studio - tabs android material design

Agregue y elimine dinámicamente las pestañas en TabLayout(diseño de material) de Android

Question

Tengo un TabLayout y dentro tengo ViewPager. Necesito agregar y eliminar dinámicamente la pestaña en tablayout (diseño de material). Puedo agregar las pestañas dinámicamente, pero al quitar la pestaña, la pestaña se está eliminando correctamente. Pero se borra el último elemento de viewpager. Así que la pestaña no muestra fragmento específico. FYI he utilizado FragmentPagerAdapter.

He seguido este tutorial para implementar esto.

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
    }
}

Código del adaptador:

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();
    }
}

Answer 1

Con la nueva biblioteca de soporte (estoy usando 23.2.1) solo debes agregar al Viewpager y no al TabLayout (de lo contrario terminarás con pestañas dobles y otros comportamientos extraños). Así que para actualizar la respuesta de TouchBoarder :

Agregue un método removeTabPage a su PagerAdapter

public void removeTabPage(int position) {
    if (!tabItems.isEmpty() && position<tabItems.size()) {
          tabItems.remove(position);
          notifyDataSetChanged();
    }
}

Agregue un método addTabPage a su PagerAdapter

public void addTabPage(String title) {
      tabItems.add(title);
      notifyDataSetChanged();
}

Answer 2

Eliminar pestaña de TabLayout

...
public void removeTab(int position) {
    if (mTabLayout.getTabCount() >= 1 && position<mTabLayout.getTabCount()) {
          mTabLayout.removeTabAt(position);
          mPagerAdapter.removeTabPage(position);
    }
}
...

Agregue un método removeTabPage a su PagerAdapter

...
public void removeTabPage(int position) {
    if (!tabItems.isEmpty() && position<tabItems.size()) {
          tabItems.remove(position);
          notifyDataSetChanged();
    }
}
...

Añadir una Tab

...
private void addTab(String title) {
        mTabLayout.addTab(mTabLayout.newTab().setText(title));
        mPagerAdapter.addTabPage(title);
}
...

Agregue un método addTabPage a su PagerAdapter

...
public void addTabPage(String title) {
      tabItems.add(title);
      notifyDataSetChanged();
}
...

Echa un vistazo a este código de ejemplo para ver un ejemplo completo: ...samples/SupportDesignDemos/src/com/example/android/support/design/widget/TabLayoutUsage.java