Fragment的隐藏于显示

 private Frag3 f3;
    private Frag2 f2;
    private Frag4 f4;
    private RadioGroup rg;
    private Frag1 f;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        rg = (RadioGroup) findViewById(R.id.rg);
        f = new Frag1();
        getSupportFragmentManager().beginTransaction().add(R.id.f1, f).commit();
          //RadioGroup的点击事件
        rg.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {

            @Override
            public void onCheckedChanged(RadioGroup radioGroup, @IdRes int i) {
                hideFragments();
                FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
                switch (i) {
                    case R.id.rb:
                        fragmentTransaction.show(f).commit();
                        break;
                    case R.id.rb1:
                        if (f2 == null) {
                            f2 = new Frag2();
                            fragmentTransaction.add(R.id.f1, f2).commit();
                        } else {
                            fragmentTransaction.show(f2).commit();
                        }
                        break;
                    case R.id.rb2:
                        if (f3 == null) {
                            f3 = new Frag3();
                            fragmentTransaction.add(R.id.f1, f3).commit();
                        } else {
                            fragmentTransaction.show(f3).commit();
                        }
                        break;
                    case R.id.rb3:
                        if (f3 == null) {
                            f4 = new Frag4();
                            fragmentTransaction.add(R.id.f1, f4).commit();
                        } else {
                            fragmentTransaction.show(f3).commit();
                        }
                        break;

                }
            }
        });

    }
//隐藏的方法
    public void hideFragments() {

        if (f != null && f.isAdded()) {
            getSupportFragmentManager().beginTransaction().hide(f).commit();
        }
        if (f2 != null && f2.isAdded()) {
            getSupportFragmentManager().beginTransaction().hide(f2).commit();
        }
        if (f3 != null && f3.isAdded()) {
            getSupportFragmentManager().beginTransaction().hide(f3).commit();
        }


    }