How to insert markers (marker) on a map in another fragment?

I'm developing an Android app where you enter a list of courier tasks (get something in point A and take it to the point B ) and these points are shown on a map

App has two snippets:

When the map is created (or recreated) it takes the coordinates of the database (which also feeds the to-do list).

The question arises when inserting a new task. New bookmarks will only appear if you force map re-creation (by rotating the device or restarting the app ).

How do I insert bookmarks into the map when inserting a new task?

UPDATE: As Ack Lay observed, my question lacked more detail. And as a picture is worth a thousand words ...

** I'm new here and I can only publish two images ... Then it will be the last two.

1.When you open the application, an empty panel appears in the left half and an empty map on the right.

**Operationsinthedatabase(SQLite)aredonebya'dbHelper'classwiththeCRUDmethods.

That is, the markers appear when the'fragment 'is (re) created. What does not work is updating the map, along with the reviewer, when I enter a new task.

Now it's time to describe the structure of app .

The main activity is

public class MainActivity extends FragmentActivity 

It loads the layout it has is made up of

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:baselineAligned="false"
    android:fitsSystemWindows="true"
    android:id="@+id/myContainer"
    android:orientation="horizontal">
    <fragment
        android:id="@+id/runFragment"
        android:name="br.com.medamais.motonoix.RecyclerFragment"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1"
        tools:layout="@layout/fragment_recycler" />
    <fragment
        android:id="@+id/markersMapFragment"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1"
        tools:layout="@layout/fragment_map"
        android:name="br.com.medamais.motonoix.MarkersFragment"
        />
</LinearLayout>

The task list class

public class RecyclerFragment extends Fragment 

The map class

public class MapFragment extends Fragment

The code is very similar to what you ordered, it is only more adapted to the app . For example, the pins are fixed. We do not want them to change by touching the map. Only updating the card. To avoid course problems.

It seems to have several possible approaches. I have some experience as a developer, but this is my first Android app.

I imagine the solution is a way to access the map instance and add the new'marker '.

This would be done in'A' event 'onClick ()' of the'positiveButton 'of the dialog that inflates the form (ie when you hit CONFIRM). Or 'B' method wouldbHelper.insert () '

But there have to be other ways.

Can someone give me a light?

UPDATE: In response to @ramaral's tips

Implementing the 'interface' worked. It was not even necessary to create a custom 'listener', since the button had already been implemented.

But it's not over yet: - (

When the device is vertically oriented (portrait), it works correctly. However, when it is horizontal (landscape) not yet.

Vertical layout is composed like this:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/myContainer"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    android:orientation="vertical">
    <android.support.design.widget.TabLayout
        android:id="@+id/sliding_tabs"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:tabGravity="fill"
        app:tabMaxWidth="0dp"
        app:tabMode="fixed" />
    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="0px"
        android:layout_weight="1"
        android:background="@android:color/white" />
</LinearLayout>

Horizontally:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:baselineAligned="false"
    android:fitsSystemWindows="true"
    android:id="@+id/myContainer"
    android:orientation="horizontal">
    <fragment
        android:id="@+id/runFragment"
        android:name="br.com.medamais.motonoix.RecyclerFragment"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1"
        tools:layout="@layout/fragment_recycler" />
    <fragment
        android:id="@+id/markersMapFragment"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1"
        tools:layout="@layout/fragment_map"
        android:name="br.com.medamais.motonoix.MarkersFragment"
        />
</LinearLayout>

Map fragment layout

<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:map="http://schemas.android.com/apk/res-auto"
    android:id="@+id/markersMapFragment"
    android:name="com.google.android.gms.maps.SupportMapFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    map:cameraTargetLat="-23.7941"
    map:cameraTargetLng="-46.8825"
    map:cameraZoom="13"
/>

Next, the parts of code that I consider pertinent to this question, especially this line of 'MainActivity':

MarkersFragment mFragment = (MarkersFragment) getSupportFragmentManager().findFragmentById(R.id.viewpager);

I tried'findFragmentById 'with R.id.markersMapFragment, R.id.myContainer, but all return null. The only one that returns the object is R.id.viewpager and it works.

The fragment that shows the list and the + button

public class RecyclerFragment extends Fragment implements AlertDialog.OnClickListener {
    ...
    ...
    public RecyclerFragment() { 
        this.mCallback = null;
    }
    ...
    ...
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        ...
        ...        
        FloatingActionButton fab = (FloatingActionButton) mInflate.findViewById(R.id.fabAdd);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // abre o dialogo de inserção de dados
                dialogInsertRun();
            }
        });
        ...
        ...
    }

    public void dialogInsertRun() { // implementa a janela de dialogo de inserção de dados
        ...
        ...
        addRunDialog.setPositiveButton(R.string.button_positive, new DialogInterface.OnClickListener() { // implementa botão <CONFIRMAR>

            @Override
            public void onClick(DialogInterface dialog, int id) { // Listener 'padrão'
                ...
                ...
                mCallback.addMarkersToMap(runData); // metodo definido na Activity
            }
            ...
            ...
        }
    }
    ...
    ...
    @Override
    public void onClick(DialogInterface dialogInterface, int i) { 
        Log.d(TAG, "onClick: ");
    }
    ...
    ...
    private OnOkButtonListener mCallback;
    public interface OnOkButtonListener {
        void addMarkersToMap(RunData runData);
    }
    ...
    ...
}

In the 'activity' that controls the fragments we have

public class MainActivity extends FragmentActivity implements RecyclerFragment.OnOkButtonListener{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // replace the splash theme with app theme
        setTheme(R.style.AppTheme);
        // finish is overdue
        checkDateLimit();
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        ScreenUtility utility = new ScreenUtility(this);
        if (utility.getWidth() < 500.0) {
            // Get the ViewPager and set it's PagerAdapter so that it can display items
            ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
            viewPager.setAdapter(new TabsPagerAdapter(getSupportFragmentManager(), getApplicationContext()));

            // Give the TabLayout the ViewPager
            TabLayout tabLayout = (TabLayout) findViewById(R.id.sliding_tabs);
            tabLayout.setupWithViewPager(viewPager);
        }
    }

    ...
    ...
    public void addMarkersToMap(RunData runData) {
        if (runData != null) {
            MarkersFragment mFragment = (MarkersFragment) getSupportFragmentManager().findFragmentById(R.id.viewpager);

            mFragment.addSingleMarker(runData); 
    }
}

And in the fragment that controls the map

public class MarkersFragment extends Fragment {
    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        setUpMapIfNeeded(); 
    }
    private void setUpMapIfNeeded() { 
        // Do a null check to confirm that we have not already instantiated the map.
        if (markersMapFragment == null) {
            markersMapFragment = ((SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.markersMapFragment));
            // Check if we were successful in obtaining the map.
            if (markersMapFragment != null) {
                markersMapFragment.getMapAsync(new OnMapReadyCallback() {
                    @Override
                    public void onMapReady(GoogleMap mGoogleMap) {
                        if (mGoogleMap != null) {
                            ...
                            ...
                            LatLng tLatLng, mLatLng;
                            mLatLng = new LatLng(-23.5492, -46.6336);
                            // iterates through the runList as instance of RunData
                            for (RunData runData : runList) { 
                                tLatLng = addMarkers(runData.collect_lat, runData.collect_lng, runData.collect_address, runData.collect_person, runData.delivery_lat, runData.delivery_lng, runData.delivery_address, runData.delivery_person, runData.run_parcel, mGoogleMap);
                                ...
                                ...                               
                            }
                            // Show the current location in Google Map
                            mGoogleMap.moveCamera(CameraUpdateFactory.newLatLng(mLatLng));
                            // Zoom in the Google Map
                            mGoogleMap.animateCamera(CameraUpdateFactory.zoomTo(13));
                            ...
                            ...
                        }
                    }
                });
            }
        }
    }

    // metodo que adiciona os marcadores.
    public LatLng addMarkers(String collectLat, String collectLng, String collectAddress, String collectPerson,
                             String deliveryLat, String deliveryLng, String deliveryAddress, String deliveryPerson,
                             String parcel, GoogleMap googleMap) {
        LatLng cLatLng, dLatLng;
        String mSnippet;
        // add collect marker
        if ((collectLat != null & collectLng != null) && (collectLat.length() > 0 & collectLng.length() > 0)) {
            ...
            ...
            googleMap.addMarker(new MarkerOptions()
                    .position(cLatLng)
                    .icon(collectMarker)
                    .title(collectAddress)
                    .draggable(false)
                    .snippet(mSnippet)
            );
        } 

        // add delivery marker
        if ((deliveryLat != null & deliveryLng != null) && (deliveryLat.length() > 0 & deliveryLng.length() > 0)) {
            ...
            ...
            googleMap.addMarker(new MarkerOptions()
                    .position(dLatLng)
                    .icon(deliveryMarker)
                    .title(deliveryAddress)
                    .draggable(false)
                    .snippet(mSnippet)
            );
        }
        // retorna LatLng ou null
        if (cLatLng != null) {
            return cLatLng;
        } else if (dLatLng != null) {
            return dLatLng;
        } else {
            return null;
        }
    }

    // metodo que adiciona os marcadores de coleta e entrega de um unico registro
    // executado pela atividade controladora
    public void addSingleMarker(RunData runData) {
        final String collectLat = runData.collect_lat;
        final String collectLng = runData.collect_lng;
        ...
        ...

        if (markersMapFragment == null) {
            markersMapFragment = ((SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.markersMapFragment));
            // Check if we were successful in obtaining the map.
            if (markersMapFragment != null) {
                markersMapFragment.getMapAsync(new OnMapReadyCallback() {
                    @Override
                    public void onMapReady(GoogleMap mGoogleMap) {
                        LatLng mLatLng;
                        mLatLng = new LatLng(-23.5492, -46.6336);
                        if (mGoogleMap != null) {
                            mLatLng = addMarkers(collectLat, collectLng, collectAddress, collectPerson, deliveryLat, deliveryLng, deliveryAddress, deliveryPerson, parcel, mGoogleMap);
                            mGoogleMap.moveCamera(CameraUpdateFactory.newLatLng(mLatLng));
                            mGoogleMap.animateCamera(CameraUpdateFactory.zoomTo(13));
                        }
                    }
                });
            }
        } else {
            if (markersMapFragment != null) {
                markersMapFragment.getMapAsync(new OnMapReadyCallback() {
                    @Override
                    public void onMapReady(GoogleMap mGoogleMap) {
                        LatLng mLatLng;
                        mLatLng = new LatLng(-23.5492, -46.6336);
                        if (mGoogleMap != null) {
                            mLatLng = addMarkers(collectLat, collectLng, collectAddress, collectPerson, deliveryLat, deliveryLng, deliveryAddress, deliveryPerson, parcel, mGoogleMap);
                            mGoogleMap.moveCamera(CameraUpdateFactory.newLatLng(mLatLng));
                            mGoogleMap.animateCamera(CameraUpdateFactory.zoomTo(13));
                        }
                    }
                });
            }
        }
    }
}

I highlight the line again

MarkersFragment mFragment = (MarkersFragment) getSupportFragmentManager().findFragmentById(R.id.viewpager);

It works vertically because the view R.id.viewpager is instantiated, and like I said the other views return null

Given the above code, could you guide me how to reference the most appropriate view?

(If you think you have too much code, feel free to eliminate any excess.)