列表视图的子项未显示在 arrayadapter 中

Question

我正在寻找每个项目看起来像的列表/网格视图：

|-----|   |--------------------------|
| H1  |   |   Short Desc1            |
|-----|   |--------------------------|    //Preferred View
|------------------------------------|
|    Long Description                |
|------------------------------------|

或喜欢：

|------| |------------------------------|
|      | |   Short Desc1                |
|  H1  | |------------------------------|
|      |                                  //Optional View
|      | |------------------------------|
|------| |______Long Description________|

首先，我从 xml 开始：

<?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"
    android:background="@color/colorPrimaryLight">


    <ListView
        android:id="@android:id/list"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_centerHorizontal="true"
        android:scrollbars="vertical">

    </ListView>

</RelativeLayout>

在 android studio 的设计视图中，显示可接受的输出为： 但是，使用这个 java 代码：

public class FourthFragment extends ListFragment {

    String names[] ={"A", "B", "C", "D"};

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onActivityCreated(savedInstanceState);
    }
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View myFragmentView = inflater.inflate(R.layout.fragment_fourth, container, false);
//        TextView tv = (TextView) myFragmentView.findViewById(R.id.textView1);
//        tv.setText("My Header");

        setListAdapter(new ArrayAdapter<String>(getActivity(),android.R.layout.simple_list_item_1,names));
        return myFragmentView;
    }
    @Override
    public void onListItemClick(ListView l, View v, int position, long id) {
        // on click display the item in toast
        Toast.makeText(getActivity(), (String)l.getItemAtPosition(position), Toast.LENGTH_SHORT).show();
    }
    static FourthFragment newInstance(int num) {
        FourthFragment fourthFragment = new FourthFragment();

        Bundle args = new Bundle();
        args.putInt("num", num);
        fourthFragment.setArguments(args);

        return fourthFragment;
    }

}

它只显示菜单，没有任何子菜单，如：

首选第一张图片，如何获得输出？ 或者，简单地说，我的代码中缺少什么？

我从pagerAdapter 调用此函数为：

        case 1:
            return FourthFragment.newInstance(4);

Answer 1

您需要通过扩展 BaseAdapter 来创建自己的适配器。您使用的是 ArrayAdapter，布局是这里提到的 android 的预定义布局
setListAdapter(new ArrayAdapter<String>(getActivity(),android.R.layout.simple_list_item_1,names));

举个例子

所以你的那个项目的 XML 布局如下

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:background="@drawable/list_selector"
    android:orientation="horizontal"
    android:padding="5dip" >

    <!--  ListRow Left sied Thumbnail image -->
    <LinearLayout android:id="@+id/thumbnail"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="3dip"
        android:layout_alignParentLeft="true"
        android:background="@drawable/image_bg"
        android:layout_marginRight="5dip">

        <ImageView
            android:id="@+id/list_image"
            android:layout_width="50dip"
            android:layout_height="50dip"
            android:src="@drawable/rihanna"/>

    </LinearLayout>

    <!-- Title Of Song-->
    <TextView
        android:id="@+id/title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignTop="@+id/thumbnail"
        android:layout_toRightOf="@+id/thumbnail"
        android:text="Rihanna Love the way lie"
        android:textColor="#040404"
        android:typeface="sans"
        android:textSize="15dip"
        android:textStyle="bold"/>

    <!-- Artist Name -->
    <TextView
        android:id="@+id/artist"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/title"
        android:textColor="#343434"
        android:textSize="10dip"
        android:layout_marginTop="1dip"
        android:layout_toRightOf="@+id/thumbnail"
        android:text="Just gona stand there and ..." />

    <!-- Rightend Duration -->
    <TextView
        android:id="@+id/duration"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_alignTop="@id/title"
        android:gravity="right"
        android:text="5:45"
        android:layout_marginRight="5dip"
        android:textSize="10dip"
        android:textColor="#10bcc9"
        android:textStyle="bold"/>

     <!-- Rightend Arrow -->
     <ImageView android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/arrow"
        android:layout_alignParentRight="true"
        android:layout_centerVertical="true"/>

    </RelativeLayout>

到目前为止，我们已经完成了列表视图的部分设计。创建一个新的类适配器

public class LazyAdapter extends BaseAdapter {

private Activity activity;
private ArrayList<HashMap<String, String>> data;
private static LayoutInflater inflater=null;
public ImageLoader imageLoader; 

public LazyAdapter(Activity a, ArrayList<HashMap<String, String>> d) {
    activity = a;
    data=d;
    inflater = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    imageLoader=new ImageLoader(activity.getApplicationContext());
}

public int getCount() {
    return data.size();
}

public Object getItem(int position) {
    return position;
}

public long getItemId(int position) {
    return position;
}

public View getView(int position, View convertView, ViewGroup parent) {
    View vi=convertView;
    if(convertView==null)
        vi = inflater.inflate(R.layout.list_row, null);

    TextView title = (TextView)vi.findViewById(R.id.title); // title
    TextView artist = (TextView)vi.findViewById(R.id.artist); // artist name
    TextView duration = (TextView)vi.findViewById(R.id.duration); // duration
    ImageView thumb_image=(ImageView)vi.findViewById(R.id.list_image); // thumb image

    HashMap<String, String> song = new HashMap<String, String>();
    song = data.get(position);

    // Setting all values in listview
    title.setText(song.get(CustomizedListView.KEY_TITLE));
    artist.setText(song.get(CustomizedListView.KEY_ARTIST));
    duration.setText(song.get(CustomizedListView.KEY_DURATION));
    imageLoader.DisplayImage(song.get(CustomizedListView.KEY_THUMB_URL), thumb_image);
    return vi;
}
}

在您的活动中：

// All static variables
static final String URL = "https://api.androidhive.info/music/music.xml";
// XML node keys
static final String KEY_SONG = "song"; // parent node
static final String KEY_ID = "id";
static final String KEY_TITLE = "title";
static final String KEY_ARTIST = "artist";
static final String KEY_DURATION = "duration";
static final String KEY_THUMB_URL = "thumb_url";

ListView list;
LazyAdapter adapter;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    ArrayList<HashMap<String, String>> songsList = new ArrayList<HashMap<String, String>>();

    XMLParser parser = new XMLParser();
    String xml = parser.getXmlFromUrl(URL); // getting XML from URL
    Document doc = parser.getDomElement(xml); // getting DOM element

    NodeList nl = doc.getElementsByTagName(KEY_SONG);
    // looping through all song nodes <song>
    for (int I = 0; I < nl.getLength(); i++) {
        // creating new HashMap
        HashMap<String, String> map = new HashMap<String, String>();
        Element e = (Element) nl.item(i);
        // adding each child node to HashMap key => value
        map.put(KEY_ID, parser.getValue(e, KEY_ID));
        map.put(KEY_TITLE, parser.getValue(e, KEY_TITLE));
        map.put(KEY_ARTIST, parser.getValue(e, KEY_ARTIST));
        map.put(KEY_DURATION, parser.getValue(e, KEY_DURATION));
        map.put(KEY_THUMB_URL, parser.getValue(e, KEY_THUMB_URL));

        // adding HashList to ArrayList
        songsList.add(map);
    }

    list=(ListView)findViewById(R.id.list);

    // Getting adapter by passing xml data ArrayList
    adapter=new LazyAdapter(this, songsList);
    list.setAdapter(adapter);

    // Click event for single list row
    list.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {

        }
    });
}}