笔记68 | 切换fragmengt的replace和add方法

replace

   private  void  LoandFragment(Fragment fragment){
        FragmentManager fm = getSupportFragmentManager();
        FragmentTransaction ft = fm.beginTransaction();
        ft.replace(R.id.fragment, fragment);
        ft.commitAllowingStateLoss();
    }

add

 private Fragment currentFragment = new Fragment();
    //Fragment优化
    private FragmentTransaction transaction(Fragment targetFragment) {

        FragmentTransaction transaction = getSupportFragmentManager()
                .beginTransaction();
        if (!targetFragment.isAdded()) {
            //第一次使用switchFragment()时currentFragment为null，所以要判断一下
            if (currentFragment != null) {
                transaction.hide(currentFragment);
            }
            transaction.add(R.id.fragment, targetFragment, targetFragment.getClass().getName());

        } else {
            transaction
                    .hide(currentFragment)
                    .show(targetFragment);
        }
        currentFragment = targetFragment;
        return transaction;
    }

性能没什么区别～～～