I'm using TabLayout with ViewPager to show tabs in my app. I have only two tabs. These two tabs uses the same fragment (different instances) and I have one recycler in each fragment. Every recycler shows different data.
In my FragmentPagerAdapter, I do this:
#Override
public Fragment getItem(int position) {
Bundle bundle = new Bundle();
if (position == 0) {
bundle.putString(TreinamentosFragment.EXTRA_TIPO, TreinamentosFragment.TIPO_PENDENTE);
} else {
bundle.putString(TreinamentosFragment.EXTRA_TIPO, TreinamentosFragment.TIPO_CONCLUIDO);
}
Fragment fragment = new TreinamentosFragment();
fragment.setArguments(bundle);
return fragment;
}
With that approach I'm able to know at runtime what type is every fragment
and Get the correct informations in web service to show.
But, the problem is, when user is in Fragment A and interact in some way with one of the recycler items, I remove this item from the adapter and I need to put this item in the adapter of Fragment B. How can I do this? How can I recover the specific instance of Fragment B and change its adapter?
I wanna to do this without use of no kind of event bus.
My Fragment A and B are already inside another fragment because I'm using Navigation Drawer too.
class TreinamentosFragment extends Fragment{
public onItemClick(Item item){
List fragments = getParentFragment().getChildFragmentManager().getFragments();
for(Fragment fragment : fragments ){
if(fragment instanceof TreinamentosFragment &&TreinamentosFragment.TIPO_CONCLUIDO .equalIgnoreCase(fragment.getArgments().getString(TreinamentosFragment.EXTRA_TIPO))){
(TreinamentosFragment )fragment.addItem(item);
}
}
//or
List fragmentA = getParentFragment().getChildFragmentManager().FindFragmentByTag("android:switcher:" + R.id.viewpager + ":1");
if(fragmentA instanceof TreinamentosFragment){
(TreinamentosFragment )fragmentA.addItem(item);
}
}
public addItem(Item item){
}
}
You need to use the Singleton data classes.
https://en.wikipedia.org/wiki/Singleton_pattern
You have 2 adapters then you need two Singleton Data classes.. When you delete item from Fragment-A then add that deleted item in Frag-Bs Singleton Data instance. As Fragment-B resume/visible the just reload data from Frag-Bs Singleton Data instance.
No event Bus solutions.. :)
public class SingletonDemo {
private static volatile SingletonDemo instance = null;
private SingletonDemo() { }
public static synchronized SingletonDemo getInstance() {
if (instance == null) {
instance = new SingletonDemo();
}
return instance;
}
}
I have a ViewPager, defined in an Activity, and many Fragments sequentially shown in the ViewPager. In these fragments there are dynamically constructed checkboxes and radiobuttons, which the user is supposed to manipulate. On the very moment that the user swipes to the next page I need the user data to be retrieved and stored in the Application object. I can't figure out what the standard way of doing this is. Since there are many Fragments I opted for using the FragmentStatePagerAdapter. Any help would be welcome, thanks in advance!
Update-1:
I do have this:
pageAdapter = new MyPageAdapter(getSupportFragmentManager());
pager = (ViewPager) findViewById(R.id.viewpager);
pager.setAdapter(pageAdapter);
// detects viewpager page change
pager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
#Override
public void onPageSelected(int position) {
Log.i("TAG", "onPageSelected");
int index = pager.getCurrentItem();
MyPageAdapter adapter = ((MyPageAdapter) pager.getAdapter());
QuestionFragment fragment = (QuestionFragment) adapter.getItem(position);
if (fragment.rdbtn != null) {
for (int i = 0; i < fragment.rdbtn.length; i++) {
if (fragment.rdbtn[i].isChecked())
Log.i("TAG", "checked");
else
Log.i("TAG", "not checked");
}
}
// fragment.refresh();
}
});
When checking the debugger, after starting up, the ViewPager instantiates Fragments 0 and 1 (standard behavior). When the user manipulates fragment-0 and swipes, the handler is indeed called but with position=1, not 0. And the public elements I want to read are null!
UPDATE-2
I notice in the debugger that the data I need is stored in adapter.mCurrentPrimaryItem.
How to retrieve CurrentPrimaryItem in the code?!
You can implement a pageChangeListener in your activity and set this to the viewPager.
Then you can have a class abstract BaseFragment extends Fragment and declare an abstract method, say, getData() that every fragment in the ViewPager extends and overrides the method.
And in onPageSelected() of the activity you can access those data.
Need some help with my problem of updating pages while using viewpager. I am using a simple viewpager with FragmentStatePagerAdapter. All I want to do is get access to the current fragment/view so as I can update some textviews in my fragment/view. I searched around in the forum and came to know few things
- One of the ways to handle this is by setting tag in instantiateItem() call back of the adapter and retreive the view by findViewbyTag. I could not understand how to implement this and I am also not sure if that will work for FragmentStatePagerAdapter.
- I explored other options as suggested in various forums, but cannot make them work.
My code is very much same as in a android http://developer.android.com/training/animation/screen-slide.html. Basic components are the same (Fragment activity xml with some display components including a textview, viewpager xml with just a view pager in it, a Fragment class and the main FragmentActivity class). in my FragmentActivity class I have added a pageChangelistener to my viewpager so as I can do my textview changes during onPageSelected().
Any help is is appreciated.
Adding the code for reference.
Public class myActivity extends FragmentActivity
//Variable declarations
protected void onCreate(Bundle savedInstanceState) {
ViewPager mPager = (ViewPager) findViewById(R.id.pager);
mPagerAdapter = new ScreenSlidePagerAdapter(getSupportFragmentManager());
mPager.setAdapter(mPagerAdapter);
View CurrView;
OnPageChangeListener pageChangelistener = new OnPageChangeListener() {
#Override
public void onPageSelected(int pageSelected) {
doTextViewChnges();//access the text view and update it based on pageSelected
---THIS IS WHERE I AM STUCK IN TRYING TO GET THE TEXTVIEW IN MY CURRENT FRAGMWNT/VIEW-------
}
mPager.setOnPageChangeListener(pageChangelistener);
}
private class ScreenSlidePagerAdapter extends FragmentStatePagerAdapter {
public ScreenSlidePagerAdapter(android.support.v4.app.FragmentManager fm) {
super(fm);
}
#Override
public android.support.v4.app.Fragment getItem(int position) {
return ScreenSlidePageFragment.create(position, <other parameters I want to pass>);
}
#Override
public int getCount() {
return NUM_PAGES;
}
}
in your OnPageChangeListener:
OnPageChangeListener pageChangelistener = new OnPageChangeListener() {
#Override
public void onPageSelected(int pageSelected) {
ScreenSlidePageFragment currentFragment = (ScreenSlidePageFragment) mPagerAdapter.getItem(pageSelected)
doTextViewChnges();//access the text view and update it based on pageSelected
---THIS IS WHERE I AM STUCK IN TRYING TO GET THE TEXTVIEW IN MY CURRENT FRAGMWNT/VIEW-------
}
i assume you want to access your fragments from your activity and update the views.Fragments are parts of activities and their views can be accessed by them. Fragments are created dynamically in viewadapters and there is no straight forward and easy way to Tag them. You may simply access a fragment by its index number.first one is 0 second one is 1 and so on...
//access your fragment(in your case your first fragment)
//this part should be inside your doTextViewChnges()
Fragment fragment = (Fragment ) adapterViewPager
.getFragment(0);
if (fragment != null) {
//call a public method inside your fragment to update your text view
fragment .updateYourTextView();
}
Edit: inside your fragment create the following method and update your textview from there.
void updateYourTextView() {
yourTextView.setText("yourtext");
}
I am having a hard time figuring out the next thing.
What I have: I have a viewpager and several pages in it. In this question only two of them is important, lets call them Fragment1 and Fragment2 and they are next to each other. Fragment1 contains a listview which is filled with data from the internet (external database). Fragment2 contains a simple button.
My goal: If I click on the button in Fragment2, I add a new item to the external database. I would like to update/refresh the listview in the Fragment1 with this new item.
The notifyDataChanged() doesnt work in my case, however so far I was convinced that it reinstantiates every pages.. I am going to introduce my problem the clearest way I can, so lets see the code I have, this is my ViewPager adapter:
class MyPagerAdapter extends FragmentStatePagerAdapter {
public List<String> fragmentsA;
public MyPagerAdapter(FragmentManager fm) {
super(fm);
fragmentsA = fragments;
}
#Override
public Fragment getItem(int position) {
return Fragment.instantiate(context, fragmentsA.get(position));
}
#Override
public CharSequence getPageTitle(int position) {
return mEntries.get(position % CONTENT.length).toUpperCase();
}
#Override
public int getCount() {
return mEntries.size();
}
#Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
}
Fragment1 onCreateView() (shortly):
public View onCreateView(LayoutInflater inflater, final ViewGroup container,
Bundle savedInstanceState) {
getData();
View view = inflater.inflate(R.layout.latestapps_tab, container, false);
lw = (ListView) view.findViewById(R.id.lw);
context = getActivity().getApplicationContext();
act = this.getActivity();
m_adapter = new ItemAdapter();
lw.setAdapter(m_adapter);
return view;
}
I create the ViewPager and the adapter, I set the adapter for the ViewPager afterwards I fill the my viewpager with my fragments in my Main class. After this I am goint to have a fully functional ViewPager with 2 fragments.
pager = (ViewPager)findViewById( R.id.viewpager );
adapter = new MyPagerAdapter(getSupportFragmentManager());
indicator = (TabPageIndicator)findViewById( R.id.indicator );
pager.setAdapter( adapter );
indicator.setViewPager( pager );
pager.setCurrentItem(INITIAL_PAGE);
pager.setOffscreenPageLimit(3);
//adding fragments to the pager
fragments.add( Fragment1.class.getName());
fragments.add( Fragment2.class.getName());
In the Fragment1 I have a listview with some textviews in every list item. The loading works perfectly: I create the ArrayLists and I fill thoes lists with data from the external database. After loading is done, I fill the listviews with these tons of data.
In Fragment 2 I click on the button and I would like that listview to be updated so a new row should be created in the listview with some data from the external database. (of course writing into the database works)
My guess, that I might not refresh the ArrayLists or I dont reinstantiate the Fragment1, so the getDataFromSQL() method never turns only if I exit and launch the application again or I swipe so much in the ViewPager that the Fragment1 gets detached. So I cannot update or refresh the Fragment1. Could someone help in this questionL?
EDIT
I managed to make it happen with delivering a message to the fragment2 to update itself. But I am not sure if it is a good solution and there is not a better way, i.e. just refreshing somehow the whole fragment.
SOLUTION
Okay I think it must have been my laziness but I solved it now. For everyone who still wants to refresh a fragment from another one or just make conection between fragments, I tell you the appropriate approach:
You have to implement your own listener which helps you communicate between the fragments through the holder activity. This can be found here: http://developer.android.com/training/basics/fragments/communicating.html . Very simple and useful.
You have to retrieve the fragment, which is again simple: Retrieve a Fragment from a ViewPager These Q offers several acceptable way, I used the SpareArray solution.
Thank you for the help anyway!
you need be able to get your fragments from your activity, to do that you need to get the fragment from your adapter, you will need to add a couple methods to your page adapter
public Fragment getFragment(ViewPager container, int position, FragmentManager fm) {
String name = makeFragmentName(container.getId(), position);
return fm.findFragmentByTag(name);
}
private String makeFragmentName(int viewId, int index) {
return "android:switcher:" + viewId + ":" + index;
}
then from your activity make the following method
public Fragment getFragmentbyPosition(int position) {
return adapter.getFragment(pager, position, getSupportFragmentManager());
}
now on fragment2 call the following:
Fragment1 fragment1 = (Fragment1) ((MyActivity)getActivity()).getFragmentbyPosition(0);
now you will be able to call public methods on fragment1 from fragment 2, so just use that in your onClick and tell fragment1 to update it's listview.
now the reason makeFragmentName works is that is how the FragmentPagerAdapter creates the tag for the fragments it makes.
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