How to rerun onCreate, after user selects preference.

Question

So to make things simple my app consists of a bunch of cards (Google style). In the settings the user can select which card is viewable in the main activity. My problem is that I cant figure how to update the main activity after the user selects which cards are enabled.

Hopefully this diagram explains what I'm trying to say.

main activity --> (menu button) --> settings (menu item) --> preference fragment (settings screen) --> (user selects which cards are enabled) --> (back button) --> (main activity should reflect the changes)

I have looked into using the onResume method, and then calling recreate() inside of it. Not sure if I'm heading the right direction. The app crashed after I added that.

Main Activity.java

public void onCreate(Bundle savedInstanceState) {
        //remove title bar
        this.requestWindowFeature(Window.FEATURE_NO_TITLE);

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // init CardView
        mCardView = (CardUI) findViewById(R.id.cardsview);
        mCardView.setSwipeable(true);

        CardStack freqUsedGroup = new CardStack();
        freqUsedGroup.setTitle("Easy Access Cards");
        mCardView.addStack(freqUsedGroup);

        loadPref();
        //Begin UMass Website Card

        MyPlayCard umassEduCard = new MyPlayCard("UMass.edu",
                "Click this card to access UMass Amherst Website", "#881c1c",
                "#CC0000", true, true);
        umassEduCard.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {

            Intent intent = new Intent(Intent.ACTION_VIEW);
            intent.setData(Uri.parse("http://www.umass.edu/"));
            startActivity(intent);

            }
            });
        //end UMass Website Card

           if(my_checkbox_preference == true)
        {
            mCardView.addCard(umassEduCard);
        }
    mCardView.refresh();
}

public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }

@Override
public boolean onOptionsItemSelected(MenuItem item) {

    Intent intent = new Intent();
    intent.setClass(MainActivity.this, SetPreferenceActivity.class);
    startActivityForResult(intent, 0); 

    return true;
 }


private void loadPref() {
      SharedPreferences mySharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);

      my_checkbox_preference = mySharedPreferences.getBoolean("umass_website", false);

     }

SettingsFragment.java

public class SettingsFragment extends PreferenceFragment {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Load the preferences from an XML resource
        addPreferencesFromResource(R.layout.preferences);
    }
}

Thanks, let me know if any more code is need like xml, etc.

Calling recreate() will force the activity to restart itself, so by calling it in onResume() you're creating an infinite loop. Try using it from the fragment before it closes via `getActivity().recreate()` — Jon, Aug 25 '13 at 12:46

Budius · Answer 1 · 2013-08-27T12:20:13.177

1

You should use the startActivityForResult mechanism.

Here some pseudo-code:

MainActivity -> startActivityForResult(Settings activity)
settingActivity.onCreate() -> setResult(RESULT_CANCELED)
if any settings is actually changed -> setResult(RESULT_OK)
mainActivity.onActivityResult -> if( RESULT_OK )
      // you can try to actually change stuff or, make it a pretty simpler.
      // just re-start the whole thing
      startActivity(new Intent(this, this.class));
      finish();

edit:

from the fragment you can call the setResult method like this

// inside SettingsFragment 
// whenever something changed in the settings and you want to re-start the MainAcitivty
getActivity().setResult(RESULT_OK);
// simple!

still is the MainActivity and the SetPreferenceActivity that are doing the "activity result" communication, by the SettingsFragment is that calls the shots ;)

edited Aug 27 '13 at 12:20

answered Aug 25 '13 at 13:14

Budius

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Since I use SettingsFragment, will startActivityForResult still work? Or do I pass the SetPreferenceActivity. That activity involves FragmentManager and beginTransaction method. – Sammy Kumar Aug 26 '13 at 12:45
then you just need an interface between the fragment and the hosting activity. Check the code I'll edit into my answer – Budius Aug 27 '13 at 12:14
actually... I've realised that you can call setResult directly from the fragment. See edit with the example code. – Budius Aug 27 '13 at 12:21

How to rerun onCreate, after user selects preference.

1 Answers1