fragment 切换 show/hide

    Fragment fragmentCurr = null;
    private void switchFragment(Fragment fragmentTo) {
        FragmentTransaction transaction = this.getSupportFragmentManager().beginTransaction();
        if(fragmentCurr == fragmentTo) {
            return;
        }

        if (fragmentTo.isAdded()) {
            transaction.show(fragmentTo);
        } else {
            transaction.add(R.id.fragment_view, fragmentTo).show(fragmentTo);
        }

        if (null != fragmentCurr) {
            transaction.hide(fragmentCurr);
        }

        transaction.commit();
        fragmentCurr = fragmentTo;
    }