android - 如何在fragment中使用findViewById，无法应用ArrayList - Android

Question

我不得不将一个类从它被归类为一个 Activity 更改为一个 fragment ，我不知道我现在将如何设置它，因为它现在说它无法解析我的 findViewById 上的方法。如果需要，可以提供任何额外的代码。感谢您的帮助。

public class CustomizedListView extends Fragment {
// All static variables
static final String URL = "http://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 View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle      savedInstanceState){
    return inflater.inflate(R.layout.main, container, false);
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);


    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.game_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) {


        }
    });
}
}

这就是导致我遇到 findViewById 问题的原因，因为它无法解析该方法:

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

这就是导致我在 ArrayList 上出现问题的原因，显然是因为 LazyAdapter 中的 LazyAdapter (android.app.Activity, ArrayList>) 无法应用于 (com.example.app.CustomizedListView, ArrayList>)

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

主.xml:

<?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"
android:background="#e5e5e5" >

<ListView
    android:id="@+id/game_list"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:divider="#e5e5e5"
    android:dividerHeight="6dp"
    android:background="#e5e5e5"
    android:layout_marginLeft="6dp"
    android:layout_marginRight="6dp"/>

</LinearLayout>

Answer 1

您的错误在方法 onCreate 上: View 创建必须转而在方法 onCreateView 上进行。

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    // Preparing user interface
    final View v = inflater.inflate(R.layout.main, container, false);
    final ListView = (ListView) v.findViewById(R.id.game_list);
    // Do what you want...

    return v;
}

...is because LazyAdapter (android.app.Activity, ArrayList>) in LazyAdapter cannot be applied to (com.example.app.CustomizedListView, ArrayList>)

您找到了解决问题的线索。恕我直言，您必须更改使用 LazyAdapter 的方式。我建议你:检查我的代码是否解决了你的 Fragment 问题，然后再问一个关于 ArrayList/LazyAdapter 问题的问题。