android.app.Fragment;

import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class Fragment1 extends Fragment {

    //初始化Fragment，实例化在Fragment中的成员变量
    @Override
    public void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
    }
    
    //给Fragment 加载UI布局，组件例如button，textview等等在这里去初始化

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        //这个布局没有父布局，所以root置空
        View view=inflater.inflate(R.layout.f1, null);
        return view;
    }
    
}

import android.os.Bundle;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.view.Menu;

public class MainActivity extends Activity {

    private FragmentManager manager;
    private FragmentTransaction transaction;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        //将activity_main中的某一块换成fragment1
        manager=getFragmentManager();
        transaction=manager.beginTransaction();
        Fragment1 fragment1=new Fragment1();
        //content_frame的内容换成fragment1
        transaction.add(R.id.content_frame, fragment1);
        transaction.commit();
    }

}