你好,我正在学习android和试图显示自定义的ListView,但它无法加载。这个问题来自我的查询,因为列表是空的。请按照下面的解析示例,我做错了什么?无法检索使用解析查询
下面是我的代码使用片段来显示视图,因为它未能充气。
EventTab.java:
//query Events for current user
private void queryEventListFromParse(){
//Create query for objects of type "Event"
ParseQuery<ParseObject> query = ParseQuery.getQuery("Event");
// Restrict to cases where the author is the current user.
//pass in a ParseUser and not String of that user
query.whereEqualTo("author", ParseUser.getCurrentUser());
query.orderByAscending("createAt");
// Run the query
query.findInBackground(new FindCallback<ParseObject>() {
@Override
public void done(List<ParseObject> eventList, ParseException e) {
if (e == null) {
// If there are results, update the list of event and notify the adapter
Log.d(TAG, "Im in background"); //im able to display image
eventList.clear();
for (ParseObject event : eventList) {
eventList.add(event);
}
updateEventsList();
} else {
Log.d(TAG, "Event retrieval error: " + e.getMessage());
}
}
});
}
重要更新: 感谢阴影的Droid您指出的错误。之所以getView()失败,是因为名为evenList的List返回0,无法调用getView,因此返回0,并且无法显示列表。
下面是错误消息,当我评论eventList.clear();
错误从控制台:
12-05 04:52:10.511 11450-11450/com.example.davchen.skibuddies E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.davchen.skibuddies, PID: 11450
java.util.ConcurrentModificationException
at java.util.ArrayList$ArrayListIterator.next(ArrayList.java:573)
at com.example.davchen.skibuddies.Fragments.EventTab$1.done(EventTab.java:87)
at com.example.davchen.skibuddies.Fragments.EventTab$1.done(EventTab.java:80)
at com.parse.ParseTaskUtils$2$1.run(ParseTaskUtils.java:115)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:5942)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
如果得到任何错误或崩溃检查,然后分享它 –
后listview_event_item.xml和堆栈跟踪 – johnrao07
@ρяσѕρєяK它无法显示自定义列表。 – user3497437