Error casting android.support.v4.app.FragmentActivity$NonConfigurationInstances to my AsyncTask

Question

I'm facing problem with line of code:

mt=(MyTask)getLastNonConfigurationInstance();

mt is instance of MyTask class

static class MyTask extends AsyncTask<String,Integer,Void>
    {
        MainActivity activity;
        void link (MainActivity act)
        {
            activity=act;
        }
        void unlink()
        {

            activity=null;
        }

        @Override
        protected Void doInBackground(String... params) {

            try{
                for(int i=1;i<=10;i++){
                    TimeUnit.SECONDS.sleep(1);
                    publishProgress(i);
                    Log.d("qwe", "i = " + i
                            + ", MyTask: " + this.hashCode()
                            + ", MainActivity: " + activity.hashCode());

                }
            }
            catch (InterruptedException ie)
            {
                ie.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onProgressUpdate(Integer... values) {
            super.onProgressUpdate(values);
            activity.tv.setText("i = "+values[0]);
        }
    }

and i save it in onRetainCustomNonConfigurationInstance method

  @Override
    public Object onRetainCustomNonConfigurationInstance() {
        mt.unlink();
        return mt;
    }

Error Arrives when I try to pass value from configuration instance to mt, error message is

java.lang.ClassCastException: android.support.v4.app.FragmentActivity$NonConfigurationInstances cannot be cast to com.example.bermud06.p091_asynctaskdisplayrotate.MainActivity$MyTask

Using nexus 5 device with API Level 22.

Answer 1

Use getLastCustomNonConfigurationInstance() instead. From the Docs for FragmentActivity :

public Object onRetainCustomNonConfigurationInstance()

Use this instead of onRetainNonConfigurationInstance() . Retrieve later with getLastCustomNonConfigurationInstance() .