Question

I have a hard time getting fragments to update their views… Specifically, fragments that exist in a ViewPager with ActionBarSherlock.

Here is my fragment class:

public class SearchFragment extends Fragment{
private String mInterests;
private String mSentence;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    return inflater.inflate(R.layout.bounty_search_layout, container, false);
}   

@Override
public void onResume() {
    super.onResume();
    getUserInterests();
}

/*
 * Get the users interests from the underlying
 * data store.
 */
public void getUserInterests() {
    TextView tv = (TextView) getView().findViewById(R.id.bounty_search_txtResult);
    DatabaseHelper dbHelper = new DatabaseHelper(getActivity());
    SQLiteDatabase db = dbHelper.getReadableDatabase();

    Cursor cursor = db.query(DatabaseConstants.TABLE_NAME, null, null, null, null, null, null);
    cursor.moveToFirst();
    mInterests = cursor.getString(cursor.getColumnIndex(DatabaseConstants.INTERESTS));
    if(mInterests.length() == 0) {
        mSentence = "You have no interests.";
    }
    else {
        mSentence = "Your interests are: ";
        mInterests = cursor.getString(cursor.getColumnIndex(DatabaseConstants.INTERESTS));
    }
    tv.setText(mSentence + mInterests);
    cursor.close();
    db.close();
    dbHelper.close();
}
}

The way I’m calling this fragment from my FragmentActivity is in the following…

SearchFragment searchInterests = new SearchFragment();

My views in the fragment are properly setup when it first runs, but when I call something like…

searchInterests.update();

from the FragmentActivity, to update some views,the getView() of

TextView tv = (TextView) getView().findViewById(R.id.results);

returns null and fails. I’m struggling to understand why this is.. Someone had mentioned to me that It’s because my Fragment is not attached to anything… I don’t quite understand this part and not only that but I just dont understand why getView() points to null if onCreateView was successful the first time? Doesn’t getView() gets the View returned by onCreateView? Here is the full code set: https://gist.github.com/1369653

Answer 1

So after some time, I figured it out… Problem was coming from how the FragmentPagerAdapter was returning the fragment…

@Override
public Fragment getItem(int position) {
    return Fragment.instantiate(mContext, mTabs.get(position), null);
}

This was returning a NEW fragment each time getItem() was called. However, I also had…

searchInterests = new SearchFragment();
selectInterests = new SelectFragment();

Which was creating a new fragment before it was added to the adapter. So the adapter was receiving a new fragment AND returning a new fragment instead of returning the same one I gave it. So I simply changed the getItem() function to return a NEW fragment if none of the same class already exist.