我使用TabLayout切换片段。它在大多数情况下都是有效的，除了当我试图以编程方式使用tab.select()，我的TabLayout选择一个选项卡时。OnTabSelectedListener将触发onTabSelected(TabLayout。Tab Tab)，这会让我很伤心。我正在寻找一种不触发侦听器的方法来做程序化选择。

So I adapted @kenodoggy 's answer to my use. I was further facing a problem where some of the internal objects would return null (because they weren't created yet, because I was answering onActivityResult() from my fragment, which occurs before onCreate() in the case the activity is singleTask or singleInstance) so I wrote up a detailed if/else sequence which would report the error and fall through without the NullPointerException that would otherwise trigger. I use Timber for logging, if you're not using that substitute with Log.e().

void updateSelectedTabTo(int position) {
    if (tabLayout != null){
        int selected = tabLayout.getSelectedTabPosition();
        if (selected != -1){
            TabLayout.Tab oldTab = tabLayout.getTabAt(0);
            if (oldTab != null){
                View view = oldTab.getCustomView();
                if (view != null){
                    view.setSelected(false);
                }
                else {
                    Timber.e("oldTab customView is null");
                }
            }
            else {
                Timber.e("oldTab is null");
            }
        }
        else {
            Timber.e("selected is -1");
        }
        TabLayout.Tab newTab = tabLayout.getTabAt(position);
        if (newTab != null){
            View view = newTab.getCustomView();
            if (view != null){
                view.setSelected(false);
            }
            else {
                Timber.e("newTab customView is null");
            }
        }
        else {
            Timber.e("newTab is null");
        }
    }
    else {
        Timber.e("tablayout is null");
    }
}

这里，tabLayout是绑定到XML中的tabLayout对象的内存变量。我不使用滚动标签功能，所以我把它也删除了。

默认情况下，如果你选择一个选项卡，它将高亮显示。如果你想选择显式意味着使用给定的注释代码在onTabSelected(TabLayout。标签标签)与您指定的标签索引位置。这段代码将解释使用viewpager在选项卡选择位置上更改片段。

public class GalleryFragment extends Fragment implements TabLayout.OnTabSelectedListener 
{
private ViewPager viewPager;public ViewPagerAdapter adapter;private TabLayout tabLayout;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_gallery, container, false);
viewPager = (ViewPager) rootView.findViewById(R.id.viewpager);
adapter = new ViewPagerAdapter(getChildFragmentManager());
adapter.addFragment(new PaymentCardFragment(), "PAYMENT CARDS");
adapter.addFragment(new LoyaltyCardFragment(), "LOYALTY CARDS");
viewPager.setAdapter(adapter);
tabLayout = (TabLayout) rootView.findViewById(R.id.tabs);
    tabLayout.setupWithViewPager(viewPager);
    tabLayout.setOnTabSelectedListener(this);
}

@Override
public void onTabSelected(TabLayout.Tab tab) {
    //This will be called 2nd when you select a tab or swipe using viewpager
    final int position = tab.getPosition();
    Log.i("card", "Tablayout pos: " + position);
    //TabLayout.Tab tabdata=tabLayout.getTabAt(position);
    //tabdata.select();
    tabLayout.post(new Runnable() {
        @Override
        public void run() {
            if (position == 0) {
                PaymentCardFragment paymentCardFragment = getPaymentCardFragment();
                if (paymentCardFragment != null) {
                   VerticalViewpager vp = paymentCardFragment.mypager;
                    if(vp!=null)
                    {
                      //vp.setCurrentItem(position,true);
                      vp.setCurrentItem(vp.getAdapter().getCount()-1,true);
                    }
                  }
            }
            if (position == 1) {
               LoyaltyCardFragment loyaltyCardFragment = getLoyaltyCardFragment();
                if (loyaltyCardFragment != null) {
                   VerticalViewpager vp = loyaltyCardFragment.mypager;
                    if(vp!=null)
                    {
                        vp.setCurrentItem(position);
                    }
                  }
            }
        }
    });
}

@Override
public void onTabUnselected(TabLayout.Tab tab) {
 //This will be called 1st when you select a tab or swipe using viewpager
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
  //This will be called only when you select the already selected tab(Ex: selecting 3rd tab again and again)
}
 private PaymentCardFragment getLoyaltyCardFragment() {
    Fragment f = adapter.mFragmentList.get(viewPager.getCurrentItem());

   if(f instanceof PaymentCardFragment)
   {
    return (PaymentCardFragment) f;
   }
   return null;
 }
private LoyaltyCardFragment getPaymentCardFragment() {
    Fragment f = adapter.mFragmentList.get(viewPager.getCurrentItem());
    if(f instanceof LoyaltyCardFragment)
   {
    return (LoyaltyCardFragment) f;
   }
   return null;
 }
  class ViewPagerAdapter extends FragmentPagerAdapter {
   public List<Fragment> mFragmentList = new ArrayList<>();
    private final List<String> mFragmentTitleList = new ArrayList<>();
   public void addFragment(Fragment fragment, String title) {
   mFragmentList.add(fragment);
   mFragmentTitleList.add(title);
  }
 }
}

你可以试着用这个来解决:

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

TabLayout.Tab tab = tabLayout.getTabAt(pos);
if (tab != null) {
    tab.select();
}

最新的简单解决方案对我很有效:

binding.tablayout.selectTab(binding.tablayout.getTabAt(tabPosisiton))

or

with(binding.tablayout) {
    selectTab(getTabAt(tabPosisiton))
}

和tabPosition从0开始

对于Viewpager2, Kotlin，其他答案都没有帮助，只有下面这个有用。位置是从片段结果监听器在我的情况下:

TabLayoutMediator(binding.tabLayout, binding.viewPager2) { _, _ ->
    binding.viewPager2 = position
}.attach()

只需设置viewpage . setcurrentitem (index)和相关的TabLayout将选择各自的选项卡。