Fragment显示隐藏

fragmentList = new ArrayList<>();
        fragmentList.add(new HomeFragment());
        fragmentList.add(new FormFragment());
        fragmentList.add(new MyFragment());
        for (Fragment fragment : fragmentList) {
            getSupportFragmentManager().beginTransaction().add(R.id.frame, fragment).hide(fragment).commit();
        }
        currentFragment = fragmentList.get(0);
        getSupportFragmentManager().beginTransaction().show(currentFragment).commit();

        // getSupportFragmentManager().beginTransaction().add(R.id.frame, new HomeFragment()).commit();
        rg.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(RadioGroup radioGroup, int i) {
                switch (i) {
                    case R.id.btn1:
                        // getSupportFragmentManager().beginTransaction().add(R.id.frame, new HomeFragment()).commit();
                        FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
                        transaction.hide(currentFragment);
                        currentFragment = fragmentList.get(0);
                        transaction.show(currentFragment).commit();
                        break;
                    case R.id.btn2:
                        FragmentTransaction transaction2 = getSupportFragmentManager().beginTransaction();
                        transaction2.hide(currentFragment);
                        currentFragment = fragmentList.get(1);
                        transaction2.show(currentFragment).commit();
                        // getSupportFragmentManager().beginTransaction().add(R.id.frame, new FormFragment()).commit();
                        break;
                    case R.id.btn3:
                        // getSupportFragmentManager().beginTransaction().add(R.id.frame, new MyFragment()).commit();
                        FragmentTransaction transaction3 = getSupportFragmentManager().beginTransaction();
                        transaction3.hide(currentFragment);
                        currentFragment = fragmentList.get(2);
                        transaction3.show(currentFragment).commit();
                        break;
                }
            }
        });