Android组件--Fragment(四)之 ListFragment

本文介绍ListFragment。

ListFragment简介

ListFragment继承于Fragment。因此它具有Fragment的特性，能够作为activity中的一部分，目的也是为了使页面设计更加灵活。

相比Fragment，ListFragment的内容是以列表(list)的形式显示的。ListFragment的布局默认包含一个ListView。因此，在ListFragment对应的布局文件中，必须指定一个 android:id 为 “@android:id/list” 的ListView控件!

ListFragment使用示例

点击查看：ListFragment的完整代码

下面介绍在Activity中显示ListFragment的步骤。

1. Activity对应的代码

public class FragmentTest extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }   
}

2. Activity对应的布局

<LinearLayout 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"
    android:orientation="horizontal" >

    <fragment 
        android:name="com.skw.fragmenttest.MyListFragment"
        android:id="@+id/myfragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</LinearLayout>

说明：该Activity的布局中只包行了一个Fragment。下面看看MyListFragment的内容。

3. MyListFragment的内容

public class MyListFragment extends ListFragment {
    private static final String TAG = "##MyListFragment##";

    private ListView selfList;

    String[] cities = {
         "Shenzhen",
         "Beijing",
         "Shanghai",
         "Guangzhou",
         "Wuhan",
         "Tianjing",
         "Changsha",
         "Xi'an",
         "Chongqing",
         "Guilin",
    };

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
            Bundle savedInstanceState) {
        Log.d(TAG, "onCreateView");
        return inflater.inflate(R.layout.list_fragment, container, false);
    }


    @Override
    public void onCreate(Bundle savedInstanceState) {
        Log.d(TAG, "onCreate");
        super.onCreate(savedInstanceState);
        // 设置ListFragment默认的ListView，即@id/android:list
        this.setListAdapter(new ArrayAdapter<String>(getActivity(), 
                android.R.layout.simple_list_item_1, cities));

    }

    public void onListItemClick(ListView parent, View v, 
            int position, long id) {
        Log.d(TAG, "onListItemClick");
        Toast.makeText(getActivity(), "You have selected " + cities[position],
                Toast.LENGTH_SHORT).show();
    }    
}

说明：MyListFragment是自定义的ListFragment。它使用了list_fragment.xml作为布局，并通过android.R.layout.simple_list_item_1显示ListView中的每一项。

4. list_fragment.xml的内容

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <!-- ListFragment对应的android:id值固定为"@id/android:list" -->
    <ListView
        android:id="@id/android:list"
        android:layout_width="match_parent"
        android:layout_height="match_parent" 
        android:drawSelectorOnTop="false"
        />

</LinearLayout>

自定义ListFragment

点击查看：自定义ListFragment的完整代码

"Activity的布局以及代码"和前面一样，这里就不再重复说明。

3. MyListFragment的内容

public class MyListFragment extends ListFragment {
    private static final String TAG = "##MyListFragment##";

    private ListView selfList;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
            Bundle savedInstanceState) {
        Log.d(TAG, "onCreateView");
        return inflater.inflate(R.layout.list_fragment, container, false);
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        final String[] from = new String[] {"title", "info"};
        final int[] to = new int[] {R.id.text1, R.id.text2};

        Log.d(TAG, "onCreate");
        super.onCreate(savedInstanceState);
        // 建立SimpleAdapter，将from和to对应起来
        SimpleAdapter adapter = new SimpleAdapter(
                this.getActivity(), getSimpleData(), 
                R.layout.item, from, to);
        this.setListAdapter(adapter);
    }

    public void onListItemClick(ListView parent, View v, 
            int position, long id) {
        Log.d(TAG, "onListItemClick");
        Toast.makeText(getActivity(), 
                "You have selected " + position,
                Toast.LENGTH_SHORT).show();
    }

    private List<Map<String, Object>> getSimpleData() {
        List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();

        Map<String, Object> map = new HashMap<String, Object>();
        map.put("title", "Ferris wheel");
        map.put("info", "Suzhou Ferris wheel");
        list.add(map);

        map = new HashMap<String, Object>();
        map.put("title", "Flower");
        map.put("info", "Roser");
        list.add(map);

        map = new HashMap<String, Object>();
        map.put("title", "Disk");
        map.put("info", "Song Disk");
        list.add(map);

        return list;
    }
}

说明：MyListFragment使用了R.layout.list_fragment作为布局，并且对于ListView中的每一项都使用了R.layout.item作为布局。

4. list_fragment.xml的内容

<!-- ListFragment对应的android:id值固定为"@id/android:list" -->
<ListView
    android:id="@id/android:list"
    android:layout_width="match_parent"
    android:layout_height="match_parent" 
    android:drawSelectorOnTop="false"
    />

5. item.xml的内容

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <TextView android:id="@+id/text1"
        android:textSize="12sp"
        android:textStyle="bold"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

    <TextView android:id="@+id/text2"
        android:textSize="24sp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

</LinearLayout>
by skywang
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