Pass value from fragment to fragment through activity with bottom navigation view

Question

I am trying to pass an auto updating text which is latitude and longitude information from fragment_map to fragment_clocking through MainActivity but the value I get inside fragment_clocking is returned as null with no errors inside Logcat.

I am trying to use bundle to pass the values but I am not sure where and how to declare and call the bundles since I have a bottom navigation view.

MainActivity.java

    public class MainActivity extends AppCompatActivity {

    TextView latitude;
    TextView longitude;
    Bundle bundle = new Bundle();

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

        BottomNavigationView bottomNav = findViewById(R.id.nav_view);
        bottomNav.setOnNavigationItemSelectedListener(navListener);

        latitude = findViewById(R.id.id_latitude);
        longitude = findViewById(R.id.id_longitude);

        bundle.putString("latitudeInfo", String.valueOf(latitude));
        bundle.putString("longitudeInfo", String.valueOf(longitude));

        getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, new MapFragment()).commit();
    }

    private BottomNavigationView.OnNavigationItemSelectedListener navListener
            = new BottomNavigationView.OnNavigationItemSelectedListener() {

            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                Fragment selectedFragment = null;
                switch (item.getItemId()) {
                    case R.id.navigation_map:
                        selectedFragment = new MapFragment();
                        selectedFragment.setArguments(bundle);
                        break;
                    case R.id.navigation_clocking:
                        selectedFragment = new ClockingFragment();
                        selectedFragment.setArguments(bundle);
                        break;

                }

                getSupportFragmentManager()
                .beginTransaction()
                .replace(R.id.fragment_container, selectedFragment)
                .commit();
                return true;
                }
        };
    }

MapFragment.java

    public class MapFragment extends Fragment implements GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener, LocationListener, OnMapReadyCallback {

    TextView latitude;
    TextView longitude;

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

        latitude = rootView.findViewById(R.id.id_latitude);
        longitude = rootView.findViewById(R.id.id_longitude);

        SupportMapFragment mapFragment = (SupportMapFragment) getChildFragmentManager()
                .findFragmentById(R.id.map);

        mapFragment.getMapAsync(this);

        return rootView;
    }

    @Override
    public void onLocationChanged(Location location) {

        latitude.setText("Longitude: "+ location.getLongitude());
        longitude.setText("Latitude:    "+ location.getLatitude());
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;

        mGoogleApiClient = new GoogleApiClient.Builder(getActivity())
                .addApi(LocationServices.API)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .build();

            mGoogleApiClient.connect();
        }
    }

ClockingFragment.java

    public class ClockingFragment extends Fragment implements LocationListener {

    TextView latitude, longitude;

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

        latitude = rootView.findViewById(R.id.id_latitudeLocation);
        longitude = rootView.findViewById(R.id.id_longitudeLocation);

       Bundle bundle = getArguments();
       if(bundle != null){
           String latitudetest = bundle.getString("latitudeInfo");
           String longitudetest = bundle.getString("longitudeInfo");

           latitude.setText(latitudetest);
           longitude.setText(longitudetest);
       }

        return rootView;
    }

activity_main.xml

    <FrameLayout
        android:id="@+id/fragment_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@+id/nav_view"/>

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/nav_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:background="?android:attr/windowBackground"
        app:menu="@menu/bottom_nav_menu" />

fragment_clocking.xml

    <FrameLayout
        android:id="@+id/fragment_clocking"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

        <TextView
            android:id="@+id/id_latitudeLocation"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentTop="true"
            android:layout_marginStart="20dp"
            android:layout_marginLeft="20dp"
            android:layout_marginTop="20dp"
            android:text="TEST PLACEHOLDER"
            android:textSize="30sp" />

        <TextView
            android:id="@+id/id_longitudeLocation"
            android:layout_below="@+id/id_latitudeLocation"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginStart="20dp"
            android:layout_marginLeft="20dp"
            android:text="TEST PLACEHOLDER"
            android:textSize="30sp"/>

fragment_map.xml

    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/fragment_map" />

        <fragment
            xmlns:map="http://schemas.android.com/apk/res-auto"
            xmlns:tools="http://schemas.android.com/tools"
            android:id="@+id/map"
            android:name="com.google.android.gms.maps.SupportMapFragment"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            tools:context=".MapsActivity" />

        <TextView
            android:id="@+id/id_latitude"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginStart="20dp"
            android:layout_marginLeft="20dp"
            android:textSize="30sp" />

        <TextView
            android:id="@+id/id_longitude"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="30dp"
            android:layout_below="@+id/id_latitude"
            android:layout_marginStart="20dp"
            android:layout_marginLeft="20dp"
            android:textSize="30sp" />

Expected result: latitude and longitude value from FragmentMap.java passed through MainActivity.java and displayed in FragmentClocking.java

Actual Result: https://imgur.com/PWMPiaj

Answer 1

Generally speaking, if you have a Fragment that collects data and you want to pass this data to another Fragment , you should implement a callback interface in your Activity . The Fragment that collects the data should call the method in the Activity using the callback interface. The Activity should implement the callback interface. The method in the Activity should store the data in some member variables when it is called. When the Activity starts another Fragment , it should add the previously stored data to the "arguments" Bundle and then call setArguments() to pass the data to the new Fragment .

See Passing data between a fragment and its container activity for several possible ways to implement this.