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Fragment with RecyclerView doesn't show second time until change orientation

I have a fragment containing a RecyclerView and a button. The fragment is brought up on pressing a button (which adds some data) in a previous fragment, and the recycler shows correctly populated, the button works. Then I go back to the previous fragmen, press the button again (adding more data) and the same piece of code brings up the same fragment, but the RecyclerView is unpopulated and the button doesn't work. From reading this question my guess is that I am doing something in my Fragment management - because as soon as I change orientation and the Fragment is recreated, the list shows fine and the button works fine.
So here is the management I'm doing on the fragments - I took it from an example on the internet, but I'm worried it's not correct
First there is a Base class which I make for my fragments:
public class BaseFragment extends Fragment {
private AbstractFragmentCallback mCallback;
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mCallback = (AbstractFragmentCallback) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement " +
AbstractFragmentCallback.class.getCanonicalName());
}
}
/**
* This method replaces the currently shown fragment with a new
fragment of a particular class.
* If a fragment of the required class already shown - does
nothing.
* #param clazz the class of the fragment to show
* #param addToBackStack whether the replacement should be added
to back-stack
* #param args arguments for the newly created fragment (can be
null)
*/
public void replaceFragment(Class<? extends Fragment> clazz,
boolean addToBackStack,
Bundle args) {
mCallback.replaceFragment(clazz, addToBackStack, args);
}
public interface AbstractFragmentCallback {
/**
* Call to this method replaces the currently shown fragment
with a new one
*
* #param clazz the class of the new fragment
* #param addToBackStack whether the old fragment should be
added to the back stack
* #param args arguments to be set for the new fragment
*/
void replaceFragment(Class<? extends Fragment> clazz, boolean addToBackStack,
Bundle args);
}
}
So then my MainActivity implements the BaseFragment.AbstractfragmentCallback so:
public class MainActivity extends AppCompatActivity implements BaseFragment.AbstractFragmentCallback {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(....);
if (null == savedInstanceState) {
replaceFragment(WelcomeFragment.class, false, null);
}
}
// ---------------------------------------------------------------------------------------------
//
// Fragments management
#Override
public void replaceFragment(Class<? extends Fragment> clazz, boolean addToBackStack,
Bundle args) {
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
Fragment newFragment;
try {
// Create new fragment
newFragment = clazz.newInstance();
if (args != null) newFragment.setArguments(args);
} catch (InstantiationException e) {
e.printStackTrace();
return;
} catch (IllegalAccessException e) {
e.printStackTrace();
return;
}
if (addToBackStack) {
ft.addToBackStack(null);
}
// Change to a new fragment
ft.replace(R.id.container, newFragment, clazz.getName());
ft.commit();
}
// End of fragments management
//
// ---------------------------------------------------------------------------------------------
}
and when my fragment with the button wants to bring up the list fragment it calls
replaceFragment(ListFragment.class, true, null);
So - to be clear, the ListFragemnt comes up, and all its code fires including recrersating the RecyclerView and repopulating it - I even see all the code in the adapter being called for each item - but the items do not appear in the list
public class ListFragment extends BaseFragment implements ListFragmentMvc.ListViewMvcListener {
private List<MyStuff> stuffList;
#Override
public View onCreateView(#NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstance) {
stuffList = new ArrayList<>();
return inflater.inflate(R.layout.list_activity, container, true);
}
#Override
public void onResume() {
super.onResume();
recyclerView = mRootView.findViewById(R.id.recycler_view);
letsGoButton = mRootView.findViewById(R.id.lets_go_button);
letsGoButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Activity activity = getActivity();
if (activity != null) {
getActivity().onBackPressed();
}
}
});
recyclerView.setItemAnimator(new DefaultItemAnimator());
DividerItemDecoration itemDecor = new DividerItemDecoration(context, HORIZONTAL);
recyclerView.addItemDecoration(itemDecor);
RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(context);
recyclerView.setLayoutManager(mLayoutManager);
setData(MyApplication.getAllStuffItems());
}
public void setData(List<MyStuff> stuff) {
stuffList = stuff;
mAdapter = new StuffAdapter(stuffList);
recyclerView.setAdapter(mAdapter);
mAdapter.notifyDataSetChanged();
}
}
So, anyone have a clue why this doesn't work until I change orientation on re-entering the listFragment?
Thanks

Can you try to move the code which sets/updates the recyclerView and letsGoButton from the onResume method to onViewCreated method as below:
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
recyclerView = view.findViewById(R.id.recycler_view);
letsGoButton = view.findViewById(R.id.lets_go_button);
letsGoButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Activity activity = getActivity();
if (activity != null) {
getActivity().onBackPressed();
}
}
});
recyclerView.setItemAnimator(new DefaultItemAnimator());
DividerItemDecoration itemDecor = new DividerItemDecoration(context, HORIZONTAL);
recyclerView.addItemDecoration(itemDecor);
RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(context);
recyclerView.setLayoutManager(mLayoutManager);
setData(MyApplication.getAllStuffItems());
}

Wow, that was a wild waste of a day.
In the end I had a couple of errors which were pasting over and hiding each other.
The real real reason this wasn't working, I think was because I should have had
return inflater.inflate(R.layout.list_activity, container, false);
instead of
return inflater.inflate(R.layout.list_activity, container, true);
I lied a little in my code because I wasn't really directly returning the result of inflater.inflate... I was calling it (with the wrong parameter) and then returning null.
I guess that will teach me to be more honest in the posting

Android - Fragments and Tabs communication

I'm pretty new to Android.
This is my scenario: I have a simple app with 3 tabs. In each tab i want to use one or more fragments. This is the situation:
Tab 1:
Fragment A
Tab 2:
Fragment B
Fragment C
Fragment D
Tab 3:
Fragment E
Fragment F
In "Tab 1" I have no issue. All works pretty good. Issues arise when I need to move in "Tab 2" and "Tab 3".
In Tab 2 I have to propagate some parameters from "Fragment B" to "Fragment C" and from "Fragment C" to "Fragment D".
Then it can happen that when user clicks on some button in "Fragment D" I have to pass to "Tab 3" and I have to propagate some parameters from "Fragment D" to "Fragment E".
In my main Activity for Tab handling I'm using these components:
android.support.design.widget.TabLayout
android.support.v4.view.ViewPager
android.support.v4.app.FragmentStatePagerAdapter (I created a custom
class)
android.support.design.widget.TabLayout.OnTabSelectedListener (I created a custom class)
My very simple FragmentStatePagerAdapter extension is:
public class MyOwnPageAdapter extends FragmentStatePagerAdapter {
private int numeroTab;
public MyOwnPageAdapter(FragmentManager fm, int numeroTab) {
super(fm);
this.numeroTab = numeroTab;
}
#Override
public Fragment getItem(int position) {
switch (position){
case 0:
return new FragmentA() ;
case 1:
return new FragmentB() ;
case 2:
return new FragmentC() ;
default:
return null;
}
}
#Override
public int getCount() {
return numeroTab;
}
}
My very simple TabLayout.OnTabSelectedListener extension is:
public class TabSelectedListener implements TabLayout.OnTabSelectedListener {
private ViewPager viewPager;
public TabSelectedListener(ViewPager viewPager){
this.viewPager = viewPager;
}
#Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
}
I'm able in switching fragments inside tabs that is in Tab 2 i can switch from Fragment B to Fragment C and so on. I'm having issues in passing parameters between fragments and above all from Fragment D in Tab 2 to Fragment E in Tab 3
In my Fragments implementation byt using the android.support.v4.app.FragmentManager I can add and remove views (e.g. fragments) by doing something like this:
mFragmentManager.beginTransaction().add(rootView.getId(),mListaEdificiFragment, "BUILDS").addToBackStack(null).commit();
The problem is the param propagation that since the FragmentStatePagerAdapter seems to cache views it happens that the fragment constructor is called but the onCreate and onCreateView are no more called so I can't handle the propagated parameters.
Is there any solution to this? Or am I simply wrong in my navigation pattern? I would like to avoid to collapse Fragment B,Fragment C and Fragment D in one "big view" where to hide some section (the same for Fragment E e Fragment F)
Any suggestion is more then welcome
Angelo

One simple solution to transfer a variable value from one fragment to another is shared preferences (can also be used to transfer values from one activity to another too). Shared preference will save data against variables that will persist across all the activities and fragments in an android app.
Now in your case, lets assume you want to transfer a value name = angelo from your fragment A to fragment B. In your fragment A, write this code:
Button updateName = findViewById(R.id.btnupdateTeamName);
updateTeamName .setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
SharedPreferences.Editor editor = sharedpreferences.edit();
editor.putString("name", "angelo");
editor.commit();
}
});
When executed, the above code will update a value name with angelo in shared preferences. This will be available throughout your app.
For more info about shared preference, check out this official document.

I write my Fragment like this for passing data to it.
public class MyFragment extends Fragment {
private static String ARG_PARAM1 = "data";
private String data;
public MyFragment() {
// Required empty public constructor
}
public static MyFragment newInstance(String data) {
MyFragment fragment = new MyFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, data);
fragment.setArguments(args);
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
data = getArguments().getString(ARG_PARAM1);
}
}
}
Now data can be passed to the Fragment by calling MyFragment.newInstance("Hello"). I hope this helps.

I have faced a similar issue in my project.
In my case, I have viewpager and each tab has multiple fragment.
So one of the simple solutions is to use LiveData and ViewModel.
In your Tab2:
Fragment B
Fragment C
Fragment D
TabTwoViewModel (with live data)
In mutable Live data observer this live data to Fragment B, C, and D.
When you update live data object, Live data notify automatically all fragment.

Finally I got a solution.
Since the main problem is the fragments communication, I followed the official documentation
Let's suppose I have Fragment A with list of articles and Fragment B where to see the selected article detail, in my Fragment A i wrote:
public class FragmentA extends Fragment {
private OnArticleSelectionListener mCallback;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
}
}
#Override
public void onStart() {
super.onStart();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.activityedifici, container, false);
return rootView;
}
public interface OnArticleSelectionListener {
void onArticleSelection(String articleId);
}
#Override
public void onDetach() {
super.onDetach();
mCallback = null;
}
public void setOnArticleSelectionListener(OnArticleSelectionListener mCallback) {
this.mCallback = mCallback;
}
}
As you can see I declared the following interface
public interface OnArticleSelectionListener {
void onArticleSelection(String articleId);
}
This is the article selection listener.
In my Main Activity I wrote the following:
public class MainActivity implements FragmentA.OnArticleSelectionListener{
//All my own stuffs
#Override
public void onAttachFragment(Fragment fragment) {
if (fragment instanceof FragmentA){
FragmentA ef = (FragmentA)fragment;
ef.setOnArticleSelectionListener(this);
}
}
#Override
public void onArticleSelection(String articleId) {
if( getSupportFragmentManager().findFragmentByTag(TAG_ARTICLE_DETAIL) != null ){
//FragmentB is the article detail and it has already been created and cached
FragmentB dcf = (FragmentB)getSupportFragmentManager().findFragmentByTag(TAG_ARTICLE_DETAIL);
dcf.updateArticleDetail( articleId );
}else{
//FragmentB is the article detail and it has never been created I create and replace the container with this new fragment
FragmentB dcf = new FragmentB();
//Parameter propagation
Bundle args = new Bundle();
args.putString(FragmentB.ARG_ARTICLE_ID, articleId);
dcf.setArguments(args);
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.container_articles, dcf, TAG_ARTICLE_DETAIL);
transaction.addToBackStack(null);
transaction.commit();
}
}
}
In this way I'm able in intercepting events in FragmentA and propagate them to the FragmentB; when I need to open a Tab all remains the same and finally (after transaction.commit() or the dcf.updateArticleDetail( articleId )) I do the following tabLayout.getTabAt(2).select(); and the third tab (tab index starts from 0) is open and the Detail is showed.
I hope this can be useful
Angelo

Android: passing data back to fragment using interfaces

Hi in my Activity I have a fragmentA with a textview, when I click on the textview , this fragmentA is replaced with fragment which has a listview. Now when I click on the litsItem I have to goback to fragmentA and update the textview with the list item.
Implementation:
I created an interface in fragment,
public interface OnListItemSelectedListener {
public void onListItemSelected(String msg);
}
and in onAttach() I have the below code
#Override
public void onAttach(Activity activity) {
// TODO Auto-generated method stub
super.onAttach(activity);
try {
mListener = (OnListItemSelectedListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString() + " must implement OnListItemSelectedListener");
}
}
In my listitem OnClickListener() I have this
mListView.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
String message = parent.getItemAtPosition(position).toString();
mListener.onListItemSelected(message);
}
});
then in my activity i implemented the interface
#Override
public void onListItemSelected(String msg) {
// TODO Auto-generated method stub
ISOFragment myFrag = (ISOFragment)
getSupportFragmentManager().findFragmentById(R.id.isomain);
if (myFrag != null) {
myFrag.incrementdata(msg);
} else {
ISOFragment newFrag = new ISOFragment();
Bundle args = new Bundle();
args.putString("selecteitem", msg);
newFrag.setArguments(args);
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.content_frame, newFrag);
transaction.addToBackStack(null);
transaction.commit();
}
}
Now since the fragmentA is not available it goes to else part now how should i get the bundle arguments to fragmentA and update the textview.
Suppose I am going from A to B and coming back from B to A, if i get arguments and update the textview in Fragment A in onCreateView(), if when i run for the first time it is checking for the arguments which will be null.

I had the same problem and the best solution for me was to extend activity and store shared data there. My new activity had a get data function that returned an object of class MyData implements Parcelable (Serializeable would work for simple data). The data was stored in onSaveInstanceState in the activity and restored in the activivitys onCreate.

Fragments stack Android

Imagine one activity with 3 fragments: starts showing the first one, select a menu option and go to the second one, select another option and go to the 3rd fragment and select again the first option an return to the second one.
f1 -> f2 -> f3 -> f2
When I press back I want the app returns to fragment 3 and when I press back again it should return to fragment 1 and if press back again, close the app.
Something like if the fragment exists, move it to top of the stack and if not, create it.
Thank you!

Here is solution I came up over time.
The idea is following, you need to keep a stack data structure and whenever you add a fragment add it to stack as well, then override onBackPress method and check if stack is not empty then replace your fragment container with new fragment from top of the stack when it is empty do super.onbackpress
So here is a parent class for all kind of fragment based navigation.
public abstract class FragmentsStackActivity extends BaseActivity {
public static final String TAG_BUNDLE = "bundle_tag";
protected final Bundle fragmentArgs = new Bundle();
protected Stack<Fragment> fragments = new Stack<>();
abstract protected void setupFragments();
public void setFragmentArguments(Fragment fragment, Bundle arguments){
if(!fragments.isEmpty() && fragments.peek()!=fragment){
fragment.setArguments(arguments);
}
}
public void setFragmentFromStack() {
if(!fragments.isEmpty()) {
Fragment fragment = fragments.peek();
final Fragment oldFragment = getSupportFragmentManager().findFragmentById(R.id.fragment_container);
if (oldFragment == null || oldFragment != fragment) {
getFragmentManager().popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
final FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
//transaction.setCustomAnimations(R.anim.animator_left_right_in, R.anim.animator_left_right_in);
transaction.replace(R.id.fragment_container, fragment).commit();
}
}else {
finish();
}
}
#Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
//TODO need to save fragment stack
}
}
example of an activity that extends this class
public class LoginActivity extends FragmentsStackActivity{
private final MyFragment1 fragment1 = new MyFragment1();
private final MyFragment2 fragment2 = new MyFragment2();
private final User mUser = new User();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
setupFragments();
setFragmentFromStack();
}
#Override
protected void setupFragments() {
fragments.add(fragment2);
//fragment2.setNotifier(this); // I use notifiers listener but you can choose whatever convenient for you
Bundle fragmentArgs = new Bundle();
fragmentArgs.putBoolean(Constants.TAG_LOGIN, true);
fragmentArgs.putParcelable(User.TAG, mUser);
fragmentArgs.putInt(Constants.TYPE, getIntent().getIntExtra(Constants.TYPE, 0));
fragment2.setArguments(fragmentArgs);
//fragment1.setNotifier(this); // I use notifiers listener but you can choose whatever convenient for you
}
// this method teals with handling messages from fragments in order to provide navigation
// when some actions taken inside the fragment, you can implement your own version
public void onReceiveMessage(String tag, Bundle bundle) {
switch (tag) {
case MyFragment2.TAG_BACK:
case MyFragment1.TAG_BACK:
fragments.pop();
setFragmentFromStack();
break;
case MyFragment2.TAG_NEXT:
fragment1.setArguments(bundle);
fragments.add(fragment1);
setFragmentFromStack();
break;
case MyFragment1.TAG_NEXT:
goToWelcomeScreen(bundle);
finish();
break;
}
}
private void goToWelcomeScreen(Bundle bundle){
}
}

You can implement this with the help of the following code:
// transaction.replace(R.id.detailFragment, frag1);
Transaction.remove(null).add(frag1) // frag1 on view
// transaction.replace(R.id.detailFragment, frag2).addToBackStack(null);
Transaction.remove(frag1).add(frag2).addToBackStack(null) // frag2 on view
// transaction.replace(R.id.detailFragment, frag3);
Transaction.remove(frag2).add(frag3) // frag3 on view
And for better understanding, have a ook at the following snippet:
// Works with either the framework FragmentManager or the
// support package FragmentManager (getSupportFragmentManager).
getSupportFragmentManager().beginTransaction()
.add(detailFragment, "detail")
// Add this transaction to the back stack
.addToBackStack()
.commit();
getSupportFragmentManager().addOnBackStackChangedListener(
new FragmentManager.OnBackStackChangedListener() {
public void onBackStackChanged() {
// Update your UI here.
}
});
have a look here http://developer.android.com/training/implementing-navigation/temporal.html

Switching Fragments in Master/Detail Flow

I am attempting to create an app which has a Master/Detail flow using Fragments. Selecting an item will open a detail fragment which may then which to "open" another fragment and add it to the back stack.
I have renamed classes to help illustrate what they do.
public class ListOfDetails extends FragmentActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
...
}
//Callback method indicating that an item with the given ID was selected.
public void onItemSelected(String id) {
// Performing logic to determine what fragment to start omitted
if (ifTwoPanes()) {
Fragment fragment = new DetailFragmentType1();
getSupportFragmentManager().beginTransaction().replace(R.id.aContainer, fragment).commit();
} else {
Intent newIntent = new Intent(this, SinglePaneFragmentWrapper.class);
newIntent.putExtra("id", id);
startActivity(newIntent);
}
}
// My attempt at making it possible to change displayed fragment from within fragments
public void changeDetailFragment(Fragment fragment) {
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
transaction.addToBackStack(null);
transaction.replace(R.id.aContainer, fragment);
transaction.commit();
}
}
An example of one of the detail fragments. There are many different Fragments that may be created in different circumstances.
public class DetailFragmentType1 extends Fragment {
private ListOfDetails parent;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Activity a = getActivity();
if (a instanceof ListOfDetails) {
parent = (ListOfDetails) a;
}
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
Button aButton = (Button) getActivity().findViewById(R.id.aButton);
aButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
parent.changeDetailFragment(new SubDetailFragment());
}
});
}
}
When on phone, a wrapper activity is used to hold the fragment
public class SinglePaneFragmentWrapper extends FragmentActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Duplicate logic must be performed to start fragment
// Performing logic to determine what fragment to start omitted
String id = getIntent().getStringExtra("id");
if(id == "DetailFragmentType1") {
Fragment fragment = new DetailFragmentType1();
getSupportFragmentManager().beginTransaction().replace(R.id.aContainer, fragment).commit();
} else {
...
}
}
}
What is the proper way to change the fragment that is open in the detail pane in this circumstance? My method feels like a hack when using two panes and doesn't even work when using only one pane because getParent() from SinglePaneFragmentWrapper returns null, making me unable to call parent.changeDetailFragment().
This is a complicated question, hopefully I explained it well. Let me know if I missed something. Thanks

There are lots of opinions around this and lots of ways of doing it. I think in this case the problem is "who is responsible for changing the fragment?" on the surface it seems that a listener on the button is the obvious place, but then the fragment shouldn't know what it is hosted in (a symptom of that is getting an undesirable result like null from getParent()).
In your case I would suggest you implement a "listener" interface in the parent and "notify" from the fragment.. when the parent is notified, it changes the fragment. This way the fragment is not changing itself (so doesn't need to know how).. so.. for your case..
Add a new interface:
public interface FragmentChangeListener {
void onFragmentChangeRequested(Fragment newFragment);
}
Implement the interface in your ListOfDetails activity
public class ListOfDetails extends FragmentActivity implements FragmentChangeListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
...
}
//Callback method indicating that an item with the given ID was selected.
public void onItemSelected(String id) {
// Performing logic to determine what fragment to start omitted
if (ifTwoPanes()) {
Fragment fragment = new DetailFragmentType1();
getSupportFragmentManager().beginTransaction().replace(R.id.aContainer, fragment).commit();
} else {
Intent newIntent = new Intent(this, SinglePaneFragmentWrapper.class);
newIntent.putExtra("id", id);
startActivity(newIntent);
}
}
// My attempt at making it possible to change displayed fragment from within fragments
public void changeDetailFragment(Fragment fragment) {
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
transaction.addToBackStack(null);
transaction.replace(R.id.aContainer, fragment);
transaction.commit();
}
// This is the interface implementation that will be called by your fragments
void onFragmentChangeRequested(Fragment newFragment) {
changeDetailFragment(newFragment);
}
}
Added listener to detail fragment
public class DetailFragmentType1 extends Fragment {
private FragmentChangeListener fragmentChangeListener;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Actually you might not have an activity here.. you should probably be
// doing this in onAttach
//Activity a = getActivity();
//if (a instanceof ListOfDetails) {
// parent = (ListOfDetails) a;
//}
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
Button aButton = (Button) getActivity().findViewById(R.id.aButton);
aButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// parent.changeDetailFragment(new SubDetailFragment());
notifyFragmentChange(new SubDetailFragment());
}
});
}
#Override
public void onAttach(Activity activity) {
// This is called when the fragment is attached to an activity..
if (activity instanceof FragmentChangeListener) {
fragmentChangeListener = (FragmentChangeListener) activity;
} else {
// Find your bugs early by making them clear when you can...
if (BuildConfig.DEBUG) {
throw new IllegalArgumentException("Fragment hosts must implement FragmentChangeListener");
}
}
}
private void notifyFragmentChange(Fragment newFragment) {
FragmentChangeListener listener = fragmentChangeListener;
if (listener != null) {
listener.onFragmentChangeRequested(newFragment);
}
}
}
And implement the same interface to your single pane activity...
public class SinglePaneFragmentWrapper extends FragmentActivity implements FragmentChangeListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Duplicate logic must be performed to start fragment
// Performing logic to determine what fragment to start omitted
String id = getIntent().getStringExtra("id");
if(id == "DetailFragmentType1") {
Fragment fragment = new DetailFragmentType1();
getSupportFragmentManager().beginTransaction().replace(R.id.aContainer, fragment).commit();
} else {
...
}
}
// My attempt at making it possible to change displayed fragment from within fragments
public void changeDetailFragment(Fragment fragment) {
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
transaction.addToBackStack(null);
transaction.replace(R.id.aContainer, fragment);
transaction.commit();
}
// This is the interface implementation that will be called by your fragments
void onFragmentChangeRequested(Fragment newFragment) {
changeDetailFragment(newFragment);
}
}
Note the similarity between your single pane and your multi-pane activities.. this suggests that you could either put all of the duplicated code (changefragment etc) into a single activity that they both extend or that in maybe they are the same activities with different layouts...
I hope that helps, Good luck.
Regards,
CJ