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How to Replace Fragment at runtime with the ChildFragmentManager and this fragment without Title of PagerSlidingTabStrip Xamarin.Android

I want to Change the Pager Layout at runtime with other fragment but without the PagerSlidingTabStrip Title. How .I can make it .
Second how .I can call method home Fragment in another fragments.
Here is The Home Layout
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:layout_marginBottom="50dp"
android:id="#+id/SlidingStrips"
android:layout_marginTop="10dp"
android:layout_below="#id/AcountBalance">
<com.refractored.PagerSlidingTabStrip
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:pstsPaddingMiddle="true"
app:pstsDividerWidth="1dp"
app:pstsDividerPadding="5dp"
app:pstsDividerColor="#50FFFFFF"
android:textColor="#50FFFFFF"
app:pstsTextColorSelected="#android:color/white"
app:pstsIndicatorColor="#android:color/white"
app:pstsUnderlineColor="#android:color/white" />
<!--Change this to true if you want to center items-->
<android.support.v4.view.ViewPager
android:id="#+id/pager"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
tools:context=".HomeFragmentLayout" />
</LinearLayout>
And how i'm Adding fragments here is the ChildFragments that added with the parent fragment these two fragments add two tabs with Hour and day Tabs.
public class HomeFragment : Fragment, IOnTabReselectedListener, ViewPager.IOnPageChangeListener
{
View view;
private MyPagerAdapter adapter;
private int count = 1;
private int currentColor;
List<Android.Support.V4.App.Fragment> fragments = new List<Android.Support.V4.App.Fragment>();
public static ViewPager pager;
private PagerSlidingTabStrip tabs;
public override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
// Create your fragment here
}
public static HomeFragment NewInstance()
{
var frag1 = new HomeFragment { Arguments = new Bundle() };
return frag1;
}
public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
base.OnCreateView(inflater, container, savedInstanceState);
if (view == null)
{
view = inflater.Inflate(Resource.Layout.HomeFragmentLayout, container, false);
return view;
}
else
{
return view;
}
}
public override void OnViewCreated(View view, Bundle savedInstanceState)
{
base.OnViewCreated(view, savedInstanceState);
try
{
fragments.Add(new HourlyFragment());
fragments.Add(new DayFragment());
adapter = new MyPagerAdapter(ChildFragmentManager, fragments);
pager = view.FindViewById<ViewPager>(Resource.Id.pager);
tabs = View.FindViewById<PagerSlidingTabStrip>(Resource.Id.tabs);
pager.Adapter = adapter;
tabs.SetViewPager(pager);
var pageMargin = (int)TypedValue.ApplyDimension(ComplexUnitType.Dip, 4, Resources.DisplayMetrics);
pager.PageMargin = pageMargin;
pager.CurrentItem = 0;
tabs.OnTabReselectedListener = this;
tabs.OnPageChangeListener = this;
}
catch (System.Exception ex)
{
}
}
.// public void ReplaceFragment(Fragment fragment)
//{
// try
// {
// FragmentManager manager = ChildFragmentManager;
// FragmentTransaction transaction = manager.BeginTransaction();
// transaction.Add(Resource.Id.content_frame, fragment);
// transaction.Commit();
// }
// catch (System.Exception ex)
// {
// }
//}
public void OnTabReselected(int position)
{
Toast.MakeText(Context.ApplicationContext, "Tab reselected: " + position, ToastLength.Short).Show();
}
public void OnPageScrollStateChanged(int state)
{
Console.WriteLine("Page scroll state changed: " + state);
}
public void OnPageScrolled(int position, float positionOffset, int positionOffsetPixels)
{
Console.WriteLine("Page Scrolled");
}
public void OnPageSelected(int position)
{
Console.WriteLine("Page selected: " + position);
}
}
Here is the pager Adapter
public class MyPagerAdapter : FragmentPagerAdapter
{
List<Android.Support.V4.App.Fragment> fragments;
private readonly string[] Titles =
{
"Hour", "Day"
};
public MyPagerAdapter(FragmentManager fm, List<Android.Support.V4.App.Fragment> fragments) : base(fm)
{
this.fragments = fragments;
}
public override ICharSequence GetPageTitleFormatted(int position)
{
return new String(Titles[position]);
}
//}
public override int Count { get { return fragments.Count; } }
public override Fragment GetItem(int position)
{
return fragments[position];
}
public override long GetItemId(int position)
{
return base.GetItemId(position);
}
}

You could do like below,suppose you need to call the replacement method in HomeFragment.
Add below codes in your MyPagerAdapter class (how to replace the fragment at runtime):
private bool[] flags;
public override int GetItemPosition(Java.Lang.Object #object)
{
return PositionNone;
}
public override Java.Lang.Object InstantiateItem(ViewGroup container, int position)
{
if (flags != null && flags[position])
{
/** Get the cached fragment and replace it with a new fragment*/
Android.Support.V4.App.Fragment fragment = (Android.Support.V4.App.Fragment)base.InstantiateItem(container, position);
string fragmentTag = fragment.Tag;
Android.Support.V4.App.FragmentTransaction ft = fm.BeginTransaction();
ft.Remove(fragment);
fragment = fragments[position];
ft.Add(container.Id, fragment, fragmentTag);
ft.Attach(fragment);
ft.Commit();
/** Set to false when the replacement is complete*/
flags[position] = false;
if (fragment != null)
{
return fragment;
}
else
{
return base.InstantiateItem(container, position);
}
}
else
{
return base.InstantiateItem(container, position);
}
}
public void setFragments(List<Android.Support.V4.App.Fragment> fragments)
{
if (this.fragments != null)
{
flags = new bool[fragments.Count];
for (int i = 0; i < fragments.Count; i++)
{
flags[i] = true;
}
}
this.fragments = fragments;
NotifyDataSetChanged();
}
then the replace method in your HomeFragment :
public void ReplaceFragment()
{
fragments[0] = new NewFragment(); //suppose you want to replace the first HourlyFragment
fragments[1] = new DayFragment();
adapter.setFragments(fragments);
}
in the other fragment(for example a click event),you could call the replace method which in the HomeFragment like :
private void Button_Click(object sender, EventArgs e)
{
foreach (Android.Support.V4.App.Fragment fragment in Activity.SupportFragmentManager.Fragments)
{
if (fragment is HomeFragment)
{
((HomeFragment)fragment).ReplaceFragment();
}
}
}

ViewPager : Navigating Back to Parent Fragment From Child Fragment Closes The Application

I am implementing nested fragments in a ViewPager. When I perform the transaction by replacing the child fragment in the parent fragment after executing addToBackStack(), I am able to see the view shown below. But when I press back button and the code reaches the MainActivity's onBackPressed() method, I notice the stack size is 1, and I successfully popout the Fragment. The problem starts now
My app closes and for a brief amount of time, I see my child fragment closing and then the app closing.
MainActivity
public class MainActivity extends FragmentActivity implements FragmentCommunicationListener {
ViewPager viewPager;
PagerAdapter pagerAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//createTabs();
viewPager = (ViewPager) findViewById(R.id.pager);
Fragment[] fragments = new Fragment[]{
new ViewStudentsFragment(),
new AddStudentFragment()
};
pagerAdapter = new PagerAdapter(getSupportFragmentManager(), this, fragments);
viewPager.setAdapter(pagerAdapter);
}
#Override
public void passMsg(Fragment fragment, Bundle msg) {
int currentItem = viewPager.getCurrentItem();
Fragment targetFragment;
if (currentItem == 0) {
targetFragment = getSupportFragmentManager().findFragmentByTag("android:switcher:" + R.id.pager + ":" + 1);
((AddStudentFragment) targetFragment).renderData(msg);
viewPager.setCurrentItem(1);
} else {
targetFragment = getSupportFragmentManager().findFragmentByTag("android:switcher:" + R.id.pager + ":" + 0);
((ViewStudentsFragment) targetFragment).updateList(msg,viewPager);
viewPager.setCurrentItem(0);
}
}
#Override
public void onBackPressed() {
ViewStudentsFragment fragment = (ViewStudentsFragment) getSupportFragmentManager().findFragmentByTag("android:switcher:" + R.id.pager + ":" + 0);
super.onBackPressed();
if (fragment.getChildFragmentManager().getBackStackEntryCount() != 0) {
fragment.getChildFragmentManager().popBackStack();
}
}
}
Parent Fragment
public class ViewStudentsFragment extends Fragment {
ArrayList<Student> studentList = new ArrayList<Student>();
ListView list;
ListViewAdapter listAdapter;
GridView grid;
FragmentCommunicationListener fragComm = null;
int resIdView, resIdSort;
GridViewAdapter gridAdapter;
static ImageButton toggleView, toggleSort;
View view;
ViewPager viewPager=null;
public ViewStudentsFragment() {
}
private static ViewStudentsFragment viewStudentsFragment;
FragmentTransaction transaction;
Fragment details ;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
view = inflater.inflate(R.layout.fragment_view_students, container, false);
toggleView = (ImageButton) view.findViewById(R.id.viewImageButton);
toggleSort = (ImageButton) view.findViewById(R.id.sortImageButton);
transaction= getChildFragmentManager().beginTransaction();
view.findViewById(R.id.container).setVisibility(View.GONE);
...
toggleView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
...
}
});
toggleSort.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
...
}
});
registerForContextMenu(list);
registerForContextMenu(grid);
return view;
}
public void updateList(Bundle bundle,ViewPager vp) {
viewPager=vp;
...
}
listAdapter.notifyDataSetChanged();
gridAdapter.notifyDataSetChanged();
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
if (activity instanceof FragmentCommunicationListener) {
fragComm = (FragmentCommunicationListener) activity;
} else {
throw new ClassCastException();
}
}
#Override
public void onCreateContextMenu(ContextMenu menu, View view, ContextMenu.ContextMenuInfo menuInfo) {
...
}
#Override
public boolean onContextItemSelected(MenuItem item) {
...
switch (menuItemIndex) {
case Constant.VIEW_STUDENT_DETAIL:
bundle.putSerializable("viewField", student); view.findViewById(R.id.container).setVisibility(View.VISIBLE);
transaction.addToBackStack(null);
details = new Details();
transaction.replace(R.id.container, details, "task");
transaction.commit();
details.setArguments(bundle);
break;
...
default:
}
listAdapter.setStudentList(studentList);
gridAdapter.setStudentList(studentList);
listAdapter.notifyDataSetChanged();
gridAdapter.notifyDataSetChanged();
return true;
}
}
ChildFragment
public class Details extends Fragment {
View view;
static Details details;
Context context;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
context=container.getContext();
Bundle bundle = getArguments();
view=inflater.inflate(R.layout.display_details, container, false);
...
return view;
}
#Override
public void onDetach() {
super.onDetach();
view.findViewById(R.id.displayDetails).setVisibility(View.GONE);
}
#Override
public void onDestroyView() {
super.onDestroyView();
view.findViewById(R.id.displayDetails).setVisibility(View.GONE);
}
#Override
public void setArguments(Bundle bundle) {
super.setArguments(bundle);
}
}
PagerAdapter
public class PagerAdapter extends FragmentPagerAdapter {
private String[] tabMenu;
private int pageCount;
private Context context;
private Fragment[] fragments;
public PagerAdapter(FragmentManager fm, Context context, Fragment[] fragments) {
super(fm);
this.context = context;
tabMenu = context.getResources().getStringArray(R.array.tab_menu);
pageCount = tabMenu.length;
this.fragments = fragments;
}
#Override
public Fragment getItem(int position) {
return fragments[position];
}
#Override
public int getCount() {
return fragments.length;
}
#Override
public CharSequence getPageTitle(int position) {
return tabMenu[position];
}
}

If you use FragmentTransaction.addToBackStack(), the back button is handled automatically for you.
When you do this:
#Override
public void onBackPressed() {
ViewStudentsFragment fragment = (ViewStudentsFragment) getSupportFragmentManager().findFragmentByTag("android:switcher:" + R.id.pager + ":" + 0);
super.onBackPressed();
if (fragment.getChildFragmentManager().getBackStackEntryCount() != 0) {
fragment.getChildFragmentManager().popBackStack();
}
}
you are basically popping the backstack twice, which is why your application quit.
Replace the onBackPressed() method in your Activity with this:
#Override
public void onBackPressed() {
ViewStudentsFragment fragment = (ViewStudentsFragment) getSupportFragmentManager().findFragmentByTag("android:switcher:" + R.id.pager + ":" + 0);
if (fragment.getChildFragmentManager().getBackStackEntryCount() != 0) {
fragment.getChildFragmentManager().popBackStack();
}
else {
super.onBackPressed();
}
}

Viewpager not working with fragment

My ViewPager is not working correctly. I don't know what's wrong with my code. I am facing some problems with my Fragments:
Basically, I have a Fragment named MyListFragment that has a list and on the click event of list item I move to the second Fragment named FlowersFragment that has a ViewPager with three items(Another three Fragments) in it. And i have a Button in my FlowersFragment and on click of that Button i move to the third screen named WelcomeFragment. now i have a problem :
If i go back to FlowersFragment from WelcomeFragment then it loses some Fragments from ViewPager after some research i got a solution like use childFragmentManager while creating adapter. That is good for my pager all Fragments are now showing correctly in my FlowersFragment Pager. But if I go back to MyListFragment and I click on second or third item of ListFragment its showing me exception with NO ACTIVITY.
Here is my FirstFragment named MyListFragment
public class MyListFragment extends Fragment{
private View view;
private FragmentManager fm;
private FragmentTransaction ft;
private ListView listviewPlaces;
private FloristAdapter adapter;
private ArrayList<FloristItems> items = new ArrayList<FloristItems>();
private FlowersFragment frag;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
inflater = LayoutInflater.from(getActivity());
view = inflater.inflate(R.layout.fragment_list, container,false);
listviewPlaces = (ListView)view.findViewById(R.id.listviewPlaces);
return view;
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
for (int i = 0; i < 10; i++) {
FloristItems florist = new FloristItems();
florist.away = "3 miles away";
florist.title = "Florist Flowers";
florist.price = "$45";
items.add(florist);
}
adapter = new FloristAdapter(getActivity().getApplicationContext(), items);
listviewPlaces.setAdapter(adapter);
listviewPlaces.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
if(frag == null){
frag = new FlowersFragment();
}
handleFragments(frag);
}
});
}
private void handleFragments(Fragment fragment){
fm = getActivity().getSupportFragmentManager();
ft = fm.beginTransaction();
ft.replace(R.id.frame_container, fragment);
ft.addToBackStack(null);
ft.commit();
}
}
Here is my FlowersFragment class that have view pager with containing three fragments:
public class FlowersFragment extends Fragment{
private View view;
private FragmentManager fm;
private FragmentTransaction ft;
private ViewPager pager;
private Button btnSendThatFlower;
private FlowerPagerAdapter pageAdapter;
private WelcomeFragment welcomeFrag;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
inflater = LayoutInflater.from(getActivity());
view = inflater.inflate(R.layout.fragment_choose_flower_buyer, container,false);
pager = (ViewPager)view.findViewById(R.id.viewpager);
btnSendThatFlower = (Button)view.findViewById(R.id.btnSendThatFlower);
return view;
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
pageAdapter = new FlowerPagerAdapter(getActivity().getSupportFragmentManager());
pager.setAdapter(pageAdapter);
btnSendThatFlower.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
if(welcomeFrag == null){
welcomeFrag = new WelcomeFragment();
}
handleFragments(welcomeFrag);
}
});
}
private void handleFragments(Fragment fragment){
fm = getActivity().getSupportFragmentManager();
ft = fm.beginTransaction();
ft.replace(R.id.frame_container, fragment);
ft.addToBackStack(null);
ft.commit();
} }
Here is my pager Adapter class:
public class FlowerPagerAdapter extends FragmentPagerAdapter{
private ArrayList<Fragment> pagerItems;
public FlowerPagerAdapter(FragmentManager fm) {
super(fm);
pagerItems = new ArrayList<Fragment>();
pagerItems.add(FlowerImage1.getInstance());
pagerItems.add(FlowerImage2.getInstance());
pagerItems.add(CustomFlowerFragment.getInstance());
}
#Override
public Fragment getItem(int num) {
if (num == 0) {
return new FlowerImage1();
}
else if(num == 1) {
return new FlowerImage2();
}
else{
return new CustomFlowerFragment.getInstance();
}
}
#Override
public int getCount() {
return pagerItems.size();
}
#Override
public void restoreState(Parcelable state, ClassLoader loader) {
//super.restoreState(state, loader);
}}
FlowerImage1 FlowerImage1 CustomFlowerFragment are fragments with only imageview.
This is my last fragment WelcomeFragment
public class WelcomeFragment extends Fragment{
private View view;
private FragmentManager fm;
private FragmentTransaction ft;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
inflater = LayoutInflater.from(getActivity());
view = inflater.inflate(R.layout.fragment_write_note_buyer, container,false);
return view;
}}
when i am pressing back press then its not showing fragments in viewpager but after swipe on view pager its showing only first or sometimes last pager fragment.

I have also faced same issue ended up adding following code inside fragment adapter.
#Override
public void restoreState(Parcelable state, ClassLoader loader) {
//super.restoreState(state, loader);
}

I was also faced with the same problem, but i fixed it by extending "FragmentStatePagerAdapter" instead of FragmentPagerAdapter. for your case,it would be:
public class FlowerPagerAdapter extends FragmentStatePagerAdapter{
private ArrayList<Fragment> pagerItems;
public FlowerPagerAdapter(FragmentManager fm) {
super(fm);
pagerItems = new ArrayList<Fragment>();
pagerItems.add(FlowerImage1.getInstance());
pagerItems.add(FlowerImage2.getInstance());
pagerItems.add(CustomFlowerFragment.getInstance());
}
#Override
public Fragment getItem(int num) {
if (num == 0) {
return new FlowerImage1();
}
else if(num == 1) {
return new FlowerImage2();
}
else{
return new CustomFlowerFragment.getInstance();
}
}
#Override
public int getCount() {
return pagerItems.size();
}
}

Facebook like dynamic viewpager

I am trying to create facebook like viewpager (swipable tabs and proper backstack) I can create swipable tabs but cant handle the proper back navigation. Bellow is my code
public class MainActivity extends FragmentActivity {
private ViewPager mPager;
// private SlidePagerAdapter mPagerAdapter;
private MyPagerAdapter mPagerAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
/* Instantiate a ViewPager and a PagerAdapter. */
mPager = (ViewPager) findViewById(R.id.pager);
mPagerAdapter = new MyPagerAdapter(getSupportFragmentManager());
mPager.setAdapter(mPagerAdapter);
mPager.setOffscreenPageLimit(4);
}
#Override
public void onBackPressed() {
Fragment currentVisibleFragment = mPagerAdapter.getRegisteredFragment(mPager.getCurrentItem());
if (currentVisibleFragment != null && currentVisibleFragment.isVisible()) {
FragmentManager childFm = currentVisibleFragment.getChildFragmentManager();
System.out.println("============================================");
System.out.println("childFm.getBackStackEntryCount()=== " + childFm.getBackStackEntryCount());
System.out.println("============================================");
if (childFm.getBackStackEntryCount() > 0) {
childFm.popBackStack();
return;
}
}
super.onBackPressed();
}
}
Adapter of my class is as bellow
public class MyPagerAdapter extends SmartFragmentStatePagerAdapter {
private static int NUM_ITEMS = 3;
public MyPagerAdapter(FragmentManager fragmentManager) {
super(fragmentManager);
}
// Returns total number of pages
#Override
public int getCount() {
return NUM_ITEMS;
}
// Returns the fragment to display for that page
#Override
public Fragment getItem(int position) {
switch (position) {
case 0: // Fragment # 0 - This will show FirstFragment
return new FragmentA();
case 1: // Fragment # 0 - This will show FirstFragment different title
return new FragmentB();
case 2: // Fragment # 1 - This will show SecondFragment
return new FragmentC();
default:
return null;
}
}
// Returns the page title for the top indicator
#Override
public CharSequence getPageTitle(int position) {
return "Page " + position;
}
}
here is the exteded adapter
public abstract class SmartFragmentStatePagerAdapter extends FragmentStatePagerAdapter {
// Sparse array to keep track of registered fragments in memory
private SparseArray<Fragment> registeredFragments = new SparseArray<Fragment>();
public SmartFragmentStatePagerAdapter(FragmentManager fragmentManager) {
super(fragmentManager);
}
// Register the fragment when the item is instantiated
#Override
public Object instantiateItem(ViewGroup container, int position) {
Fragment fragment = (Fragment) super.instantiateItem(container, position);
registeredFragments.put(position, fragment);
return fragment;
}
// Unregister when the item is inactive
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
registeredFragments.remove(position);
super.destroyItem(container, position, object);
}
// Returns the fragment for the position (if instantiated)
public Fragment getRegisteredFragment(int position) {
return registeredFragments.get(position);
}
}
and Fragments are as bellow
public class FragmentA extends Fragment {
public static final String TAG = "FragmentA";
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.first_fragment, container, false);
Button btn = (Button) view.findViewById(R.id.btn);
btn.setText(TAG);
btn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
FragmentTransaction trans = getChildFragmentManager().beginTransaction();
/*
* IMPORTANT: We use the "root frame" defined in
* "root_fragment.xml" as the reference to replace fragment
*/
trans.replace(R.id.framelayout_infragment_one, new FragmentA1());
/*
* IMPORTANT: The following lines allow us to add the fragment
* to the stack and return to it later, by pressing back
*/
trans.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
trans.addToBackStack(null);
trans.commit();
}
});
return view;
}
}
public class FragmentA1 extends Fragment {
public static final String TAG = "FragmentA1";
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.first_fragment, container, false);
view.setBackgroundColor(Color.RED);
Button btn = (Button) view.findViewById(R.id.btn);
btn.setText(TAG);
btn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
FragmentTransaction trans = getChildFragmentManager().beginTransaction();
/*
* IMPORTANT: We use the "root frame" defined in
* "root_fragment.xml" as the reference to replace fragment
*/
trans.replace(R.id.framelayout_infragment_one, new FragmentA2());
/*
* IMPORTANT: The following lines allow us to add the fragment
* to the stack and return to it later, by pressing back
*/
trans.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
trans.addToBackStack(null);
trans.commit();
}
});
return view;
}
}
//second inner fragment
public class FragmentA2 extends Fragment {
public static final String TAG = "FragmentA2";
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.second_fragment, container, false);
view.setBackgroundColor(Color.GRAY);
Button btn = (Button) view.findViewById(R.id.btn);
btn.setText(TAG);
btn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
FragmentTransaction trans = getFragmentManager().beginTransaction();
trans.replace(R.id.root_frame, new FragmentC());
trans.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
trans.addToBackStack(null);
trans.commit();
}
});
return view;
}
}
When I am going to frament A2 expected behaviour when user press back is I want to go to Frament A1 but I am going to Frament A. Fragment B,B1,B2 are same as A A1 A2 resp...
Please help

I managed it by maintaining stacks by myself
public static HashMap<String, Stack<Fragment>> mStacks;
mStacks = new HashMap<String, Stack<Fragment>>();
mStacks.put("TAB1", new Stack<Fragment>());
mStacks.put("TAB2", new Stack<Fragment>());
mStacks.put("TAB3", new Stack<Fragment>());
mStacks.put("TAB4", new Stack<Fragment>());
//when starting new fragment add that to stack like this
public void pushFragments(Fragment fragment) {
setSelectedPageN(pager.getCurrentItem());
mStacks.get(ApplicationConstants.CURRENT_TAB).push(fragment);
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction ft = manager.beginTransaction();
if (ApplicationConstants.CURRENT_TAB.equals("TAB1")) {
ft.replace(R.id.container_feed, fragment);
} else if (ApplicationConstants.CURRENT_TAB.equals("TAB2")) {
ft.replace(R.id.container_chart, fragment);
} else if (ApplicationConstants.CURRENT_TAB.equals("TAB3")) {
ft.replace(R.id.container_explore, fragment);
} else if (ApplicationConstants.CURRENT_TAB.equals("TAB4")) {
ft.replace(R.id.container_profile, fragment);
}
ft.commit();
}
//When you want to finish
public void popFragments() {
/*
* Select the second last fragment in current tab's stack.. which will
* be shown after the fragment transaction given below
*/
setSelectedPageN(pager.getCurrentItem());
Fragment fragment = mStacks.get(ApplicationConstants.CURRENT_TAB).elementAt(mStacks.get(ApplicationConstants.CURRENT_TAB).size() - 2);
if (fragment instanceof ProfileContainerFragment) {
fragment = new ProfileFragment();
} else if (fragment instanceof FeedNewUserGuideline && !isShowFeedTutorial) {
fragment = new FeedFragment();
}
/* pop current fragment from stack.. */
mStacks.get(ApplicationConstants.CURRENT_TAB).pop();
/*
* We have the target fragment in hand.. Just show it.. Show a standard
* navigation animation
*/
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction ft = manager.beginTransaction();
ft.setCustomAnimations(R.anim.abc_fade_in, R.anim.abc_fade_out);
if (ApplicationConstants.CURRENT_TAB.equals(ApplicationConstants.TAB_FEED)) {
ft.replace(R.id.container_feed, fragment);
} else if (ApplicationConstants.CURRENT_TAB.equals(ApplicationConstants.TAB_CHART)) {
ft.replace(R.id.container_chart, fragment);
} else if (ApplicationConstants.CURRENT_TAB.equals(ApplicationConstants.TAB_EXPLORE)) {
ft.replace(R.id.container_explore, fragment);
} else if (ApplicationConstants.CURRENT_TAB.equals(ApplicationConstants.TAB_PROFILE)) {
ft.replace(R.id.container_profile, fragment);
}
ft.commit();
}
//When user back press
#Override
public void onBackPressed() {
try {
if (((BaseFragment) mStacks.get(ApplicationConstants.CURRENT_TAB).lastElement()).onBackPressed() == false) {
switch (pager.getCurrentItem()) {
case KeyConstants.POSITION_ONE_FEED:
if (mStacks.get(ApplicationConstants.TAB_FEED).size() == 1) {
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
this.finish();
// super.onBackPressed(); // or call finish..
} else {
popFragments();
}
break;
case KeyConstants.POSITION_TWO_CHART:
if (mStacks.get(ApplicationConstants.TAB_CHART).size() == 1) {
pager.setCurrentItem(KeyConstants.POSITION_ONE_FEED);
} else {
popFragments();
}
break;
case KeyConstants.POSITION_THREE_EXPLORE:
if (mStacks.get(ApplicationConstants.TAB_EXPLORE).size() == 1) {
pager.setCurrentItem(KeyConstants.POSITION_TWO_CHART);
} else {
popFragments();
}
break;
case KeyConstants.POSITION_FOUR_PROFILE:
if (mStacks.get(ApplicationConstants.TAB_PROFILE).size() == 1) {
pager.setCurrentItem(KeyConstants.POSITION_THREE_EXPLORE);
} else {
popFragments();
}
break;
default:
break;
}
} else {
// do nothing.. fragment already handled back button press.
}
} catch (Exception e) {
e.printStackTrace();
}
}

Replace one Fragment with another in ViewPager

I'm having some problems when I try to replace one Fragment with another one in a ViewPager.
Current situation
I have a ViewPager with 3 pages, each one is a Fragment. In first page, I have a ListView inside a ListFragment ("FacturasFragment"). When I click on an item of that list, I use onListItemClick method for handle that event.
What I want
When list item is clicked, I want to replace ListFragment (contains a list of invoices) with another Fragment ("DetallesFacturaFragment", contains details of invoice).
When I'm in "DetallesFacturaFragment" and press Back Button, should return to ListFragment.
Scrolling between pages should not change Fragment displayed in first one. It is, if I'm in first page with "DetallesFacturaFragment" and scroll to second page, when return to first one should continue displaying "DetallesFacturaFragment".
Code
FragmentActivity
public class TabsFacturasActivity extends SherlockFragmentActivity {
private MyAdapter mAdapter;
private ViewPager mPager;
private PageIndicator mIndicator;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_pager);
mAdapter = new MyAdapter(getSupportFragmentManager());
mPager = (ViewPager)findViewById(R.id.pager);
mPager.setAdapter(mAdapter);
mIndicator = (TitlePageIndicator)findViewById(R.id.indicator);
mIndicator.setViewPager(mPager);
}
private static class MyAdapter extends FragmentPagerAdapter {
private String[] titles = { "VER FACTURAS", "VER CONSUMO", "INTRODUCIR LECTURA" };
private final FragmentManager mFragmentManager;
private Fragment mFragmentAtPos0;
private Context context;
public MyAdapter(FragmentManager fragmentManager) {
super(fragmentManager);
mFragmentManager = fragmentManager;
}
#Override
public CharSequence getPageTitle(int position) {
return titles[position];
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0: // Fragment # 0
return new FacturasFragment();
case 1: // Fragment # 1
return new ConsumoFragment();
case 2:// Fragment # 2
return new LecturaFragment();
}
return null;
}
#Override
public int getCount() {
return titles.length;
}
#Override
public int getItemPosition(Object object)
{
if (object instanceof FacturasFragment && mFragmentAtPos0 instanceof DetallesFacturaFragment)
return POSITION_NONE;
return POSITION_UNCHANGED;
}
}
}
ListFragment
public class FacturasFragment extends ListFragment {
private ListView lista;
private ArrayList<TuplaFacturaWS> facturas;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRetainInstance(true);
}
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
{
View view = inflater.inflate(R.layout.activity_facturas, container, false);
facturas = myApplication.getFacturas();
lista = (ListView) view.findViewById(id.list);
MyAdapter myAdaptador = new MyAdapter(this, facturas);
setListAdapter(myAdaptador);
return view;
}
public void onListItemClick (ListView l, View v, int position, long id) {
myApplication.setFacturaActual(position);
mostrarDatosFactura();
}
private void mostrarDatosFactura() {
final DetallesFacturaFragment fragment = new DetallesFacturaFragment();
FragmentTransaction transaction = null;
transaction = getFragmentManager().beginTransaction();
transaction.replace(R.id.pager, fragment); //id of ViewPager
transaction.addToBackStack(null);
transaction.commit();
}
private class MyAdapter extends BaseAdapter {
private final FacturasFragment actividad;
private final ArrayList<TuplaFacturaWS> facturas;
public MyAdapter(FacturasFragment facturasActivity, ArrayList<TuplaFacturaWS> facturas) {
super();
this.actividad = facturasActivity;
this.facturas = facturas;
}
#Override
public View getView(int position, View convertView,
ViewGroup parent) {
LayoutInflater inflater = actividad.getLayoutInflater(null);
View view = inflater.inflate(R.layout.list_row, null, true);
//Set data to view
return view;
}
#Override
public int getCount() {
return facturas.size();
}
#Override
public Object getItem(int pos) {
return facturas.get(pos);
}
#Override
public long getItemId(int position) {
return position;
}
private OnClickListener checkListener = new OnClickListener()
{
#Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
}
};
}
}
Fragment
public class DetallesFacturaFragment extends SherlockFragment {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRetainInstance(true);
}
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
{
View view = inflater.inflate(R.layout.activity_factura, container, false);
//Set data to view
return view;
}
}
At the moment, when I click on list item, white view appears in first page. I've verified and onCreateView method of "DetallesFacturaFragment" is executed, but nothing appears on that page.
And first time I click on list item, it shows that white screen. But after coming back to list, I have to click twice to a list item for showing white screen.
I've been googling and looking at some many questions but couldn't find anyone solved with completed code.

After so many hours spent, I've found correct solution modifying code in that answer.
It replaces Fragment in first page of ViewPager with another one, and if you return back from second Fragment, first Fragment is correctly displayed. Doesn't matter Fragment displayed in first page, if you swipe from one page to another, it doesn't change its Fragment.
Here is my code:
FragmentActivity
public class TabsFacturasActivity extends SherlockFragmentActivity {
public void onBackPressed() {
if(mPager.getCurrentItem() == 0) {
if (mAdapter.getItem(0) instanceof DetallesFacturaFragment) {
((DetallesFacturaFragment) mAdapter.getItem(0)).backPressed();
}
else if (mAdapter.getItem(0) instanceof FacturasFragment) {
finish();
}
}
}
private static class MyAdapter extends FragmentPagerAdapter {
private final class FirstPageListener implements
FirstPageFragmentListener {
public void onSwitchToNextFragment() {
mFragmentManager.beginTransaction().remove(mFragmentAtPos0)
.commit();
if (mFragmentAtPos0 instanceof FacturasFragment){
mFragmentAtPos0 = new DetallesFacturaFragment(listener);
}else{ // Instance of NextFragment
mFragmentAtPos0 = new FacturasFragment(listener);
}
notifyDataSetChanged();
}
}
private String[] titles = { "VER FACTURAS", "VER CONSUMO", "INTRODUCIR LECTURA" };
private final FragmentManager mFragmentManager;
public Fragment mFragmentAtPos0;
private Context context;
FirstPageListener listener = new FirstPageListener();
public MyAdapter(FragmentManager fragmentManager) {
super(fragmentManager);
mFragmentManager = fragmentManager;
}
#Override
public CharSequence getPageTitle(int position) {
return titles[position];
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0: // Fragment # 0
if (mFragmentAtPos0 == null)
{
mFragmentAtPos0 = new FacturasFragment(listener);
}
return mFragmentAtPos0;
case 1: // Fragment # 1
return new ConsumoFragment();
case 2:// Fragment # 2
return new LecturaFragment();
}
return null;
}
#Override
public int getCount() {
return titles.length;
}
#Override
public int getItemPosition(Object object)
{
if (object instanceof FacturasFragment &&
mFragmentAtPos0 instanceof DetallesFacturaFragment) {
return POSITION_NONE;
}
if (object instanceof DetallesFacturaFragment &&
mFragmentAtPos0 instanceof FacturasFragment) {
return POSITION_NONE;
}
return POSITION_UNCHANGED;
}
}
}
FirstPageFragmentListener
public interface FirstPageFragmentListener {
void onSwitchToNextFragment();
}
FacturasFragment (FirstFragment)
public class FacturasFragment extends ListFragment implements FirstPageFragmentListener {
static FirstPageFragmentListener firstPageListener;
public FacturasFragment() {
}
public FacturasFragment(FirstPageFragmentListener listener) {
firstPageListener = listener;
}
public void onListItemClick (ListView l, View v, int position, long id) {
firstPageListener.onSwitchToNextFragment();
}
}
DetallesFacturaFragment (SecondFragment)
public class DetallesFacturaFragment extends SherlockFragment {
static FirstPageFragmentListener firstPageListener;
public DetallesFacturaFragment() {
}
public DetallesFacturaFragment(FirstPageFragmentListener listener) {
firstPageListener = listener;
}
public void backPressed() {
firstPageListener.onSwitchToNextFragment();
}
}

To solve minor issue that Android suggest not using non-default constructor for fragment. You should change the constructor to something like this:
in FacturasFragment :
public static FacturasFragment createInstance(FirstPageFragmentListener listener) {
FacturasFragment facturasFragment = new FacturasFragment();
facturasFragment.firstPageListener = listener;
return facturasFragment;
}
Then you can call it from getItem function like this :
mFragmentAtPos0 = FacturasFragment.createInstance(listener);
in DetallesFacturaFragment :
public static DetallesFacturaFragment createInstance(FirstPageFragmentListener listener) {
DetallesFacturaFragment detallesFacturaFragment= new DetallesFacturaFragment();
detallesFacturaFragment.firstPageListener = listener;
return detallesFacturaFragment;
}
Then you can call it from FirstPageListener.onSwitchToNextFragment() function like this :
mFragmentAtPos0 = DetallesFacturaFragment.createInstance(listener);

I found two ways to replace fragment in viewpager.
Way 1: By updating ViewPagerAdapter
Way 2: By using a root fragment
Way1:
In this way, we need to update the fragment from viewpager adapter's fragment list and notify the fragment about the change.
For example:
private void changefragment(int position) {
Fragment newFragment = CategoryPostFragment.newInstance();
adapter.fragments.set(position, newFragment);
adapter.notifyDataSetChanged();
viewPager.setCurrentItem(position);
}
Here is the viewpager adapter code for this
import java.util.List;
import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentPagerAdapter;
import androidx.fragment.app.FragmentStatePagerAdapter;
import androidx.viewpager.widget.PagerAdapter;
import com.trickbd.trickbdapp.ui.activity.homeactivity.fragments.FavFragment;
import com.trickbd.trickbdapp.ui.activity.homeactivity.fragments.HomePostFragment;
public class ViewPagerAdapter extends FragmentStatePagerAdapter {
public List<Fragment> fragments;
public ViewPagerAdapter(FragmentManager manager, List<Fragment> fragments) {
super(manager);
this.fragments = fragments;
}
#NonNull
#Override
public Fragment getItem(int position) {
if (fragments.get(position)!=null){
return fragments.get(position);
}else {
if (position==0){
return new HomePostFragment();
}else {
return new FavFragment();
}
}
}
#Override
public int getCount() {
return fragments.size();
}
//method to add fragment
public void addFragment(Fragment fragment) {
fragments.add(fragment);
}
#Override
public int getItemPosition(#NonNull Object object) {
if (object instanceof FavFragment) {
return POSITION_UNCHANGED; // don't force a reload
} else {
// POSITION_NONE means something like: this fragment is no longer valid
// triggering the ViewPager to re-build the instance of this fragment.
return POSITION_NONE;
}
}
}
I was doing fine with this code. I become concerned when the super(manager) method of FragmentStatePagerAdapter deprecated in api 28.
When I use "super(manager,BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT);" along with first way of replacing fragment the application crash on runtime.
Also, there is a back draw that when we called adapter.notifydatasetchanged() from the viewpager adapter it's not efficient. It's recreating the whole viewpager while we are trying to change only a specific fragment.
So, way no 2 come with the solution of all problems.
Way 2:
Without adding the actual fragment to the viewpager we should add a root fragment to the viewpager. In root fragment there will be actual fragment added(previously we added in the viewpager. Then we can replace any fragment easily without the help of FragmentStatePagerAdapter.
Code of the root fragment:
Rootfragment.java
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import androidx.annotation.NonNull;
import androidx.fragment.app.FragmentTransaction;
import com.trickbd.trickbdapp.R;
import dagger.android.support.DaggerFragment;
public class RootFragment extends DaggerFragment {
public RootFragment() {
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(#NonNull LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.root_layout, container, false);
if (getFragmentManager() != null) {
FragmentTransaction transaction = getFragmentManager()
.beginTransaction();
transaction.replace(R.id.root_frame, new HomePostFragment());
transaction.commit();
}
return view;
}
}
root_layout.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/root_frame">
</FrameLayout>
So previous replacing code will be updated like below
private void changefragment(int position) {
Fragment newFragment = CategoryPostFragment.newInstance();
replacefragment(newFragment);
viewPager.setCurrentItem(position);
}
public void replacefragment(Fragment fragment){
getSupportFragmentManager();
FragmentTransaction trans = getSupportFragmentManager()
.beginTransaction();
trans.replace(R.id.root_frame, fragment);
trans.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
trans.addToBackStack(null);
trans.commit();
}
By this way, we can replace the fragment more efficiently.
To get the currently added fragment in rootfragment we may use this code.
if (getSupportFragmentManager().findFragmentById(R.id.root_frame) instanceof HomePostFragment){
HomePostFragment postFragment = (HomePostFragment) getSupportFragmentManager().findFragmentById(R.id.root_frame);
}
You may learn more about this here