a method

Question

I have a method which I want to execute on a background thread:

public class MainActivity extends AppCompatActivity {
     @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        foo();
    }

    public static void foo(){
        AsyncTask.execute(() -> {
            // perform some object creations
        });
    }

    public static void foo2(){
      // Method that updates UI (lists and views) which requires the main thread.
    }
}

I would like to execute foo2 when AsynTask is complete ie onPostExecute() . How can I override onPostExecute() in this case?

Answer 1

不能直接实现，可以通过扩展Async类来实现。

Answer 2

It may be helpful, You can achieve this by class instead of method. Please try the below snippet:

@Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);

      foo asyncTask=new foo();
      asyncTask.execute();

   }

private class foo extends AsyncTask<void, void, void> {
      @Override
      protected void onPreExecute() {
         super.onPreExecute();

      }
      @Override
      protected void doInBackground(String... strings) {

      }
      @Override
      protected void onPostExecute() {
         super.onPostExecute();
         foo2 asyncTask=new foo2();
         asyncTask.execute();
      }
   }

private class foo2 extends AsyncTask<void, void, void> {
      @Override
      protected void onPreExecute() {
         super.onPreExecute();

      }
      @Override
      protected void doInBackground(String... strings) {

      }
      @Override
      protected void onPostExecute() {
         super.onPostExecute();

      }
   }

Answer 3

It's Work For me

public class MyTask extends AsyncTask<String, Void, String>
{
    @Override
    protected Void doInBackground(String... params) {
        //Do background 
    }

    protected void onPostExecute() {
        foo2();
    }
}

void foo2(){
    //your function
}

If you want to perform some function once the Asynctask is complete, You can also update the UI from within onPostExecute, which is simpler if it works for you.