First of all please correct me if my ideology is incorrect, it is my first time working with fragments and not that good at ListView adapters.
I am currently using DrawerLayout which consist of fragments as you'd expect, I have a FAB which upon clicking will add a new entry to the SQLite db entry and will refresh the ListView (data pulled from the db).
My thinking was that I could get the ListView adapter (which is in Profiles fragment class) in the ActivityMain (as the FAB is not part of the fragment and will have different actions depending on current fragment) and then call .notifyDataSetChanged()
The Profiles fragment class
public class Profiles extends Fragment{
public ProfileListAdapter adapter;
(...)
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
DBHandler db = new DBHandler(getActivity().getBaseContext());
adapter = new ProfileListAdapter(getActivity().getBaseContext(), db.getAllProfiles());
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
ListView profileListView = (ListView)view.findViewById(R.id.profileListView);
profileListView.setAdapter(adapter);
}
ProfilesListAdapter (from here)
public class ProfileListAdapter extends ArrayAdapter<Profile> {
private static class ViewHolder {
TextView name;
}
public ProfileListAdapter(Context context, ArrayList<Profile> profileList) {
super(context, R.layout.profile_row, profileList);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// Get the data item for this position
Profile profile = getItem(position);
// Check if an existing view is being reused, otherwise inflate the view
ViewHolder viewHolder; // view lookup cache stored in tag
if (convertView == null) {
// If there's no view to re-use, inflate a brand new view for row
viewHolder = new ViewHolder();
LayoutInflater inflater = LayoutInflater.from(getContext());
convertView = inflater.inflate(R.layout.profile_row, parent, false);
viewHolder.name = (TextView) convertView.findViewById(R.id.profileListRowValue);
// Cache the viewHolder object inside the fresh view
convertView.setTag(viewHolder);
} else {
// View is being recycled, retrieve the viewHolder object from tag
viewHolder = (ViewHolder) convertView.getTag();
}
// Populate the data into the template view using the data object
viewHolder.name.setText(profile.name);
// Return the completed view to render on screen
return convertView;
}
}
Inside the DBHelper class
// Getting All Profiles
public ArrayList<Profile> getAllProfiles() {
ArrayList<Profile> profileListItems = new ArrayList<Profile>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_PROFILE;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, new String[] {});
// looping through all rows and adding to list
if (cursor.moveToLast()) {
do {
Profile profile = new Profile();
profile.setId(Integer.parseInt(cursor.getString(0)));
profile.setName(cursor.getString(1));
// Adding contact to list
profileListItems.add(profile);
} while (cursor.moveToPrevious());
}
// return contact list
cursor.close();
return profileListItems;
}
And this is what I am trying to do upon FAB click controlled in MainActivity, magic number is just an int which starts at 0 and increments by one for me to test the db / ListView easier.
db.addProfile(new Profile("Test Profile " + magicNumber));
magicNumber++;
FragmentManager fm = getSupportFragmentManager();
Profiles fragment = (Profiles) fm.findFragmentById(R.id.fragmentProfiles);
//I gave the fragment xml main FrameLayout an ID
fragment.updateListView();
Inside the Fragment class
public void updateListView(){
adapter.notifyDataSetChanged();
}
I also tried returning the adapter from the Profiles fragment class which I feel is the wrong way to tackle this problem.
public ProfileListAdapter getAdapter(){
return adapter;
}
I always end up with
java.lang.NullPointerException: Attempt to invoke virtual method 'void layout.Profiles.updateListView()' on a null object reference
or
java.lang.NullPointerException: Attempt to invoke virtual method 'com.xxxxx.xxxxx.appName.ProfileListAdapter layout.Profiles.getAdapter()' on a null object reference
To my noobish eye it seems that the adapter cannot be access from outside the fragment Profiles class, not sure if that's what it is - even if so not sure how to work around this. Let me know if any other code / logcat is required. Thank you!
