I'm creating application which has FragmentPagerAdapter with two pages.
The class for FragmentPagerAdapter looks like this
public static class AppSectionsPagerAdapter extends FragmentPagerAdapter {
public AppSectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int i) {
Fragment fragment;
switch (i) {
case 0: fragment = new CurrentRateFragment(); break;
case 1: fragment = new HistoryFragment(); break;
default: fragment = new CurrentRateFragment(); break;
}
return fragment;
}
#Override
public int getCount() {
return 2;
}
}
I want that some changes on first page (for example change Spinner selected item) caused changes on second page.
As I've read about Fragment communication (https://developer.android.com/training/basics/fragments/communicating.html) and understand that fragments can communicate only through Activity.
For this case I've created public interface in my first page class fragment
public interface CurrencyListener {
public void onCurrencyChanged();
}
And implement it in my Activity.
Now I can call void onCurrencyChanged in my Activity from my first page fragment.
But the problem is:
How to recreate second page fragment in my FragmentPagerAdapter?
Fragment creation operation is heavy.
1. If you recreate fragment the all the views will be created and previous Fragment needs to be garbage collected. Therefore there will extra memory.
Therefore rather than recreating the FirstPageFragment just refresh the data based on the callback received on your currencyChanged() method.
In this case, fragment will be created once and data will be updated every time the currencyChanged() method is called.
HistoryFragment Code(Fragment to be refreshed)
public class HistoryFragment extends Fragment implements MyActivity.IUpdateData{
/**
* Other method goes here
*/
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
//
if(getActivity() instanceof /**Your Activity**/){
((/**Your Activity**/)getActivity()).setOnUpdateListener(this);
}
return super.onCreateView(inflater, container, savedInstanceState);
}
#Override
public void updateData(Object object) {
//Refresh Data
}
}
Activity (Which will refresh data)
public class MyActivity extends Activity {
/**
* Other method goes here
*/
private IUpdateData dataUpdateListener;
public void setOnUpdateListener(IUpdateData listener){
dataUpdateListener = listener;
}
public void onCurrencyChanged(){
if(dataUpdateListener!=null){
dataUpdateListener.updateData(/**Update Data**/);
}
}
public interface IUpdateData{
void updateData(Object o);
}
}
I've Viewpager wit 2 fragments: CurrentWeatherFragment and ForecastFragment. I need to pass string from one to another, Iam using interface like below, but I keep getting NullPointerException, the message is not passing propertly...
public class CurrentWeatherFragment extends Fragment {
SendMessage SM
public void onCreateView(...) {
String Message = "Hello"
SM.sendData(Message);
}
interface SendMessage
{
public void sendData(String message);
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
SM = (SendMessage) activity;
} catch(ClassCastException e) {
throw new ClassCastException("Musisz zaimplementowac metode sendData");
}
}
}
MainActivity.java
import android.support.v4.app.FragmentActivity;
import android.support.v4.view.ViewPager;
import android.os.Bundle;
public class MainActivity extends FragmentActivity implements CurrentWeatherFragment.SendMessage {
ViewPager viewPager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//setting fragment view pager
viewPager = (ViewPager)findViewById(R.id.pager);
PagerAdapter pagerAdapter = new PagerAdapter(getSupportFragmentManager());
viewPager.setAdapter(pagerAdapter);
}
public void sendData (String message){
ForecastFragment FF = new ForecastFragment();
FF.getData(message);
}
}
ForecastFragment.java
public class ForecastFragment extends Fragment {
public View onCreateView(){
TextView txt = (TextView)v.findViewById(R.id.txt_forecast);
}
public void getData(String message){
txt.setText(message);
}
}
I've used this method succesfully in other app where I've had 2 fragments in one activity and i could call them by ID
public void sendData(String message) {
SecondFragment f2 = (SecondFragment)getFragmentManager().findFragmentById(R.id.F2);
f2.getData(message);
}
But here Fragments dont have IDs and I think that message is not passed because i dont use FragmentManager(), but how to find fragment in viewpager without ID, any suggestion/ideas?
Although a little hacky what you can do is get the fragment by its tag by using the following code:
String tag = "android:switcher:" + R.id.pager + ":" + index;
Fragment f = getSupportFragmentManager().findFragmentByTag(tag);
Where R.id.pager is the id of the viewpager in your layout and index is the position (as an integer) in the Viewpager Adapter.
I can't say this will work forever but it works for me at the moment.
The Alternative i would suggest is using a LocalBroadcastManager and a BroadcastReciver to send data internally between your fragments as although its a little more work it helps get rid of the spaghetti code situation you may end up finding yourself in trying to reference the fragments directly.
To pass data between fragments you need to pass the data in the object constructor.
Be aware to don't override the default constructor, instead create a static method getInstance(String data).
public static YourClass getInstance(String data)
{
YourClass object = new YourClass();
Bundle bundle = new Bundle();
bundle.putString(key, data);
object.setArguments(bundle);
return object;
}
Then you can get the data in the fragment's onCreate method with getArguments()
For some other users like me who looking for fragment to viewpager data sending
Here is working solution :
Sending data from fragment TO tab layout's view pager's fragments:
In Main fragment :
For tab layout i am using two fragments
1) BillDetailFragment and
2) ClientDepMonFragment
private TabLayout tabLayout;
private ViewPager viewPager;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
view= inflater.inflate(R.layout.fragment_detail, container, false);
// adding fragment and passing data to it
BillDetailFragment billDetailFragment=new BillDetailFragment();
Bundle bundle=new Bundle();
bundle.putString("mobile",mobile);
bundle.putInt("c_id",client_id);
bundle.putInt("server_id",server_id);
billDetailFragment.setArguments(bundle);
ClientDepMonFragment clientDepMonFragment=new ClientDepMonFragment();
Bundle bundle1=new Bundle();
bundle1.putString("mobile",mobile);
bundle1.putInt("c_id",client_id);
bundle1.putInt("server_id",server_id);
clientDepMonFragment.setArguments(bundle1);
tabLayout=(TabLayout)view.findViewById(R.id.detail_txn_tab_layout);
viewPager=(ViewPager)view.findViewById(R.id.detail_txn_viewpager);
dtViewPagerAdapter=new DtViewPagerAdapter(getChildFragmentManager(),DetailFragment.this);
dtViewPagerAdapter.addFragments(billDetailFragment,"Lending Money");
dtViewPagerAdapter.addFragments(clientDepMonFragment,"Deposited Money");
viewPager.setAdapter(dtViewPagerAdapter);
tabLayout.setupWithViewPager(viewPager);
}
and here is how to access that data from fragment
BillDetailFragment: override onCreate method
private int client_id,server_id;
private String client_mobile;
#Override
public void onCreate(#Nullable Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
client_mobile=getArguments().getString("mobile");
client_id=getArguments().getInt("c_id");
server_id=getArguments().getInt("server_id");
}
I'm currently trying to work with fragment, but I'm stuck with an issue I can't solve.
I have one activity, which holds 4 different fragment. From this activity, I launch an ASyncTask which goes to the web and get different data I need, and then will send it to the fragments.
But, when my app gets killed and opened again, or when I change the orientation, my fragments are apparently recreated and my custom FragmentAdapter doesn't hold the good reference to the fragment.
Here is the code of my main activity.
public class MainActivity extends FragmentActivity {
MyPagerAdapter fgsAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//...
FragmentManager fm = super.getSupportFragmentManager();
fgsAdapter = new MyPagerAdapter(fm,this);
ViewPager myPager = (ViewPager) findViewById(R.id.home_pannels_pager);
myPager.setAdapter(fgsAdapter);
myPager.setCurrentItem(0);
}
#Override
protected void onResume() {
super.onResume();
ATaskGetUser task = new ATaskGetUser(callback, (ProgressBar) findViewById(R.id.PB_AsyncTask));
task.execute();
}
//What's called by the ASyncTask onPostExecute()
private void notifyDataChanged() {
fgsAdapter.notifyFragments(user.getItems());
}
private class MyPagerAdapter extends FragmentPagerAdapter {
private List<CardFragment> fragments = new ArrayList<CardFragment>();
private Context c;
public MyPagerAdapter(FragmentManager fm, Context c) {
super(fm);
CardFragment h = new HabitFragment();
CardFragment d = new DailyFragment();
CardFragment t = new ToDoFragment();
CardFragment r = new RewardFragment();
fragments.add(h);
fragments.add(d);
fragments.add(t);
fragments.add(r);
}
public int getCount() {
return fragments.size();
}
#Override
public CardFragment getItem(int position) {
Log.v("MainActivity_fgsmanager", "getItem()");
CardFragment f = (CardFragment) this.fragments.get(position);
return f;
}
public void notifyFragments(List<HabitItem> items) {
for(OnTasksChanged f : fragments) {
f.onChange(items);
}
}
}
}
So, what I want to be able to do, is to be able to call the onChange (an interface implemented by my four fragments), in my notifyDataChanged function. Is this possible, are am I thinking the wrong way?
I got the same problems once with Fragments, I was losing the current fragment after every screen rotation.
I simply solved it by adding one line in the Fragment class (not in the parent FragmentActivity class):
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.rate_fragment, container,false);
setRetainInstance(true);//Added not to lose the fragment instance during screen rotations
(...)
For your case where your app gets killed and opened again, I am not sure it will work though.
I wrote an activity with ViewPager, which gets populated after an AsyncTask is executed. Each TestDataObject is tied to the relevant TestFragment. When the screen is rotated the application crushes due to a NullPointerException inside onCreateView method. I believe this is because of ViewPager/Adapter onSaveInstanceState methods, onCreateView tries to restore data prior to the AsyncTask data load when data isn't available yet.
I could just if onCreateView code but it doesn't feel to me like a right solution, because amount of fragments inside ViewPager might vary so it might end up doing unnecessary job: restore altered viewpager content and then replace with initial. In this case onSaveInstanceState seems to be excessively harmful. Presumably, I could extend ViewPager or Adapter to cancel save procedure - I find it weird as well.
Do you have any better suggestions to offer?
public class MainActivity extends LoggerActivity {
private ArrayList<TestDataObject> mDataObjects = new ArrayList<MainActivity.TestDataObject>();
private ViewPager mViewPager;
private TestFragmentAdapter mViewPagerAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPagerAdapter = new TestFragmentAdapter(
getSupportFragmentManager(), mDataObjects);
mViewPager.setAdapter(mViewPagerAdapter);
new TestAsyncTask().execute();
}
private class TestAsyncTask extends AsyncTask<Void, Void, Void> {
#Override
protected Void doInBackground(Void... params) {
try {
TimeUnit.SECONDS.sleep(3);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
mDataObjects.add(new TestDataObject());
mDataObjects.add(new TestDataObject());
mDataObjects.add(new TestDataObject());
mViewPagerAdapter.notifyDataSetChanged();
}
}
public static class TestFragment extends Fragment {
private TestDataObject mDataObject;
public static TestFragment getInstance(TestDataObject obj) {
TestFragment f = new TestFragment();
f.mDataObject = obj;
return f;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// layout.find...
mDataObject.toString();
return inflater.inflate(R.layout.fragment_test, null, false);
}
}
public static class TestFragmentAdapter extends FragmentStatePagerAdapter {
private List<TestDataObject> mDataObjects;
public TestFragmentAdapter(FragmentManager fm, List<TestDataObject> objs) {
super(fm);
mDataObjects = objs;
}
#Override
public Fragment getItem(int position) {
return TestFragment.getInstance(mDataObjects.get(position));
}
#Override
public int getCount() {
return mDataObjects == null ? 0 : mDataObjects.size();
}
}
public static class TestDataObject {
}
}
I believe this is because of ViewPager/Adapter onSaveInstanceState
methods. onCreateView tries to restore data prior to the asynctask
dataload when data isn't available yet.
That is not what is happening(I'm assuming you get the exception at mDataObject.toString();), even if the AsyncTask would finish its job instantaneously the exception will still be thrown. After the first run of the app the ViewPager will have three fragments in it. When you'll turn the phone the Activity will be destroyed an recreated again. The ViewPager will try to recreate the fragments in it, but this time it will do it by using the default empty constructor(that is why you shouldn't use a non empty constructor to pass data). As you can see, the first time the Fragment is created by the adapter it will be created by the getInstance method(that is also the only point where you initialize mDataObject) to which you pass a TestDataObject object. When the ViewPager reinitializes its fragments that field will not be initialized as well.
If TestDataObject can be put in a Bundle then you could simply adapt your getInstance method to pass some arguments to your fragments(so the data field will be initialized when the ViewPager will recreate them). I'm sure you've seen:
public static TestFragment getInstance(TestDataObject obj) {
TestFragment f = new TestFragment();
// f.mDataObject = obj; <- don't do this
// if possible
Bundle args = new Bundle();
args.put("data", obj); // only if obj can be put in a Bundle
f.setArguments(args);
return f;
}
private TestDataObject mDataObject;
#Override
public void onCreate(Bundle savedInstance) {
mDataObject = getArguments().get("data"); // again, depends on your TestDataObject
}
Another approach would be to pass the smallest amount of data to the Fragment(like above) so it has enough information to recreate it's data whenever it's recreated.
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?
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
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.
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.
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.
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.
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
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.
you can read this doc .this concept is well explained here http://developer.android.com/training/basics/fragments/communicating.html
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<?> 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<?> 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<?> 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<?> 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);
}
}
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 && 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/
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.
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 ..
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.