Navigation Drawer Activity, send through fragments

Question

I have created a navigation drawer activity. I want to send information (via a EditText and button) to my receive_fragment where the information should appear in a TextView. When I tried to implement an interface in my mainActivity and added "sendText" and "SetText" methods in my respective fragments I got the errormessage that "null is not defined" so I had to consider an alternative usage but am totally stuck. How can I go about sending a message from my Communicate-class to end up in my Recieve_fragmentclass?

COMMUNICATE:

public class communicate_fragment extends Fragment{   

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

        return rootView;
    }    
    }

SEND_FRAGMENT

public class recieve_fragment extends Fragment{    

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

I have tried to add an interface in my Main_activity that handles the request from communicate_fragment and sends it back to recieve_fragment, however I get the error message that "cannot instansiate"

MAIN_ACTIVITY

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener{

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

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.setDrawerListener(toggle);
        toggle.syncState();

        NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);

        android.app.FragmentManager fm = getFragmentManager();
        fm.beginTransaction().replace(R.id.content_frame, new mainfragment()).commit();
    }

    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }

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

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {
        // Handle navigation view item clicks here.

        android.app.FragmentManager fm = getFragmentManager();

        int id = item.getItemId();

        if (id == R.id.about_me) {
            fm.beginTransaction().replace(R.id.content_frame, new about_me_fragment()).commit();

        } else if (id == R.id.another_fragment) {
            fm.beginTransaction().replace(R.id.content_frame, new another_fragment()).commit();    

        } else if (id == R.id.send) {
            fm.beginTransaction().replace(R.id.content_frame, new communicate_fragment()).commit();

        }
        else if (id == R.id.recieve) {
            fm.beginTransaction().replace(R.id.content_frame, new recieve_fragment()).commit();
        }

            DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }    
}

http://stackoverflow.com/questions/25134645/get-edittext-value-from-fragment, this should help you. — BradleyIW, Sep 28 '16 at 21:25

Divyesh Patel · Answer 1 · 2016-10-26T08:41:56.110

First create Listener Interface:

public interface YourCustomListener {
    void onItemClick(int position, int ID);
}

Now add this to your first fragment:

YourCustomListener mListener;

And your fragment onclick method:

mListener.onItemClick(position,"YOUR ID");

Add this :

@Override
    public void onAttach(Context con) {
        super.onAttach(con);
        try {
            mListener= (YourCustomListener ) con;
        } catch (ClassCastException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onDetach() {
        mListener=null;
        super.onDetach();
    }

Implement interface in Activity class. In derived method:

@Override
    public void onItemClick(int position,int ID) {
        fragment2 =new SecondFragment();
        Bundle arg= new Bundle();
        arg.putInt("ID",ID);
        arg.putString("title","ANY TITLE");
        fragment2.setArguments(arg);

        if (fragment2 != null) {
            FragmentManager fragmentManager = getSupportFragmentManager();
            FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
            fragmentTransaction.setCustomAnimations(R.anim.slide_left_enter,R.anim.slide_left_exit,R.anim.slide_left_enter,R.anim.slide_left_exit);
            fragmentTransaction.replace(R.id.container_body, fragment2,"PROF");
            fragmentTransaction.addToBackStack(null);
            fragmentTransaction.commit();
            getSupportActionBar().setLogo(null);
        }
    }

Now on Your Second Fragment, In on Create Method use this:

Bundle pb=getArguments();
        h=pb.getInt("ID");
        title=pb.getString("title");

Now you have Value of int h, and String Title. Use this value to show in your textview.

Navigation Drawer Activity, send through fragments

1 Answers1