Fragment和ViewPager的替换关联

public class MainActivity extends AppCompatActivity {    private FrameLayout frameLayout;    private RadioGroup group;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        frameLayout = (FrameLayout) findViewById(R.id.fream);        group = (RadioGroup) findViewById(R.id.group);        getSupportFragmentManager().beginTransaction().replace(R.id.fream, new Fragment_Sy()).commit();        group.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {            @Override            public void onCheckedChanged(RadioGroup group, @IdRes int checkedId) {                switch (checkedId){                    case R.id.rb1:                        getSupportFragmentManager().beginTransaction().replace(R.id.fream, new Fragment_Sy()).commit();                        break;                    case R.id.rb2:                        getSupportFragmentManager().beginTransaction().replace(R.id.fream, new Fragment_Fx()).commit();                        break;                    case R.id.rb3:                        getSupportFragmentManager().beginTransaction().replace(R.id.fream, new Fragment_Ss()).commit();                        break;                    case R.id.rb4:                        getSupportFragmentManager().beginTransaction().replace(R.id.fream, new Fragment_My()).commit();                        break;                }            }        });    }}