MainActivity.java

package com.yokmama.learn10.chapter05.lesson23;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentTransaction;


public class MainActivity extends FragmentActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Fragment fragment = getSupportFragmentManager().findFragmentById(R.id.contents);
        if (fragment == null) {
            fragment = new MyFragment1();
            FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
            fragmentTransaction.add(R.id.contents, fragment);
            fragmentTransaction.commit();
        }
    }

}