android – 如何使用设计库选项卡布局更改工具栏标题？

我正在使用设计库支持TabLayout,我试图在Tab被按下或ViewPager被滑动时更改工具栏的标题.但到目前为止无法取得任何成功.这是以下代码： –

public class ActivityHomePage extends AppCompatActivity {
    private TabLayout tabLayout;
    private ViewPager viewPager;
    Toolbar toolbar;
    DesignDemoPagerAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceStatE) {
        super.onCreate(savedInstanceStatE);
        setContentView(R.layout.activity_homepagE);

        toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayShowtitleEnabled(false);




        viewPager = (ViewPager) findViewById(R.id.viewpager);
        setupViewPager(viewPager);
      //  viewPager.getAdapter().getPagetitle();
        tabLayout = (TabLayout) findViewById(R.id.tablayout);
        tabLayout.setupWithViewPager(viewPager);
        setupTabIcons();


    }
    privatE int[] tabIcons = {

            R.drawable.ic_action_star,R.drawable.ic_action_heart,R.drawable.ic_action_square
    };
    private void setupViewPager(ViewPager viewPager) {
        adapter = new DesignDemoPagerAdapter(getSupportFragmentManager());

        adapter.addFrag(new FragmentStar(),"star");
        adapter.addFrag(new FragmentHeart(),"heart");
        adapter.addFrag(new FragmentSquare(),"square");
        viewPager.setAdapter(adapter);



    }



    @Override
    public Boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main,menu);
        return true;
    }

    private void setupTabIcons() {
        tabLayout.getTabAt(0).setIcon(tabIcons[0]);
        tabLayout.getTabAt(1).setIcon(tabIcons[1]);
        tabLayout.getTabAt(2).setIcon(tabIcons[2]);

    }


    @Override
    public Boolean onOptionsItemSELEcted(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button,so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        switch (id) {
            case android.R.id.home:
                mDrawerLayout.openDrawer(GravityCompat.START);
                return true;
            case R.id.action_setTings:
                return true;
        }

        return super.onOptionsItemSELEcted(item);
    }




     class DesignDemoPagerAdapter extends FragmentStatePagerAdapter {
        private final List<Fragment> mFragmentList = new ArrayList<>();
        private final List<String> mFragmenttitleList = new ArrayList<>();

        public DesignDemoPagerAdapter(FragmentManager manager) {
            super(manager);
        }

        @Override
        public Fragment getItem(int position) {
            return mFragmentList.get(position);
        }

        @Override
        public int getCount() {
            return mFragmentList.size();
        }

        public void addFrag(Fragment fragment,String titlE) {
            mFragmentList.add(fragment);
            mFragmenttitleList.add(titlE);

        }

        @Override
        public CharSequence getPagetitle(int position) {


            return null;
        }
    }

}

/** Tab & PageViewer Controller**/
        tabLayout = (TabLayout) findViewById(R.id.tablayout);
        tabLayout.addTab(tabLayout.newTab().setIcon(R.drawable.ic_action_star));
        tabLayout.addTab(tabLayout.newTab().setIcon(R.drawable.ic_action_heart));
        tabLayout.addTab(tabLayout.newTab().setIcon(R.drawable.ic_action_squarE));

        tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
       // setupTabIcons();

      viewPager = (ViewPager) findViewById(R.id.viewpager);
        pAdapter = new PagerAdapter
                (getSupportFragmentManager(),tabLayout.getTabCount());
        viewPager.setAdapter(pAdapter);
        toolbar.settitle("Same Page");
        viewPager.addOnPagechangelistener(new TabLayout.TabLayoutOnPagechangelistener(tabLayout));
        tabLayout.setOnTabSELEctedListener(new TabLayout.onTabSELEctedListener() {
            @Override
            public void onTabSELEcted(TabLayout.Tab tab) {
                switch(tab.getPosition()) {
                    case 0:
                        viewPager.setCurrentItem(0);
                        toolbar.settitle("Fragment Star");
                        break;
                    case 1:
                        viewPager.setCurrentItem(1);
                        toolbar.settitle("Fragment Heart");
                        break;
                    case 2:
                        viewPager.setCurrentItem(2);
                        toolbar.settitle("Fragment Squae");
                        break;

                    default:

                        viewPager.setCurrentItem(tab.getPosition());
                        toolbar.settitle("Fragment Star");
                        break;
                }



            }

            @Override
            public void onTabUnSELEcted(TabLayout.Tab tab) {

            }

            @Override
            public void onTabReSELEcted(TabLayout.Tab tab) {

            }
        });


    }
/** **/
 public class PagerAdapter extends FragmentStatePagerAdapter {
        int mNumOfTabs;

        public PagerAdapter(FragmentManager fm,int numOfTabs) {
            super(fm);
            this.mNumOfTabs = NumOfTabs;
        }

        @Override
        public Fragment getItem(int position) {

            switch (position) {
                case 0:
                    FragmentStar tab0 = new FragmentStar();
                    return tab0;
                case 1:
                    FragmentHeart tab1 = new FragmentHeart();
                    return tab1;
                case 2:
                    FragmentSquare tab2 = new FragmentSquare();
                    return tab2;

                default:
                    return null;
            }
        }

        @Override
        public int getCount() {
            return mNumOfTabs;
        }
    }