适配设备的简易新闻浏览器

同时兼容手机和平板。

进入应用后先显示新闻列表，当在手机上使用时，使用单页模式，单击列表项会打开新的页面。

当在平板上使用时，使用双页模式，单击左侧列表项时直接更新右侧新闻内容页。

MainActivity.java

package com.example.newsdemos;import android.os.Bundle;import androidx.appcompat.app.AppCompatActivity;public class MainActivity extends AppCompatActivity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);}
}

NewsContentActivity.java

package com.example.newsdemos;import android.content.Context;
import android.content.Intent;
import android.os.Bundle;import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.FragmentManager;public class NewsContentActivity extends AppCompatActivity {public static void actionStart(Context context,String title,String content){Intent intent = new Intent(context,NewsContentActivity.class);intent.putExtra("news_title",title);intent.putExtra("news_content",content);context.startActivity(intent);}@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_news_content);Intent intent = getIntent();String newsTitle = intent.getStringExtra("news_title");String newsContent = intent.getStringExtra("news_content");FragmentManager fm = getSupportFragmentManager();NewsContentFragment fragment =(NewsContentFragment) fm.findFragmentById(R.id.news_content_fragment);fragment.refresh(newsTitle,newsContent);}
}

NewsContentFragment.java

package com.example.newsdemos;import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;import androidx.fragment.app.Fragment;/*** A simple {@link Fragment} subclass.*/
public class NewsContentFragment extends Fragment {private  View fragment_view;public NewsContentFragment() {// Required empty public constructor}@Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {// Inflate the layout for this fragmentfragment_view =  inflater.inflate(R.layout.fragment_news_content, container, false);return fragment_view;}public void refresh(String newsTitle,String newsContent){View visibilityLayout = fragment_view.findViewById(R.id.visibility_layout);visibilityLayout.setVisibility(View.VISIBLE);TextView titleView = (TextView)fragment_view.findViewById(R.id.news_title);TextView contentView = (TextView)fragment_view.findViewById(R.id.news_content);titleView.setText(newsTitle);contentView.setText(newsContent);}}

NewsTitleFragment.java

package com.example.newsdemos;import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;import java.util.ArrayList;
import java.util.List;
import java.util.Random;/*** A simple {@link Fragment} subclass.*/
public class NewsTitleFragment extends Fragment {private List<News> newsList;private Boolean isTwoPane;public NewsTitleFragment() {// Required empty public constructor}@Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {// Inflate the layout for this fragmentView view =  inflater.inflate(R.layout.fragment_news_title, container, false);//view.RecyclerView组件RecyclerView newsTitleRecyclerView =(RecyclerView) view.findViewById(R.id.news_title_recycler_view);//准备子项布局news_item.xml//准备新闻数据newsList = getNews();//准备AdapterLinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());newsTitleRecyclerView.setLayoutManager(layoutManager);NewsAdapter adapter = new NewsAdapter(newsList);newsTitleRecyclerView.setAdapter(adapter);return view;}@Nullable@Overridepublic void onActivityCreated(@Nullable Bundle savedInstanceState) {super.onActivityCreated(savedInstanceState);if(getActivity().findViewById(R.id.news_content_layout)!=null){isTwoPane = true;}else {isTwoPane = false;}}private List<News> getNews(){List<News> newsList = new ArrayList<>();for(int i = 1 ;i<=20;i++){News news = new News();news.setTitle("This is news title" +i);news.setContent(getRandomLengthContent("This is news title" + i + "."));newsList.add(news);}return newsList;}private  String getRandomLengthContent(String s){Random random = new Random();int length = random.nextInt(20)+1;StringBuilder builder = new StringBuilder();for(int i = 1;i<=length;i++){builder.append(s);}return builder.toString();}class NewsAdapter extends RecyclerView.Adapter<NewsAdapter.ViewHolder>{private List<News> mnewsList;class ViewHolder extends RecyclerView.ViewHolder{TextView titleView;public ViewHolder(@NonNull View itemView) {super(itemView);titleView = (TextView)itemView.findViewById(R.id.news_title);}}public NewsAdapter(List<News> newsList) {mnewsList = newsList;}//创建子项布局的视图，itemView@NonNull@Overridepublic ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {LayoutInflater mInflater = LayoutInflater.from(parent.getContext());View itemView = mInflater.inflate(R.layout.news_title_item,parent,false);final ViewHolder holder = new ViewHolder(itemView);itemView.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {News news = mnewsList.get(holder.getAdapterPosition());if(isTwoPane)//双页模式{FragmentManager fm = getFragmentManager();NewsContentFragment fragment = (NewsContentFragment) fm.findFragmentById(R.id.news_content_fragment);fragment.refresh(news.getTitle(),news.getContent());}else {// News news = mnewsList.get(holder.getAdapterPosition());NewsContentActivity.actionStart(getActivity(),news.getTitle()  ,news.getContent());}}});return holder;}@Overridepublic void onBindViewHolder(@NonNull ViewHolder holder, int position) {News news = mnewsList.get(position);holder.titleView.setText(news.getTitle());}@Overridepublic int getItemCount() {return mnewsList.size();}}}

News.java

package com.example.newsdemos;public class News {private String title;private String  content;public String getTitle() {return title;}public String getContent() {return content;}public void setTitle(String title) {this.title = title;}public void setContent(String content) {this.content = content;}
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".MainActivity"><fragmentandroid:id="@+id/news_title_fragment"android:name="com.example.newsdemos.NewsTitleFragment"android:layout_width="match_parent"android:layout_height="match_parent"/></LinearLayout>

activity_main.xml(land)

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".MainActivity"><fragmentandroid:id="@+id/news_title_fragment"android:name="com.example.newsdemos.NewsTitleFragment"android:layout_width="0dp"android:layout_height="match_parent"android:layout_weight="1" /><FrameLayoutandroid:id="@+id/news_content_layout"android:layout_width="0dp"android:layout_height="match_parent"android:layout_weight="2"><fragmentandroid:id="@+id/news_content_fragment"android:name = "com.example.newsdemos.NewsContentFragment"android:layout_width="match_parent"android:layout_height="match_parent"/></FrameLayout></LinearLayout>

activity_news_content.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical"tools:context=".NewsContentActivity"><fragmentandroid:id="@+id/news_content_fragment"android:name = "com.example.newsdemos.NewsContentFragment"android:layout_width="match_parent"android:layout_height="match_parent"/></LinearLayout>

fragment_news_content.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:layout_width="match_parent"android:layout_height="match_parent"tools:context=".NewsContentFragment"><!-- TODO: Update blank fragment layout --><LinearLayoutandroid:id="@+id/visibility_layout"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical"android:visibility="invisible"><TextViewandroid:id="@+id/news_title"android:layout_width="match_parent"android:layout_height="wrap_content"android:gravity="center"android:padding="10dp"android:textSize="20sp" /><Viewandroid:id="@+id/view"android:layout_width="match_parent"android:layout_height="1dp"android:background="#000" /><TextViewandroid:id="@+id/news_content"android:layout_width="match_parent"android:layout_height="0dp"android:layout_weight="1"android:padding="15dp"android:textSize="14sp" /></LinearLayout><Viewandroid:layout_width="2dp"android:layout_height="match_parent"android:background="#f00"/></FrameLayout>

fragment_news_title.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:layout_width="match_parent"android:layout_height="match_parent"tools:context=".NewsTitleFragment"><!-- TODO: Update blank fragment layout --><androidx.recyclerview.widget.RecyclerViewandroid:id="@+id/news_title_recycler_view"android:layout_width="match_parent"android:layout_height="match_parent" />
</FrameLayout>

news_title_item.xml

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"android:id="@+id/news_title"android:layout_width="match_parent"android:layout_height="wrap_content"android:singleLine="true"android:ellipsize="end"android:textSize="18sp"android:paddingLeft="10dp"android:paddingRight="10dp"android:paddingTop="15dp"android:paddingBottom="15dp"></TextView>