Fragment-hide and show

private Fragment mContent = new Fragment();// Record the current fragment due to replacementprivate Fragment mPerson;private Fragment mRanking;private Fragment mSummary;private FragmentTransaction transaction;

mPerson = new Personal();mRanking = new Ranking();mSummary = new Summary();fragmentManager = getSupportFragmentManager();mContent = mRanking;FragmentTransaction transaction = fragmentManager.beginTransaction();transaction.add(R.id.fragment, mContent).commit();navigation.setSelectedItemId(R.id.navigation_home);

private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener= new BottomNavigationView.OnNavigationItemSelectedListener() {@Overridepublic boolean onNavigationItemSelected(@NonNull MenuItem item) {switch (item.getItemId()) {case R.id.navigation_home:switchContent(mPerson);return true;case R.id.navigation_dashboard:switchContent(mRanking);return true;case R.id.navigation_ranking:switchContent(mSummary);return true;}return false;}};

 private void switchContent(Fragment to) {if (mContent != to) {FragmentTransaction transaction = fragmentManager.beginTransaction();if (!to.isAdded()) { // Determine if it has been added// Hide the current fragment and add the next fragment to ittransaction.hide(mContent).add(R.id.fragment, to).commit();} else {// Hide the current fragment and show the next fragmenttransaction.hide(mContent).show(to).commit();}mContent = to;}}