I have a TabLayout and inside that I have ViewPager. I need to dynamically add and remove tab in tablayout(material design). I can able to add the tabs dynamically but while removing the tab, tab is removing correctly. But viewpager last item is deleted. So tab is not showing specific fragment. FYI i have used FragmentPagerAdapter.
I have followed this tutorial to implement this
https://androidbelieve.com/navigation-drawer-with-swipe-tabs-using-design-support-library
public class TabFragment extends Fragment {
public static TabLayout tabLayout;
public static ViewPager viewPager;
public static int int_items = 2;
private MyNewsFragment mMyNewsFragment;
private ArrayList<TabFragmentModelClass> mFragmentArrayList;
private TabLayoutAdapter mTabLayoutAdapter;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
mMyNewsFragment = new MyNewsFragment();
/**
*Inflate tab_layout and setup Views.i;;a
*/
View x = inflater.inflate(R.layout.tab_layout, null);
tabLayout = (TabLayout) x.findViewById(R.id.tabs);
tabLayout.setTabMode(TabLayout.MODE_SCROLLABLE); // scorllable tab
tabLayout.setTabGravity(TabLayout.GRAVITY_FILL); // tab name fill parent
viewPager = (ViewPager) x.findViewById(R.id.viewpager);
mFragmentArrayList = new ArrayList<>();
mFragmentArrayList.add(new TabFragmentModelClass(new MyNewsSelectionFragment(), "", ""));
mFragmentArrayList.add(new TabFragmentModelClass(mMyNewsFragment, "", getResources().getString(R.string.mynews)));
mFragmentArrayList.add(new TabFragmentModelClass(new BreakingNewsFragment(), "", getResources().getString(R.string.breakingnews)));
// Selected news from shared preference
ArrayList<MyNewsSharedPreferenceModelClass> tempSharedPreferenceModelClass = new MyNewsSharedPreferenceClass().loadFavorites(getActivity());
for (int i = 0; i < tempSharedPreferenceModelClass.size(); i++) {
mFragmentArrayList.add(new TabFragmentModelClass(new CategoreyNewsFragment(tempSharedPreferenceModelClass.get(i).getmCatID()), tempSharedPreferenceModelClass.get(i).getmCatID(),
tempSharedPreferenceModelClass.get(i).getmCatName()));
}
}
/**
*Set an Apater for the View Pager
*/
mTabLayoutAdapter = new TabLayoutAdapter(getChildFragmentManager(), mFragmentArrayList);
viewPager.setAdapter(mTabLayoutAdapter);
viewPager.setOffscreenPageLimit(mFragmentArrayList.size());
tabLayout.setupWithViewPager(viewPager);
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
tabLayout.getTabAt(position);
}
@Override
public void onPageScrollStateChanged(int state) {
if (state == 1) {
updateMyNewsFragment();
}
}
});
/**
* Now , this is a workaround ,
* The setupWithViewPager dose't works without the runnable .
* Maybe a Support Library Bug .
*/
tabLayout.post(new Runnable() {
@Override
public void run() {
tabLayout.getTabAt(0).setIcon(R.mipmap.mynewselection);
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
@Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
switch (tab.getPosition()) {
case 1:
System.out.println("000000000000000000000 ");
updateMyNewsFragment();
break;
}
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
}
});
return x;
}
/**
* update the mynews selection
* this method trigger from the MainNewsActivity
*/
public void updateMyNewsFragment() {
if (ApplicationController.getInstance().getBoolPref(CommonVariableInterFace.isNewsSelected)) {
mMyNewsFragment.sendMyNewsRequest();
ApplicationController.getInstance().setBoolPref(CommonVariableInterFace.isNewsSelected, false);
}
}
/**
* update the tab values
* this method trigger from the MainNewsActivity
* if value is zero need to add in tab
* if value is one need to remove in tab
*/
public void updateTabvalue(String catId, String catName, int value) {
if (value == 0) { // add the value in tab
mFragmentArrayList.add(new TabFragmentModelClass(new CategoreyNewsFragment(catId), catId,
catName));
} else { // Removing the tab
for (int i = 0; i < mFragmentArrayList.size(); i++) {
if (mFragmentArrayList.get(i).getmCatID().equalsIgnoreCase(catId)) {
Log.i("-----same id ", catId);
mFragmentArrayList.remove(i);
mTabLayoutAdapter = new TabLayoutAdapter(getChildFragmentManager(), mFragmentArrayList);
viewPager.setAdapter(mTabLayoutAdapter);
}
}
}
mTabLayoutAdapter.notifyDataSetChanged();
viewPager.setOffscreenPageLimit(mFragmentArrayList.size());
tabLayout.getTabAt(0).setIcon(R.mipmap.mynewselection);
tabLayout.setupWithViewPager(viewPager);
tabLayout.post(new Runnable() {
@Override
public void run() {
tabLayout.getTabAt(0).setIcon(R.mipmap.mynewselection);
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
@Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
switch (tab.getPosition()) {
case 1:
updateMyNewsFragment();
break;
}
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
}
});
}
public void openSpecificTab() {
// tabLayout.settab
// tabLayout.se
}
}
Adapter code:
public class TabLayoutAdapter extends FragmentPagerAdapter {
private long baseId = 0;
ArrayList<TabFragmentModelClass> fragmentAdapterArrayList;
public TabLayoutAdapter(FragmentManager fm, ArrayList<TabFragmentModelClass> fragmentArrayList) {
super(fm);
fragmentAdapterArrayList = fragmentArrayList;
}
@Override
public Fragment getItem(int position) {
if (position == 0)
return fragmentAdapterArrayList.get(position).getmFragment();
if (position == 1)
return fragmentAdapterArrayList.get(position).getmFragment();
if (position == 2)
return fragmentAdapterArrayList.get(position).getmFragment();
return new CategoreyNewsFragment().newInstance(fragmentAdapterArrayList.get(position).getmCatID());
}
@Override
public int getCount() {
return fragmentAdapterArrayList.size();
}
//this is called when notifyDataSetChanged() is called
@Override
public int getItemPosition(Object object) {
// refresh all fragments when data set changed
return TabLayoutAdapter.POSITION_NONE;
}
@Override
public long getItemId(int position) {
// give an ID different from position when position has been changed
return baseId + position;
}
/**
* Notify that the position of a fragment has been changed.
* Create a new ID for each position to force recreation of the fragment
*
* @param n number of items which have been changed
*/
public void notifyChangeInPosition(int n) {
// shift the ID returned by getItemId outside the range of all previous fragments
baseId += getCount() + n;
}
/**
* // * This method returns the title of the tab according to the position.
* //
*/
@Override
public CharSequence getPageTitle(int position) {
return fragmentAdapterArrayList.get(position).getmCatName();
}
}
Remove tab from TabLayout
...
public void removeTab(int position) {
if (mTabLayout.getTabCount() >= 1 && position<mTabLayout.getTabCount()) {
mTabLayout.removeTabAt(position);
mPagerAdapter.removeTabPage(position);
}
}
...
Add a removeTabPage method to your PagerAdapter
...
public void removeTabPage(int position) {
if (!tabItems.isEmpty() && position<tabItems.size()) {
tabItems.remove(position);
notifyDataSetChanged();
}
}
...
Add a Tab
...
private void addTab(String title) {
mTabLayout.addTab(mTabLayout.newTab().setText(title));
mPagerAdapter.addTabPage(title);
}
...
Add a addTabPage method to your PagerAdapter
...
public void addTabPage(String title) {
tabItems.add(title);
notifyDataSetChanged();
}
...
Check out this sample code for a full example: ...samples/SupportDesignDemos/src/com/example/android/support/design/widget/TabLayoutUsage.java
MidasLefko
With the new support library (I'm using 23.2.1) you should only add to the Viewpager and not the TabLayout (otherwise you end up with double tabs and other funky behavior). So to update TouchBoarder's answer:
Add a removeTabPage method to your PagerAdapter
public void removeTabPage(int position) {
if (!tabItems.isEmpty() && position<tabItems.size()) {
tabItems.remove(position);
notifyDataSetChanged();
}
}
Add a addTabPage method to your PagerAdapter
public void addTabPage(String title) {
tabItems.add(title);
notifyDataSetChanged();
}
In addition to existing answers, to remove all tabs from tabLayout.
tabLayout.removeAllTabs();
来源：https://stackoverflow.com/questions/34306476/dynamically-add-and-remove-tabs-in-tablayoutmaterial-design-android