How to pass data between fragments

Question

Im trying to pass data between two fragmens in my program  Its just a simple string that is stored in the List  The List is made public in fragments A  and when the user clicks on a list item  I need it to show up in fragment B  The content provider only seems to support ID s  so that will not work  Any suggestions

User · Answer

Why don t you use a Bundle  From your first fragment  here s how to set it up   Fragment fragment   new Fragment    Bundle bundle   new Bundle    bundle putInt key  value   fragment setArguments bundle     Then in your second Fragment  retrieve the data using   Bundle bundle   this getArguments    int myInt   bundle getInt key  defaultValue     Bundle has put methods for lots of data types  Please see http   developer android com reference android os Bundle html

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Fragment class A  public class CountryListFragment extends ListFragment           List of countries to be displayed in the ListFragment         ListFragmentItemClickListener ifaceItemClickListener              An interface for defining the callback method        public interface ListFragmentItemClickListener           This method will be invoked when an item in the ListFragment is clicked        void onListFragmentItemClick int position             A callback function  executed when this fragment is attached to an activity       Override public void onAttach Activity activity        super onAttach activity        try              This statement ensures that the hosting activity implements ListFragmentItemClickListener            ifaceItemClickListener    ListFragmentItemClickListener  activity                 catch Exception e           Toast makeText activity getBaseContext     Exception  Toast LENGTH SHORT  show              Fragment Class B   public class CountryDetailsFragment extends Fragment    Override public View onCreateView LayoutInflater inflater  ViewGroup container  Bundle savedInstanceState             Inflating the layout country details fragment layout to the view object v        View v   inflater inflate R layout country details fragment layout  null            Getting the textview object of the layout to set the details         TextView tv    TextView  v findViewById R id country details                  Getting the bundle object passed from MainActivity   in Landscape   mode    or from          CountryDetailsActivity   in Portrait Mode                   Bundle b   getArguments             Getting the clicked item s position and setting corresponding  details in the textview of the detailed fragment        tv setText  Details of     Country name b getInt  position                return v             Main Activity class for passing data between fragments  public class MainActivity extends Activity implements ListFragmentItemClickListener       Called when the activity is first created      Override public void onCreate Bundle savedInstanceState        super onCreate savedInstanceState       setContentView R layout main           This method will be executed when the user clicks on an item in the listview     Override public void onListFragmentItemClick int position             Getting the orientation   Landscape or Portrait   of the screen        int orientation   getResources   getConfiguration   orientation            Landscape Mode        if orientation    Configuration ORIENTATION LANDSCAPE                Getting the fragment manager for fragment related operations            FragmentManager fragmentManager   getFragmentManager                 Getting the fragmenttransaction object  which can be used to add  remove or replace a fragment            FragmentTransaction fragmentTransaction   fragmentManager beginTransaction                 Getting the existing detailed fragment object  if it already exists               The fragment object is retrieved by its tag name                Fragment prevFrag   fragmentManager findFragmentByTag  in wptrafficanalyzer country details                 Remove the existing detailed fragment object if it exists            if prevFrag  null      fragmentTransaction remove prevFrag                           Instantiating the fragment CountryDetailsFragment      CountryDetailsFragment fragment   new CountryDetailsFragment                 Creating a bundle object to pass the data the clicked item s   position  from the activity to the fragment             Bundle b   new Bundle                 Setting the data to the bundle object            b putInt  position   position                Setting the bundle object to the fragment            fragment setArguments b                           Adding the fragment to the fragment transaction            fragmentTransaction add R id detail fragment container    fragment  in wptrafficanalyzer country details                 Adding this transaction to backstack            fragmentTransaction addToBackStack null                Making this transaction in effect            fragmentTransaction commit          else               Portrait Mode or Square mode                Creating an intent object to start the CountryDetailsActivity            Intent intent   new Intent  in wptrafficanalyzer CountryDetailsActivity                 Setting data   the clicked item s position   to this intent            intent putExtra  position   position                Starting the activity by passing the implicit intent            startActivity intent                                Detailde acitivity class  public class CountryDetailsActivity extends Activity   Override protected void onCreate Bundle savedInstanceState        super onCreate savedInstanceState            Setting the layout for this activity        setContentView R layout country details activity layout            Getting the fragment manager for fragment related operations        FragmentManager fragmentManager   getFragmentManager             Getting the fragmenttransaction object  which can be used to add  remove or replace a fragment        FragmentTransaction fragmentTransacton   fragmentManager beginTransaction             Instantiating the fragment CountryDetailsFragment        CountryDetailsFragment detailsFragment   new CountryDetailsFragment             Creating a bundle object to pass the data the clicked item s position  from the activity to the fragment        Bundle b   new Bundle             Setting the data to the bundle object from the Intent       b putInt  position   getIntent   getIntExtra  position   0             Setting the bundle object to the fragment        detailsFragment setArguments b            Adding the fragment to the fragment transaction        fragmentTransacton add R id country details fragment container  detailsFragment                   Making this transaction in effect        fragmentTransacton commit               Array Of Contries   public class Country        Array of countries used to display in CountryListFragment    static String name     new String              India            Pakistan            Sri Lanka            China            Bangladesh            Nepal            Afghanistan            North Korea            South Korea            Japan            Bhutan         For More Details visit this link  http   wptrafficanalyzer in blog itemclick-handler-for-listfragment-in-android    There are full example

User · Answer

I m working on a similar project and I guess my code may help in the above situation  Here is the overview of what i m doing   My project Has two fragments Called  FragmentA  and  FragmentB   -FragmentA Contains  one list View when you click an item in FragmentA It s INDEX is passed to FragmentB using Communicator interface    The design pattern is totally based on the concept of java interfaces that says  interface reference variables can refer to a subclass object  Let MainActivity implement the interface provided by fragmentA otherwise we can t make interface reference variable to point to MainActivity  In the below code communicator object is made to refer to  MainActivity s object by using  setCommunicator Communicatot c   method present in fragmentA  I m  triggering  respond   method of interface from FrgamentA using the MainActivity s reference   Interface communcator is defined inside fragmentA  this is to provide least access previlage to communicator interface    below is my complete working code  FragmentA java  public class FragmentA extends Fragment implements OnItemClickListener    ListView list  Communicator communicater     Override public View onCreateView LayoutInflater inflater  ViewGroup container          Bundle savedInstanceState           TODO Auto-generated method stub     return inflater inflate R layout fragmenta  container false      public void setCommunicator Communicator c       communicater c      Override public void onActivityCreated Bundle savedInstanceState           TODO Auto-generated method stub     super onActivityCreated savedInstanceState       communicater  Communicator  getActivity        list    ListView  getActivity   findViewById R id lvModularListView       ArrayAdapter lt   gt  adapter   ArrayAdapter createFromResource getActivity                R array items  android R layout simple list item 1       list setAdapter adapter       list setOnItemClickListener this        Override public void onItemClick AdapterView lt   gt  arg0  View arg1  int index  long arg3    communicater respond index       public interface Communicator      public void respond int index          fragmentB java  public class FragmentA extends Fragment implements OnItemClickListener    ListView list  Communicator communicater     Override public View onCreateView LayoutInflater inflater  ViewGroup container          Bundle savedInstanceState           TODO Auto-generated method stub     return inflater inflate R layout fragmenta  container false      public void setCommunicator Communicator c       communicater c      Override public void onActivityCreated Bundle savedInstanceState           TODO Auto-generated method stub     super onActivityCreated savedInstanceState       communicater  Communicator  getActivity        list    ListView  getActivity   findViewById R id lvModularListView       ArrayAdapter lt   gt  adapter   ArrayAdapter createFromResource getActivity                R array items  android R layout simple list item 1       list setAdapter adapter       list setOnItemClickListener this        Override public void onItemClick AdapterView lt   gt  arg0  View arg1  int index  long arg3    communicater respond index       public interface Communicator      public void respond int index          MainActivity java  public class MainActivity extends Activity implements FragmentA Communicator   FragmentManager manager getFragmentManager     Override protected void onCreate Bundle savedInstanceState        super onCreate savedInstanceState       setContentView R layout activity main        FragmentA fragA  FragmentA  manager findFragmentById R id fragmenta       fragA setCommunicator this         Override public void respond int i           TODO Auto-generated method stub  FragmentB FragB  FragmentB  manager findFragmentById R id fragmentb   FragB changetext i

User · Answer

Basically here we are dealing with communication between Fragments  Communication between fragments can never be directly possible  It involves activity under the context of which both the fragments are created   You need to create an interface in the sending fragment and implement the interface in the activity which will reprieve the message and transfer to the receiving fragment

User · Answer

1- The first way is define an interface  public interface OnMessage      void sendMessage int fragmentId  String message      public interface OnReceive      void onReceive String message       2- In you activity implement OnMessage interface  public class MyActivity implements OnMessage               Override    public void sendMessage int fragmentId  String message          Fragment fragment   getSupportFragmentManager   findFragmentById fragmentId            OnReceive  fragment  sendMessage             3- In your fragment implement OnReceive interface  public class MyFragment implements OnReceive               Override     public void onReceive String message           myTextView setText  Received message     message             This is the boilerplate version of handling message passing between fragments   Another way of handing data passage between fragments are by using an event bus   1- Register unregister to an event bus   Override public void onStart         super onStart        EventBus getDefault   register this       Override public void onStop         EventBus getDefault   unregister this       super onStop        2- Define an event class  public class Message      public final String message       public Message String message           this message   message            3- Post this event in anywhere in your application  EventBus getDefault   post new Message  hello world       4- Subscribe to that event to receive it in your Fragment   Subscribe threadMode   ThreadMode MAIN  public void onMessage Message event       mytextview setText event message       For more details  use cases  and an example project about the event bus pattern

User · Answer

IN my case i had to send the data backwards from FragmentB- FragmentA hence Intents was not an option as the fragment would already be initialised All though all of the above answers sounds good it takes a lot of boiler plate code to implement  so i went with a much simpler approach of using LocalBroadcastManager  it exactly does the above said but without alll the nasty boilerplate code  An example is shared below   In Sending Fragment Fragment B   public class FragmentB        private void sendMessage           Intent intent   new Intent  custom-event-name          intent putExtra  message    your message          LocalBroadcastManager getInstance this  sendBroadcast intent              And in the Message to be Received Fragment FRAGMENT A     public class FragmentA        Override     public void onCreate Bundle savedInstanceState                         Register receiver       LocalBroadcastManager getInstance this  registerReceiver receiver            new IntentFilter  custom-event-name                  This will be called whenever an Intent with an action named  custom-event-name  is broadcasted      private BroadcastReceiver receiver   new BroadcastReceiver            Override       public void onReceive Context context  Intent intent            String message   intent getStringExtra  message                       Hope it helps someone

User · Answer

If you use Roboguice you can use the EventManager in Roboguice to pass data around without using the Activity as an interface  This is quite clean IMO    If you re not using Roboguice you can use Otto too as a event bus  http   square github com otto   Update 20150909  You can also use Green Robot Event Bus or even RxJava now too  Depends on your use case

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Basically Implement the interface to communicate between Activity and fragment   1  Main activty  public class MainActivity extends Activity implements SendFragment StartCommunication     Override protected void onCreate Bundle savedInstanceState    super onCreate savedInstanceState   setContentView R layout activity main       Override public void setComm String msg       TODO Auto-generated method stub DisplayFragment mDisplayFragment    DisplayFragment getFragmentManager   findFragmentById R id fragment2   if mDisplayFragment    null  amp  amp  mDisplayFragment isInLayout      mDisplayFragment setText msg     else   Toast makeText this   Error Sending Message   Toast LENGTH SHORT  show            2  sender fragment  fragment-to-Activity   public class SendFragment extends Fragment   StartCommunication mStartCommunicationListner  String msg    hi    Override public View onCreateView LayoutInflater inflater  ViewGroup container  Bundle savedInstanceState       TODO Auto-generated method stub View mView    View  inflater inflate R layout send fragment  container   final EditText mEditText    EditText mView findViewById R id editText1   Button mButton    Button  mView findViewById R id button1   mButton setOnClickListener new OnClickListener       Override public void onClick View arg0       TODO Auto-generated method stub msg   mEditText getText   toString    sendMessage          return mView     interface StartCommunication   public void setComm String msg       Override public void onAttach Activity activity       TODO Auto-generated method stub super onAttach activity   if activity instanceof StartCommunication    mStartCommunicationListner    StartCommunication activity    else throw new ClassCastException        public void sendMessage     mStartCommunicationListner setComm msg          3  receiver fragment  Activity-to-fragment       public class DisplayFragment extends Fragment   View mView   Override public View onCreateView LayoutInflater inflater  ViewGroup container  Bundle savedInstanceState       TODO Auto-generated method stub mView    View  inflater inflate R layout display frgmt layout  container   return mView     void setText String msg    TextView mTextView    TextView  mView findViewById R id textView1   mTextView setText msg          I used this link for the same solution  I hope somebody will find it usefull  Very simple and basic example   http   infobloggall com 2014 06 22 communication-between-activity-and-fragments

User · Answer

So lets say you have Activity AB that controls Frag A and Fragment B   Inside Fragment A you need an interface that Activity AB can implement   In the sample android code  they have   private Callbacks mCallbacks   sDummyCallbacks     A callback interface that all activities containing this fragment must implement  This mechanism allows activities to be notified of item selections      public interface Callbacks     Callback for when an item has been selected               public void onItemSelected String id        A dummy implementation of the   link Callbacks  interface that does nothing  Used only when this fragment is not attached to an activity         private static Callbacks sDummyCallbacks   new Callbacks          Override     public void onItemSelected String id               The Callback interface is put inside one of your Fragments  let   s say Fragment A   I think the purpose of this Callbacks interface is like a nested class inside Frag A which any Activity can implement  So if Fragment A was a TV  the CallBacks is the TV Remote  interface  that allows Fragment A to be used by Activity AB  I may be wrong about the detail because I m a noob but I did get my program to work perfectly on all screen sizes and this is what I used   So inside Fragment A  we have   I took this from Android   s Sample programs    Override public void onListItemClick ListView listView  View view  int position  long id    super onListItemClick listView  view  position  id      Notify the active callbacks interface  the activity  if the    fragment is attached to one  that an item has been selected  mCallbacks onItemSelected DummyContent ITEMS get position  id     mCallbacks onItemSelected  PUT YOUR SHIT HERE  int  String  etc      mCallbacks onItemSelected  Object       And inside Activity AB we override the onItemSelected method    public class AB extends FragmentActivity implements ItemListFragment Callbacks          Override   public void onItemSelected  CATCH YOUR SHIT HERE      public void onItemSelected  Object obj        public void onItemSelected String id          Pass Data to Fragment B  For example      Bundle arguments   new Bundle        arguments putString    FragmentB package     id       FragmentB fragment   new FragmentB        fragment setArguments arguments       getSupportFragmentManager   beginTransaction   replace R id item detail container  fragment  commit            So inside Activity AB  you basically throwing everything into a Bundle and passing it to B  If u are not sure how to use a Bundle  look the class up   I am basically going by the sample code that Android provided  The one with the DummyContent stuff  When you make a new Android Application Package  it s the one titled MasterDetailFlow

User · Answer

getParentFragmentManager   setFragmentResultListener is the 2020 way of doing this  Your only limitation is to use a bundle to pass the data  Check out the docs for more info and examples  Some other ways  Call to getActivity   and cast it to the shared activity between your fragments  then use it as a bridge to pass the data  This solution is highly not recommended because of the cupelling it requires between the activity and the fragments  but it used to be the popular way of doing this back in the KitKat days    Use callbacks  Any events mechanism will do  This would be a Java vanilla solution  The benefit over FragmentManager is that it s not limited to Bundles  The downside  however  is that you may run into edge cases bugs where you mess up the activity life cycle and get exceptions like IllegalStateException when the fragment manager is in the middle of saving state or the activity were destroyed  Also  it does not support cross-processing communication

User · Answer

you can read this doc  this concept is well explained here http   developer android com training basics fragments communicating html

User · Answer

That depends on how the fragment is structured  If you can have some of the methods on the Fragment Class B static and also the target TextView object static  you can call the method directly on Fragment Class A  This is better than a listener as the method is performed instantaneously  and we don t need to have an additional task that performs listening throughout the activity  See example below   Fragment class B setmyText String yourstring     On Fragment B you can have the method defined as   public static void setmyText final String string    myTextView setText string       Just don t forget to have myTextView set as static on Fragment B  and properly import the Fragment B class on Fragment A    Just did the procedure on my project recently and it worked  Hope that helped

User · Answer

From the Fragment documentation      Often you will want one Fragment to communicate with another  for example to change the content based on a user event  All Fragment-to-Fragment communication is done through the associated Activity  Two Fragments should never communicate directly    So I suggest you have look on the basic fragment training docs in the documentation  They re pretty comprehensive with an example and a walk-through guide

[android] How to pass data between fragments

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