Android编程权威指南之Activity的抽象类使用

SingleFragmentActivity.java:

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;

/**
 * Created by Administrator on 2017/4/8.
 */

public abstract class SingleFragmentActivity extends FragmentActivity {
    protected abstract Fragment creatFragment( );

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView( R.layout.activity_main );
        FragmentManager fm = getSupportFragmentManager( );
        Fragment fragment = fm.findFragmentById( R.id.fragment_container );
        if( fragment == null ) {
            fragment = creatFragment();
            fm.beginTransaction().add(R.id.fragment_container, fragment ).commit();
        }
    }
}

DataListActivity.java:

public class DataListActivity extends SingleFragmentActivity{
    @Override
    protected Fragment creatFragment() {
        return new DataListFragment();
    }

}

DataListFragment.java:
import android.support.v4.app.Fragment;

/**
 * Created by Administrator on 2017/4/8.
 */

public class DataListFragment extends Fragment {

}

activity_main.xml:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/fragment_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.administrator.recycleviewtest.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!" />
</FrameLayout>