MainActivity

package com.example.week;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.support.v7.app.AppCompatActivity;
import android.widget.FrameLayout;
import android.widget.RadioButton;
import android.widget.RadioGroup;

public class MainActivity extends FragmentActivity {

    private RadioGroup gr;
    private RadioButton shouye;
    private RadioButton xigua;
    private RadioButton wei;
    private RadioButton wode;
    private FrameLayout zhan;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        getSupportFragmentManager().beginTransaction().replace(R.id.zhan,new Fragment1()).commit();
        gr.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                switch (checkedId){
                    case R.id.shouye:
                        getSupportFragmentManager().beginTransaction().
                                replace(R.id.zhan,new Fragment1()).commit();
                        break;
                    case R.id.xigua:
                        getSupportFragmentManager().beginTransaction().
                                replace(R.id.zhan, new Fragment2()).commit();
                        break;
                    case R.id.wei:
                        getSupportFragmentManager().beginTransaction().
                                replace(R.id.zhan,new Fragment3()).commit();
                        break;
                    case R.id.wode:
                        getSupportFragmentManager().beginTransaction().
                                replace(R.id.zhan,new Fragment4()).commit();
                        break;
                }
            }
        });
    }

    private void initView() {
        gr = (RadioGroup) findViewById(R.id.gr);
        shouye = (RadioButton) findViewById(R.id.shouye);
        xigua = (RadioButton) findViewById(R.id.xigua);
        wei = (RadioButton) findViewById(R.id.wei);
        wode = (RadioButton) findViewById(R.id.wode);
        zhan = (FrameLayout) findViewById(R.id.zhan);
    }
}