当我想解析JSON时，我发现了这个错误：
04-06 13:39:13.517: W/dalvikvm(2582): threadid=1: thread exiting with uncaught exception (group=0xa62f9288)
04-06 13:39:13.521: E/AndroidRuntime(2582): FATAL EXCEPTION: main
04-06 13:39:13.521: E/AndroidRuntime(2582): java.lang.NullPointerException
04-06 13:39:13.521: E/AndroidRuntime(2582): at JSONParser.GetTunes.onPostExecute(GetTunes.java:207)
04-06 13:39:13.521: E/AndroidRuntime(2582): at JSONParser.GetTunes.onPostExecute(GetTunes.java:1)
04-06 13:39:13.521: E/AndroidRuntime(2582): at android.os.AsyncTask.finish(AsyncTask.java:631)
04-06 13:39:13.521: E/AndroidRuntime(2582): at android.os.AsyncTask.access$600(AsyncTask.java:177)
04-06 13:39:13.521: E/AndroidRuntime(2582): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644)
04-06 13:39:13.521: E/AndroidRuntime(2582): at android.os.Handler.dispatchMessage(Handler.java:99)
04-06 13:39:13.521: E/AndroidRuntime(2582): at android.os.Looper.loop(Looper.java:137)
04-06 13:39:13.521: E/AndroidRuntime(2582): at android.app.ActivityThread.main(ActivityThread.java:4745)
04-06 13:39:13.521: E/AndroidRuntime(2582): at java.lang.reflect.Method.invokeNative(Native Method)
04-06 13:39:13.521: E/AndroidRuntime(2582): at java.lang.reflect.Method.invoke(Method.java:511)
04-06 13:39:13.521: E/AndroidRuntime(2582): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
更新： 上课在这里：
public class GetTunes extends AsyncTask<Void, Void, Void> {
private Activity activity;
private ArrayList<HashMap<String, String>> DATA;
private String DOMAIN, URL;
private ProgressDialog pDialog;
LazyAdapter Lazyadapter;
ListView list;
private static final String TAG_TONE = "objects";
// =================================================================
// CATEGORY INFORMATION
private static final String TAG_CAT = "category";
private static final String TAG_CAT_CNT = "cnt_tones";
private static final String TAG_CAT_ID = "id";
private static final String TAG_CATID = "cat_id";
private static final String TAG_CAT_IMG = "image";
private static final String TAG_CAT_TITLE = "title";
private static final String TAG_CATTITLE = "cat_title";
private static final String TAG_CAT_RES_URI = "resource_uri";
// ================================================================= TONE
// INFORMATION
private static final String TAG_DOWNLOAD = "cnt_download";
private static final String TAG_LIKE = "cnt_like";
private static final String TAG_CREATE_DATE = "create_time";
private static final String TAG_URL = "file_url";
private static final String TAG_TONE_ID = "id";
private static final String TAG_TONEID = "tone_id";
private static final String TAG_TITLE = "title";
private static final String TAG_TONETITLE = "tone_title";
private static final String TAG_RES_URI = "resource_uri";
// ================================================================= USER
// INFORMATION
private static final String TAG_USER = "user";
private static final String TAG_USER_AVATAR = "avatar";
private static final String TAG_USER_ID = "id";
private static final String TAG_USERID = "user_id";
private static final String TAG_USER_NAME = "name";
// CONSTRUCTOR
public GetTunes(Activity a, ArrayList<HashMap<String, String>> d, String domain, String url) {
activity = a;
DATA = d;
DOMAIN = domain;
URL = url;
}
JSONArray Ringtunes = null;
// =====================================================================
// onPreExecute
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(activity);
pDialog.setMessage("Wait...");
pDialog.setCancelable(false);
pDialog.show();
Log.d("phase1 ", "> " + "DONE");
}
// =====================================================================
// =====================================================================
// doInBackground
@Override
protected Void doInBackground(Void... arg0) {
// CREATING SERVICE HANDLER CLASS INSTANCE
ServiceHandler sh = new ServiceHandler();
// MAKING A RESQUEST TO URL AND GETTING RESPONSE
String jsonStr = sh.makeServiceCall(URL, ServiceHandler.GET);
Log.d("phase2 ", "> " + "DONE");
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// GETTING JSON ARRAY NODE
Ringtunes = jsonObj.getJSONArray(MainActivity.TAG_TONE);
// LOOPIN THROUGH ALL TONES
for (int i = 0; i < Ringtunes.length(); i++) {
JSONObject ring = Ringtunes.getJSONObject(i);
// CATEGORY NODE IS A JSON OBJECT
JSONObject category = ring.getJSONObject(MainActivity.TAG_CAT);
String cat_cnt = category.getString(MainActivity.TAG_CAT_CNT);
String cat_id = category.getString(MainActivity.TAG_CAT_ID);
String cat_img = category.getString(MainActivity.TAG_CAT_IMG);
String cat_title = category.getString(MainActivity.TAG_CAT_TITLE);
String cat_uri = category.getString(MainActivity.TAG_CAT_RES_URI);
String tone_download = ring.getString(MainActivity.TAG_DOWNLOAD);
String tone_like = ring.getString(MainActivity.TAG_LIKE);
String tone_createDate = ring.getString(MainActivity.TAG_CREATE_DATE);
String tone_url = DOMAIN + ring.getString(MainActivity.TAG_URL);
String tone_id = ring.getString(MainActivity.TAG_TONE_ID);
String tone_title = ring.getString(MainActivity.TAG_TITLE);
String tone_uri = ring.getString(MainActivity.TAG_RES_URI);
// USER NODE IS A JSON OBJECT
JSONObject user = ring.getJSONObject(MainActivity.TAG_USER);
String user_avatar = DOMAIN + user.getString(MainActivity.TAG_USER_AVATAR);
String user_id = user.getString(MainActivity.TAG_USER_ID);
String user_name = user.getString(MainActivity.TAG_USER_NAME);
// TEM HASHMAP FOR EACH TONE
HashMap<String, String> tones = new HashMap<String, String>();
// ADDING EACH CHILD NODE TO HASH MAP KEY > VALUE
tones.put(TAG_CAT_CNT, cat_cnt);
tones.put(TAG_CATID, cat_id);
tones.put(TAG_CAT_IMG, cat_img);
tones.put(TAG_CATTITLE, cat_title);
// ======================================
tones.put(TAG_DOWNLOAD, tone_download);
tones.put(TAG_LIKE, tone_like);
tones.put(TAG_CREATE_DATE, tone_createDate);
tones.put(TAG_URL, tone_url);
tones.put(TAG_TONEID, tone_id);
tones.put(TAG_TONETITLE, tone_title);
// ======================================
tones.put(TAG_USER_AVATAR, user_avatar);
tones.put(TAG_USERID, user_id);
tones.put(TAG_USER_NAME, user_name);
Set keys = tones.keySet();
for (Iterator iter = keys.iterator(); iter.hasNext();) {
String key = (String) iter.next();
String value = (String) tones.get(key);
Log.d(key, value);
}
// ADDING TONES TO LIST
DATA.add(tones);
Log.d("phase3 ", "> " + "DONE");
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
Toast.makeText(activity, "Couldn't get any data from the url",
Toast.LENGTH_LONG).show();
}
return null;
}
// =====================================================================
// =====================================================================
// onPostExecute
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the Progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
// Updating parsed JSON data into List view
Lazyadapter = new LazyAdapter(activity, DATA);
AnimationAdapter animAdapter = new SwingBottomInAnimationAdapter(Lazyadapter);
animAdapter.setInitialDelayMillis(300);
animAdapter.setAbsListView(list);
list.setAdapter(animAdapter);
}
// =====================================================================
}
我想在我的主要活动中使用这个calss并将其称为：
新的GetTunes（MainActivity.this，TunesList，thumb，url）.execute（）;
答案 0 :(得分：1)
list为空。您没有在代码中的任何位置初始化它。所以这就是错误所在的行：list.setAdapter(animAdapter);。通过动态创建或设置资源ID来初始化它，您的问题就会得到解决。