以下代码的Hashmap适用于simpleadapter数组，但不适用于自定义数组适配器。为什么？以及如何解决？请帮助。无法解决。一切都好。
我正在使用lazyLoading类来加载图片。
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
HashMap<String, String> o = (HashMap<String, String>) list.getItemAtPosition(position);
Toast.makeText(CustomizedListView.this, "ID '" + o.get("KEY_TITLE") + "' was clicked.", Toast.LENGTH_SHORT).show();
}
上面显示的onclick崩溃的整个代码：
public class CustomizedListView extends Activity {
// All static variables
static final String URL = "https://itunes.apple.com/us/rss/topalbums/limit=20/json";
// 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;
HashMap<String, String> map;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ArrayList<HashMap<String, String>> songsList = new ArrayList<HashMap<String, String>>();
JSONObject json = JSONfunctions.getJSONfromURL(URL);
try {
JSONObject arr2 = json.getJSONObject("feed");
JSONArray arr = arr2.getJSONArray("entry");
for (int i = 0; i < arr.length(); i++) {
JSONObject e1 = arr.getJSONObject(i);
JSONArray arr3 = e1.getJSONArray("im:image");
JSONObject arr8 = e1.getJSONObject("im:name");
JSONObject arr10 = e1.getJSONObject("im:artist");
JSONObject e12 = arr3.getJSONObject(0);
// creating new HashMap
map = new HashMap<String, String>();
map.put(KEY_THUMB_URL, e12.getString("label"));
map.put(KEY_ARTIST, arr8.getString("label"));
map.put(KEY_TITLE, arr10.getString("label"));
// adding HashList to ArrayList
songsList.add(map);
}
} catch (JSONException e) {
// Log.e("log_tag", "Error parsing data "+e.toString());
Toast.makeText(getBaseContext(),
"Network communication error!", 5).show();
}
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) {
HashMap<String, String> o= (HashMap<String, String>) list.getItemAtPosition(position);
Toast.makeText(CustomizedListView.this, "ID '" + o.get("title") + "' was clicked.", Toast.LENGTH_SHORT).show();
}
});
}
}
以下此代码完美无缺：
public class Main extends ListActivity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.listplaceholder);
ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();
JSONObject json = JSONfunctions.getJSONfromURL("http://api.geonames.org/earthquakesJSON?north=44.1&south=-9.9&east=-22.4&west=55.2&username=demo");
try{
JSONArray earthquakes = json.getJSONArray("earthquakes");
for(int i=0;i<earthquakes.length();i++){
HashMap<String, String> map = new HashMap<String, String>();
JSONObject e = earthquakes.getJSONObject(i);
map.put("id", String.valueOf(i));
map.put("name", "Earthquake name:" + e.getString("eqid"));
map.put("magnitude", "Magnitude: " + e.getString("magnitude"));
mylist.add(map);
}
}catch(JSONException e) {
Log.e("log_tag", "Error parsing data "+e.toString());
}
ListAdapter adapter = new SimpleAdapter(this, mylist , R.layout.main,
new String[] { "name", "magnitude" },
new int[] { R.id.item_title, R.id.item_subtitle });
setListAdapter(adapter);
final ListView lv = getListView();
lv.setTextFilterEnabled(true);
lv.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
@SuppressWarnings("unchecked")
HashMap<String, String> o = (HashMap<String, String>) lv.getItemAtPosition(position);
Toast.makeText(Main.this, "ID '" + o.get("id") + "' was clicked.", Toast.LENGTH_SHORT).show();
}
});
}
}
logcat的：
threadid=1: thread exiting with uncaught exception (group=0x40ab0228)
FATAL EXCEPTION: main
java.lang.ClassCastException: java.lang.Integer cannot be cast to java.util.HashMap
at com.example.androidhive.CustomizedListView$1.onItemClick(CustomizedListView.java:94)
at android.widget.AdapterView.performItemClick(AdapterView.java:292)
at android.widget.AbsListView.performItemClick(AbsListView.java:1077)
at android.widget.AbsListView$PerformClick.run(AbsListView.java:2533)
at android.widget.AbsListView$1.run(AbsListView.java:3198)
at android.os.Handler.handleCallback(Handler.java:605)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:4945)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
at dalvik.system.NativeStart.main(Native Method)
LazyAdapter.java
public class LazyAdapter extends BaseAdapter {
private Activity activity;
private ArrayList<HashMap<String, String>> data=new ArrayList<HashMap<String, String>>();
private static LayoutInflater inflater=null;
public ImageLoader imageLoader;
public static HashMap<String, String> song;
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
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;
}
}
答案 0 :(得分：3)
在自定义适配器中，您将返回位置而不是项目
public Object getItem(int position) {
return position;
}
尝试使用此
public Object getItem(int position) {
return data.get(position);
}
这将解决您的问题