Fragment基本描述（四）移动开发qq35698774的博客-

上一章讲到fragment的生命周期，这一章我们使用fragment完成一个新闻客户端。并使用一套代码适配手机和pad的UI。

先看一下效果图“

具体如何使用一套代码实现配置不同的UI呢？

新建一个News的对象：

 public class News {     private String title;     private String content;      public News(String title, String content) {         this.title = title;         this.content = 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;     } }

分别创建两个fragment，一个是NewsTitleFragment，另一个是NewsContentFragment。

先来说NewsContentFragment，这个简单些许

 public class NewsContentFragment extends Fragment {     private View view;       @Nullable     @Override     public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {         view = inflater.inflate(R.layout.news_content_frag, container, false);          return view;      }      public void refresh(String newsTitle, String newsContent) {         View visiblityLayout = view.findViewById(R.id.visiblity_layout);         visiblityLayout.setVisibility(View.VISIBLE);         TextView newsViewTitle = view.findViewById(R.id.news_title);         TextView newsViewContent = view.findViewById(R.id.news_content);         newsViewTitle.setText(newsTitle);         newsViewContent.setText(newsContent);     } } 

重写onCreateView方法，加载咱们的xml文件：

 <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="https://schemas.android.com/apk/res/android"     android:layout_width="match_parent"     android:layout_height="match_parent">      <LinearLayout         android:id="@+id/visiblity_layout"         android:layout_width="match_parent"         android:layout_height="match_parent"         android:visibility="invisible"         android:orientation="vertical">          <TextView             android:id="@+id/news_title"             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:gravity="center"             android:padding="10dp"             android:text="454324555"             android:layout_gravity="center"             android:textColor="#000000"             android:textSize="20sp" />          <View             android:layout_width="match_parent"             android:layout_height="1dp"             android:background="#000000" />          <TextView             android:text="45646"             android:id="@+id/news_content"             android:layout_width="match_parent"             android:layout_height="0dp"             android:layout_weight="1"             android:padding="15dp"             android:textSize="18sp" />      </LinearLayout>      <View         android:layout_width="1dp"         android:layout_height="match_parent"         android:layout_alignParentLeft="true"         android:background="#000000" />  </RelativeLayout> 

这个不多解释了。

其中refresh(String newsTitle, String newsContent)就是获取数据后更形UI的。

然后我们说NewsTitleFragment这个就比较复杂了，在原来的加载fragment的基础基础上多了一个新闻标题列表，这个列表我们使用的是recyclerview来实现的。具体如下：

 public class NewsTitleFragment  extends Fragment {     private boolean isTwoPane;      @Nullable     @Override     public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {         View view = inflater.inflate(R.layout.news_title_frag, container, false);          RecyclerView newsTitleRecyclerView = view.findViewById(R.id.news_title_recycler_view);         LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity());         newsTitleRecyclerView.setLayoutManager(linearLayoutManager);         NewsAdapter newsAdapter = new NewsAdapter(getNews());         newsTitleRecyclerView.setAdapter(newsAdapter);          return view;     }      @Override     public void onActivityCreated(@Nullable Bundle savedInstanceState) {         super.onActivityCreated(savedInstanceState);         if (getActivity().findViewById(R.id.news_content_layout) != null) {             isTwoPane = true;             NewsContentFragment newsContentFragment = (NewsContentFragment)                     getFragmentManager().findFragmentById(R.id.news_content_fragment);             newsContentFragment.refresh("这是标题：0", "这是内容：0");           } else {             isTwoPane = false;         }     }      public List<News> getNews() {         List<News> news = new ArrayList<>();         for (int i = 0; i < 50; i++) {             news.add(new News("这是标题：" + i, "这是内容：" + i));         }         return news;     }       class NewsAdapter extends RecyclerView.Adapter<NewsAdapter.ViewHolder> {           private List<News> mNewsList;          public NewsAdapter(List<News> mNewsList) {             this.mNewsList = mNewsList;         }          @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 v) {                     News news = mNewsList.get(holder.getAdapterPosition());                     if (isTwoPane) {                         NewsContentFragment newsContentFragment = (NewsContentFragment)                                 getFragmentManager().findFragmentById(R.id.news_content_fragment);                         newsContentFragment.refresh(news.getTitle(), news.getContent());                      } else {                         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();         }          class ViewHolder extends RecyclerView.ViewHolder {             TextView newsTitleText;              public ViewHolder(View itemView) {                 super(itemView);                 newsTitleText = itemView.findViewById(R.id.news_title);             }         }     } } 

对应的news_title_frag xml：

 <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="https://schemas.android.com/apk/res/android"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:orientation="vertical">      <android.support.v7.widget.RecyclerView         android:id="@+id/news_title_recycler_view"         android:layout_width="match_parent"         android:layout_height="match_parent"/>  </LinearLayout> 

和news_item 的xml：

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

里面有用到NewsContentActivity，当是手机的时候就挑转到这个activity里面展示内容：

 public class NewsContentActivity extends AppCompatActivity {      @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_news_content);         String news_title = getIntent().getStringExtra("news_title");         String news_content = getIntent().getStringExtra("news_content");          NewsContentFragment newsContentFragment = (NewsContentFragment) getSupportFragmentManager().                 findFragmentById(R.id.news_content_fragment);          newsContentFragment.refresh(news_title, news_content);     }      public static void actionStart(Activity activity, String newsTitle, String newsContent) {         Intent intent = new Intent(activity, NewsContentActivity.class);         intent.putExtra("news_title", newsTitle);         intent.putExtra("news_content", newsContent);         activity.startActivity(intent);     } } 

对应的activity_news_content   xml：

 <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="https://schemas.android.com/apk/res/android"     xmlns:app="https://schemas.android.com/apk/res-auto"     xmlns:tools="https://schemas.android.com/tools"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:orientation="vertical">      <fragment         android:id="@+id/news_content_fragment"         android:name="com.example.myfragment4.NewsContentFragment"         android:layout_width="match_parent"         android:layout_height="match_parent" /> </LinearLayout>

最后看：MainActivity

 public class MainActivity extends AppCompatActivity {      @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);     } }  

对应的xml有连个一个是默认的activity_main：

 <?xml version="1.0" encoding="utf-8"?> <FrameLayout xmlns:android="https://schemas.android.com/apk/res/android"     xmlns:app="https://schemas.android.com/apk/res-auto"     xmlns:tools="https://schemas.android.com/tools"     android:id="@+id/news_title_layout"     android:layout_width="match_parent"     android:layout_height="match_parent">      <fragment         android:id="@+id/news_title_fragment"         android:name="com.example.myfragment4.NewsTitleFragment"         android:layout_width="match_parent"         android:layout_height="match_parent" />  </FrameLayout>

另一个是需要和在和layout同目录下新建一个layout-sw600dp目录，里面新建一个activity_main.xml:

具体代码：

 <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="https://schemas.android.com/apk/res/android"     xmlns:app="https://schemas.android.com/apk/res-auto"     xmlns:tools="https://schemas.android.com/tools"     android:id="@+id/news_title_layout"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:orientation="horizontal">      <fragment         android:id="@+id/news_title_fragment"         android:name="com.example.myfragment4.NewsTitleFragment"         android:layout_width="0dp"         android:layout_height="match_parent"         android:layout_weight="1" />      <FrameLayout         android:id="@+id/news_content_layout"         android:layout_width="0dp"         android:layout_height="match_parent"         android:layout_weight="3">          <fragment             android:id="@+id/news_content_fragment"             android:name="com.example.myfragment4.NewsContentFragment"             android:layout_width="match_parent"             android:layout_height="match_parent" />     </FrameLayout>  </LinearLayout> 

转发表明出处：https://blog.csdn.net/qq_35698774/article/details/106457599

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感谢：郭霖的《第一行代码 第二版》