Data from savedInstanceState is always empty in Android

Question

I am developing an Android app. I am testing using onSaveInstanceState event in activity. But it is not working as I expected, because value string is always empty when I retrieve it back onCreate event.

This is my activity

@Override
    public void onSaveInstanceState(Bundle outState, PersistableBundle outPersistentState) {
        super.onSaveInstanceState(outState, outPersistentState);
        outState.putString("message","Hello world!");
    }

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if(savedInstanceState!=null)
    {
        Toast.makeText(getBaseContext(),savedInstanceState.getString("message"),Toast.LENGTH_SHORT).show();
        //Log.i("DATA_FROM_STATE",savedInstanceState.getString("message"));
    }
}

When I run activity and change orientation, it is always toasting empty message. When I test uncommenting the Log line, it is giving me error because data string is empty or null. Why it is not working? How can I save and retrieve correctly?

score 1 · Accepted Answer · answered Jun 05 '16 at 09:20

Wrong method override. Should use onSaveInstanceState(Bundle outState) and it will work. You can copy below snippet and test it.

public class MainActivity extends AppCompatActivity {

    private final String SAVED_MESSAGE_KEY = "SAVED_MESSAGE";

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

        if(savedInstanceState != null) {
            if(savedInstanceState.containsKey(SAVED_MESSAGE_KEY)) {
                Log.i("Saved message is:", savedInstanceState.getString(SAVED_MESSAGE_KEY));
            }
        }
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putString(SAVED_MESSAGE_KEY, "Hello world!");
    }
}

Abdullah · Answer 2 · 2016-06-05T09:28:30.433

At first glance I saw that your are calling super before you saved the data And I guess your app is running on API21+ version of Android, because it is needed to call your method

public void onSaveInstanceState (Bundle outState, PersistableBundle outPersistentState);

@Override
    public void onSaveInstanceState(Bundle outState,PersistableBundle outPersistentState) {
        outState.putString("message","Hello world!");
        super.onSaveInstanceState(outState, outPersistentState);

    }

Data from savedInstanceState is always empty in Android

2 Answers2