Develop Reference

Clear data of fragments in ViewPager with each swipe

#Override
public void onViewDetachedFromWindow(#NonNull FragmentViewHolder holder) {
super.onViewDetachedFromWindow(holder);
}
I have many independent EditText with different id in each fragments of viewpager. For each swipe I want to clear these EditText and make them default.
I can clear text using:
holder.itemview.findViewById(R.id.first).setText("something");
but it won't a clear text.
What should I do?
Edit: whole testing Code:
I prepare a test fragment. When I click button,it changes text in current fragment. When I swipe to second fragment, It should be cleared or changed into its default value at xml.
TestFragment
public class TestFragment extends Fragment {
private TestViewModel mViewModel;
private ViewPager2 mViewPager;
private Button btnTest;
public static TestFragment newInstance() {
return new TestFragment();
}
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container,
#Nullable Bundle savedInstanceState) {
View view=inflater.inflate(R.layout.test_fragment, container, false);
btnTest=(Button)view.findViewById(R.id.etTest);
return view;
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
mViewModel = ViewModelProviders.of(this).get(TestViewModel.class);
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mViewPager = view.findViewById(R.id.myPager);
mViewPager.setSaveFromParentEnabled(false);
mViewPager.setOffscreenPageLimit(1);
mViewPager.setAdapter(new ViewPagerAdapter(getChildFragmentManager(),getLifecycle()));
TabLayout tabLayout = view.findViewById(R.id.tabs);
new TabLayoutMediator(tabLayout, mViewPager,
new TabLayoutMediator.TabConfigurationStrategy() {
#Override
public void onConfigureTab(#NonNull TabLayout.Tab tab, int position) {
tab.setText(((ViewPagerAdapter)(mViewPager.getAdapter())).mFragmentNames[position]);//Sets tabs names as mentioned in ViewPagerAdapter fragmentNames array, this can be implemented in many different ways.
}
}
).attach();
tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
Fragment current=((ViewPagerAdapter)(mViewPager.getAdapter())).createFragment(tab.getPosition());//clear data here or below
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}});
btnTest.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
int cur=((ViewPagerAdapter)(mViewPager.getAdapter())).getCurrentPos();
switch (cur){
case 0:
Fragment current=((ViewPagerAdapter)(mViewPager.getAdapter())).createFragment(0);
TextView tF= current.getView().findViewById(R.id.first);
tF.setText("Clicked while 1");
break;
case 1:
Fragment current2=((ViewPagerAdapter)(mViewPager.getAdapter())).createFragment(1);
TextView tF2= current2.getView().findViewById(R.id.second);
tF2.setText("Clicked while 2");
break;
}
}
});
}
public class ViewPagerAdapter extends FragmentStateAdapter {
private int currentPos;
private final Fragment[] mFragments = new Fragment[] {
new FirstFragment(),
new SecondFragment(),
};
public final String[] mFragmentNames = new String[] {
"First",
"Second"
};
public ViewPagerAdapter(#NonNull FragmentManager fragmentManager, #NonNull Lifecycle lifecycle) {
super(fragmentManager, lifecycle);
}
#Override
public void onViewDetachedFromWindow(#NonNull FragmentViewHolder holder) {
super.onViewDetachedFromWindow(holder);
if(currentPos!=0){
TextView textView =(TextView)holder.itemView.findViewById(R.id.first);//clear data here or up
}
}
#Override
public int getItemCount() {
return mFragments.length;
}
#Override
public long getItemId(int position) {
this.setCurrentPos(position);
return super.getItemId(position);
}
public int getCurrentPos() {
return currentPos;
}
public void setCurrentPos(int currentPos) {
this.currentPos = currentPos;
}
#NonNull
#Override
public Fragment createFragment(int position) {
return mFragments[position];
}
}}
I can handle on onViewDetachedFromWindow or onTabUnselected. Both can change view.
First Fragment
public class FirstFragment extends Fragment {
private View mLeak;
private TextView tvTest;
public FirstFragment() {
}
public static FirstFragment newInstance(String param1, String param2) {
FirstFragment fragment = new FirstFragment();
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
mLeak = inflater.inflate(R.layout.fragment_first, container, false);
tvTest=mLeak.findViewById(R.id.first);
return mLeak;
}
#Override
public void onDetach() {
super.onDetach();
mLeak=null;
}}

Approach 1:
Set this line on your viewpager :
viewPager.setOffscreenPageLimit(1);
This will simply refresh each fragment again when it's loaded.
Approach 2:
Create an interface and implement it on each fragment. In your activity/fragment where viewpager is defined, use "addOnPageChangeListener" on viewpager, and when the different page is selected, simply use the interface to get back the fragment instance and call the required methods in the fragment, to clear/change the text.
Code :
//Your Activity
class HomeActivity extends Activity{
...Methods...
public void setUpViewpager(){
//setup your viewpager
viewpager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {}
#Override
public void onPageSelected(int position) {
ChangeText fragment = (ChangeText) viewpager.getFragment(position);
fragment.changeText();
}
#Override
public void onPageScrollStateChanged(int state) {}
});
}
interface ChangeText{
void changeText();
}
}
//Your fragment
class FirstFragment extends Fragment implements HomeActivity.ChangeText{
...Methods...
public void changeText(){
//change the textview text here
}
}
class SecondFragment extends Fragment implements HomeActivity.ChangeText{
...Methods...
public void changeText(){
//change the textview text here
}
}

Can't change the tabItem ( program crashes ), when I delete one of my tabItems with code

I have an application in which I create TabItems dynamically and I add them to the TabLayout. I'll show you the code below. then I also have a mechanism that when a tabitem is created, the user can close it with a click of a button. NOW: the problem happens here. when the user deletes that tabitem and program automatically directs the user to another tab. I can no longer click on the other tabs that I created at the start of the application. I Can click on them, but the program closes with the error
java.lang.IllegalStateException: The application's PagerAdapter changed the adapter's contents without calling PagerAdapter#notifyDataSetChanged! Expected adapter item count: 4, found: 3 Pager
and all of this happens when I delete a tabitem with a code written for a click. below is my MainActivity.java code :
public class MainActivity extends AppCompatActivity implements ContactsFragment.CallBacks, UserDetailFragment.DetailCallBacks {
android.support.v7.widget.Toolbar toolbar;
public static List<Fragment> fragments = new ArrayList<>();
public static List<String> fragmentsTitle = new ArrayList<>();
ViewPager viewPager;
TabLayout tabLayout;
int tabposition_number;
public List<Fragment> getFragments() {
return fragments;
}
public List<String> getFragmentsTitle() {
return fragmentsTitle;
}
public void addToFragments(Fragment fragment) {
fragments.add(fragment);
}
public void addToFragmentsTitle(String title) {
fragmentsTitle.add(title);
}
public Fragment getFragmentsWithPosition(int position) {
return fragments.get(position);
}
public String getFragmentsTitleWithPosition(int position) {
return fragmentsTitle.get(position);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater menuInflater = new MenuInflater(this);
menuInflater.inflate(R.menu.top_main_menu,menu);
return super.onCreateOptionsMenu(menu);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
if(item.getItemId() == R.id.remove_tab) {
remove_tab_details(3);
}
return super.onOptionsItemSelected(item);
}
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_page_drawer);
this.tabLayout = findViewById(R.id.tab_layout);
this.viewPager = findViewById(R.id.view_pager);
tabLayout.setupWithViewPager(viewPager);
SetUpViewPager(viewPager);
this.toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
NavigationView navigationView = findViewById(R.id.navigation_view);
navigationView.setItemIconTintList(null);
tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener(){
#Override
public void onTabSelected(TabLayout.Tab tab) {
if(tab.getPosition() > 2) {
tabposition_number = tab.getPosition();
}
// viewPager.setCurrentItem(tab.getPosition());
if(tab.getPosition() == 1) {
toolbar.setBackgroundColor(ContextCompat.getColor(MainActivity.this,R.color.tab_contacts));
tabLayout.setBackgroundColor(ContextCompat.getColor(MainActivity.this,R.color.main_contacts));
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
getWindow().setStatusBarColor(ContextCompat.getColor(MainActivity.this,R.color.status_contacts));
}
} else if(tab.getPosition() == 2) {
toolbar.setBackgroundColor(ContextCompat.getColor(MainActivity.this,R.color.tab_register));
tabLayout.setBackgroundColor(ContextCompat.getColor(MainActivity.this,R.color.main_register));
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
getWindow().setStatusBarColor(ContextCompat.getColor(MainActivity.this,R.color.status_register));
}
} else {
toolbar.setBackgroundColor(ContextCompat.getColor(MainActivity.this,R.color.tab_signin));
tabLayout.setBackgroundColor(ContextCompat.getColor(MainActivity.this,R.color.main_signin));
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
getWindow().setStatusBarColor(ContextCompat.getColor(MainActivity.this,R.color.status_signin));
}
}
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
}
public void SetUpViewPager(ViewPager viewPager) {
MyViewPagerAdapter Adapter = new MyViewPagerAdapter((getSupportFragmentManager()));
Adapter.AddFragmentPage(new SignInFragment(),"ورود");
Adapter.AddFragmentPage(new ContactsFragment(),"ارتباطات");
Adapter.AddFragmentPage(new RegisterFragment(),"ثبت نام");
Adapter.notifyDataSetChanged();
viewPager.setAdapter(Adapter);
}
#Override
public void create_user_detail_tab(UserObject userObject) {
MyViewPagerAdapter Adapter = new MyViewPagerAdapter(getSupportFragmentManager());
UserDetailFragment userDetailFragment = new UserDetailFragment();
Bundle bundle = new Bundle();
bundle.putString("name",userObject.getName());
bundle.putString("family",userObject.getFamily());
bundle.putString("email",userObject.getEmail());
userDetailFragment.setArguments(bundle);
Adapter.AddFragmentPage(userDetailFragment,userObject.getName());
viewPager.setAdapter(Adapter);
TabLayout.Tab tab = tabLayout.getTabAt(1);
tab.select();
}
#Override
public void delete_previous_tab(int tabposition_number) {
remove_tab_details(tabposition_number);
MyViewPagerAdapter myViewPagerAdapter = new MyViewPagerAdapter(getSupportFragmentManager());
myViewPagerAdapter.notifyDataSetChanged();
}
#Override
public void changeTabItem(boolean mustdelete) {
ContactsFragment contactsFragment = new ContactsFragment();
if(tabposition_number > 2 && mustdelete) {
contactsFragment.setTextView(tabposition_number,mustdelete);
TabLayout.Tab tab = tabLayout.getTabAt(1);
tab.select();
}
}
public class MyViewPagerAdapter extends FragmentPagerAdapter {
public MyViewPagerAdapter(FragmentManager manager) {
super(manager);
}
public void removeTabPage(int position) {
fragments.remove(position);
fragmentsTitle.remove(position);
MyViewPagerAdapter myViewPagerAdapter = new MyViewPagerAdapter(getSupportFragmentManager());
myViewPagerAdapter.notifyDataSetChanged();
myViewPagerAdapter.notifyDataSetChanged();
}
public void AddFragmentPage(Fragment frag,String title) {
MainActivity.this.addToFragments(frag);
MainActivity.this.addToFragmentsTitle(title);
MyViewPagerAdapter myViewPagerAdapter = new MyViewPagerAdapter(getSupportFragmentManager());
myViewPagerAdapter.notifyDataSetChanged();
}
public Fragment getItem(int position) {
return MainActivity.this.getFragmentsWithPosition(position);
}
public CharSequence getPageTitle(int position) {
return MainActivity.this.getFragmentsTitleWithPosition(position);
}
public int getCount() {
return fragments.size();
}
}
public void remove_tab_details(int tab_to_delete) {
// TabLayout.Tab tab = tabLayout.getTabAt(2);
// tab.select();
tabLayout.removeTabAt(tab_to_delete);
MyViewPagerAdapter Adapter = new MyViewPagerAdapter(getSupportFragmentManager());
Adapter.removeTabPage(tab_to_delete);
Adapter.notifyDataSetChanged();
}
}
and the code for UserDetailFragment ( which creates when the user click on one of the items in a listview fragment .
public class UserDetailFragment extends Fragment {
View view;
DetailCallBacks detailCallBacks;
public UserDetailFragment() {}
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
view = inflater.inflate(R.layout.user_detail_fragment,null);
return view;
}
#Override
public void onResume() {
super.onResume();
final Bundle bundle = getArguments();
String name = (String) bundle.get("name");
String family = (String)bundle.get("family");
String email = (String)bundle.get("email");
TextView nameFamilytv = view.findViewById(R.id.user_detail_name_and_family);
String nameAndfamily = name + " " + family;
nameFamilytv.setText(nameAndfamily);
TextView emailtv = view.findViewById(R.id.user_detail_email);
emailtv.setText(email);
Button closebtn = view.findViewById(R.id.detail_close_button);
closebtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
detailCallBacks.changeTabItem(true);
}
});
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
detailCallBacks = (DetailCallBacks)context;
}
public interface DetailCallBacks {
public void changeTabItem(boolean mustdelete);
}
and last but not least : the code for that list item that creates dynamic tabs when user clicks on its items :
public class ContactsFragment extends ListFragment {
CallBacks callBacks;
View view;
public static int came_fromTabItem;
public static boolean do_delete;
public ContactsFragment() { }
ArrayList<UserObject> userObjects;
BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
userObjects = intent.getParcelableArrayListExtra(Intent_Service.SERVICE_PAYLOAD);
ArrayAdapter<UserObject> userObjectArrayAdapter = new UserArrayAdapter(context,0,userObjects);
setListAdapter(userObjectArrayAdapter);
}
};
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent intent = new Intent(getActivity(), Intent_Service.class);
getActivity().startService(intent);
LocalBroadcastManager.getInstance(getActivity().getApplicationContext()).
registerReceiver(broadcastReceiver,new IntentFilter(Intent_Service.SERVICE_MESSAGE));
}
public void setTextView(int position,Boolean mustDelete) {
came_fromTabItem = position;
do_delete = mustDelete;
}
#Override
public void onResume() {
super.onResume();
if(came_fromTabItem > 2 && do_delete) {
final Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
callBacks.delete_previous_tab(came_fromTabItem);
do_delete = false;
Toast.makeText(getActivity().getApplicationContext(),String.valueOf(came_fromTabItem),Toast.LENGTH_LONG).show();
}
}, 2000);
}
}
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
this.view = inflater.inflate(R.layout.fragment_contacts,null);
return this.view;
}
public void onListItemClick(ListView l, View v, int position, long id) {
UserObject userObject = userObjects.get(position);
callBacks.create_user_detail_tab(userObject);
}
public interface CallBacks {
public void create_user_detail_tab(UserObject userObject);
public void delete_previous_tab(int positions);
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
this.callBacks = (CallBacks)context;
}
}
So... can anyone help me please? the problem is simple, why the error The application's PagerAdapter changed the adapter's contents without calling PagerAdapter#notifyDataSetChanged! Expected adapter item count: 4, found: 3 appears when a tabitem is removed, how can I solve it?

the problem occur because you delete a tab item and your pager still has 4 in item count , you have to make pager item count dynamic , and call notifyDataSetChanged() after you remove an item
here is an example
public class MyPagerAdapter extends FragmentPagerAdapter {
int nbrItem;
public ProfilPagerAdapter(FragmentManager fm,String token,Int nbrItem) {
super(fm);
this.nbrItem= nbrItem;
}
#Override
public Fragment getItem(int position) {
switch(position) {
case 0 :
new SignInFragment();
case 1 :
new ContactsFragment()
case 2 :
new RegisterFragment()
}
return null;
}
#Override
public int getCount() {
return nbrItem;
}
public void setNbrItem(int nbrItem) {
this.nbrItem= nbrItem;
}
now when you remove an item you will pass to new number of item to your adapater
getAdapter().setNbrItem(2);
getAdapter().notifyDataSetChanged();

I solved my Problem, But with a hack, you see the error was because: TabItems are counting and indexing from 0, but as my pages are dynamically creating, I set the
getCount() method of my FragmentPagerAdapter to return the ArrayList<Fragment> fragments size , with fragments.size() , on the other hand, the size of an ArrayList doesn't count 0. so for 3 elements, instead of 0 1 2, or number 2, it returns to number 3.
so back to business, I was compelled to add null to my ArrayList and one null to my ArrayList titles, so this way when I removed my last TabItem, program doesn't crash anymore, and to be more convenient, when a user closes all Tabs , everytime user opens ( adds ) a new tab, I call fragments.removeAll(Collections.singleton(null)); to clear every null element i have inserted, for the TabTitles Too .
anyway cheers you guys, I'm sure this would be a good tutorial for those who want to create such applications because I've included all of my codes. please give a thumbs up. thanks.

in android how to put exit or close button on tabitems of an android tablayout

I have an android app with TabLayout , I create TabItems and assign them to my TabLayout Dynamically with code in my MainActivity , in one of my Fragments, which is the Fragment for a TabItem , i have a button . what I want is when that button is clicked, its TabItem closes and destroys, how can I achieve that?
extra explanation: bellow is my MainActivity.java Code ( where most of my code for creating dynamic TabItems exists :
public class MainActivity extends AppCompatActivity implements ContactsFragment.CallBacks {
public static List<Fragment> fragments = new ArrayList<>();
public static List<String> fragmentsTitle = new ArrayList<>();
ViewPager viewPager;
TabLayout tabLayout;
public List<Fragment> getFragments() {
return fragments;
}
public List<String> getFragmentsTitle() {
return fragmentsTitle;
}
public void addToFragments(Fragment fragment) {
fragments.add(fragment);
}
public void addToFragmentsTitle(String title) {
fragmentsTitle.add(title);
}
public Fragment getFragmentsWithPosition(int position) {
return fragments.get(position);
}
public String getFragmentsTitleWithPosition(int position) {
return fragmentsTitle.get(position);
}
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_page_drawer);
this.tabLayout = findViewById(R.id.tab_layout);
this.viewPager = findViewById(R.id.view_pager);
tabLayout.setupWithViewPager(viewPager);
SetUpViewPager(viewPager);
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
}
public void SetUpViewPager(ViewPager viewPager) {
MyViewPagerAdapter Adapter = new MyViewPagerAdapter((getSupportFragmentManager()));
Adapter.AddFragmentPage(new SignInFragment(),"ورود");
Adapter.AddFragmentPage(new ContactsFragment(),"ارتباطات");
Adapter.AddFragmentPage(new RegisterFragment(),"ثبت نام");
viewPager.setAdapter(Adapter);
}
#Override
public void send_user_object() {
/* this is the implementation of abstract function defined
in one of my tab , in which it has a button and when
button is clicked i want the tab to be removed . */
}
public class MyViewPagerAdapter extends FragmentPagerAdapter {
public MyViewPagerAdapter(FragmentManager manager) {
super(manager);
}
public void AddFragmentPage(Fragment frag,String title) {
MainActivity.this.addToFragments(frag);
MainActivity.this.addToFragmentsTitle(title);
}
public Fragment getItem(int position) {
return MainActivity.this.getFragmentsWithPosition(position);
}
public CharSequence getPageTitle(int position) {
return MainActivity.this.getFragmentsTitleWithPosition(position);
}
public int getCount() {
List<Fragment> frag = MainActivity.this.getFragments();
return frag.size();
}
}
}
in one of my predefined tabs , i have a listview , when user clickes on an item on the list view , the detail of the item opens in a new tab , then user can see the detail by clicking on that tab . what i want is how user can close ( destroy ) that detail tab about one of items ? ( remember it is creating dynamically )
how can I remove ( close ) the TabItem with Click of a Button in that TabItem Fragment?
Plase help me , thank you beforehand .

It's not a good practice to change horizontal navigation by adding another fragment. If it's not absolutely required by your customer, create a new fragment and just replace the current one like this:
Fragment detailsFragment=new ContactsFragment()
getSupportFragmentManager.beginTransaction()
.addToBackStack("tag")
.replace(R.id.containerName, detailsFragment, "another_tag")
.commit()
At your detailsFragment your close button's clickListener just call getActivity.getSupportFragmentManager.popBackStack()
and it restores previous state.
Hope I could help you.

I solved my problem by :
first ) creating an interface in the UserDetailFragment, which you all know for communication with MainActivity, I had to do that.
but for what did I need communicating with the MainActivity ?
Answer : as you see in my code , my FragmentPagerAdapter class is defined there , and i needed my public List<Fragment> fragments = new ArrayList<>(); and public static List<String> fragmentsTitle = new ArrayList<>(); that i had saved my fragments into them , and also mytabLayout.
Seconde ) i had to define tabLayout.addOnTabSelectedListener(){} with its method OnTabSelected() , i needed that because i get the current index of the tab using addOnTabSelectedListener(){} .
Third ) i defined removeTabPage(int position) in the FragmentPagerAdapter .
Forth ) i created a method as bellow ( which is the implementation of the abstract method of UserDetailFragment interface.
#Override
public void close_tabitem() {
tabLayout.removeTabAt(tabposition_number);
MyViewPagerAdapter Adapter = new MyViewPagerAdapter(getSupportFragmentManager());
Adapter.removeTabPage(tabposition_number);
Adapter.notifyDataSetChanged();
}
and here is my whole code for: MainActivity.Java
public class MainActivity extends AppCompatActivity implements ContactsFragment.CallBacks, UserDetailFragment.DetailCallBacks {
android.support.v7.widget.Toolbar toolbar;
public static List<Fragment> fragments = new ArrayList<>();
public static List<String> fragmentsTitle = new ArrayList<>();
ViewPager viewPager;
TabLayout tabLayout;
int tabposition_number;
public List<Fragment> getFragments() {
return fragments;
}
public List<String> getFragmentsTitle() {
return fragmentsTitle;
}
public void addToFragments(Fragment fragment) {
fragments.add(fragment);
}
public void addToFragmentsTitle(String title) {
fragmentsTitle.add(title);
}
public Fragment getFragmentsWithPosition(int position) {
return fragments.get(position);
}
public String getFragmentsTitleWithPosition(int position) {
return fragmentsTitle.get(position);
}
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_page_drawer);
this.tabLayout = findViewById(R.id.tab_layout);
this.viewPager = findViewById(R.id.view_pager);
tabLayout.setupWithViewPager(viewPager);
SetUpViewPager(viewPager);
this.toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
NavigationView navigationView = findViewById(R.id.navigation_view);
navigationView.setItemIconTintList(null);
tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener(){
#Override
public void onTabSelected(TabLayout.Tab tab) {
tabposition_number = tab.getPosition();
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
}
public void SetUpViewPager(ViewPager viewPager) {
MyViewPagerAdapter Adapter = new MyViewPagerAdapter((getSupportFragmentManager()));
Adapter.AddFragmentPage(new SignInFragment(),"ورود");
Adapter.AddFragmentPage(new ContactsFragment(),"ارتباطات");
Adapter.AddFragmentPage(new RegisterFragment(),"ثبت نام");
viewPager.setAdapter(Adapter);
}
#Override
public void send_user_object(UserObject userObject) {
// tabLayout.removeTabAt(tabposition_number);
// myViewPagerAdapter.remove
}
#Override
public void create_user_detail_tab(UserObject userObject) {
MyViewPagerAdapter Adapter = new MyViewPagerAdapter(getSupportFragmentManager());
UserDetailFragment userDetailFragment = new UserDetailFragment();
Bundle bundle = new Bundle();
bundle.putString("name",userObject.getName());
bundle.putString("family",userObject.getFamily());
bundle.putString("email",userObject.getEmail());
userDetailFragment.setArguments(bundle);
Adapter.AddFragmentPage(userDetailFragment,userObject.getName());
viewPager.setAdapter(Adapter);
}
#Override
public void close_tabitem() {
tabLayout.removeTabAt(tabposition_number);
MyViewPagerAdapter Adapter = new MyViewPagerAdapter(getSupportFragmentManager());
Adapter.removeTabPage(tabposition_number);
Adapter.notifyDataSetChanged();
}
public class MyViewPagerAdapter extends FragmentPagerAdapter {
public MyViewPagerAdapter(FragmentManager manager) {
super(manager);
}
public void removeTabPage(int position) {
fragments.remove(position);
fragmentsTitle.remove(position);
notifyDataSetChanged();
}
public void AddFragmentPage(Fragment frag,String title) {
MainActivity.this.addToFragments(frag);
MainActivity.this.addToFragmentsTitle(title);
}
public Fragment getItem(int position) {
return MainActivity.this.getFragmentsWithPosition(position);
}
public CharSequence getPageTitle(int position) {
return MainActivity.this.getFragmentsTitleWithPosition(position);
}
public int getCount() {
List<Fragment> frag = MainActivity.this.getFragments();
return frag.size();
}
}
}
and here is the UserDetailFragment.Java , which acts as my TabItem :
public class UserDetailFragment extends Fragment {
View view;
DetailCallBacks detailCallBacks;
public UserDetailFragment() {}
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
view = inflater.inflate(R.layout.user_detail_fragment,null);
return view;
}
#Override
public void onResume() {
super.onResume();
Button closebtn = view.findViewById(R.id.detail_close_button);
closebtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
detailCallBacks.close_tabitem();
}
});
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
detailCallBacks = (DetailCallBacks)context;
}
public interface DetailCallBacks {
public void close_tabitem();
}
}
Hope It Helps You.
But do remember, you can not use this button. put the button in some other tabitem or in the menu.
or you can use :
TabLayout.Tab tab = tabLayout.getTabAt(2);
tab.select();
to change the tabitem and then fire the event .
enjoy .....

Refresh Fragment View on Tab Change

Hello I'm implementing a dynamic TabLayout using a single fragment, i have manage to create the tabs so far but there is a problem using a single fragment. When im changing the tabs the fragment view is not updating repeatedly, although im updating the data in the fragment's onCreateView method based on the tab selection. I have a recyclerview in the that fragment which should change according to the tab selection. SO can anyone help me with it or do anyone have a better way of approach?
TabView Activity
public class SubCategory extends AppCompatActivity {
private Toolbar toolbar;
private TabLayout tabLayout;
private ViewPager viewPager;
Activity a;
String url;
List<CategoryEncapsulation> categories = new ArrayList<>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sub_category);
a=this;
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
viewPager = (ViewPager) findViewById(R.id.viewpager);
tabLayout = (TabLayout) findViewById(R.id.tabs);
categories=((MyshinzGlobal)getApplicationContext()).getCategoryList();
setupViewPager(viewPager);
((MyshinzGlobal)getApplicationContext()).setCategory_id(categories.get(0).getCategory_id());
}
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
try {
for (int i = 0; i < categories.size(); i++) {
try {
adapter.addFragment(new ListFragment(), categories.get(i).getCategory_name());
} catch (Exception e) {
e.printStackTrace();
}
}
}catch (Exception e) {
e.printStackTrace();
}
viewPager.setAdapter(adapter);
tabLayout.setupWithViewPager(viewPager);
viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
((MyshinzGlobal)getApplicationContext()).setCategory_id(categories.get(position).getCategory_id());
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
}
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
#Override
public int getItemPosition(Object object) {
return super.getItemPosition(object);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
}
Fragment class
public class ListFragment extends Fragment{
String category_id;
Activity a;
RecyclerView rv;
SubCategoryAdapter sca;
List<ParentListItem> parentListItems;
List<CategoryEncapsulation> categories = new ArrayList<>();
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View view =inflater.inflate(R.layout.sub_category_fragment, container, false);
a=getActivity();
categories=((MyshinzGlobal)a.getApplicationContext()).getCategoryList();
category_id=((MyshinzGlobal)a.getApplicationContext()).getCategory_id();
parentListItems= new ArrayList<>();
Toast.makeText(getActivity(), String.valueOf(category_id), Toast.LENGTH_SHORT).show();
rv= (RecyclerView) view.findViewById(R.id.recycler_view);
for (int i=0; i<categories.size();i++){
if(categories.get(i).getCategory_id().equals(category_id)){
parentListItems=categories.get(i).getParentListItems();
}
}
sca=new SubCategoryAdapter(a,parentListItems);
rv.setAdapter(sca);
rv.setLayoutManager(new LinearLayoutManager(a));
//new GetAllSubCategoryTask(a,url,"1001").execute();
return view;
}
}

I have two solution for this.
1) make your view pager offset limit 0. Which default 1. If you are switching another fragment which not in offset, that fragment re-creating.
viewPager.setOffscreenPageLimit(0);
2) Tell your adapter, fragment has been changed. So your adapter will re-create its views again.
rv.notifyDataSetChanged();
I hope these will solve your problem.

First thing as you are using ViewPager, onCreateView() of Fragment will be called only when getItem() of FragmentPagerAdapter will be called.
If need to create a method in Fragment which will call RecyclerView.notifyDataSetChanged().
Check out updated code for both classes
TabView Activity
public class SubCategory extends AppCompatActivity {
//....
#Override
protected void onCreate(Bundle savedInstanceState) {
//...
}
private void setupViewPager(ViewPager viewPager) {
//...
viewPager.setAdapter(adapter);
tabLayout.setupWithViewPager(viewPager);
viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
((MyshinzGlobal)getApplicationContext()).setCategory_id(categories.get(position).getCategory_id());
adapter.getItem(position).listUpdated();
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
}
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<ListFragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public ListFragment getItem(int position) {
return mFragmentList.get(position);
}
//...
}
}
Fragment class
public class ListFragment extends Fragment {
//...
public void listUpdated() {
for (int i = 0; i < categories.size(); i++) {
if (categories.get(i).getCategory_id().equals(category_id)) {
parentListItems.clear();
parentListItems.addAll(categories.get(i).getParentListItems());
}
}
sca.notifyDataSetChanged();
}
}

Sliding Tabs to load XML Data using RecyclerView Adapter is not displaying content properly

I have been working on an app to take the blog feed and parse and display it in the app using the Recycler and Card View. I got to the point of adding sliding tabs to display articles in each of the categories in the site in separate tabs. I parse the feed using the category URL and am able to display it using the same Recycler view adapter.
Here comes the problem, as I swipe through the tabs quickly, the content doesn't load in some cases. In some cases, I get articles from one category displayed in another category's tab.
Below is the code for my Tabs fragment:
public class TabsFragment extends Fragment {
ViewPager mViewPager;
ViewPagerAdapter mAdapter;
SlidingTabLayout mSlidingTabLayout;
CharSequence Titles[] = {"Home", "Events", "Category", "Bookmarks", "News"};
int NoOfTabs = 5;
private ProgressBar mProgressBar;
private RecyclerView mRecyclerView;
private MyRecyclerViewAdapter myRecyclerViewAdapter;
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.activity_tabs, container, false);
}
#Override
public void onViewCreated(View view, #Nullable Bundle savedInstanceState) {
mAdapter = new ViewPagerAdapter(Titles, NoOfTabs);
mProgressBar = (ProgressBar) view.findViewById(R.id.loading_spinner);
mViewPager = (ViewPager) view.findViewById(R.id.pager);
mViewPager.setAdapter(mAdapter);
mSlidingTabLayout = (SlidingTabLayout) view.findViewById(R.id.tabs);
mSlidingTabLayout.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
#Override
public int getIndicatorColor(int position) {
return getResources().getColor(R.color.secondaryBackgroundColor);
}
#Override
public int getDividerColor(int position) {
return getResources().getColor(R.color.secondaryBackgroundColor);
}
});
mSlidingTabLayout.setViewPager(mViewPager);
}
public class ViewPagerAdapter extends PagerAdapter {
CharSequence mTitles[];
int mNoOfTabs;
public ViewPagerAdapter(CharSequence[] titles, int noOfTabs) {
mTitles = titles;
mNoOfTabs = noOfTabs;
}
public CharSequence getPageTitle(int position) {
return mTitles[position];
}
#Override
public int getCount() {
return mNoOfTabs;
}
#Override
public Object instantiateItem(ViewGroup container, int position) {
View view = getActivity().getLayoutInflater().inflate(R.layout.pager_item_articles,
container, false);
container.addView(view);
ProcessArticles processArticles;
processArticles = new ProcessArticles(null, mTitles[position]);
processArticles.execute();
mRecyclerView = (RecyclerView) view.findViewById(R.id.recycler_view);
mRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity().getApplicationContext()));
myRecyclerViewAdapter = new MyRecyclerViewAdapter(new ArrayList<Article>(),
getActivity().getApplicationContext());
mRecyclerView.setAdapter(myRecyclerViewAdapter);
return view;
}
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView((View) object);
}
#Override
public boolean isViewFromObject(View view, Object object) {
return object == view;
}
}
public class ProcessArticles extends GetXmlData {
public ProcessArticles(String searchCriteria, String category) {
super(searchCriteria, category);
}
#Override
public void execute() {
super.execute();
ProcessData processData = new ProcessData();
processData.execute();
}
public class ProcessData extends DownloadXmlData {
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
ParseArticles parseArticles = new ParseArticles(getData());
boolean operationStatus = parseArticles.process();
if (operationStatus) {
ArrayList<Article> allArticles = parseArticles.getArticles();
myRecyclerViewAdapter.loadNewData(allArticles);
} else {
Toast.makeText(getActivity().getApplicationContext(), "Error establishing correction.", Toast.LENGTH_SHORT).show();
Log.d("MainActivity", "Error establishing correction.");
}
}
}
}
}
The code for the activity displaying the tabs is:
public class TabsActivity extends BaseActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_tabs);
activateToolbarWithHomeEnabled();
if (savedInstanceState == null) {
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
TabsFragment fragment = new TabsFragment();
transaction.replace(R.id.tab_content_frame, fragment);
transaction.commit();
}
}
}
How do I separate the content according to category in the tabs? I have tried to reduce the amount of code, so, I have used the same Recycler adapter. Is there any solution to this problem? Or should I change the method of implementation? I am looking to implement something like the Play Newsstand app.