碎片的实例
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)
<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.example.fragmentbestpractice.NewsContentFragment"//将刚刚制作的布局引进来
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</LinearLayout>
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
<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/new_title_recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</LinearLayout>
8.布局---新建RecyclerView子项的布局
<TextureView 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"
/>
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
<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_title_fragment"//碎片一
android:name="com.example.fragmentbestpractice.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//碎片二放新闻内容
android:id="@+id/news_content_fragment"
android:name="com.example.fragmentbestpractice.NewsContentFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</FrameLayout>>
</LinearLayout>
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<NewsAdapter.ViewHolder> {
private List<News> 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<News> 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<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"+""));
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<length;i++)
{
bulider.append(content);
}
return bulider.toString();
}