android - 如何知道用户正在查看哪个 fragment ？

Question

我使用 ViewPager 创建了一个 TabLayout。我有四个 fragment 。

private void setupViewPager(ViewPager viewPager) {
    ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
    adapter.addFragment(new AdminFragment(), "Admin Posts");
    adapter.addFragment(new MemberFragment(), "Member Posts");
    adapter.addFragment(new JoinFragment(), "Our Members");
    adapter.addFragment(new WebFragment(), "Our Website");
    viewPager.setAdapter(adapter);
}

我如何从父 Activity 中知道用户在哪个 fragment 中。

public class AdminFragment extends Fragment{

    public AdminFragment() {
        // Required empty public constructor
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_admin, container, false);
    }

}

Answer 1

此方法将返回当前正在查看的 fragment 用户的名称。

 public String returnCurrentFragmentName(){  

     int position = viewPager.getCurrentItem();

    switch (position) {
                case 0:
    //fragment is
                    return "AdminFragment";
                case 1:
    //fragment is
                   return "MemberFragment";
                case 2:
    //fragment is
                    return "JoinFragment";
                case 3:
    //fragment is
                    return "WebFragment";
                default:
                    return null;
    }

祝你好运。