Update recyclerView data from another class

Question

I want to populate a list array with a string every button click and then feed that in to the recycler view. Everytime a string is added to the array, now cards show up in my recyclerview.

I have for the button

submitButton.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View view) {
                diaryName = (EditText)findViewById(R.id.diaryName);
                dName = diaryName.getText().toString();

                titles2[i] = dName;

                i++;

                RecyclerAdapter.titles = titles2;

                titles2 = RecyclerAdapter.titles;

                }
        });

titles2 and titles are static so I can pass the array to another class file. But once I pass the array to the array that gets put into the recycler, no new cards show up.

heres the adapter and the other array

public class RecyclerAdapter extends
        RecyclerView.Adapter<RecyclerAdapter.ViewHolder> {

    public static int i = 0;

    public static String[] titles = new String[i];

    class ViewHolder extends RecyclerView.ViewHolder {
        //ImageView itemImage;
        TextView itemTitle;
        //TextView itemDetail;

        ViewHolder(View itemView) {
            super(itemView);
            //itemImage = itemView.findViewById(R.id.item_image);
            itemTitle = itemView.findViewById(R.id.item_title);
            //itemDetail = itemView.findViewById(R.id.item_detail);
        }
    }

    public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
        View v = LayoutInflater.from(viewGroup.getContext())
                .inflate(R.layout.card_layout, viewGroup, false);
        ViewHolder viewHolder = new ViewHolder(v);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(ViewHolder viewHolder, int i) {
        viewHolder.itemTitle.setText(titles[i]);
        //viewHolder.itemDetail.setText(details[i]);
        //viewHolder.itemImage.setImageResource(images[i]);
    }

    @Override
    public int getItemCount() {
        return titles.length;
    }


}

thanks!

recyclerview on here

public class Tab1Fragment extends Fragment {

    RecyclerView recyclerView;
    RecyclerView.LayoutManager layoutManager;
    RecyclerView.Adapter adapter;
    //private Activity view;

    public Tab1Fragment() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_tab1, container, false);


        recyclerView = (RecyclerView) view.findViewById(R.id.recycler_view);

        layoutManager = new LinearLayoutManager(this.getActivity());
        recyclerView.setLayoutManager(layoutManager);

        adapter = new com.example.growdiary.RecyclerAdapter();
        recyclerView.setAdapter(adapter);

        // Inflate the layout for this fragment
        return view;
    }



    public interface OnFragmentInteractionListener {


        // TODO: Update argument type and name
        void onFragmentInteraction(Uri uri);
    }

}

main

public class MainActivity extends AppCompatActivity implements
        Tab1Fragment.OnFragmentInteractionListener,
        Tab2Fragment.OnFragmentInteractionListener,
        Tab3Fragment.OnFragmentInteractionListener,
        Tab4Fragment.OnFragmentInteractionListener {

    RecyclerView recyclerView;
    RecyclerView.LayoutManager layoutManager;
    RecyclerView.Adapter adapter;

    //String testString = "pass this";
    //Intent intent = new Intent(MainActivity.this, RecyclerAdapter.class);

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);




        FloatingActionButton fab = findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                startActivity(new Intent(MainActivity.this, CreateDiary.class));
            }
        });
        configureTabLayout();
    }


    private void configureTabLayout() {
            TabLayout tabLayout = findViewById(R.id.tab_layout);

        tabLayout.addTab(tabLayout.newTab().setText("Tab 1 Item"));
        tabLayout.addTab(tabLayout.newTab().setText("Tab 2 Item"));
        tabLayout.addTab(tabLayout.newTab().setText("Tab 3 Item"));
        tabLayout.addTab(tabLayout.newTab().setText("Tab 4 Item"));

        final ViewPager viewPager = findViewById(R.id.pager);
        final PagerAdapter adapter = new TabPagerAdapter(getSupportFragmentManager(), tabLayout.getTabCount());
        viewPager.setAdapter(adapter);

        viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
        tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                viewPager.setCurrentItem(tab.getPosition());
            }

            @Override
            public void onTabUnselected(TabLayout.Tab tab) {

            }

            @Override
            public void onTabReselected(TabLayout.Tab tab) {

            }
        });
    }

    @Override
    public void onFragmentInteraction(Uri uri) {

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

}

where the button is

package com.example.growdiary;

import android.net.Uri;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

public class CreateDiary extends AppCompatActivity {

    Button submitButton;

    public static int i = 0;

    public static String[] titles2 = new String[i];


    EditText diaryName;

    String dName;

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

        submitButton = findViewById(R.id.submitButton);

        submitButton.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View view) {
                diaryName = (EditText)findViewById(R.id.diaryName);
                dName = diaryName.getText().toString();

                titles2[i] = dName;

                i++;

                RecyclerAdapter.titles = titles2;

                titles2 = RecyclerAdapter.titles;

                }
        });
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

Answer 1

you forget to add this line after setting your adapter in your fragment

adapter.notifyDataSetChanged();

Also make your adapter as public and stactic do the same for your recycleview and the recycleview.layoutmanger

So you can call them from your activity at onclick listeñer

And refill the recycleview