下面是xml布局文件 activity_main.xml： 屏幕宽度小于600dp加载这个布局文件
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent"> <fragment android:id="@+id/news_title" android:name="com.ukulele.fragmentbestpractice.NewsTitleFragment" android:layout_width="match_parent" android:layout_height="match_parent" tools:layout_editor_absoluteY="8dp" tools:layout_editor_absoluteX="8dp" /> </LinearLayout>activity_main.xml(sw600dp)： 屏幕宽度大于600dp加载这个布局文件
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="horizontal" android:layout_width="match_parent" android:layout_height="match_parent"> <fragment android:id="@+id/news_title_fragment" android:name="com.ukulele.fragmentbestpractice.NewsTitleFragment" android:layout_width="0dp" android:layout_height="match_parent" android:layout_weight="1"/> <fragment android:id="@+id/news_content_fragment" android:name="com.ukulele.fragmentbestpractice.NewsContentFragment" android:layout_width="0dp" android:layout_height="match_parent" android:layout_weight="3"/> </LinearLayout>news_title_frag.xml：新闻标题碎片需要加载的布局
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent"> <android.support.v7.widget.RecyclerView android:id="@+id/news_title_recycler_view" android:layout_width="match_parent" android:layout_height="match_parent"/> </LinearLayout>news_title_item.xml：新闻标题recyclerview的item
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginBottom="20dp"> <TextView android:id="@+id/news_title" android:layout_width="match_parent" android:layout_height="wrap_content" /> </LinearLayout>news_content.xml：新闻内容碎片
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent"> <fragment android:id="@+id/news_content_fragment" android:name="com.ukulele.fragmentbestpractice.NewsContentFragment" android:layout_width="match_parent" android:layout_height="match_parent"/> </LinearLayout>news_content_frag.xml： 新闻内容碎片需要加载的布局
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="horizontal" android:layout_width="match_parent" android:layout_height="match_parent"> <View android:layout_width="1dp" android:layout_height="match_parent" android:background="#000"/> <LinearLayout android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent"> <TextView android:id="@+id/news_title" android:layout_width="match_parent" android:layout_height="wrap_content" android:gravity="center" android:padding="10dp" android:textSize="20sp"/> <View android:layout_width="match_parent" android:layout_height="1dp" android:background="#000"/> <TextView android:id="@+id/news_content" android:layout_width="match_parent" android:layout_height="wrap_content" android:padding="15dp" android:textSize="18sp"/> </LinearLayout> </LinearLayout>下面是代码 News实体类：
public class News { private String title; private String content; public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } public String getContent() { return content; } public void setContent(String content) { this.content = content; } }MainActivity：
public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } }NewsTitleFragment： 新闻标题Fragment
public class NewsTitleFragment extends Fragment { private boolean isTwoPane; @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View view = inflater.inflate(R.layout.news_title_frag,container,false); RecyclerView newsTitleRecyclerView = view.findViewById(R.id.news_title_recycler_view); LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity()); newsTitleRecyclerView.setLayoutManager(layoutManager); NewsAdapter adapter = new NewsAdapter(getNews()); newsTitleRecyclerView.setAdapter(adapter); return view; } private List<News> getNews() { List<News> newsList = new ArrayList<>(); for (int i = 1; i <= 50; i++) { News news = new News(); news.setTitle("This is news title " + i); news.setContent(getRandomLengthContent("This is news content " + i + ". ")); newsList.add(news); } return newsList; } private String getRandomLengthContent(String content) { Random random = new Random(); int length = random.nextInt(20) + 1; StringBuilder builder = new StringBuilder(); for (int i = 0; i < length; i++) { builder.append(content); } return builder.toString(); } @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); if(getActivity().findViewById(R.id.news_content_fragment)!=null){ isTwoPane = true;//可以找到news_content_layout布局时，为双页模式 }else{ isTwoPane = false;//找不到news_content_layout布局时，为单页模式 } } class NewsAdapter extends RecyclerView.Adapter<NewsAdapter.ViewHolder>{ private List<News> mNewsList; class ViewHolder extends RecyclerView.ViewHolder{ TextView newsTitleText; public ViewHolder(View view){ super(view); newsTitleText = view.findViewById(R.id.news_title); } } public NewsAdapter(List<News> newsList){ mNewsList = newsList; } @Override public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.news_item,parent,false); final ViewHolder holder = new ViewHolder(view); view.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { News news = mNewsList.get(holder.getAdapterPosition()); if(isTwoPane){ //如果是双页模式，则刷新NewsContentFragment 中的内容 NewsContentFragment newsContentFragment = (NewsContentFragment) getFragmentManager(). findFragmentById(R.id.news_content_fragment); newsContentFragment.refresh(news.getTitle(),news.getContent()); }else{ //如果是单页模式，则启动NewsContentActivity NewsContentActivity.actionStart(getActivity(),news.getTitle(),news.getContent()); } } }); return holder; } @Override public void onBindViewHolder(ViewHolder holder, int position) { News news = mNewsList.get(position); holder.newsTitleText.setText(news.getTitle()); } @Override public int getItemCount() { return mNewsList.size(); } } }NewsContentActivity：如果屏幕小于600dp的设备，点击新闻标题列表就会跳转到该活动。如果大于600dp，就不会跳转到该活动，就会直调用NewsContentFragment的refresh()方法进行刷新
public class NewsContentActivity extends AppCompatActivity { public static void actionStart(Context context,String newsTitle,String newsContent){ Intent intent = new Intent(context,NewsContentActivity.class); intent.putExtra("news_title",newsTitle); intent.putExtra("news_content",newsContent); context.startActivity(intent); } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.news_content); String newsTitle = getIntent().getStringExtra("news_title");//获取传入的新闻标题 String newsContent = getIntent().getStringExtra("news_content");//获取传入新闻内容 NewsContentFragment newsContentFragment = (NewsContentFragment) getSupportFragmentManager().findFragmentById(R.id.news_content_fragment); newsContentFragment.refresh(newsTitle,newsContent);//刷新NewsContentFragment界面 } }NewsContentFragment： 新闻内容Fragment
public class NewsContentFragment extends Fragment { private View view; @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { view = inflater.inflate(R.layout.news_content_frag,container,false); return view; } public void refresh(String newsTitle,String newsContent){ TextView newsTitleText = view.findViewById(R.id.news_title); TextView newsContentTitle = view.findViewById(R.id.news_content); newsTitleText.setText(newsTitle); newsContentTitle.setText(newsContent); } }