getSupportFragmentManager（）。findFragmentByTag（）返回null？

Question

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home_screen_bottombar);
        BottomNavigationView bottomNavigationView = findViewById(R.id.navigation);
        BottomNavigationViewHelper.disableShiftMode(bottomNavigationView);
        initBottomBar(bottomNavigationView);}
    private void initBottomBar(BottomNavigationView bottomNavigationView) {
        bottomNavigationView.setOnNavigationItemSelectedListener
                (new BottomNavigationView.OnNavigationItemSelectedListener() {
                    @Override
                    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                        switch (item.getItemId()) {
                            case R.id.home:
                                fragmentTag = "home";
                                savedFragment = getSupportFragmentManager().findFragmentByTag(fragmentTag);
                                if (savedFragment == null)
                                    savedFragment = NeedyFeedyHomeTabFragment.getInstance();
                                break;
                            case R.id.search:
                                fragmentTag = "search";
                                savedFragment = getSupportFragmentManager().findFragmentByTag(fragmentTag);
                                if (savedFragment == null) {
                                    savedFragment = SearchResultFragment.getInstance();
                                }
                                break;
                            case R.id.profile:
                                fragmentTag = "profile";
                                savedFragment = getSupportFragmentManager().findFragmentByTag(fragmentTag);
                                if (savedFragment == null) {
                                    savedFragment = FragmentProfileDetails.getInstance();
                                }
                                break;
                            case R.id.favourite:
                                fragmentTag = "favourite";
                                savedFragment = getSupportFragmentManager().findFragmentByTag(fragmentTag);
                                if (savedFragment == null) {
                                    savedFragment = FavouriteListFragment.getInstance();
                                }
                                break;
                        }
                        fragmentTransactionExecution(savedFragment, fragmentTag);
                        return true;
                    }
                });
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
        transaction.replace(R.id.frame_layout, NeedyFeedyHomeTabFragment.getInstance(), "home");
        transaction.commit();
        getSupportFragmentManager().executePendingTransactions();
    }
private void fragmentTransactionExecution(Fragment selectedFragment, String fragmentTag) {
        if (selectedFragment != null) {
            FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.frame_layout, selectedFragment, fragmentTag);
            transaction.commit();
            getSupportFragmentManager().executePendingTransactions();
        }
    } 

Answer 1

在view.setTag(this);中的每个片段中添加onCreateView。