碎片的实践

新闻内容的布局

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <LinearLayout
        android:id="@+id/visibility_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:visibility="visible">
        <TextView
            android:id="@+id/news_tittle"
            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="10dp"
            android:background="#000"/>
        <TextView
            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="#000"/>

</RelativeLayout>

NewsContentFragment类

public class NewsContentFragment extends Fragment {
    private View view;

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        view = inflater.inflate(R.layout.news_content_frag,container,false);
        return view;
    }

    public void refresh(String newsTittle,String newsContent){
        View visibilityLayout = view.findViewById(R.id.visibility_layout);
        visibilityLayout.setVisibility(View.VISIBLE);
        TextView newsTittleText = view.findViewById(R.id.news_tittle);
        TextView newsContentText = view.findViewById(R.id.news_content);
        newsTittleText.setText(newsTittle);
        newsContentText.setText(newsContent);
    }
}

提供了refresh（）方法将新闻内容和题目显示在界面上。

news_content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">
    
    <fragment
        android:id="@+id/news_content_fragment"
        android:name="com.example.newspaper.NewsContentFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
    
</LinearLayout>

直接在布局中引用了NewsContentActivity，相当于把news_content_frag布局加入

NewsContentActivity类

public class NewsContentActivity extends AppCompatActivity {

    public static void actionStart(Context context,String newsTittle,String newsContent){
        Intent intent = new Intent(context,NewsContentActivity.class);
        intent.putExtra("news_title",newsTittle);
        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");//获取传入的新闻内容
        NewsContentFragment newsContentFragment = (NewsContentFragment)
                getSupportFragmentManager().findFragmentById(R.id.news_content_fragment);
        newsContentFragment.refresh(newsTitle,newsContent);//刷新NewsContentFragment界面
    }
}

news_item布局

<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/news_tittle"
    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:padding="15dp"/>

ellipse：文本的缩略方式（end：在尾部缩略）

NewsTitleFragment类

public class NewsTitleFragment extends Fragment {

    private boolean isTwoPane;

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.news_title_frag,container,false);
        return view;
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        if(getActivity().findViewById(R.id.news_content_layout)!=null){
            isTwoPane = true;
        }else{
            isTwoPane = false;
        }
    }
}

通过能否找到news_content_layout来判断当前是双页还是单页

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/news_tittle_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <fragment
        android:id="@+id/news_tittle_fragment"
        android:name="com.example.newspaper.NewsTitleFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</FrameLayout>

单页指挥加载一个碎片

<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.example.newspaper.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:layout_width="match_parent"
            android:layout_height="match_parent"
    </FrameLayout>

</LinearLayout>

双页加载