FrameLayout布局切换

1，activity_main

<RadioGroup
    android:id="@+id/rg"
    android:layout_width="100dp"
    android:layout_height="wrap_content" >

    <RadioButton
        android:id="@+id/radioButton1"
        android:layout_width="match_parent"
        android:layout_height="30dp"
        android:layout_weight="1"
        android:text="商家1"
        android:button="@null"
        android:gravity="center"
        />

    <RadioButton
        android:id="@+id/radioButton2"
        android:layout_width="match_parent"
        android:layout_height="30dp"
        android:layout_weight="1"
        android:text="商家2"
        android:button="@null"
        android:gravity="center"/>

    <RadioButton
        android:id="@+id/radioButton3"
        android:layout_width="match_parent"
        android:layout_height="30dp"
        android:layout_weight="1"
        android:text="商家3"
        android:button="@null"
        android:gravity="center"/>
</RadioGroup>

<FrameLayout
    android:id="@+id/fram"
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:layout_weight="1"></FrameLayout>

2,MainActivity
public class MainActivity extends FragmentActivity {

private FrameLayout fram;
private RadioGroup rg;
private Fra1 fra1=new Fra1();
private Fra2 fra2=new Fra2();
private Fra3 fra3=new Fra3();
private FragmentManager manager;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    fram = findViewById(R.id.fram);
    rg = findViewById(R.id.rg);
    manager = getSupportFragmentManager();


    manager.beginTransaction().replace(R.id.fram,fra1).commit();

    rg.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(RadioGroup group, int checkedId) {
            FragmentTransaction tran = manager.beginTransaction();
            switch (checkedId)
            {
                case R.id.radioButton1:
                    tran.replace(R.id.fram,fra1);

                    break;
                case R.id.radioButton2:
                    tran.replace(R.id.fram,fra2);

                    break;
                case R.id.radioButton3:
                    tran.replace(R.id.fram,fra3);
                    break;
            }

            tran.commit();
        }
    });


}

}