碎片的实例-白红宇

碎片的实例

阅读量：4509 次

发布时间：2019-06-08

本文共 6086 字，大约阅读时间需要 20 分钟。

1.添加依赖因为要用到RecyclerView的控件

2类--.建立新闻的类（两个字段（title和content））

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;     } } 3.布局--新建新闻内容的布局 布局有两块（标题（TextView）和内容（TextView）中间用一个View隔开（装一条线）） 4.类--新建NewContentFrament类继承Frament

public class NewsContentFragment extends Fragment {
      private View view;     @Override     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle saveInstanceState)     {
        view=inflater.inflate(R.layout.news_content_frag,container,false);         return view;     }//先找到刚刚建立的布局中的View的界面返回赋给之前定义好的View     public void refresh(String newsTitle,String newsContent)     {
          View visibilityLayout=view.findViewById(R.id.visibility_layout);         visibilityLayout.setVisibility(View.VISIBLE);         TextView newsTitleText=(TextView)view.findViewById(R.id.new_title);         TextView newsContentText=(TextView) view.findViewById(R.id.new_content);         newsTitleText.setText(newsTitle);//刷新新闻的标题         newsContentText.setText(newsContent);//刷新内容     }//从View中获得各种需要使用的信息包括，标题和内容 } 以上完成双页模式显示 5.布局--新建一个新活动（NewsContentActivity相应为产生的布局添加一个碎片）


         
      
     6.修改最开始那个活动的代码

public class NewsContentActivity extends AppCompatActivity {
  public static void actionStart(Context context, String newsTitle,String newsContent) {
      Intent intent=new Intent(context,NewsContentActivity.class);//定义活动传进新闻活动标题和内容     intent.putExtra("news_title",newsTitle);     intent.putExtra("newsContent",newsContent);     context.startActivity(intent); }     @Override     protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);         setContentView(R.layout.activity_news_content);         String newsTitle=getIntent().getStringExtra("news_title");         String newContent=getIntent().getStringExtra("news_content");         NewsContentFragment newsContentFragment=(NewsContentFragment)getSupportFragmentManager().findFragmentById(R.id.news_content_fragment);         newsContentFragment.refresh(newsTitle,newContent);     } } 7.布局--新建新闻列表的布局此处要用到recyclerView的列表布局


         
      
     8.布局---新建RecyclerView子项的布局


     9.类--新建新闻列表的碎片里面放新闻列表

public class NewsTitleFragment extends Fragment {
      private boolean isTwoPane;     @Override     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle saveInstanceState)     {
          View view=inflater.inflate(R.layout.news_title_frag,container,false);         return view;     }//传进来布局

public void onActivityCreated(Bundle saveInstanceState) {
      super.onActivityCreated(saveInstanceState);     if(getActivity().findViewById(R.id.news_content_fragment)!=null)     {
      isTwoPane=true;         }     else     {
          isTwoPane=false;     } } 10.新建一个主活动的布局//两个碎片


         
          
              
               
     > 
     11.在NewsTitleFragment中通过Recycler将新闻列表展示处理来，需要在其内部放一个适配器，就在里面定义

class NewsAdapter extends RecyclerView.Adapter
    
      {
      private List
     
       mNewList;     class ViewHolder extends RecyclerView.ViewHolder     {
          TextView newsTitleText;         public ViewHolder(View view)         {
              super(view);             newsTitleText=(TextView) view.findViewById(R.id.news_title);         }     }     public NewsAdapter(List
      
        newsList)     {
          mNewList=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 v)             {
                  News news=mNewList.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=mNewList.get(position);     holder.newsTitleText.setText(news.getTitle()); }         @Override         public int getItemCount()         {
              return mNewList.size();         }     } } 最后向RecycleView中填充数据修改NewsTitleFragement中代码

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle saveInstanceState) {
      View view=inflater.inflate(R.layout.news_title_frag,container,false);     RecyclerView newsTitleRecyclerView=(RecyclerView) view.findViewById(R.id.new_title_recycler_view);     LinearLayoutManager layoutManager=new LinearLayoutManager(getActivity());     newsTitleRecyclerView.setLayoutManager(layoutManager);     NewsAdapter adapter=new NewsAdapter(getNews());     newsTitleRecyclerView.setAdapter(adapter);     return view; } private  List
    
      getNews() {
      List
     
       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"+""));         newsList.add(news);     }     return  newsList; } public String  getRandomLengthContent(String content) {
      Random random=new Random();     int length=random.nextInt(20)+1;     StringBuilder bulider=new StringBuilder();     for (int i=0;i