如何在 TabsLayout 中将一个片段的内容替换为另一个片段的内容？

Question

I use a tablayout with two tabs. Each tab has a viewpager fragment. The code:

ALoginFragment AFragment = new ALoginFragment();
BLoginFragment BFragment = new BLoginFragment();
SectionsPageAdapter sectionsPageAdapter = new SectionsPageAdapter(getSupportFragmentManager());
sectionsPageAdapter.addFragment(AFragment, "A");
sectionsPageAdapter.addFragment(BFragment, "B");
viewPager.setAdapter(sectionsPageAdapter);
tabLayout.setupWithViewPager(viewPager);

The SectionsPageAdapter is my custom sections page adapter. The code:

public class SectionsPageAdapter extends FragmentPagerAdapter {
    private final List<Fragment> mFragmentList = new ArrayList<>();
    private final List<String> mFragmentTitleList = new ArrayList<>();

    public SectionsPageAdapter(FragmentManager fragmentManager) {
        super(fragmentManager,BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT);
    }

    public void addFragment(Fragment fragment, String title) {
        mFragmentList.add(fragment);
        mFragmentTitleList.add(title);
    }

    @Nullable
    @Override
    public CharSequence getPageTitle(int position) {
        return mFragmentTitleList.get(position);
    }

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

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

When I click some button in fragment A I want to replace the content of tab A with tab C . I tried;

getChildFragmentManager().beginTransaction().replace(fragmentView.getId(), new CLoginFragment())
                .addToBackStack(null).commit();

Where save fragmentView in the A 's onCreateView method. But fragmentView.getId() is -1 for some reason. How can I replace the content of A with C ?

Answer 1

to replace fragment which are inside viewpager put this function in SectionsPageAdapter

public void replaceFragment(int position,Fragment newFragment ){
    mFragmentList.set(position, newFragment);
    notifyDataSetChanged();
}

then call it with the position of fragment that need to be changed and the newFragment

sectionsPageAdapter.replaceFragment(0,new CFragment());// replace ALoginFragment which is at zero index with CFragment