更改操作栏标题时，刷一个标签

Question

所以我在我的项目中设置了一个标签活动，但事情是我想改变我的ActionBar标题基于哪个选项卡是活动的。

我有单个文件中的所有类（默认从android studio），我遵循这么多的教程和东西，但仍然没有工作。

这是我的标签活动代码

public class TabPages extends AppCompatActivity{ 
 

 

 
    private SectionsPagerAdapter mSectionsPagerAdapter; 
 

 

 
    private ViewPager mViewPager; 
 
    private int[] tabIcons = { 
 
      R.drawable.ic_search_24dp, 
 
      R.drawable.ic_forum_24dp, 
 
    }; 
 

 

 
    @Override 
 
    public void onBackPressed() { 
 
     Intent intent = new Intent(Intent.ACTION_MAIN); 
 
     intent.addCategory(Intent.CATEGORY_HOME); 
 
     intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); 
 
     startActivity(intent); 
 
    } 
 

 
    @Override 
 
    protected void onCreate(Bundle savedInstanceState) { 
 
     super.onCreate(savedInstanceState); 
 
     setContentView(R.layout.activity_tab_pages); 
 

 
     Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
 
     setSupportActionBar(toolbar); 
 

 
     mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager()); 
 

 
     
 
     mViewPager = (ViewPager) findViewById(R.id.container); 
 
     mViewPager.setAdapter(mSectionsPagerAdapter); 
 

 
     TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs); 
 
     tabLayout.setupWithViewPager(mViewPager); 
 

 

 

 
    @Override 
 
    public boolean onCreateOptionsMenu(Menu menu) { 
 
     
 
     getMenuInflater().inflate(R.menu.addbutton,menu); 
 
     getMenuInflater().inflate(R.menu.menu_tab_pages, menu); 
 
     return true; 
 
    } 
 

 
    @Override 
 
    public boolean onOptionsItemSelected(MenuItem item) { 
 
     
 
     int id = item.getItemId(); 
 

 
     if(id==R.id.signOut){ 
 
      FirebaseAuth.getInstance().signOut(); 
 
      startActivity(new Intent(TabPages.this, MainActivity.class)); 
 
     } 
 

 
     return super.onOptionsItemSelected(item); 
 
    } 
 
    
 
    public static class PlaceholderFragment extends Fragment { 
 
     
 
     private static final String ARG_SECTION_NUMBER = "section_number"; 
 

 
     public PlaceholderFragment() { 
 

 
     } 
 

 

 
     public static PlaceholderFragment newInstance(int sectionNumber) { 
 
      PlaceholderFragment fragment = new PlaceholderFragment(); 
 
      Bundle args = new Bundle(); 
 
      args.putInt(ARG_SECTION_NUMBER, sectionNumber); 
 
      fragment.setArguments(args); 
 
      return fragment; 
 
     } 
 

 
     @Override 
 
     public View onCreateView(LayoutInflater inflater, ViewGroup container, 
 
           Bundle savedInstanceState) { 
 
      View rootView; 
 
      if(getArguments().getInt(ARG_SECTION_NUMBER)==1){ 
 
       return rootView = inflater.inflate(R.layout.fragment_browse_title, container, false); 
 
      } else{ 
 
       return rootView = inflater.inflate(R.layout.fragment_chat_history, container, false); 
 
      } 
 

 

 
     } 
 
    } 
 

 

 
    lic class SectionsPagerAdapter extends FragmentPagerAdapter{ 
 

 
     public SectionsPagerAdapter(FragmentManager fm) { 
 
      super(fm); 
 
     } 
 

 
     @Override 
 
     public Fragment getItem(int position) { 
 
      
 
      return PlaceholderFragment.newInstance(position + 1); 
 
     } 
 

 
     @Override 
 
     public int getCount() { 
 
      // Show 2 total pages. 
 
      return 2; 
 
     } 
 

 
     @Override 
 
     public CharSequence getPageTitle(int position) { 
 

 
      return null; 
 
     } 
 

 
    } 
 
}

多谢您与帮助

Answer 1

tabLayout.setupWithViewPager(mViewPager); 
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() { 
     @Override 
     public void onTabSelected(TabLayout.Tab tab) { 
      mViewPager.setCurrentItem(tab.getPosition()); 
      //Set title here using setTitle() 
     } 

     @Override 
     public void onTabUnselected(TabLayout.Tab tab) { 
     } 

     @Override 
     public void onTabReselected(TabLayout.Tab tab) { 
     } 
    }); 

请给上面的一个尝试。