When I start the app everything works ok but when I rotate to landscape it crashes because in the Fragment there is a field that is NULL.
I dont use setRetainInstance(true) or adding Fragments to FragmentManagerI create new Fragments on app start and when app rotate.
In the Activity OnCreate() I create the Fragment and adding them to the viewPager like this.
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ParentBasicInfoFragment parentBasicInfoFragment = new ParentBasicInfoFragment();
ParentUTCFragment parentUTCFragment = new ParentUTCFragment();
ParentEventsFragment parentEventsFragment = new ParentEventsFragment();
this.mFragments = new ArrayList<>();
this.mFragments.add(parentBasicInfoFragment);
this.mFragments.add(parentUTCFragment);
this.mFragments.add(parentEventsFragment);
this.viewpage.setOffscreenPageLimit(3);
setCurrentTab(0);
this.viewpage.setAdapter(new MainActivityPagerAdapter(getSupportFragmentManager(), this.mFragments));
}
Then I have a test button on the app that when I press it will do like
public void test(View view) {
((BaseFragment) MainActivity.this.mFragments.get(MainActivity.this.viewpage.
getCurrentItem())).activityNotifiDataChange("hello");
}
This will work and the current Fragments in the ViewPager have the method, activityNotifiDataChange() that are being called and all is ok.
When I rotate the app and do the same thing pressing the button the activityNotifiDataChange() is being called alright but there a null pointer exception because the ArrayList<Fragment> mFragment is now NULL.
Here´s a small sample Android Studio project showing this behavior:
https://drive.google.com/file/d/1Swqu59HZNYFT5hMTqv3eNiT9NmakhNEb/view?usp=sharing
Start app and press button named "PRESS TEST", then rotate device and press the button again and watch the app crash
UPDATE SOLUTION thanks #GregMoens and #EpicPandaForce
public class MainActivityPagerAdapter extends PersistenPagerAdapter<BaseFragment> {
private static int NUM_ITEMS = 3;
public MainActivityPagerAdapter(FragmentManager fm) {
super(fm);
}
public int getCount() {
return NUM_ITEMS;
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return ParentBasicInfoFragment.newInstance(0, "Page # 1");
case 1:
return ParentUTCFragment.newInstance(1, "Page # 2");
case 2:
return ParentEventsFragment.newInstance(2, "Page # 3");
default:
return null;
}
}
}
public abstract class PersistenPagerAdapter<T extends BaseFragment> extends FragmentPagerAdapter {
private SparseArray<T> registeredFragments = new SparseArray<T>();
public PersistenPagerAdapter(FragmentManager fragmentManager) {
super(fragmentManager);
}
#Override
public T instantiateItem(ViewGroup container, int position) {
T fragment = (T)super.instantiateItem(container, position);
registeredFragments.put(position, fragment);
return fragment;
}
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
registeredFragments.remove(position);
super.destroyItem(container, position, object);
}
public T getRegisteredFragment(ViewGroup container, int position) {
T existingInstance = registeredFragments.get(position);
if (existingInstance != null) {
return existingInstance;
} else {
return instantiateItem(container, position);
}
}
}
The main problem I see with your app is your misunderstanding with how FragmentPagerAdapter works. I see this a lot and it's due to lack of good javadocs on the class. The adapter should be implemented so that getItem(position) returns a new fragment instance when called. And then getItem(position) will only be called by the pager when it needs a new instance for that position. You should not pre-create the fragments and pass then into the adapter. You should also not be holding strong references to the fragments from either your activity or from parent fragments (like ParentBasicInfoFragment). Because remember, the fragment manager is managing fragments and you are also managing fragments by newing them and keeping references to them. This is causing a conflict and after rotation, you are trying to invoke activityNotifiDataChange() on a fragment that is not actually initialized (onCreate() was not called). Using the debugger and tracking object IDs will confirm this.
If you change your code so that the FragmentPagerAdapter creates the fragments when they are needed and don't store references to fragments or lists of fragments, you will see much better results.
this.mFragments = new ArrayList<>();
Because this is wrong. You should never hold a reference to the fragment list if you are using ViewPager. Just return new instance of Fragment from getItem(int position) of FragmentPagerAdapter and you are good to go.
But to fix your code, you must delete mFragments entirely.
See https://stackoverflow.com/a/58605339/2413303 for more details.
Use setRetainInstance(true) is not a good approach. If you need to same some simple information such as: position of recyclerView, selected item of recyclerView, maybe some model(Parcelable) you could do it with method onSaveInstanceState / onRestoreInstanceState, there is one limitation is 1MB. Here is an example with animations how it works.
For more durable persistance use SharedPreferences, Room(Google ORM) or you could try to use ViewModel with LiveData (best approach some data which should live while user session).
//change in AndroidManifest.xml file,
<activity
android:name=".activity.YourActivity"
android:configChanges="orientation|keyboardHidden|screenSize"
android:screenOrientation="sensor"
/>
//YourActivity in which you defines fragment.
//may be it helps
I have a ViewPager with 3 Fragments and my FragmentPagerAdapter:
private class test_pager extends FragmentPagerAdapter {
public test_pager(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int i) {
return fragments[i];
}
#Override
public long getItemId(int position) {
if (position == 1) {
long res = fragments[position].hashCode()+fragment1_state.hashCode();
Log.d(TAG, "getItemId for position 1: "+res);
return res;
} else
return fragments[position].hashCode();
}
#Override
public int getCount() {
return fragments[2] == null ? 2 : 3;
}
#Override
public int getItemPosition(Object object) {
Fragment fragment = (Fragment) object;
for (int i=0; i<3; i++)
if (fragment.equals(fragments[i])){
if (i==1) {
return 1; // not sure if that makes a difference
}
return POSITION_UNCHANGED;
}
return POSITION_NONE;
}
}
In one of the page (#1), I keep changing the fragment to be displayed. The way I remove the old fragment is like this:
FragmentManager fm = getSupportFragmentManager();
fm.beginTransaction().remove(old_fragment1).commit();
And then just changing the value of fragments[1]
I found that I cannot really add or replace the new one or it will complain the ViewPager is trying to add it too with another tag... (am I doing something wrong here?)
All the fragments I display have setRetainInstance(true); in their onCreate function.
My problem is that this usually works well for the first few replacement, but then when I try to reuse a fragment, sometimes (I have not really figured out the pattern, the same fragment may be displayed several times before this happens) it will only show a blank page.
Here is what I have found happened in the callback functions of my Fragment I am trying to display when the problem happens:
onAttach is called (but at that time, getView is still null)
onCreateView is not called (that's expected)
onViewStateRestored is not called (why not?)
onResume is not called (I really thought it would...)
If it changes anything, I am using the support package, my activity is a SherlockFragmentActivity
EDIT (to answer Marco's comment):
The fragments are instantiated in the onCreate function of the Activity, I fill an ArrayList with those fragments:
char_tests = new ArrayList<Fragment>(Arrays.asList(
new FragmentOptionA(), new FragmentOptionB(), new FragmentOptionC()));
The I pick from that list to set fragments[1] (that's all done in the UI thread)
I fixed this by changing test_pager to extends FragmentStatePagerAdapter instead.
I am still confused as to what PagerAdapter should be used depending on the usage. The only thing I can find in the documentation says that FragmentPagerAdapter is better for smaller number of pages that would be kept in memory and FragmentPagerStateAdapter better for a larger number of pages where they would be destroyed and save memory...
When trying to do (fancy?) things with Fragments, I found FragmentStatePagerAdapter is better when pages are removed and re-inserted like in this case. And FragmentPagerAdapter is better when pages move position (see bug 37990)
I'm using a ViewPager together with a FragmentStatePagerAdapter to host three different fragments:
[Fragment1]
[Fragment2]
[Fragment3]
When I want to get Fragment1 from the ViewPager in the FragmentActivity.
What is the problem, and how do I fix it?
The main answer relies on a name being generated by the framework. If that ever changes, then it will no longer work.
What about this solution, overriding instantiateItem() and destroyItem() of your Fragment(State)PagerAdapter:
public class MyPagerAdapter extends FragmentStatePagerAdapter {
SparseArray<Fragment> registeredFragments = new SparseArray<Fragment>();
public MyPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public int getCount() {
return ...;
}
#Override
public Fragment getItem(int position) {
return MyFragment.newInstance(...);
}
#Override
public Object instantiateItem(ViewGroup container, int position) {
Fragment fragment = (Fragment) super.instantiateItem(container, position);
registeredFragments.put(position, fragment);
return fragment;
}
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
registeredFragments.remove(position);
super.destroyItem(container, position, object);
}
public Fragment getRegisteredFragment(int position) {
return registeredFragments.get(position);
}
}
This seems to work for me when dealing with Fragments that are available. Fragments that have not yet been instantiated, will return null when calling getRegisteredFragment. But I've been using this mostly to get the current Fragment out of the ViewPager: adapater.getRegisteredFragment(viewPager.getCurrentItem()) and this won't return null.
I'm not aware of any other drawbacks of this solution. If there are any, I'd like to know.
For grabbing fragments out of a ViewPager there are a lot of answers on here and on other related SO threads / blogs. Everyone I have seen is broken, and they generally seem to fall into one of the two types listed below. There are some other valid solutions if you only want to grab the current fragment, like this other answer on this thread.
If using FragmentPagerAdapter see below. If using FragmentStatePagerAdapter its worth looking at this. Grabbing indexes that are not the current one in a FragmentStateAdapter is not as useful as by the nature of it these will be completely torn down went out of view / out of offScreenLimit bounds.
THE UNHAPPY PATHS
Wrong: Maintain your own internal list of fragments, added to when FragmentPagerAdapter.getItem() is called
Usually using a SparseArray or Map
Not one of the many examples I have seen accounts for lifecycle events so this solution is fragile. As getItem is only called the first time a page is scrolled to (or obtained if your ViewPager.setOffscreenPageLimit(x) > 0) in the ViewPager, if the hosting Activity / Fragment is killed or restarted then the internal SpaseArray will be wiped out when the custom FragmentPagerActivity is recreated, but behind the scenes the ViewPagers internal fragments will be recreated, and getItem will NOT be called for any of the indexes, so the ability to get a fragment from index will be lost forever. You can account for this by saving out and restoring these fragment references via FragmentManager.getFragment() and putFragment but this starts to get messy IMHO.
Wrong: Construct your own tag id matching what is used under the hood in FragmentPagerAdapter and use this to retrieve the page Fragments from the FragmentManager
This is better insomuch as it copes with the losing-fragment-references problem in the first internal-array solution, but as rightly pointed out in the answers above and elsewhere on the net - it feels hacky as its a private method internal to ViewPager that could change at any time or for any OS version.
The method thats recreated for this solution is
private static String makeFragmentName(int viewId, long id) {
return "android:switcher:" + viewId + ":" + id;
}
A HAPPY PATH: ViewPager.instantiateItem()
A similar approach to getItem() above but non-lifecycle-breaking is to this is to hook into instantiateItem() instead of getItem() as the former will be called everytime that index is created / accessed. See this answer
A HAPPY PATH: Construct your own FragmentViewPager
Construct your own FragmentViewPager class from the source of the latest support lib and change the method used internally to generate the fragment tags. You can replace it with the below. This has the advantage that you know the tag creation will never change and your not relying on a private api / method, which is always dangerous.
/**
* #param containerViewId the ViewPager this adapter is being supplied to
* #param id pass in getItemId(position) as this is whats used internally in this class
* #return the tag used for this pages fragment
*/
public static String makeFragmentName(int containerViewId, long id) {
return "android:switcher:" + containerViewId + ":" + id;
}
Then as the doc says, when you want to grab a fragment used for an index just call something like this method (which you can put in the custom FragmentPagerAdapter or a subclass) being aware the result may be null if getItem has not yet been called for that page i.e. its not been created yet.
/**
* #return may return null if the fragment has not been instantiated yet for that position - this depends on if the fragment has been viewed
* yet OR is a sibling covered by {#link android.support.v4.view.ViewPager#setOffscreenPageLimit(int)}. Can use this to call methods on
* the current positions fragment.
*/
public #Nullable Fragment getFragmentForPosition(int position)
{
String tag = makeFragmentName(mViewPager.getId(), getItemId(position));
Fragment fragment = getSupportFragmentManager().findFragmentByTag(tag);
return fragment;
}
This is a simple solution and solves the issues in the other two solutions found everywhere on the web
Add next methods to your FragmentPagerAdapter:
public Fragment getActiveFragment(ViewPager container, int position) {
String name = makeFragmentName(container.getId(), position);
return mFragmentManager.findFragmentByTag(name);
}
private static String makeFragmentName(int viewId, int index) {
return "android:switcher:" + viewId + ":" + index;
}
getActiveFragment(0) has to work.
Here is the solution implemented into ViewPager https://gist.github.com/jacek-marchwicki/d6320ba9a910c514424d. If something fail you will see good crash log.
Another simple solution:
public class MyPagerAdapter extends FragmentPagerAdapter {
private Fragment mCurrentFragment;
public Fragment getCurrentFragment() {
return mCurrentFragment;
}
//...
#Override
public void setPrimaryItem(ViewGroup container, int position, Object object) {
if (getCurrentFragment() != object) {
mCurrentFragment = ((Fragment) object);
}
super.setPrimaryItem(container, position, object);
}
}
I know this has a few answers, but maybe this will help someone. I have used a relatively simple solution when I needed to get a Fragment from my ViewPager. In your Activity or Fragment holding the ViewPager, you can use this code to cycle through every Fragment it holds.
FragmentPagerAdapter fragmentPagerAdapter = (FragmentPagerAdapter) mViewPager.getAdapter();
for(int i = 0; i < fragmentPagerAdapter.getCount(); i++) {
Fragment viewPagerFragment = fragmentPagerAdapter.getItem(i);
if(viewPagerFragment != null) {
// Do something with your Fragment
// Check viewPagerFragment.isResumed() if you intend on interacting with any views.
}
}
If you know the position of your Fragment in the ViewPager, you can just call getItem(knownPosition).
If you don't know the position of your Fragment in the ViewPager, you can have your children Fragments implement an interface with a method like getUniqueId(), and use that to differentiate them. Or you can cycle through all Fragments and check the class type, such as if(viewPagerFragment instanceof FragmentClassYouWant)
!!! EDIT !!!
I have discovered that getItem only gets called by a FragmentPagerAdapter when each Fragment needs to be created the first time, after that, it appears the the Fragments are recycled using the FragmentManager. This way, many implementations of FragmentPagerAdapter create new Fragments in getItem. Using my above method, this means we will create new Fragments each time getItem is called as we go through all the items in the FragmentPagerAdapter. Due to this, I have found a better approach, using the FragmentManager to get each Fragment instead (using the accepted answer). This is a more complete solution, and has been working well for me.
FragmentPagerAdapter fragmentPagerAdapter = (FragmentPagerAdapter) mViewPager.getAdapter();
for(int i = 0; i < fragmentPagerAdapter.getCount(); i++) {
String name = makeFragmentName(mViewPager.getId(), i);
Fragment viewPagerFragment = getChildFragmentManager().findFragmentByTag(name);
// OR Fragment viewPagerFragment = getFragmentManager().findFragmentByTag(name);
if(viewPagerFragment != null) {
// Do something with your Fragment
if (viewPagerFragment.isResumed()) {
// Interact with any views/data that must be alive
}
else {
// Flag something for update later, when this viewPagerFragment
// returns to onResume
}
}
}
And you will need this method.
private static String makeFragmentName(int viewId, int position) {
return "android:switcher:" + viewId + ":" + position;
}
For my case, none of the above solutions worked.
However since I am using the Child Fragment Manager in a Fragment, the following was used:
Fragment f = getChildFragmentManager().getFragments().get(viewPager.getCurrentItem());
This will only work if your fragments in the Manager correspond to the viewpager item.
In order to get current Visible fragment from ViewPager. I am using this simple statement and it's working fine.
public Fragment getFragmentFromViewpager()
{
return ((Fragment) (mAdapter.instantiateItem(mViewPager, mViewPager.getCurrentItem())));
}
I handled it by first making a list of all the fragments (List<Fragment> fragments;) that I was going to use then added them to the pager making it easier to handle the currently viewed fragment.
So:
#Override
onCreate(){
//initialise the list of fragments
fragments = new Vector<Fragment>();
//fill up the list with out fragments
fragments.add(Fragment.instantiate(this, MainFragment.class.getName()));
fragments.add(Fragment.instantiate(this, MenuFragment.class.getName()));
fragments.add(Fragment.instantiate(this, StoresFragment.class.getName()));
fragments.add(Fragment.instantiate(this, AboutFragment.class.getName()));
fragments.add(Fragment.instantiate(this, ContactFragment.class.getName()));
//Set up the pager
pager = (ViewPager)findViewById(R.id.pager);
pager.setAdapter(new MyFragmentPagerAdapter(getSupportFragmentManager(), fragments));
pager.setOffscreenPageLimit(4);
}
so then this can be called:
public Fragment getFragment(ViewPager pager){
Fragment theFragment = fragments.get(pager.getCurrentItem());
return theFragment;
}
so then i could chuck it in an if statement that would only run if it was on the correct fragment
Fragment tempFragment = getFragment();
if(tempFragment == MyFragmentNo2.class){
MyFragmentNo2 theFrag = (MyFragmentNo2) tempFragment;
//then you can do whatever with the fragment
theFrag.costomFunction();
}
but thats just my hack and slash approach but it worked for me, I use it do do relevent changes to my currently displayed fragment when the back button is pushed.
This is based on Steven's answer above. This will return actual instance of the fragment which is already attached to the parent activity.
FragmentPagerAdapter fragmentPagerAdapter = (FragmentPagerAdapter) mViewPager.getAdapter();
for(int i = 0; i < fragmentPagerAdapter.getCount(); i++) {
Fragment viewPagerFragment = (Fragment) mViewPager.getAdapter().instantiateItem(mViewPager, i);
if(viewPagerFragment != null && viewPagerFragment.isAdded()) {
if (viewPagerFragment instanceof FragmentOne){
FragmentOne oneFragment = (FragmentOne) viewPagerFragment;
if (oneFragment != null){
oneFragment.update(); // your custom method
}
} else if (viewPagerFragment instanceof FragmentTwo){
FragmentTwo twoFragment = (FragmentTwo) viewPagerFragment;
if (twoFragment != null){
twoFragment.update(); // your custom method
}
}
}
}
I couldn't find a simple, clean way to do this. However, the ViewPager widget is just another ViewGroup , which hosts your fragments. The ViewPager has these fragments as immediate children. So you could just iterate over them (using .getChildCount() and .getChildAt() ), and see if the fragment instance that you're looking for is currently loaded into the ViewPager and get a reference to it. E.g. you could use some static unique ID field to tell the fragments apart.
Note that the ViewPager may not have loaded the fragment you're looking for since it's a virtualizing container like ListView.
FragmentPagerAdapter is the factory of the fragments. To find a fragment based on its position if still in memory use this:
public Fragment findFragmentByPosition(int position) {
FragmentPagerAdapter fragmentPagerAdapter = getFragmentPagerAdapter();
return getSupportFragmentManager().findFragmentByTag(
"android:switcher:" + getViewPager().getId() + ":"
+ fragmentPagerAdapter.getItemId(position));
}
Sample code for v4 support api.
You don't need to call getItem() or some other method at later stage to get the reference of a Fragment hosted inside ViewPager. If you want to update some data inside Fragment then use this approach: Update ViewPager dynamically?
Key is to set new data inside Adaper and call notifyDataSetChanged() which in turn will call getItemPosition(), passing you a reference of your Fragment and giving you a chance to update it. All other ways require you to keep reference to yourself or some other hack which is not a good solution.
#Override
public int getItemPosition(Object object) {
if (object instanceof UpdateableFragment) {
((UpdateableFragment) object).update(xyzData);
}
//don't return POSITION_NONE, avoid fragment recreation.
return super.getItemPosition(object);
}
Must extends FragmentPagerAdapter into your ViewPager adapter class.
If you use FragmentStatePagerAdapter then you will not able to find your Fragment by its ID
public static String makeFragmentName(int viewPagerId, int index) {
return "android:switcher:" + viewPagerId + ":" + index;
}
How to use this method :-
Fragment mFragment = ((FragmentActivity) getContext()).getSupportFragmentManager().findFragmentByTag(
AppMethodUtils.makeFragmentName(mViewPager.getId(), i)
);
InterestViewFragment newFragment = (InterestViewFragment) mFragment;
Hey I have answered this question here. Basically, you need to override
public Object instantiateItem(ViewGroup container, int position)
method of FragmentStatePagerAdapter.
Best solution is to use the extension we created at CodePath called SmartFragmentStatePagerAdapter. Following that guide, this makes retrieving fragments and the currently selected fragment from a ViewPager significantly easier. It also does a better job of managing the memory of the fragments embedded within the adapter.
The easiest and the most concise way. If all your fragments in ViewPager are of different classes you may retrieve and distinguish them as following:
public class MyActivity extends Activity
{
#Override
public void onAttachFragment(Fragment fragment) {
super.onAttachFragment(fragment);
if (fragment.getClass() == MyFragment.class) {
mMyFragment = (MyFragment) fragment;
}
}
}
I implemented this easy with a bit different approach.
My custom FragmentAdapter.getItem method returned not new MyFragment(), but the instance of MyFragment that was created in FragmentAdapter constructor.
In my activity I then got the fragment from the adapter, check if it is instanceOf needed Fragment, then cast and use needed methods.
Create integer resource id in /values/integers.xml
<integer name="page1">1</integer>
<integer name="page2">2</integer>
<integer name="page3">3</integer>
Then in PagerAdapter getItem function:
public Fragment getItem(int position) {
Fragment fragment = null;
if (position == 0) {
fragment = FragmentOne.newInstance();
mViewPager.setTag(R.integer.page1,fragment);
}
else if (position == 1) {
fragment = FragmentTwo.newInstance();
mViewPager.setTag(R.integer.page2,fragment);
} else if (position == 2) {
fragment = FragmentThree.newInstance();
mViewPager.setTag(R.integer.page3,fragment);
}
return fragment;
}
Then in activity write this function to get fragment reference:
private Fragment getFragmentByPosition(int position) {
Fragment fragment = null;
switch (position) {
case 0:
fragment = (Fragment) mViewPager.getTag(R.integer.page1);
break;
case 1:
fragment = (Fragment) mViewPager.getTag(R.integer.page2);
break;
case 2:
fragment = (Fragment) mViewPager.getTag(R.integer.page3);
break;
}
return fragment;
}
Get the fragment reference by calling the above function and then cast it to your custom fragment:
Fragment fragment = getFragmentByPosition(position);
if (fragment != null) {
FragmentOne fragmentOne = (FragmentOne) fragment;
}
Easy way to iterate over fragments in fragment manager. Find viewpager, that has section position argument, placed in public static PlaceholderFragment newInstance(int sectionNumber).
public PlaceholderFragment getFragmentByPosition(Integer pos){
for(Fragment f:getChildFragmentManager().getFragments()){
if(f.getId()==R.id.viewpager && f.getArguments().getInt("SECTNUM") - 1 == pos) {
return (PlaceholderFragment) f;
}
}
return null;
}
In Fragment
public int getArgument(){
return mPage;
{
public void update(){
}
In FragmentActivity
List<Fragment> fragments = getSupportFragmentManager().getFragments();
for(Fragment f:fragments){
if((f instanceof PageFragment)&&(!f.isDetached())){
PageFragment pf = (PageFragment)f;
if(pf.getArgument()==pager.getCurrentItem())pf.update();
}
}
in TabLayout there are multiple tab for Fragment. you can find the fragment by Tag using the index of the fragment.
For ex. the index for Fragment1 is 0, so in findFragmentByTag() method, pass the tag for the Viewpager.after using fragmentTransaction you can add,replace the fragment.
String tag = "android:switcher:" + R.id.viewPager + ":" + 0;
Fragment1 f = (Fragment1) getSupportFragmentManager().findFragmentByTag(tag);
Ok for the adapter FragmentStatePagerAdapter I fund a solution :
in your FragmentActivity :
ActionBar mActionBar = getSupportActionBar();
mActionBar.addTab(mActionBar.newTab().setText("TAB1").setTabListener(this).setTag(Fragment.instantiate(this, MyFragment1.class.getName())));
mActionBar.addTab(mActionBar.newTab().setText("TAB2").setTabListener(this).setTag(Fragment.instantiate(this, MyFragment2.class.getName())));
mActionBar.addTab(mActionBar.newTab().setText("TAB3").setTabListener(this).setTag(Fragment.instantiate(this, MyFragment3.class.getName())));
viewPager = (STViewPager) super.findViewById(R.id.viewpager);
mPagerAdapter = new MyPagerAdapter(getSupportFragmentManager(), mActionBar);
viewPager.setAdapter(this.mPagerAdapter);
and create a methode in your class FragmentActivity - So that method give you access to your Fragment, you just need to give it the position of the fragment you want:
public Fragment getActiveFragment(int position) {
String name = MyPagerAdapter.makeFragmentName(position);
return getSupportFragmentManager().findFragmentByTag(name);
}
in your Adapter :
public class MyPagerAdapter extends FragmentStatePagerAdapter {
private final ActionBar actionBar;
private final FragmentManager fragmentManager;
public MyPagerAdapter(FragmentManager fragmentManager, com.actionbarsherlock.app.ActionBarActionBar mActionBar) {super(fragmentManager);
this.actionBar = mActionBar;
this.fragmentManager = fragmentManager;
}
#Override
public Fragment getItem(int position) {
getSupportFragmentManager().beginTransaction().add(mTchatDetailsFragment, makeFragmentName(position)).commit();
return (Fragment)this.actionBar.getTabAt(position);
}
#Override
public int getCount() {
return this.actionBar.getTabCount();
}
#Override
public CharSequence getPageTitle(int position) {
return this.actionBar.getTabAt(position).getText();
}
private static String makeFragmentName(int viewId, int index) {
return "android:fragment:" + index;
}
}
Fragment yourFragment = yourviewpageradapter.getItem(int index);
index is the place of fragment in adapter like you added fragment1 first so retreive fragment1 pass index as 0 and so on for rest