How to refresh the data after click the item on listview for fragment

Question

I have two fragments both AFragment and BFragment. The AFragment has a ListView . The BFragment has a Texview and a Button . The Afragment will change the fragment and putString to BFragment when the user clicked the item on ListView . The BFragment got the data from Afragment and display the date to TextView . How can I do?

The sample is like that

Answer 1

You can use libs https://github.com/greenrobot/EventBus . very easy!!!

EventBus in 3 steps

Define events:

 public static class MessageEvent { /* Additional fields if needed */ }

Prepare subscribers: Declare and annotate your subscribing method, optionally specify a thread mode:

@Subscribe(threadMode = ThreadMode.MAIN)  
public void onMessageEvent(MessageEvent event) {/* Do something */};

Register and unregister your subscriber. For example on Android, activities and fragments should usually register according to their life cycle:

 @Override
 public void onStart() {
 super.onStart();
 EventBus.getDefault().register(this);
 }

 @Override
 public void onStop() {
 super.onStop();
 EventBus.getDefault().unregister(this);
 }

Post events:

 EventBus.getDefault().post(new MessageEvent());

Answer 2

You can use Interface and LocalBroadcastReceiver both for refreshing the Fragment. Create one LocalBroadcastReceiver

LocalBroadcastManager.getInstance(context).registerReceiver(refreshFragment ,
            new IntentFilter("refreshFragment"));

and its Method in BFragment

private BroadcastReceiver refreshFragment = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {

        // Do The Changes You Want To Refresh BFragment

    }
};

And Than Call This LocalBroadcastReceiver in OnClick Event of the Button in AFragment.

    Intent intent =new Intent("refreshFragment");

    LocalBroadcastManager.getInstance(context).sendBroadcast(intent);

Answer 3

You can do this by below approach without using external libraries:

Assume you've a MainActivity which hosts the two fragments FragmetA (which has a ListView ) and FragmentB (which has the TextView )

Here's the full scenario:

1. Create an interface @ FragmentB which will be used by MainActivity to know when a list item is selected
2. MainActivity will register a listener to FragmentA by overriding onAttachFramemnt() and implementing this interface
3. When the user selects a list item from FragmentA ; FragmentB will trigger the callback back to MainActivity
4. MainActivity will forward the trigger to a public method in FragmentB which is used to set the text of the TextView to the current item.

Here is the code:

1. Layout

1.1 activity_main

<?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:orientation="vertical"
    tools:context=".MainActivity">

    <fragment
        android:id="@+id/fragment_b"
        android:name="com.example.android.sendingdatafromfragmenta_to_fragmentb.FragmentB"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <fragment
        android:id="@+id/fragment_a"
        android:name="com.example.android.sendingdatafromfragmenta_to_fragmentb.FragmentA"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

1.2 fragment_a

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <ListView
        android:id="@+id/listView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

1.3 fragment_b

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:id="@+id/tvSelectedItem"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="No Item selected" />

</LinearLayout>

2. Java

2.1 MainActivity

public class MainActivity extends AppCompatActivity implements FragmentA.OnListItemClickListener {

    private static final String LOG_TAG = "LOG_TAG";
    private FragmentB mFragmentB;


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

        // inflating fragment B from xml
        mFragmentB = (FragmentB) getSupportFragmentManager().findFragmentById(R.id.fragment_b);

    }


    @Override
    public void onAttachFragment(Fragment fragment) {
        Log.i(LOG_TAG, "onAttachFragment");
        super.onAttachFragment(fragment);
        if (fragment instanceof FragmentA) {
            ((FragmentA) fragment).setOnListItemClickListener(this);
        }

    }

    @Override
    public void onListItemClick(String selectedITem) {
        mFragmentB.setSelectedITemText(selectedITem);
    }
}

2.2 FragmentA

public class FragmentA extends Fragment {

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.fragment_a, container, false);

        final String[] data = {"item 1", "item 2", "item 3", "item 4", "item 5"};

        ListView listView = view.findViewById(R.id.listView);

        ArrayAdapter adapter = new ArrayAdapter(requireContext(), android.R.layout.simple_list_item_1, data);

        listView.setAdapter(adapter);

        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                if (mOnListItemClickListener != null) {
                    mOnListItemClickListener.onListItemClick(data[position]);
                }
            }
        });

        return view;
    }

    interface OnListItemClickListener {
        void onListItemClick(String selectedITem);
    }

    OnListItemClickListener mOnListItemClickListener;

    public void setOnListItemClickListener(OnListItemClickListener listener) {
        mOnListItemClickListener = listener;
    }
}

2.3 FragmentB

public class FragmentB extends Fragment {

    View view;

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

    public void setSelectedITemText(String text) {
        TextView selectedItemTextView = view.findViewById(R.id.tvSelectedItem);
        selectedItemTextView.setText(text);
    }
}

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