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Lukas Baumgartner
14,817 PointsHow to: notifyDatasetChanged();
Hey fellow students!
I have a problem with my app and after 2 hrs of reading stackoverflow i give up.
When the user taps on the floating actionbutton a new listitem in the recyclerview should be displayed. I have it like this so far:
public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener,
MainFragment.OnListItemSelectedInterface,
MainFragment.OnHorizontalListItemSelectedInterface,
MainFragment.OnListItemLongSelectedInterface {
private static final String MAIN_LIST_FRAGMENT = "main_list_fragment";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
RecyclerViewAdapter adapter = new RecyclerViewAdapter() //<<-- what belongs in the brackets?!
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Exercises.mainList.add("Test");
//adapter.notifyDataSetChanged();
Toast.makeText(MainActivity.this, "The arraylist is " + Exercises.mainList.size() + " long", Toast.LENGTH_SHORT).show();
}
});
MainFragment savedFragment = (MainFragment) getSupportFragmentManager().findFragmentByTag(MAIN_LIST_FRAGMENT);
if (savedFragment == null){
MainFragment fragment = new MainFragment();
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.add(R.id.placeholder, fragment, MAIN_LIST_FRAGMENT);
fragmentTransaction.commit();
}
The recyclerview is displayed in the MainFragment fragment and my data is stored in a String ArrayList.
So: How do I get the notifyDataSetChanged(); method working?
1 Answer
Lukas Baumgartner
14,817 PointsSolved it. I moved the onclick method for the fab into the fragment. Now it works fine :)