Communicating activity with fragments in TabBar

We need
– Interface.
– Actvity.
– ManagerFragment.
– Adapter
– FirstFragment.
– SecondFragment.

Complete code in github

First Step

In our Activity we will call a Manager fragment

mManagerFragment.update(newText);

You can check the complete activity

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "MainActivity";
    private MenuItem mSearchMenuItem;

    private SearchView mSearchView;

    ManagerFragment mManagerFragment;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
       
        mManagerFragment = new ManagerFragment().newInstance();
        replaceFragment();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_main, menu);

        mSearchMenuItem = menu.findItem(R.id.menu_main_action_search);

        mSearchView = (SearchView) MenuItemCompat.getActionView(mSearchMenuItem);

        mSearchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
            @Override
            public boolean onQueryTextSubmit(String query) {
                return true;
            }

            @Override
            public boolean onQueryTextChange(String newText) {
                //sent to ManagerAdapter
                mManagerFragment.update(newText);
                return false;
            }
        });

        return super.onCreateOptionsMenu(menu);
    }


    public void replaceFragment() {

        try {

            FragmentManager fragmentManager = getSupportFragmentManager();
            fragmentManager.beginTransaction().replace(R.id.content_main, mManagerFragment, "tag").commit();

        } catch (Exception e) {
            Log.d(TAG, e.toString());
        }

    }
    
}

Now in Our ManagerFragment we received the string in this method

public void update(String string)

In Our Fragment we send the string from Manager To Adapter

public void update(String string){
        mAdapter.update(string);
    }

This is ManagerFragment

public class ManagerFragment extends Fragment {

    private ViewPager mViewPager;
    private TabsAdapter mAdapter;

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

    public static ManagerFragment newInstance() {
        ManagerFragment fragment = new ManagerFragment();
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view = inflater.inflate(R.layout.fragment_manager, container, false);

        TabLayout tabLayout = (TabLayout) view.findViewById(R.id.fragment_manager_tab_bar_tab_layout);
        mViewPager = (ViewPager) view.findViewById(R.id.fragment_manager_tab_bar_pager);

        mAdapter = new TabsAdapter(getFragmentManager(), getActivity());

        mViewPager.setAdapter(mAdapter);
        tabLayout.setupWithViewPager(mViewPager);

        return view;
    }

    //received from Activity
    public void update(String string){
        //sent to Adapter
        mAdapter.update(string);
    }

}

Second Step

This is the most importa step
In Our adapter We receive from ManagerFragment

//received from ManagerFragment
    public void update(String string) {
        mGeneralString = string;
        //updated
        notifyDataSetChanged();
    }

And we sent to FirstFragment and SecondFragment

@Override
    public int getItemPosition(Object object) {
        if (object instanceof UpdateableFragmentListener) {
            //sent to FirstFragment and SecondFragment
            ((UpdateableFragmentListener) object).update(mGeneralString);
        }
        return super.getItemPosition(object);
    }

You can see the adapter

public class TabsAdapter extends FragmentStatePagerAdapter {

    public static final int TOTAL_TABS = 2;
    public String mGeneralString;
    public Context mContext;

    public TabsAdapter(FragmentManager fm, Context context) {
        super(fm);
        mContext = context;
    }

    @Override
    public Fragment getItem(int position) {
        switch (position) {
            case 0:
                return new FirstFragment().newInstance();

            case 1:
                return new SecondFragment().newInstance();
        }
        return null;
    }

    //received from ManagerFragment
    public void update(String string) {
        mGeneralString = string;
        //updated
        notifyDataSetChanged();
    }

    @Override
    public int getItemPosition(Object object) {
        if (object instanceof UpdateableFragmentListener) {
            //sent to FirstFragment and SecondFragment
            ((UpdateableFragmentListener) object).update(mGeneralString);
        }
        return super.getItemPosition(object);
    }

    @Override
    public int getCount() {
        return TOTAL_TABS;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        switch (position) {
            case 0:
                return mContext.getString(R.string.fragment_first_title);
            case 1:
                return mContext.getString(R.string.fragment_second_title);
            default:
                return mContext.getString(R.string.fragment_first_title);
        }
    }
}

And our listener is a simple interface

 
public interface UpdateableFragmentListener {
    public void update(String string);
}

Third Step

In FirstFragment and SecondFragment we receive the string with our Listener,
We implement the listener

public class FirstFragment extends Fragment implements UpdateableFragmentListener{

//received from Adapter with our Listener
    @Override
    public void update(String string) {
        mTextView.setText(string);
    }

you can see the simple Fragment

public class FirstFragment extends Fragment implements UpdateableFragmentListener{

    TextView mTextView;

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

    public static FirstFragment newInstance() {
        FirstFragment fragment = new FirstFragment();
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view = inflater.inflate(R.layout.fragment_first, container, false);
        mTextView = (TextView) view.findViewById(R.id.fragment_first_text);
        return view;
    }

    //received from Adapter with our Listener
    @Override
    public void update(String string) {
        mTextView.setText(string);
    }
}

Complete code in github